October 2, 2013 full packet issuu by Capitol Region Watershed District

Regular Meeting of the Capitol Region Watershed District (CRWD) Board Of Managers, for Wednesday, October 2, 2013 6:00 p.m. at the office of the CRWD, 1410 Energy Park Drive, Suite 4, St. Paul, Minnesota. REGULAR MEETING AGENDA

Materials Enclosed

Call to Order of Regular Meeting (President Joe Collins) A) Attendance B) Oath of Office, Managers Texer and Reider C) Review, Amendments and Approval of the Agenda

II.

Public Comment – For Items not on the Agenda (Please observe a limit of three minutes per person.)

III.

Permit Applications and Program Updates (Permit Process: 1) Staff Review/Recommendation, 2) Applicant Response, 3) Public Comment, and 4) Board Discussion and Action.) A) Permit # 13-024 Met Council Sanitary Sewer Realignment Project (Kelley) B) Permit # 13-025 Vandalia Redevelopment (Kelley) C) Permit # 13-026 Associated Bank (Kelley) D) Permit # 13-027 Vintage on Selby (Kelley) E) Permit Program/Rules Update (Kelley)

IV. V.

VI.

VII.

Special Reports – A) Strategic Stormwater Solutions for Transit Oriented Development, Wes Saunders Pearce, City of St. Paul and Joni Giese, SRF Consulting Group, Inc. Action Items A) AR: Approve Minutes of the September 18, 2013 Regular Meeting (Sylvander) B) AR: Authorize 2014 Special Grant Agreements (Zwonitzer) C) AR: Approve Curtiss Pond Improvement Project Feasibility Study (Fossum) D) AR: Authorize FY 2014 Clean Water Fund Grant Application (Zwonitzer) Unfinished Business A. FI: Villa Park Wetland Restoration Project Update (Fossum) B. FI: Trout Brook Nature Sanctuary Update (Fossum) C. FI: Lake McCarrons Update (Doneux) D. FI: CAC Update (Doneux) General Information A) Administrator’s Report

VIII. Next Meeting A) Wednesday, October 16, 2013 Meeting Agenda Review IX.

Adjournment

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Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District

Capitol Region Watershed District Applicant:

Jeny Shah MCES 3565 Kennebec Dr Eagan, MN 55122

Permit Application 13-024 Met Council Sanitary Realignment Consultant:

Eric Leagjeld CNA Consulting Engineers, Inc. 2800 University Ave SE, Suite 102 Minneapolis, MN 55414

Description: Abandon existing sanitary in Trout Brook underneath 35E and realign north of Maryland Avenue Stormwater Management: None, MS4 connection and erosion control only District Rule: E, F, and G Disturbed Area: Unkown Impervious Area: None Recommendation: Table with 6 Conditions 1. Determine and clarify on the plans if the annular space around the 24-inch sewer pipe is empty. If so, provide fill for the entire annular space. 2. Provide notes or details to address the following: a. Work must be performed to ensure the structural integrity of the TBI is not compromised. b. Work must be performed to ensure the annular space is cleaned and flushed prior to filling, and completely filled with CLSM to prevent air pockets. 3. Identify and delineate wetland areas on plans and document extent of impacts. Obtain Wetland Conservation Act permits if necessary. 4. Floating silt curtain is shown to be installed perpendicular to flow in the open channel. Provide alternative BMP to ensure minimization of sediment transport off of the project. 5. Document total project land disturbance and provide NPDES permit if required. 6. Provide plans signed by a professional engineer per the Minnesota Board of AELSLAGID.

Lâ&#x20AC;&#x2122;Orient Maryland Avenue

Permit Location Permit Report 13-024

Aerial Photo October 2, 2013 Board Meeting

Capitol Region Watershed District Permit Report CRWD Permit #:

13-024

Review date:

September 20, 2013

Project Name:

Metropolitan Council Sanitary Realigment

Applicant:

Jeny Shah, MCES 3565 Kennebec Drive Eagan, MN 55122

Purpose:

Remove sanitary sewer from Trout Brook East Branch and reconstruct north of existing alignment

Location:

North of Maryland Avenue under I-35E

Applicable Rules:

E, F, and G

Recommendation:

Table with 6 Conditions

EXHIBITS: 1. 100% Review Plan set by CNA, 20 sheets dated 8/20/13, recd 9/6/13 HISTORY & CONSIDERATIONS: None.

RULE E: WETLAND MANAGEMENT Standard ď&#x192;&#x2DC; Wetlands shall not be drained, filled (wholly or in part), excavated, or have sustaining hydrology impacted such that there will be a decrease in the inherent (existing) functions and values of the wetland. ď&#x192;&#x2DC; A minimum buffer of 25 feet of permanent nonimpacted vegetative ground cover abutting and surrounding a wetland is required. Findings 1. There may be wetlands located on the property. 2. It is unknown if permanent wetland impacts will result as part of the project. RULE F: EROSION AND SEDIMENT CONTROL

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Standards  A plan shall demonstrate that appropriate erosion and sediment control measures protect downstream water bodies from the effects of a landdisturbing activity.  Erosion Control Plans must adhere to the MPCA Protecting Water Quality in Urban Areas Manual. Findings 1. Erosion and sediment control measures are not consistent with best management practices, as demonstrated in the MPCA manual Protecting Water Quality in Urban Areas. 2. Adjacent properties are protected from sediment transport/deposition. 3. Wetlands, waterbodies and water conveyance systems are not protected from erosion/sediment transport/deposition. 4. Total land disturbance is unknown; an NPDES permit may be required. RULE G: ILLICIT DISCHARGE AND CONNECTION Standard  Stormwater management and utility plans shall indicate all existing and proposed connections from developed and undeveloped lands for all water that drains to the District MS4. Findings Approximately 760 feet of 24-inch sanitary sewer pipe-in-pipe section will be abandoned and filled with controlled low-strength material (CLSM). The existing TBI includes a 7-ft 6-in. (90-inch) diameter RCP between Sta. 1+65 and 5+90, and a 7-ft (84-inch) diameter RCP between Sta.5+90 and 9+25. 2. Although the September 2007 TBI assessment (TKDA/CNA) identified this section of the East Extension to be in Good Condition. Some spalling was noted along the external side of the pipe-in-pipe section during recent projects. 3. Review of the XP-SWMM model does not identify areas of flooding concern upstream of the project. 4. Details 3 and 6 on Sheet D3 of the submitted preliminary plans suggest that the annular space around the 24-inch sewer pipe may not be filled. It is CRWD’s understanding that when this pipe was constructed inside the TBI that the annular space was filled with concrete or grout. If the annular space around the 24-inch sewer pipe is empty, then the entire annular space should be filled as well. 1.

RECOMMENDATION: Table with 6 Conditions Conditions: 1. Determine and clarify on the plans if the annular space around the 24-inch sewer pipe is empty. If so, provide fill for the entire annular space. 2. Provide notes or details to address the following: a. Work must be performed to ensure the structural integrity of the TBI is not compromised.

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3. 4.

5. 6.

b. Work must be performed to ensure the annular space is cleaned and flushed prior to filling, and completely filled with CLSM to prevent air pockets. Identify and delineate wetland areas on plans and document extent of impacts. Obtain Wetland Conservation Act permits if necessary. Floating silt curtain is shown to be installed perpendicular to flow in the open channel. Provide alternative BMP to ensure minimization of sediment transport off of the project. Document total project land disturbance and provide NPDES permit if required. Provide plans signed by a professional engineer per the Minnesota Board of AELSLAGID.

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Capitol Region Watershed District Applicant:

Melissa Gorman First & First 105 North First Street Minneapolis, MN 55401

Permit Application 13-025 Vandalia Redevelopment Consultant:

Matt Pavek Civil Site Group, Inc.. 4931 W. 35th Street, Suite 200 St. Louis Park, MN 55416

Description: Redevelopment of existing warehouse and light industrial property Stormwater Management: Underground infiltration system District Rule: C, D, and F Disturbed Area: 0.98 Acres Impervious Area: 1.63 Acres (future phases) PERMIT RECOMMENDATION: Approve with 8 Conditions 1. Receipt of $8,150 surety and recorded maintenance agreement. 2. Provide updated land disturbance area due to utilities and provide a copy of the NPDES permit if required. 3. Extend erosion control and project limits to include the proposed sanitary sewer and water main located outside the delineated disturbed area and erosion control. 4. Provide a detail for the underground system. 5. Provide a detail for the underground system outlet structure. 6. Specify in plan set or detail that rock placed around underground system shall be washed, angular stone and exclude limestone and crushed concrete. 7. Demonstrate how runoff from the roof area is directed into the underground system. A portion of the roof is delineated to contribute runoff to the proposed underground system, but it is not clear how runoff is directed to the system. 8. Provide a map showing the 1.63 acres anticipated for ultimate development. VOLUME BANK RECOMMENDATION: Approve deposit of 8,179 cubic feet of volume reduction bank credits to First and First for use on future phases of development.

Va nd ali a

Wa bas h

Permit Location Permit Report 13-025

Aerial Photo October 2, 2013 Board Meeting

Capitol Region Watershed District Permit Report CRWD Permit #:

13-025

Review date:

September 23, 2013

Project Name:

Vandalia Redevelopment and Volume Bank Request

Applicant:

Ms. Melissa Gorman First & First 105 N 1st Street Minneapolis, MN 55401

Purpose:

A partial redevelopment of a site including upgraded buildings, parking facilities, entrances and landscape features.

Location:

550 North Vandalia St., St Paul, MN

Applicable Rules:

C, D, and F

PERMIT RECOMMENDATION: Approve with 8 Conditions VOLUME BANK RECOMMENDATION Approve deposit of 8,179 cubic feet of volume reduction bank credits to First and First for use on future phases of development.

EXHIBITS: 1. Stormwater Management Report, by Civil Site Group, dated 9/11/13, recd. 9/11/13. 2. Construction Plans (Sheets C-0 â&#x20AC;&#x201C; C-4, C-4A, C-6, L-1, L-2), by Civil Site Group, dated 9/11/13, recd. 9/11/13. HISTORY & CONSIDERATIONS: The first phase of the development disturbs less than one acre (0.98 acres), so a CRWD permit is not required. However, the applicant anticipates that ultimate development will disturb approximately 1.63 acres. The purpose of this application is to deposit volume reduction credits in an account to be used for future development on the site. RULE C: STORMWATER MANAGEMENT

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Standards  Proposed discharge rates for the 2-, 10-, and 100-year events shall not exceed existing rates.  Developments and redevelopments must reduce runoff volumes in the amount equivalent to an inch of runoff from the impervious areas of the site.  Stormwater must be pretreated before discharging to infiltration areas to maintain the long-term viability of the infiltration area.  Developments and redevelopments must incorporate effective non-point source pollution reduction BMPs to achieve 90% total suspended solid removal. Findings 1. A hydrograph method based on sound hydrologic theory is used to analyze runoff for the design or analysis of flows and water levels. 2. Runoff rates for the proposed activity do not exceed existing runoff rates for the 2-, 10-, and 100-year critical storm events. Stormwater leaving the project area is discharged into a well-defined receiving channel or pipe and routed to a public drainage system. 3. Stormwater runoff volume retention is not required at this time because the disturbed area is less than 1.0 acre. a. Ultimate development will result in 62,145 sf of impervious surface. b. Volume retention required for ultimate development: Volume Retention Required (cu. ft.) Volume Retention Provided (cu. ft.) 5,179 cf BMP Volume Below Underground 12,937 cf c. Infiltration volume and facility size has been calculated using the appropriate hydrological soil group classification and design infiltration rate. d. The infiltration area is capable of infiltrating the required volume (5,179 cf) within 48 hours. However, the full storage volume (12,937 cf) takes approximately 68 hours to infiltrate. The volume that takes longer than 48 hours to infiltrate is not eligible for deposit into the volume retention bank (between 896.5 and 894.7; 4,758 cf). e. Banking of excess volume retention of 8,179 cubic feet is proposed. When ultimate development occurs, a balance of approximately 3,000 cubic feet would remain in the applicant’s volume retention bank. f. Stormwater runoff is pretreated to remove solids before discharging to infiltration areas. 4. Alternative compliance sequencing has not been requested. 5. Best management practices achieve 90% total suspended solids removal from the runoff generated on an annual basis. 6. A recordable executed maintenance agreement has not been submitted. RULE D: FLOOD CONTROL

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Standards  Compensatory storage shall be provided for fill placed within the 100-year floodplain.  All habitable buildings, roads, and parking structures on or adjacent to a project site shall comply with District freeboard requirements. Findings 1. There is no floodplain on the property according to FEMA. 2. All habitable buildings, roads, and parking structures on or adjacent to the project site comply with CRWD freeboard requirements. RULE E: WETLAND MANAGEMENT Standard  Wetlands shall not be drained, filled (wholly or in part), excavated, or have sustaining hydrology impacted such that there will be a decrease in the inherent (existing) functions and values of the wetland.  A minimum buffer of 25 feet of permanent nonimpacted vegetative ground cover abutting and surrounding a wetland is required. Findings 1. There are no known wetlands located on the property. RULE F: EROSION AND SEDIMENT CONTROL Standards  A plan shall demonstrate that appropriate erosion and sediment control measures protect downstream water bodies from the effects of a landdisturbing activity.  Erosion Control Plans must adhere to the MPCA Protecting Water Quality in Urban Areas Manual. Findings 1. Erosion and sediment control measures are consistent with best management practices, as demonstrated in the MPCA manual Protecting Water Quality in Urban Areas. 2. Adjacent properties are protected from sediment transport/deposition. 3. Wetlands, waterbodies and water conveyance systems are protected from erosion/sediment transport/deposition. 4. Project site may be greater than 1 acre; an NPDES permit is required. RULE G: ILLICIT DISCHARGE AND CONNECTION Standard  Stormwater management and utility plans shall indicate all existing and proposed connections from developed and undeveloped lands for all water that drains to the District MS4.

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Findings 1. New direct connections or replacement of existing connections are not proposed. 2. Prohibited discharges are not proposed. PERMIT RECOMMENDATION: Approve with 8 Conditions Conditions: 1. Receipt of $8,150 surety and recorded maintenance agreement. 2. Provide updated land disturbance area due to utilities and provide a copy of the NPDES permit if required. 3. Extend erosion control and project limits to include the proposed sanitary sewer and water main located outside the delineated disturbed area and erosion control. 4. Provide a detail for the underground system. 5. Provide a detail for the underground system outlet structure. 6. Specify in plan set or detail that rock placed around underground system shall be washed, angular stone and exclude limestone and crushed concrete. 7. Demonstrate how runoff from the roof area is directed into the underground system. A portion of the roof is delineated to contribute runoff to the proposed underground system, but it is not clear how runoff is directed to the system. 8. Provide a map showing the 1.63 acres anticipated for ultimate development. VOLUME BANK RECOMMENDATION Approve creation and deposit of 8,179 cubic feet of volume reduction bank credits to First and First for use on future phases of development.

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4931 West 35th Street Suite 200 St. Louis Park, Minnesota 55416 T...952.541.9969 www.wcla.com

VANDALIA

550 NORTH VANDALIA ST ST. PAUL, MN 55114

  952.250.2003 / 763.213.3944 CivilSiteGroup.com

I hereby certify that this plan, specification, or report was prepared by me or under my direct supervision and that I am a duly Licensed Professional Engineer under the laws of the State of Minnesota. Signature : Name :

MATTHEW R. PAVEK

Registration :

44263

Project Contact : MATTHEW R. PAVEK Phone Number :

763-213-3944

Print History

Date

CITY SITE PLAN SUBMITTAL

7/2/13

ISSUED WITH CITY REVISIONS

7/29/13

ISSUED FOR BID

8/2/13

FINAL BID

8/5/13

OWNER CHECK SET

8/30/13

WATERSHED SUBMITTAL

9/11/13

GRADING, DRAINAGE & EROSION CONTROL PLAN Project

Drawn

RLB

Checked

PJS

C-3

Capitol Region Watershed District Applicant:

Doug Harber Associated Bank 2655 Campus Drive Plymouth MN 55441

Permit Application 13-026 Associated Bank Consultant:

David Ahrens Stantec 2335 Highway 36 West St. Paul, MN 55113

Description: Demolition and construction of a new bank at the corner of Snelling and Dayton Stormwater Management: Underground infiltration/filtration system District Rule: C, D, and F Disturbed Area: 1.5 Acres Impervious Area: 1.03 Acres PERMIT RECOMMENDATION: Table with 10 Conditions 1. Receipt of $5,150 surety and recorded maintenance agreement. 2. Provide a copy of the NPDES permit. 3. Provide plans signed by a professional engineer per the Minnesota Board of AELSLAGID. 4. Revise the proposed HydroCAD model to include runoff draining to the northwest through the new swale. Under existing conditions, this area drains to the south through storm sewer. Demonstrate that the new drainage route does not negatively impact downstream properties. 5. Specify within the plan set or include a detail to show the number and volume of underground chambers. Confirm these values correspond with HydroCAD Model. 6. Provide documentation that the parking lot removal and grading of swale on Soo Line ROW is acceptable to the property owners. Document who owns the property. 7. Demonstrate how the Associated Bank building runoff is directed to underground system. 8. Revise plans or HydroCAD to correspond; the underground system outlet invert elevation is 925.56 on the plans and 924.80 in HydroCAD. The outlet pipe length is 60 feet on the plans and 70 feet in HydroCAD. 9. Increase the elevation of the 6-inch outlet pipe to provide at least 4,361 cf of storage between the outlet invert elevation and the top of the sand. Ensure that the 4,361 cf will drawdown within 48 hours. 10.Remove the geotextile fabric between the sand and storage rock.

Marshall

Dayton

Permit Location Permit Report 13-026

Aerial Photo October 2, 2013 Board Meeting

Capitol Region Watershed District Permit Report CRWD Permit #:

13-026

Review date:

September 23, 2013

Project Name:

Associated Bank

Applicant:

Mr. Doug Harber Associated Bank 2655 Campus Drive Plymouth, MN 55441

Purpose:

Construction of new building and parking lot with an underground storage and filtration system.

Location:

Northeast Corner of the intersection of Snelling Avenue North and West Dayton Avenue.

Applicable Rules:

C, D, and F

Recommendation:

Table with 10 conditions

EXHIBITS: 1. CRWD Volume Control Worksheet, recd. 9/11/13. 2. Memo to CRWD, by Stantec, dated 9/11/13, recd. 9/11/13. 3. Geotechnical Evaluation Report, by Braun Intertec Corporation, dated 9/6/13, recd. 9/11/13. 4. HydroCAD results, by Stantec, dated 9/11/13, recd. 9/11/13. 5. Construction plans (G1-01, C0-01, C0.02, C1.01, C2-01, C2-02, C2-03, C3-01, C4-01, C5-01, C8.01, C8.02, L1.01), by Stantec, dated 8/27/13, recd. 9/11/13. HISTORY & CONSIDERATIONS: Permit application 13-027 includes redevelopment surrounding the 13-026 project site. RULE C: STORMWATER MANAGEMENT Standards ď&#x192;&#x2DC; Proposed discharge rates for the 2-, 10-, and 100-year events shall not exceed existing rates. ď&#x192;&#x2DC; Developments and redevelopments must reduce runoff volumes in the amount equivalent to an inch of runoff from the impervious areas of the site.

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 Stormwater must be pretreated before discharging to infiltration areas to maintain the long-term viability of the infiltration area.  Developments and redevelopments must incorporate effective non-point source pollution reduction BMPs to achieve 90% total suspended solid removal. Findings 1. A hydrograph method based on sound hydrologic theory is used to analyze runoff for the design or analysis of flows and water levels. 2. Runoff rates for the proposed activity do not exceed existing runoff rates for the 2-, 10-, and 100-year critical storm events. Stormwater leaving the project area is not discharged into a well-defined receiving channel or pipe and routed to a public drainage system. 3. Stormwater runoff volume retention is not achieved onsite in the amount equivalent to the runoff generated from one inch of rainfall over the impervious surfaces of the development. a. The amount of proposed impervious onsite is 44,724 square feet. b. Volume retention: Volume Retention Required (cu. ft.) Volume Retention Provided (cu. ft.) 3,354 None, filtration is proposed. c. Filtration is proposed due to poor soils on-site: Volume Retention Required (cu. ft.) Volume Retention Provided (cu. ft.) 4,361 None, outlet is located at bottom of filtration volume. Void space within the sand filter is not eligible for volume retention credit. d. Banking of excess volume retention is not proposed. e. It is not known if the filtration volume and size has been calculated using the appropriate hydrological soil group classification and design filtration rate. f. It is not known if the filtration area is capable of infiltrating the required volume within 48 hours. g. Stormwater runoff is pretreated to remove solids before discharging to infiltration areas. 4. Alternative compliance sequencing has not been requested. 5. If the CRWD volume retention standard is met, the project will achieve 90% total suspended solids removal from the runoff generated on an annual basis. 6. A recordable executed maintenance agreement has not been submitted. RULE D: FLOOD CONTROL Standards  Compensatory storage shall be provided for fill placed within the 100-year floodplain.

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 All habitable buildings, roads, and parking structures on or adjacent to a project site shall comply with District freeboard requirements. Findings 1. There is no floodplain on the property according to FEMA. 2. All habitable buildings, roads, and parking structures on or adjacent to the project site comply with CRWD freeboard requirements. RULE E: WETLAND MANAGEMENT Standard  Wetlands shall not be drained, filled (wholly or in part), excavated, or have sustaining hydrology impacted such that there will be a decrease in the inherent (existing) functions and values of the wetland.  A minimum buffer of 25 feet of permanent nonimpacted vegetative ground cover abutting and surrounding a wetland is required. Findings 1. There are no known wetlands located on the property. RULE F: EROSION AND SEDIMENT CONTROL Standards  A plan shall demonstrate that appropriate erosion and sediment control measures protect downstream water bodies from the effects of a landdisturbing activity.  Erosion Control Plans must adhere to the MPCA Protecting Water Quality in Urban Areas Manual. Findings 1. Erosion and sediment control measures are consistent with best management practices, as demonstrated in the MPCA manual Protecting Water Quality in Urban Areas. 2. Adjacent properties are protected from sediment transport/deposition. 3. Wetlands, waterbodies and water conveyance systems are protected from erosion/sediment transport/deposition. 4. Project site is greater than 1 acre; an NPDES permit is required. RULE G: ILLICIT DISCHARGE AND CONNECTION Standard  Stormwater management and utility plans shall indicate all existing and proposed connections from developed and undeveloped lands for all water that drains to the District MS4. Findings 1. New direct connections or replacement of existing connections are not proposed. 2. Prohibited discharges are not proposed.

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RECOMMENDATION: Table with 10 Conditions Conditions: 1. Receipt of $5,150 surety and recorded maintenance agreement. 2. Provide a copy of the NPDES permit. 3. Provide plans signed by a professional engineer per the Minnesota Board of AELSLAGID. 4. Revise the proposed HydroCAD model to include runoff draining to the northwest through the new swale. Under existing conditions, this area drains to the south through storm sewer. Demonstrate that the new drainage route does not negatively impact downstream properties. 5. Specify within the plan set or include a detail to show the number and volume of underground chambers. Confirm these values correspond with HydroCAD Model. 6. Provide documentation that the parking lot removal and grading of swale on Soo Line ROW is acceptable to the property owners. Document who owns the property. 7. Demonstrate how the Associated Bank building runoff is directed to underground system. 8. Revise plans or HydroCAD to correspond; the underground system outlet invert elevation is 925.56 on the plans and 924.80 in HydroCAD. The outlet pipe length is 60 feet on the plans and 70 feet in HydroCAD. 9. Increase the elevation of the 6-inch outlet pipe to provide at least 4,361 cf of storage between the outlet invert elevation and the top of the sand. Ensure that the 4,361 cf will drawdown within 48 hours. 10. Remove the geotextile fabric between the sand and storage rock.

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SITE PROPERTY LINE

DO NOT INSTALL CHAMBERS UNDER LANDSCAPING. 100 LF - 6" DRAINTILE 6 LF - 15" STRM @ 1.0%

MH 6 R=931.14 I=926.12 SUMP=923.12

ASSOCIATED BANK BUILDING FFE=100'-0"=931.30

6" DRAINTILE - REFER TO B/C8.02

CB 5 R=930.63 I=927.13

6" STRM OUTLET @ 925.56

58 LF - 12" STRM @ 0.5%

60 LF - 6" STRM @ 1.0% 60 LF - 4" DRAINTILE @ 0.5%

42 LF - 12" STRM @ 1.8%

CBMH 4 R=929.85 I=926.85

CB 1 R=931.70 I=928.70

52' X 109' UNDERGROUND STORM WATER CHAMBERS. 17 LF - 15" STRM @ 1.1%

MH 3 R=930.60 I=926.30

50 LF - 15" STRM @ 3.3%

CBMH 2 R=930.95 I=927.95 (12") I=927.70 (15")

55 LF - 12" STRM @ 1.0%

MH 6 CONSTRUCT STORM MANHOLE OVER EX. 18" RCP. R=930.95 I=924.96 (6") I=923.25 (4" DT) I=923.01 (EX. 18")

Horizontal Scale In Feet

Capitol Region Watershed District Applicant:

Tony Barranco Ryan Companies, Inc. 50 South Tenth Street Suite 300 Minneapolis, MN 55403

Permit Application 13-027 Vintage on Selby Consultant:

Dan Elenbaas Ryan A+E 50 South Tenth Street Suite 300 Minneapolis, MN 55403

Snelling Avenue

Description: Demolition of existing Associated Bank and construction of a new mixed use development at Snelling and Selby Stormwater Management: Rooftop filtration, underground infiltration, surface infiltration basin, and tree trenches District Rule: C, D, and F Disturbed Area: 3.7 Acres Impervious Area: 3.06 Acres PERMIT RECOMMENDATION: Table with 12 Conditions 1. Receipt of $15,300 surety and recorded maintenance agreement. 2. Provide a copy of the NPDES permit. 3. Provide plans signed by a professional engineer per the Minnesota Board of AELSLAGID. 4. Provide a re-vegetation or landscape plan for area not being developed in the northwest corner. 5. Provide a pretreatment system and details for how water enters the raingarden. 6. Provide elevations for contours on Sheet C501 7. Separate the two underground systems in the Hydraflow Model. They appear to be hydraulically separated rather than operating as one system. 8. Specify Stormtech crown and invert elevations and rock elevations in the plan set. 9. Clarify the outlet pipe size from the Stormtech system. The narrative states a 4-inch outlet pipe, but sheet C502 indicates a 12 inch pipe. 10.Provide soil borings for the south portion of the site. If Type B or C soils, assume that infiltration is feasible and design the required volume retention to infiltrate within 48 hours. 11.Specify the location of the proposed tree trenches in the plan set. Include a cross-section and/or longitudinal detail. The narrative indicates tree trenches for stormwater management are proposed, but these are not identified on the plan set. 12.Include a detail in the plan set to substantiate volume retention claimed for the roof filters..

Permit Location Permit Report 13-027

Selby

Aerial Photo October 2, 2013 Board Meeting

Capitol Region Watershed District Permit Report CRWD Permit #:

13-027

Review date:

September 23, 2013

Project Name:

Vintage on Selby

Applicant:

Mr. Tony Barranco Ryan Companies, Inc. 50 S 10th Street, Suite 300 Minneapolis, MN 55403

Purpose:

Redevelopment into apartment building, underground parking, and stormwater management systems.

Location:

East side of the intersection of Snelling Avenue North and West Dayton Avenue

Applicable Rules:

C, D, and F

Recommendation:

Table with 12 Conditions

EXHIBITS: 1. Stormwater Design Summary, by Ryan Companies, dated 9/11/13, recd. 9/11/13. 2. Schematic Design Plans (sheets C001, C101, C201, C202, C301, C302, C401, C402, C501, C502, C601, C701, Fig A, Fig B, L101, L102, L103, L104), by Ryan Companies, dated 9/11/13, recd. 9/11/13. 3. Hydraflow results, by Ryan Companies, dated 9/11/13, recd. 9/11/13. 4. Geotechnical Evaluation Report, by Braun Intertec Corporation, dated 9/6/13, recd. 9/11/13. 5. CRWD Volume Control Worksheet, recd. 9/11/13. HISTORY & CONSIDERATIONS: Permit application 13-026 includes redevelopment within the 13-027 project site. RULE C: STORMWATER MANAGEMENT Standards ď&#x192;&#x2DC; Proposed discharge rates for the 2-, 10-, and 100-year events shall not exceed existing rates.

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 Developments and redevelopments must reduce runoff volumes in the amount equivalent to an inch of runoff from the impervious areas of the site.  Stormwater must be pretreated before discharging to infiltration areas to maintain the long-term viability of the infiltration area.  Developments and redevelopments must incorporate effective non-point source pollution reduction BMPs to achieve 90% total suspended solid removal. Findings 1. A hydrograph method based on sound hydrologic theory is used to analyze runoff for the design or analysis of flows and water levels. 2. Runoff rates for the proposed activity do not exceed existing runoff rates for the 2-, 10-, and 100-year critical storm events. Stormwater leaving the project area is discharged into a well-defined receiving channel or pipe and routed to a public drainage system. 3. Stormwater runoff volume retention is not achieved onsite in the amount equivalent to the runoff generated from one inch of rainfall over the impervious surfaces of the development. a. The amount of proposed impervious onsite is 133,450 square feet. b. Volume retention: Volume Retention Required (cu. ft.) Volume Retention Provided (cu. ft.) 10,009 None, filtration is proposed. However, infiltration may be necessary upon review of soil boring results. c. Filtration is proposed due to poor soils: Volume Retention Required (cu. ft.) Volume Retention Provided (cu. ft.) 13,011 To be determined after review of soil borings. d. Banking of excess volume retention is not proposed. e. Soil boring results were only provided for the portion of the site north of Dayton Street. f. If infiltration is not feasible south of Dayton Street, a filtration layer must be included in the design of the underground system. g. Stormwater runoff is not pretreated to remove solids before discharging to infiltration areas. 4. Alternative compliance sequencing has not been requested. 5. If the CRWD volume retention standard is met, the project will achieve 90% total suspended solids removal from the runoff generated on an annual basis. 6. A recordable executed maintenance agreement has not been submitted. RULE D: FLOOD CONTROL

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Standards  Compensatory storage shall be provided for fill placed within the 100-year floodplain.  All habitable buildings, roads, and parking structures on or adjacent to a project site shall comply with District freeboard requirements. Findings 1. There is no floodplain on the property according to FEMA. 2. All habitable buildings, roads, and parking structures on or adjacent to the project site comply with CRWD freeboard requirements. RULE E: WETLAND MANAGEMENT Standard  Wetlands shall not be drained, filled (wholly or in part), excavated, or have sustaining hydrology impacted such that there will be a decrease in the inherent (existing) functions and values of the wetland.  A minimum buffer of 25 feet of permanent nonimpacted vegetative ground cover abutting and surrounding a wetland is required. Findings 1. There are no known wetlands located on the property. RULE F: EROSION AND SEDIMENT CONTROL Standards  A plan shall demonstrate that appropriate erosion and sediment control measures protect downstream water bodies from the effects of a landdisturbing activity.  Erosion Control Plans must adhere to the MPCA Protecting Water Quality in Urban Areas Manual. Findings 1. Erosion and sediment control measures are consistent with best management practices, as demonstrated in the MPCA manual Protecting Water Quality in Urban Areas. 2. Adjacent properties are protected from sediment transport/deposition. 3. Wetlands, waterbodies and water conveyance systems are protected from erosion/sediment transport/deposition. 4. Project site is greater than 1 acre; an NPDES permit is required. RULE G: ILLICIT DISCHARGE AND CONNECTION Standard  Stormwater management and utility plans shall indicate all existing and proposed connections from developed and undeveloped lands for all water that drains to the District MS4.

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Findings 1. New direct connections or replacement of existing connections are not proposed. 2. Prohibited discharges are not proposed. RECOMMENDATION: Table with 12 Conditions Conditions: 1. Receipt of $15,300 surety and recorded maintenance agreement. 2. Provide a copy of the NPDES permit. 3. Provide plans signed by a professional engineer per the Minnesota Board of AELSLAGID. 4. Provide a re-vegetation or landscape plan for area not being developed in the northwest corner. 5. Provide a pretreatment system and details for how water enters the raingarden. 6. Provide elevations for contours on Sheet C501 7. Separate the two underground systems in the Hydraflow Model. They appear to be hydraulically separated rather than operating as one system. 8. Specify Stormtech crown and invert elevations and rock elevations in the plan set. 9. Clarify the outlet pipe size from the Stormtech system. The narrative states a 4inch outlet pipe, but sheet C502 indicates a 12 inch pipe. 10. Provide soil borings for the south portion of the site. If Type B or C soils, assume that infiltration is feasible and design the required volume retention to infiltrate within 48 hours. 11. Specify the location of the proposed tree trenches in the plan set. Include a crosssection and/or longitudinal detail. The narrative indicates tree trenches for stormwater management are proposed, but these are not identified on the plan set. 12. Include a detail in the plan set to substantiate volume retention claimed for the roof filters.

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October 2, 2013 Board Meeting IV. Special Reports A) Strategic Stormwater Solutions for Transit Oriented Development (Doneux) DATE: TO: FROM: RE:

September 26, 2013 CRWD Board of Managers Mark Doneux, Administrator Strategic Stormwater Solutions for Transit Oriented Development

Background At the July 18, 2012 Board meeting, Wes Saunders-Pearce, the City of Saint Paul Water Resource Coordinator, gave a presentation about the City’s Strategic Stormwater Solutions for Transit Oriented Design (Formerly called Central Corridor Stormwater and Green Infrastructure Planning Project). The purpose of the project is to create a framework for the development of shared, stacked-function green infrastructure for stormwater management as transit-oriented redevelopment occurs in the Central Corridor. Started in 2012, the project is now in complete and a draft final report is ready for review and comment. Issues Excerpt from the Executive Summary of the report: “The Strategic Stormwater Solutions for TransitOriented Development project investigated whether stormwater management along the Central Corridor could more robustly achieve the community’s redevelopment vision for the corridor. When redevelopment occurs in established urban communities, stormwater management facilities are competing with other site features for limited and valuable space, resulting in stormwater facilities being relegated underground a vast majority of the time. Since 2011, 92 percent of Saint Paul redevelopment sites along the Green Line requiring stormwater management placed stormwater below ground for the purpose of slowly releasing the water into the City’s storm sewer system. When this happens, an opportunity to use stormwater to create a green, sustainable and vibrant community is lost. The study provides a stormwater management framework for the implementation of shared, stackedfunction green infrastructure (SSGI) – a system in which stormwater runoff generated from multiple parcels is jointly treated in shared green infrastructure. Communities both locally and nationally are incorporating green infrastructure into their stormwater management toolbox.” Enclosed is the final draft of the report. Wes Saunders-Pearce from the City of St. Paul and Joni Giese from the SRF Consulting Group, Inc. will present the findings of this study. Staff will seek approval of comments on this report from the Board at the October 16th meeting. Requested Action For informational purposes and soliciting feedback from CRWD’s Board of Managers. enc:

Final Draft Strategic Stormwater Solutions for Transit Oriented Development

W:\06 Projects\CCLRT\Saint Paul Central Corridor SSGI\Board Memo - SSS for TOD 9-26-13.docx

Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District.

Strategic Stormwater Solutions for Transit-Oriented Development Draft Final Report

Saint Paul, MN

September 10, 2013

Strategic Stormwater Solutions

for Transit-Oriented Development DRAFT Final Report Client Wes Saunders-Pearce, City of Saint Paul

Consultant Team SRF Consulting Group, Inc. Wenck Associates, Inc. Craig David Kennedy & Graven Low Impact Development Center

Stakeholder Advisory Committee Participants Anne Hunt, City of Saint Paul Mayorâ&#x20AC;&#x2122;s Office

Donna Drummond, City of Saint Paul PED - Planning

Anna Eleria, Capitol Region Watershed District

Tom Beach, City of Saint Paul DSI - Zoning

Lorrie Stromme, Mississippi Watershed Management Organization

Bruce Elder, City of Saint Paul Public Works - Sewer Utility

Wes Saunders-Pearce, City of Saint Paul DSI - Zoning

Dan Kalmon, Mississippi Watershed Management Organization

Ellen Stewart, City of Saint Paul Parks - Design

Haila Maze, City of Minneapolis CPED

Tim Griffin, Saint Paul Riverfront Corporation

Josh Williams, City of Saint Paul PED - Planning

Lois Eberhart, City of Minneapolis Public Works

Josh Kinney, Saint Paul Riverfront Corporation

Anton Jerve, City of Saint Paul PED - Planning

Cathy Abene, University of Minnesota

Christine Baeumler, Public Art Saint Paul

Anne Weber, City of Saint Paul Public Works - Sewer Utility

Additional Participants Jenna Fletcher, Trust for Public Land Nora Riemenschneider, Metropolitan Council Kallen Hayes, Metropolitan Council Don Stein, City of Saint Paul Public Works- Right-of-Way

Mark Doneux, Capitol Region Watershed District Shanai Matteson, Works Progress Kelly Moriarity, City of Minneapolis Public Works Doug Snyder, Mississippi Watershed Management Organization

Consulting Group, Inc.

The work that provided the basis for this publication was supported by funding under an award with the U.S. Department of Housing and Urban Development. The substance and findings of the work are dedicated to the public. The author and publisher are solely responsible E NGINEERS the of the statements and interpretations contained in this publication. Such Pfor LA N N E accuracy RS Dinterpretations ESIGNERS do not necessarily reflect the views of the Government.

Strategic Stormwater Solutions for Transit-Oriented Development Final Report

Table of Contents

Executive Summary

6-9

Explore Opportunities

18-21

Key National Studies

1. Introduction

10-13

Review of National and Local Precedents

18-19

Project Focus

Public Art Integration

20-21

Partners,Funding and Timeline

Evaluate and Select Options

22-27

Corridor Redevelopment Goals

Potential Redevelopment Sites Identification

Potential SSGI Approaches

Minneapolis

Application of SSGI at Different Development Scales 25-27

Stormwater Management Along the Corridor

Work through the Details

28-37

Boeser Site

28-31

Curfew Commons Park Site

32-37

3. SSGI Implementation

38 - 41

Draft Policy Resolution

Perform Pilot Studies

Revise Regulatory Framework

Institutionalize SSGI into Agency Processes

Implementation Tools

SSGI Assessment Tool

Public Art Implementation

Saint Paul

2. Project Approach

14-37

Set the Foundation

14-17

Shared, Stacked-Function Green Infrastructure (SSGI) Definition

Potential SSGI Implementation Barriers

Right-of-Way Considerations

Developers Focus Group

Governmental Authority Relating to Stormwater Infrastructure

Existing Stormwater Rules and Regulations

List of Figures

4. Findings & Conclusion

42 - 43

List of Figures

Flexibility Supports Vision

42 42

Existing Stormwater Approach on LRT Green Line in Saint Paul

Development Scale is Important

Figure 1.1 Corridor Map

Potential for Financial Balance

Be Opportunistic

Figure 1.2 Existing Stormwater Approach on LRT Green Line in Saint Paul

Appendices

43 - X

A. White Paper: Governmental Authority Relating to Stormwater Infrastructure

Figure 2.7 Context Map

Figure 2.8 Boeser Site Concept Drainage Area

Figure 2.9 Representative Public Art Concepts

Figure 1.3 SSGI relation to benefits

Figure 2.10 Boeser Concept Plan

Figure 1.4 Corridor Planning Efforts

Figure 1.5 Excerpt from â&#x20AC;&#x153;Rooting Out Pollutionâ&#x20AC;? Poster

Figure 2.11 Boeser Concept: Illustrative Section Perspective Figure 2.12 Conceptual Drainage Area

B. Technical Memorandum: Existing Stormwater Rules and Regulations

Figure 2.1 Definition of SSGI

Figure 2.13 Representative Public Art Concepts

Figure 2.2 Governmental Authority

D. Technical Memorandum: Technical Analysis and Evaluation

Figure 2.3 Potential Redevelopment Sites Minneapolis

Figure 2.14 Curfew Commons Concept: Illustrative Plan

E. Technical Memorandum: Prior-University Redevelopment (Green Alley)

Figure 2.4 Potential Redevelopment Sites Saint Paul (West Segment)

Figure 2.15 Curfew Commons Concept : Illustrative Section

Figure 2.5 Potential Redevelopment Sites Saint Paul (East Segment)

Figure 2.16 Curfew Commons Concept : Section Detail

Figure 2.6

Figure 2.7 Bus Barn Street R/W Concept

Figure 2.8 Brownstone New Private Open Space Concept

Define a Process

C. White Paper: Fluxion ~ gARTens F. Technical Memorandum: Advance Design

G. White Paper: Policy Investigation

X X

H. White Paper: FLUXION~gARTens Implementation

Figure 3.1 SSGI Assessment Tool Template 41 Figure 4.1 Possible SSGI 43 Implementation Approaches

Strategic Stormwater Solutions for Transit-Oriented Development Final Report

Strategic Stormwater Solutions for Transit-Oriented Development

Executive Summary Currently under construction, Metro Transit’s Light Rail Transit Green Line (also known as the Central Corridor) will run 11 miles from Target Field in downtown Minneapolis, Minnesota, passing through the University of Minnesota Twin Cities campus to Union Depot in downtown St. Paul, Minnesota, beginning in 2014. This new LRT line is expected to spur desired redevelopment along the corridor. The redeveloped corridor is envisioned with new parks and open spaces and incorporating transit-oriented development and sustainable design principles, creating healthy and vibrant neighborhoods.

Project Focus The Strategic Stormwater Solutions for TransitOriented Development project investigated whether stormwater management along the Central Corridor could more robustly achieve the community’s redevelopment vision for the corridor. When redevelopment occurs in established urban communities, stormwater management facilities are competing with other site features for limited and valuable space, resulting in stormwater facilities being relegated underground a vast majority of the time. Since 2011, 92 percent of Saint Paul redevelopment sites along the Green Line requiring stormwater management placed stormwater below ground for

»»Project Focus »»SSGI Implementation »»Findings & Conclusions the purpose of slowly releasing the water into the City’s storm sewer system. When this happens, an opportunity to use stormwater to create a green, sustainable and vibrant community is lost. The study provides a stormwater management framework for the implementation of shared, stacked-function green infrastructure (SSGI) – a system in which stormwater runoff generated from multiple parcels is jointly treated in shared green infrastructure. Communities both locally and nationally are incorporating green infrastructure into their stormwater management toolbox. Green infrastructure uses landscape features and/or natural processes to manage and/or treat stormwater in a manner that provides environmental benefits. The green infrastructure is designed to enhance the urban fabric, providing economic, environmental and social (triple bottom line) benefits to the community beyond treating stormwater (referred to as “stackedfunction”) thereby galvanizing redevelopment. The study also investigated how public art could highlight stormwater management and green infrastructure along the Green Line. A critical project premise was to develop strategic solutions that were fair, equitable, and provided mutual benefit to all parties involved; otherwise the solution would not be successful or replicable.

Existing Stormwater Approach on LRT Green Line in Saint Paul

SSGI Implementation While SSGI can be used to assist with the creation of TOD, the development of effective policies and implementation tools is critical to the successful implementation of SSGI. Proposed implementation procedures include:

Draft Policy Resolution The initial policy resolution brought forward should highlight SSGI benefits and how it can assist in the creation of a vibrant, green, and sustainable corridor. To increase policy makers’ comfort with its use and to

Executive Summary

refine implementation protocols, it is recommended that the resolution request authorization for SSGI pilot implementation.

Perform Pilot Studies Several pilot studies should be performed for the purpose of testing and refining the SSGI framework developed in this study. If the pilot studies indicate that SSGI provides development benefits, another policy resolution authorizing the use of SSGI should be brought forward for adoption.

Revise Regulatory Framework Current stormwater regulations differ across the cities and WMOs. If it is decided to move beyond pilot studies into a long-term implementation mode, existing stormwater rules and local ordinances will likely require modification. Pertinent topics (not necessarily exhaustive) to scrutinize at a finer level of detail would include on-site management, encroachments, code consolidation, and green requirements.

Institutionalize SSGI into Agency Processes The feasibility of SSGI should be discussed between implementing agencies and developers early in the development process, before significant time or funds are invested in developing a traditional site »» Green infrastructure is designed to enhance the urban fabric, providing economic, environmental and social (triple bottom line) benefits to the community beyond treating stormwater (referred to as “stacked-function”) thereby galvanizing redevelopment.

Strategic Stormwater Solutions for Transit-Oriented Development Final Report 7

Strategic Stormwater Solutions for Transit-Oriented Development

plan. The implementation of SSGI is not limited to the redevelopment of individual parcels. There are various scenarios that could trigger SSGI feasibility discussions, such as street reconstruction projects, replatting, or development of small area master plans. SSGI may provide cost-efficient stormwater management for runoff from small parcels that otherwise would not receive treatment in the near future. Therefore, the development of a retrofit program that provides a process to initiate the SSGI feasibility discussion, evaluate opportunities and to identify potential funding mechanisms may be advantageous.

Implementation Tools The successful implementation of SSGI entails the creation and use of multiple tools to educate Green Line development stakeholders about TOD benefits that can be achieved through the use of SSGI. The tools also serve to assist agencies with incorporating SSGI feasibility evaluations and implementation as standard practice. The following tools have been developed as base templates that agencies can modify to meet their agencyâ&#x20AC;&#x2122;s specific needs and goals.

8 Chapter Number

SSGI Assessment Tool The assessment tool provides a series of questions that agency staff can ask early in the development process to assess whether SSGI is a tool that can be used to further the goal of TOD for the proposed project at hand. Decision-making Flowcharts and Matrices At times the multitude of options and complexity of funding options can appear to be overwhelming. To assist agency staff, a series of flow charts and matrices templates have been developed that articulate the various funding options currently available. Pilot Project Educational & Outreach Materials Educational and outreach materials should be utilized to inform Green Line development stakeholders about potential pilot opportunities, if a community is interested in advancing SSGI approaches.

Findings and Conclusions In a highly urban corridor, SSGI represents a balancing of risk, roles, and responsibilities (particularly for city departments) in the context of broader triple-bottom line benefits. Leadership from elected/appointed officials will be necessary to effectively support and advance with this strategic stormwater solution initiative. This may involve adopting resolutions, sponsoring code modifications, or other similar actions.

Flexibility Supports Vision Stormwater management is currently performed on a parcel by parcel basis and segregated between private and non-private ownership. This is done to address mandates for on-site compliance, manage risk exposure for long term maintenance demands, and simply due to the fact that urban parcels redevelop in a sporadic manner making it difficult to coordinate shared facilities. In practice, the status quo results in development managing stormwater underground . Yet, there are key events such as the construction of major infrastructure projects like light rail transit that trigger concentrated redevelopment where sharing of stormwater facilities may be feasible and conducive to the creation of desired TOD. This is of

Executive Summary

particular importance for small, space-constrained, urban redevelopment parcels where numerous programmatic requirements are competing for valuable space. In these situations, flexibility should be provided in the current stormwater management approach to allow for SSGI implementation, if doing so would be beneficial to the City/WMO for purpose of achieving the community’s corridor vision of a green, vibrant, sustainable neighborhood.

Define a Process SSGI can be successfully implemented, but will likely involve a case-by-case approach. Therefore, processes must be put in place to assess its feasibility early in the development process. Tools must also be in place to assist agency staff and developers to efficiently structure a SSGI approach that creates a balanced approach for funding and risk management. These processes and tools must be general enough to work across a variety of possible development scenarios while acknowledging many stakeholders may potentially participate. The SSGI Assessment Tool (in combination with an outreach brochure) is essential to establish a structured dialogue to identify where a potential project may be feasible, while also maintaining baseline expectations for stormwater management.

Development Scale is Important

Be Opportunistic

While there are likely more, this study identified four SSGI approaches (Parks, Parking, Alleys, and Street Right-of-way) that successfully provide triple bottom line benefits supportive of TOD. The study indicated that several of these approaches lent themselves more strongly to a particular scale of development (.i.e., small parcels versus urban villages).

Runoff from untreated, small parcels that otherwise would not redevelop (i.e. receive stormwater management) in the near future can be effectively included in SSGI projects. SSGI provides an approach to opportunistically realize “excess capacity” in stormwater treatment in a cost effective manner. This is very useful in a corridor where overall redevelopment is very incremental (especially small sites) and public land control is very limited. As well, excess treatment capacity potentially can be a brokered commodity. This may warrant the discussion or development of a retrofit program to capitalize on these opportunities when they arise.

Potential for Financial Balance Government units have broad authority and multiple options to raise revenue for SSGI costs. This will likely require significant political leadership. Yet a financially “neutral” funding source is preferable, rather than sequestering funds solely from one municipal department. Regardless of funding source, compared to estimated costs for stormwater facilities on an individual parcel basis, SSGI estimated costs result in net capital cost efficiencies overall. However, consideration must be given when determining funding sources and developing cost recovery approaches for SSGI to ensure a balanced distribution of costs and benefits. Specifically SSGI implementation will place a significant emphasis on the use of Development Agreements to establish acceptable requirements, fees, noncompliance recourses, and other practicalities.

“The many separate initiatives designed to maximize the Corridor’s potential are starting to link together in significant ways...This plan will provide a critical tool for creating the vibrant, green and sustainable spaces envisioned in the station area plans-- while improving the quality of the Mississippi River.” -Mayor Christopher B. Coleman letter to Stakeholder Advisory Committee, August 2012.

Strategic Stormwater Solutions for TRANSIT ORIENTED DEVELOPMENT Final Report 9

Introduction Chapter

Currently under construction, Metro Transit’s Light Rail Transit Green Line (also known as the Central Corridor) will run 11 miles from Target Field in downtown Minneapolis, Minnesota, to Union Depot in downtown St. Paul, Minnesota, beginning in 2014 (see Figure 1.1). The corridor is host to a wide variety of land uses, such as the highly urban downtown cores of Saint Paul and Minneapolis, the Minnesota State Capitol, the University of Minnesota Twin Cities Campus, industrial and retail uses, and multi-family and single-family residences. A vast majority of the corridor is covered with impervious surfaces, resulting in few parks or green spaces along the corridor. The corridor also

»»Project Focus »»Partners, Funding and Timeline »»Corridor Redevelopment Goals »»Stormwater Management Along the Corridor

hosts a wide range of socio-economic conditions and is a key gathering location for, and home to, a diverse array of ethnic communities, creating a rich cultural resource for the community.

Project Focus The Strategic Stormwater Solutions for Transit-Oriented Development project investigated whether stormwater management along the Central Corridor could more robustly achieve the community’s redevelopment vision for the corridor. When redevelopment occurs in established urban communities, stormwater LAUDERDALE management facilities are competing with other site FALCON HEIGHTS

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features for limited and valuable space, resulting in stormwater facilities being relegated underground a vast majority of the time. Since 2011, 92 percent of Saint Paul redevelopment sites along the Green Line requiring stormwater management placed stormwater below ground for the purpose of slowly releasing the water into the City’s storm sewer system (see Figure 1.2). When this happens, an opportunity to use stormwater to create a green, sustainable and vibrant community is lost.

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CAPITOL REGION

LOWER MISSISSIPPI RIVER

Introduction

which stormwater runoff generated from multiple parcels is jointly treated in shared green infrastructure. The green infrastructure is located and designed to provide economic, environmental and social (triple bottom line) benefits to the community beyond treating stormwater (referred to as “stacked-function” see Figure 1.3). The study also investigated how public art could highlight stormwater management and green infrastructure along the Green Line. A critical project premise was to develop strategic solutions that were fair, equitable, and provided mutual benefit to all parties involved; otherwise the solution would not be successful or replicable.

Partners, Funding and Timeline The study was facilitated by the City of Saint Paul and was funded through a Sustainable Communities Regional Planning grant from the U.S. Department of Housing and Urban Development (administered by the Metropolitan Council) and through a grant from the MWMO. A 20-member Stakeholder Advisory Committee (SAC) was established for the project. Committee members represented various departments in the Cities of Saint Paul and Minneapolis, the Capitol Region Watershed

Shared

Stacked

District (CRWD), the Minneapolis Watershed Management Organization (MWMO), the University of Minnesota, the Saint Paul Riverfront Corporation, and the Metropolitan Council. The Stakeholder Advisory Committee met fourteen times over a 20-month period (February 2012 to September 2013) to provide insight and advise the project team.

Corridor Redevelopment Goals Sixty percent (6.2 miles) of the Green Line lies within the municipal boundaries of the City of Saint Paul. The other 40 percent (4.8 miles) of the Green Line lies within the City of Minneapolis. The University of Minnesota Twin Cities campus comprises 1 mile of Minneapolis’ 4.8-mile segment. As these agencies have planned for this new LRT line, the implementation of TOD emerged as a primary redevelopment goal for the Central Corridor. The Center for Transit-Oriented Development (CTOD) provides the following definition of TOD: Transit-oriented development is often defined as higherdensity mixed-use development within walking distance – or a half mile – of transit stations. Transit-oriented development projects should also:

Green Infrastructure

Figure 1.2 Existing Stormwater Approach on LRT Green Line in Saint Paul

• Increase “location efficiency” so people can walk and bike and take transit • Boost transit ridership and minimize traffic • Provide a rich mix of housing, shopping and transportation choices • Generate revenue for the public and private sectors and provide value for both new and existing residents • Create a sense of place TOD is really about creating attractive, walkable, sustainable communities that allow residents to have housing and transportation choices and to live

vibrant spaces for enhanced environmental health and community livability

Figure 1.3 SSGI relation to benefits Strategic Stormwater Solutions for Transit-Oriented Development Final Report 11

Corridor Redevelopment Goals

convenient, affordable, pleasant lives—with places for our kids to play and for our parents to grow old comfortably. In essence, TOD enhances livability. For the purposes of this report, these two terms will be used interchangeably.

Saint Paul Traversing the corridor from east to west, the Saint Paul segment of the corridor starts in, and runs through, the heart of downtown Saint Paul, past the Minnesota State Capitol, and then follows University Avenue to the western municipal limits. Numerous parcels along University Avenue are currently underperforming and are ready for redevelopment. With 14 of the 18 new stations along the Green Line lying within the Saint Paul municipal limits, the City and partnering organizations have been activity planning for anticipated redevelopment along the line. Previous City-led Central Corridor planning efforts highlight the Community’s desire for TOD, an increase in the number of parks and open spaces along the corridor, and the use of green infrastructure. These previous efforts have continued to build upon each other (see Figure 1.4) and include the following plans and studies: • Central Corridor Development Strategy plan • Central Corridor station area plans (10 plans for stations along University Avenue; plus, one plan addressing all of the downtown stations) • Mitigating the Loss of Parking in the Central Corridor study 12 Chapter Number

• Saint Paul Transit-Oriented Development Guidebook for the Central Corridor These City adopted plans call for the evaluation and revision, if appropriate, of existing policies such as stormwater management to better support the City’s vision for the Central Corridor. Additional efforts to facilitate desired development include: • Development of a Central Corridor Overlay District • Creation of the Traditional Neighborhood 4 Zoning District that will facilitate higher density development, reduce parking demand, and create a more of a pedestrian- and transit-oriented environment • Rezoning of parcels along of the Central Corridor. In addition to the previous planning and zoning efforts, and concurrent with this plan, a park creation analysis is underway. The Minnesota Chapter of the Trust for Public Land, with participation from city partners, is spearheading the “Green Line Parks and Commons Initiative.”

Figure 1.4 Corridor Planning Efforts

Minneapolis From east to west, the City of Minneapolis’ segment of the Green Line traverses University Avenue, the University of Minnesota campus and downtown. The City is experiencing significant redevelopment activity within, and adjacent to, the University. The downtown segment is also experiencing significant redevelopment as this section of the corridor is also a part of Metro Transit’s Blue Line that has been operating for approximately eight years. The City’s comprehensive plan, along with area planning studies, call for increased density, enhanced sustainability and improved connectivity – all of which are components of TOD.

“The many separate initiatives designed to maximize the Corridor’s potential are starting to link together in significant ways.... This plan will provide a critical tool for creating the vibrant, green and sustainable spaces envisioned in the station area plans-- while improving the quality of the Mississippi River.” -Mayor Christopher B. Coleman letter to Stakeholder Advisory Committee, August 2012.

Stormwater Management along the Corridor

Stormwater Management along the Corridor While providing triple bottom line benefits to the community, new TOD must also meet current stormwater treatment regulations. Stormwater requirements along the corridor are currently met on a parcel by parcel and a project by project basis with stormwater regulations varying based on jurisdictional standards and site size. As depicted in Figure 1.1, the Saint Paul segment lies within the jurisdiction of the Capitol Region Watershed District (CRWD), while the Minneapolis segment of the Green Line lies within the jurisdiction of the Mississippi Watershed Management Organization (MWMO). Both watershed organizations have a regulatory role as well as an advocacy and partnering role for stormwater management.

partnering agencies collaborated to construct a stormwater “tree trench” system almost 5 miles in length on both sides of the light rail. Runoff from the public right-of-way was used to irrigate 1,200 newly installed street trees along the corridor. This outcome resulted from viewing runoff as a resource that could be used to support environmental health and overall livability. Not only will this water support the longterm health and vitality of the urban forest, it will also reduce the quantity, and improve the quality, of water reaching the Mississippi River. In addition, healthy and mature street trees provide environmental benefits such as carbon sequestration and reduced heat island

effects, while also creating a shady, comfortable environment that is supportive of walking. Due to active coordination between all parties involved, this street right-of-way now successfully accommodates numerous transportation, utility, environmental and social uses. Influenced by this creative approach, the study hypothesized that stormwater could be innovatively used to achieve new community-desired, vibrant, green spaces along the Central Corridor while still meeting stormwater regulations.

Saint Paul and Minneapolis are both Phase I permittees under the National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) program. While several communities nationally are exploring green infrastructure to reduce wet weather flows to combined sewer systems, that driver is not a significant local issue as both Saint Paul and Minneapolis have predominantly separated their stormwater and sanitary sewer systems. The green infrastructure focus is to enhance the urban fabric by achieving multiple benefits in a spatially constrained environment, thereby galvanizing redevelopment. An exemplary first step towards green infrastructure along the corridor occurred with the construction of the Green Line itself. The City of Saint Paul and Figure 1.5 Excerpt from “Rooting Out Pollution” Poster Source : Capitol Regions Watershed Strategic Stormwater Solutions for Transit-Oriented Development Final Report 13

Project Approach

Chapter

Strategic Stormwater Solutions for Transit-Oriented Development included both policy and technical evaluations. The study was organized into the following four phases, forming a replicable approach for other similar regions with TOD to consider: • Set the Foundation • Explore Opportunities • Evaluate and Select Options • Work through the Details

Set the Foundation This phase of the study focused on establishing an information base that the following phases would be built on. Select Phase One work tasks included issues identification, along with framing concepts and capabilities. For other regions considering replicating this initiative, it will be important to explore their own definitions and authorities, as this can vary based on community context, needs, and preferences.

Shared, Stacked-Function Green Infrastructure (SSGI) Definition Governmental agencies across the country are looking for techniques to improve environmental health and community livability. Agencies are also looking for more efficient approaches to delivering community services. This project developed the concept of shared, stacked-function green infrastructure (SSGI) as a stormwater management approach that addresses environmental health, community livability and cost efficiencies within current statutory standards (see Figure 2.1) 14 Chapter Number

»»Set the Foundation »»Explore Opportunities »»Evaluate and Select Options »»Work through the Details Shared When redevelopment occurs in older, established urban communities such as the Central Corridor, buildings, open space, surface parking, streets, alleys and stormwater facilities are all competing for limited and valuable space. In response to this situation, stormwater is typically being managed in expensive underground facilities that are quite large in order to meet water quantity and/or rate control requirements. In addition, most of the recently constructed facilities do not integrate stormwater with reuse or other features that could support corridor enhancements. This study hypothesized it would be beneficial to construct shared stormwater facilities that collect and treat runoff from multiple parcels (both smaller and larger than one acre). These shared facilities could provide cost efficiencies, enable runoff/pollutant reduction for small parcels that otherwise may not require such treatment, and provide substantial water supplies that could be reused to improve the environmental and social character of the corridor.

Stacked-Function This study hypothesized the space used for stormwater management, along with the captured stormwater runoff itself, can be used to provide triple bottom line benefits to the corridor beyond stormwater management, thereby creating a “stacked-function.” For example, economic benefits can be achieved when space can be used to accommodate multiple functions such as stormwater facilities and parking facilities. Environmental benefits are realized when stormwater facilities mimic the natural hydrologic

cycle or introduce new habitat into the urban environment. Social benefits result from the provision of new street trees and open spaces that improve corridor livability. In addition, when stormwater facilities are placed below ground, the community loses their understanding and personal experience with natural systems.. Also lost is the opportunity to learn about the environmental impacts associated with increased impervious surfaces. By expressing stormwater management on the surface or using stormwater to support environmental benefits, a richer and meaningful environment is created. The goal of this study was to identify feasible stormwater stacking opportunities that: • Merged triple bottom line uses with stormwater facilities to make efficient use of valuable urban land. • Reused captured stormwater runoff to enhance the environmental health and corridor livability. • Provided opportunities to interpret, educate and celebrate water in the corridor through the artful design of stormwater facilities.

Green Infrastructure Both nationally and locally, there is a movement towards the use of green infrastructure to manage stormwater. Several representative definitions of green infrastructure follow: • Green infrastructure uses vegetation, soils, and natural processes to manage water and create healthier urban environments. At the scale of a city or county, green infrastructure refers to the patchwork of natural areas that provides habitat, flood

Set the Foundation

protection, cleaner air, and cleaner water. At the scale of a neighborhood or site, green infrastructure refers to stormwater management systems that mimic nature by soaking up and storing water. (United States Environmental Protection Agency) • Green infrastructure is strategically planned and managed networks of natural lands, working landscapes and other open spaces that conserve ecosystem values and functions and provide associated benefits to human populations. (The Conservation Fund) • Stormwater management approach that utilizes natural landscape features and hydrologic processes to treat stormwater by infiltrating, evapotranspiring, and/or reusing runoff. Green infrastructure also achieves other environmental goals such as carbon sequestration, reductions in urban heat island effect, improved air quality, improved wildlife habitat and increased opportunities for outdoor recreation. (Capitol Region Watershed District) While there are variations between these definitions, they all consistently state that green infrastructure uses landscape features and/or natural processes to manage and/or treat stormwater in a manner that provides environmental benefits. Green infrastructure aligns well with the vision for a revitalized central corridor that includes new green spaces along the corridor, along with environmentally sound and sustainable redevelopment.

Potential SSGI Implementation Barriers Many of the potential SSGI implementation barriers identified by the SAC and a developer focus group revolved around long-term risk management and associated cost implications. The investigation quickly raised a number of logistic issues that a successful SSGI implementation approach must address, such as: • Where will the SSGI be located and who will own the property? • Who will administer, operate and maintain the SSGI? • Can SSGI facilities be constructed in a phased manner to coincide with phased redevelopment? • How can the initial SSGI construction be funded in a fair and equitable manner? • How can the SSGI long-term operations and maintenance be funded in a fair and equitable manner? • What contingency plans are needed in case redevelopment doesn’t occur, or only partially occurs?

Figure 2.1 Definition of SSGI

• Will SSGI work within the existing statutory framework? The study quickly concluded that a “one size fits all” may not be a realistic SSGI implementation approach. The variable ways in which SSGI can be implemented lends to a case-by-case evaluation. However, general frameworks are needed to help guide implementation feasibility discussions.

Strategic Stormwater Solutions for Transit-Oriented Development Final Report 15

Set the Foundation

Right-of-Way Considerations Often, off-site stormwater management is construed as possibly involving the public right-of-way. Cities are the stewards of the right-of-way as the public right-ofway supplies a benefit to the civic community at large. The right-of-way must accommodate a variety of public needs, such as transportation facilities (e.g., streets, sidewalks, and transit), above and below ground utility services (e.g., water mains, sanitary sewers, electric, gas, and cable services) and environmental enhancements (e.g., street trees and ground vegetation). Frequently, these various public uses are competing for the limited space available within the right-of-way. Therefore, the addition of any non-public use within the right-of-way involves significant risk for any governmental agency responsible for the public right-of-way. Both Minneapolis and St. Paul have long-standing processes to evaluate and control uses proposed for the right-of-way that may have direct benefit to only a limited group. Encroachment Permits are issued only when it can be clearly demonstrated that a private â&#x20AC;&#x153;needâ&#x20AC;? cannot be met within private property. The public right-of-way provides possible real estate for hosting shared stormwater management. However, the placement of shared stormwater facilities in the right-of-way must provide public services and value beyond simply benefiting the developer.

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Figure 2.2 Governmental Authority

Developers Focus Group Over the course of the project, the project team met with select developers with project experience in the Cities of Saint Paul and/or Minneapolis. The focus group indicated that sharing stormwater facilities between private developments and public agencies is the preferred approach versus sharing occurring solely between private developments. This is primarily due to perceived risk by developers and their financiers. The group also stated adjacencies to open space provide value to residential and retail developments through increased rents or unit sale prices. Finally, they indicated that predictive development processes are valuable. These insights help inform the development of potential SSGI approaches.

Governmental Authority Relating to Stormwater Infrastructure Current statutes provide cities, watershed districts and joint powers Watershed Management Organizations (WMO) authority to require stormwater management as a condition of subdivision or building activities. These governmental entities also have authority to acquire land and to construct, operate and maintain stormwater management infrastructure, either individually or in cooperation with other governmental units (see Figure 2.2). The statutes provide governmental units a broad array of options for funding stormwater facilities by raising funds from appropriate parties, which range from utility

Rules and Regulations

charges and assessments against targeted or benefited properties to ad valorem tax levies over the entire taxing jurisdiction or an appropriate sub district.

Therefore, dependent on size, the following three stormwater regulatory requirement categories may apply to redevelopment projects.

The existing statutory framework provides cities, watershed districts and joint powers WMOs with the key tools they need to implement desired stormwater infrastructure, including SSGI. Additional information regarding governmental authority relating to stormwater infrastructure can be found in Appendix A.

• Rate Control – Controls the rate at which stormwater runoff is discharged from a developed site, typically discharge rates are controlled to existing or presettlement conditions for a variety of storm events.

Existing Stormwater Rules and Regulations Existing stormwater regulations within the corridor was another key project informant. Projects within the corridor generally need to meet the regulations of the following agencies: • Cities of Saint Paul and Minneapolis • Capitol Region Watershed District (CRWD) • MPCA via the NPDES General Construction Permit

• Volume Control – Controls the amount of stormwater runoff from a site to encourage groundwater recharge, limit impacts to downstream systems, and remove soluble nutrients from runoff discharged from the site. • Water Quality – Refers to the removal of specified pollutants to a designated level. Additional information on the stormwater management regulations that applied to the corridor during the course of this study can be found in Appendix B.

In addition, the Mississippi Watershed Management Organization (MWMO) has a set of guidelines that need to be adhered to if the project is being funded with a grant from the MWMO. In general, redevelopment projects along the corridor will need to adhere to the most restrictive regulatory requirement that applies to that site. In all cases, requirements are triggered by a size threshold; each agency has different size criteria. Parcels less than one acre are considered “small” and generally are not required to achieve runoff/pollutant reduction.

Strategic Stormwater Solutions for Transit-Oriented Development Final Report 17

Explore Opportunities

Explore Opportunities Key National Studies Previous Central Corridor studies were reviewed to gain a clear understanding of Saint Paul’s and Minneapolis’ redevelopment visions for this corridor. In addition, reviews were preformed over the course of the project of national studies related to SSGI. Several concurrent studies of particular interest titled, River North: Area Wide Green Infrastructure Study (Wenk Associates, 2013), Creating Clean Water Cash Flows (Natural Resources Defense Council, EKO Asset Management Partners, the Nature Conservancy, 2013) and Banking on Green (American Rivers, the Water Environment Federation, the American Society of Landscape Architects, ECONorthwest, 2012) were all investigating variations of SSGI, which affirmed this is an issue of interest across the country. These national studies consistently indicated that green infrastructure was less expensive to construct than traditional gray infrastructure, regardless of scale.

Normal, IL Roundabout Source: Insert 18 Chapter Number

The studies also illustrated that new models for stormwater management must be initiated through leadership within municipal government. Other regions can use these national studies to help inform replicability but communities should also evaluate their own local precedents.

Review of National and Local Precedents Conceptually, shared, stacked-function stormwater management is not a new approach. Historically, for new developments in growing municipalities, the term “regional pond” was often used to describe a similar situation where one stormwater facility was built by a city for the benefit of many parcels, and by virtue of size may also provide passive recreational amenities and/or wildlife habitat. In other instances, smaller developments built common (shared) ponds in outlots, owned by Homeowner Associations. (However, often the outlot would go into tax-forfeiture and become owned by a city.)

SSGI builds on this general concept but seeks to employ it on a much smaller scale in a fully developed environment. Examples of SSGI can be found both locally and nationally. The following precedent projects were examined in more detail to better understand how SSGI is being applied, along with associated opportunities and constraints. Fee-in-Lieu Program, Charlotte, NC – This project highlights another community providing flexibility in their stormwater regulations in order to better facilitate desired redevelopment along a transit corridor. The City of Charlotte instituted an off-site mitigation program to provide flexibility and reduce cost barriers for site-constrained redevelopment properties that supported growth and economic development along Charlotte’s light rail system. The ordinance allows property developers to pay a onetime fee if cost or site constraints prevent them from meeting their stormwater retention mandates. The City charges developers a fee per impervious acre and constructs off-site facilities in a cost-efficient manner on city-controlled lands.

Canal Park Source: Insert

Precedents

Stormwater Management Enhancement Districts, Philadelphia, PA – The City of Philadelphia facilitates the aggregation of properties into Stormwater Management Enhancement Districts (SMEDs), which are areas identified as having potential for a large, coordinated green infrastructure project The city takes leadership in identifying SMEDs and contracts with an engineering specialist to evaluate potential green infrastructure retrofits that are technically, economically, and practically attractive and prepare a Stormwater Improvement Plan. These proactive steps taken by the City encourage the use of stormwater facilities that take advantage of economies of scale and also lower retrofit project assessment and analysis costs, thus incenting desired development. Normal, IL Roundabout – This project harvests, cleanses, and reuses co-mingled (public and nonpublic) stormwater runoff to create a water-based amenity in a new community open space. FUTURE TRAIL EXPANSION BUS DROP-OFF / PARKING (12-16 CARS)

RAINGARDEN

B K

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CONNECT TO T.B.I LIFT STATION TRAILHEAD FACILITY Trou t Inte Broo rce k St pt orm or

Canal Park, Washington DC – Stormwater runoff captured from the site and adjacent private buildings will be harvested, cleansed and reused to create new water-based amenities and for toilet flushing in a new urban park. Tartan Crossings, Oakdale, MN – As part of the redevelopment of an underperforming strip mall into new commercial sites, the city’s Public Works constructed an artistically designed shared stormwater feature that functions as a new recreational, aesthetic and educational amenity in public right-of-way. Trout Brook Nature Sanctuary, Saint Paul, MN Stormwater runoff from an adjacent existing residential neighborhood will be daylighted from storm sewers, and cleansed through a series of ponds. Public art is woven into various site features, such as retaining walls and native plantings, to animate the space and educate sanctuary visitors. The treated runoff will provide a significant water source for a newly re-established historic waterway that will run through the sanctuary.

Central Corridor, Saint Paul, MN – Boulevards cross streets to the Green Line were retrofitted by the CRWD to incorporate stormwater planters and rain gardens at a dozen locations. Localized runoff from the streetscape and, in some instances, parking lots, are treated by these features. Victoria Park, Saint Paul, MN – Stormwater runoff from an adjacent street was directed into a stormwater swale within the newly created Victoria Park and will function as an aesthetic park feature. Heritage Park, Minneapolis, MN – Stormwater runoff from residential redevelopment sites and adjacent neighborhoods is daylighted from storm sewers and cleansed through a series of filtration basins that are incorporated into a neighborhood street design to emulate a parkway. The harvested stormwater provides water for new parkland amenity ponds. Hamline Library Green Alley, Saint Paul, MN – The City constructed a porous bituminous pavement alley that collects and infiltrates stormwater runoff from the alley itself and adjacent private parcels.

STORMWATER COLLECTION POND

PEDESTRIAN CONNECTION

SOURCE POND

PRESERVE HIGH QUALITY TREES i

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PEDESTRIAN CONNECTION AND OVERLOOK

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PULL-OFF WITH INTERPRETIVE SIGNAGE AND BENCHES

Central Corridor

Heritage Park

Hamline Green Alley

WORD ART STREAM CROSSING

TO BE COMPLETED BY MnDOT 35E/CAYUGA PROJECT COMBINED TROUT BROOK/GATEWAY TRAIL

Cayuga St.

SIMS-AGATE POND

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Jackson St.

ACCESSIBLE PEDESTRIAN CONNECTION

R E C R E AT I O N

HANDCART ART ON TRACKS

Strategic Stormwater Solutions for Transit-Oriented Development Final Report 19

Explore Opportunities

Public Art Integration In 2009, the City of Saint Paul passed a public art ordinance that calls for public artist involvement in city planning studies and City capital improvement projects. The ordinance states that, “Public art strengthens public places and enhances and promotes Saint Paul’s identity as a livable and creative city and a desirable place to live, work and visit.” Public art is a key contributor to enhanced livability. As stated above, it helps to create unique, identifiable, and stimulating environments that provide meaning and value to those who interact with the artwork. The Strategic Stormwater Solutions for Transit-Oriented Development study developed a public art concept titled, “FLUXion ≈ gARTens.” This concept was based on the idea of ‘Public Art’ as ‘Green Placemaking’ and ‘Green Placemaking as Public Art’ where harvested stormwater is integrated into a proposed network of green art spaces/places (gARTens) (e.g., gardens, pocket parks and art works) that are collaboratively designed by artists, the property owners, and engineers. The individual gARTens would be publically accessible, authentic, placed-based, green places created as environmental, economic, social, and aesthetic sites along the corridor. These public artworks would help

build a distinct community narrative so neighborhood residents would be invested in, use, and take ownership of these newly created spaces. ‘FLUXion ≈ gARTens’ could be branded and utilized with an interactive website that maps, illustrates, documents and describes all the connected ‘gARTens’ where a person could travel gARTen to gARTen with the help of a smart phone or ipad. ‘FLUXion ≈ gARTens’ could also function as satellite arboretums and botanical gardens that are mapped, illustrated and utilized through an interactive website, and possibly integrated into the University of Minnesota Arboretum System. This could introduce neighborhood residents and visitors to different plant species and aid in their identification. Additional information about ‘FLUXion ≈ gARTens’ can be found in Appendix C.

»» Top- Title, Source: To be inserted »» Bottom- Title, Source: To be inserted

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Public Art Integration

»» Top- Title, Source: To be inserted »» Bottom- Title, Source: To be inserted

Strategic Stormwater Solutions for Transit-Oriented Development Final Report 21

Evaluate and Select Options

Evaluate and Select Options Potential Redevelopment Sites Identification The project team solicited stakeholders and reviewed previous station area plans and sub area studies to identify potential future redevelopment projects along the corridor. A total of 37 potential redevelopment sites were identified (see Figures 2.3-2.5). This list was screened and narrowed down to a pool of ten. Sites were selected from the pool to perform the conceptual design studies. While a number of screening criteria were used, final selection was primarily based on:

Figure 2.3 Potential Redevelopment Sites Minneapolis 22 Chapter Number

• A geographical distribution of sites – the number of potential sites selected were approximately proportionate to the length of the Green Line within each of the cities. • A range of large and small sites – The success of various SSGI approaches may be influenced by the size of the site; therefore, a range of site sizes was desired. • Potentially contaminated sites – A large number of sites along the corridor are assumed to be contaminated, given the long history of development along the corridor. Therefore, some of the sites should allow the project team to

examine whether the sites could accommodate the larger filtration requirements associated with contaminated soils. • Near to mid-term development potential – Sites that were further along in the development process would allow the project team to work with known development programs, which would better flush out implementation issues.

Potential Redevelopment Sites Identification

Figure 2.4 Potential Redevelopment Sites, Saint Paul (West Segment)

Figure 2.5 Potential Redevelopment Sites, Saint Paul (East Segment) Strategic Stormwater Solutions for Transit-Oriented Development Final Report 23

Evaluate and Selection Options

Potential SSGI Approaches Potential SSGI approaches were developed and four were selected for additional feasibility analysis. As stated earlier, a critical project premise was to develop strategic solutions that were fair, equitable, and provided mutual benefit to all parties involved. The successful implementation of any of the potential approaches is contingent upon the development of a balanced distribution of benefits, costs, and risk. Note that these approaches are not mutually exclusive but were evaluated individually to simplify analysis.

New public parks/open spaces Hosting stormwater in new public parks benefits adjacent redevelopment as it eliminates the spatial constraints of treating stormwater on site and reduces soft development costs. Developers also benefit by the adjacency of a new open space, which makes their parcel more desirable to potential tenants or purchasers. By taking stormwater into a park facility, the City obtains capital and maintenance funding from the developer that will help finance the shared, stacked-function

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portion of park construction and maintenance. It also allows other city projects to participate in the facility, such as stormwater treatment for new or reconstructed streets. By sharing a stormwater facility, economies of scale can be achieved, resulting in reduced construction costs for all parties sharing the shared facility. Shared stormwater facilities in public parks also provide a cost effective opportunity to treat stormwater from adjacent parcels currently not receiving treatment that are not anticipated to redevelop in the near future.

Shared parking facilities A key component of TOD, is the creation of a pedestrian friendly environment and the efficient use of available space, which may result in the development of shared parking facilities. Owners of parking facilities and those using it typically develop mutually-agreeable operating and liability arrangements. It is feasible that a water treatment facility could be built into new parking structures or under shared parking lots and the legal agreement expanded to include the shared

stormwater facility. This type of shared facility also allows for the accumulation of a significant volume of water that will support reuse options, such as irrigation or building toilet flushing.

Green alleys A vast majority of blocks in Saint Paul are served by alley access. These â&#x20AC;&#x153;sharedâ&#x20AC;? driving facilities are strategically located to conveniently collect and store stormwater runoff. New pervious pavements allow for the infiltration of water, while still providing the structural support needed for vehicle movement. Alleys are also typically free of major underground utilities that compete for underground space with stormwater facilities. While this approach doesnâ&#x20AC;&#x2122;t heighten awareness of water, it does support efficient use of space in highly urbanized environments.

Street Right-of-way Green Infrastructure located in street boulevards (e.g., tree trenches, rain gardens, and boulevard swales) can host shared stormwater treatment facilities.

Potential SSGI Approaches

Runoff collected in these facilities can be used to irrigate new streetscape plantings that would increase environmental health, improve streetscape aesthetics, and provide a comfortable walking environment. These facilities also heighten residentsâ&#x20AC;&#x2122; awareness of and connection to water and natural processes in the urban landscape.

Application of SSGI at Different Development Scales Two potential redevelopment sites were used to test how SSGI could be incorporated into redevelopment projects of varying scale. The first site selected, known as the Bus Barn site, is representative of large-scale, urban village redevelopment areas (see Figure 2.6). With a size of 34-acres, the Bus Barn site is envisioned as a longterm, phased, development area. It was assumed that select streets and blocks would be reconfigured and that significant demolition and reconstruction of buildings would occur. The Saint Paul Transit-Oriented Development Guidebook for the Central Corridor identifies four urban village redevelopment sites along the Saint Paul segment of the Green Line.

The second site, known as the Brownstone site, is representative of small parcel redevelopment projects. The Brownstone site was selected as it small in scale, yet exceeded one acre (see Figure 2.6). Small projects typically consist of existing building expansions, or the complete demolition of several structures, parcel assembly and development of a larger building. Concepts were developed for each of the four SSGI approaches on both the Bus Barn and Brownstone sites, for a total of eight SSGI concepts. One representative concept for each of the development scales are illustrated in Figures 2.7 and 2.8. The concepts illustrated how the stormwater runoff can be artistically expressed as it supports new corridor vegetation or as an artwork or interpretative element. A comparison of the individual basis estimated costs to conceptual SSGI estimated costs indicated that cost efficiencies can be achieved through the sharing of stormwater facilities. It

Brownstone Site

Bus Barn Site

lrt green line

potential Development Sites

watershed boundary

advance Design Sites

open Space candidate Site

Municipal boundary

Figure 2.6 Development Scale Concept Sites Strategic Stormwater Solutions for Transit-Oriented Development Final Report 25

Evaluate and Select Options

may have less access to financial resources. The relative need for SSGI to service small parcels is high yet the ability to implement SSGI may be more complex, compared to other redevelopment types.

The investigation highlighted that certain SSGI approaches are able to be constructed in phases to better correlate to phased redevelopment (e.g., alleys and street right-of-way), while other SSGI approaches are best constructed simultaneously with the first phase of redevelopment with future phases hooking into the existing stormwater facility (e.g., shared parking and parks).

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Brownstone Development

University Avenue Victoria Station Park/Open Space

d e t da

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b o st

Future Development

ic h p

a gr

Figure 2.8 Brownstone New Private Open Space Concept

Irrigation Cistern

Avon Street

Victoria Street

Another finding indicated a distinct SSGI dichotomy with between small parcels and other redevelopment types. The dichotomy is apparent when comparing ease of implementation against need or benefit. Specifically, it is easier to implement a SSGI facility that serves a limited number of large parcels than numerous small, scattered unrelated redevelopment parcels. (This is due to fewer voices in the public-private dialogue, less modifications required to existing drainage systems, and more predictability in timing and financing.) However, small parcels have less available space for overall site design including landscaping, are not required to provide volume/pollutant reduction, and

Sherburne Avenue

Theater

was also determined that the incremental cost increase associated with the provision of runoff/pollutant reduction measures, in addition to rate control, for a shared facility is not significant. Additional information on the concepts can be found in Appendices D and E.

Application of SSGI at Different Development Scales

Snelling Station

University Avenue

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ic h ap e r l g her a n d o i e t t i r d se d a in be

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Figure 2.7 Bus Barn Street R/W Concept

Strategic Stormwater Solutions for Transit-Oriented Development Final Report 27

Work Through the Details

Work through the Details Based on the findings from the investigation of different development scales, it was deemed appropriate to continue investigating the four potential SSGI approaches and to further test two of the SSGI approaches on potential active development sites along the corridor. The concepts developed for these sites were theoretical in nature and did not imply that development of the concept would ultimately occur.

Boeser Site The first site selected, known as the Boeser site, is located near the Green Line Prospect Park/29th Avenue station in Minneapolis (see Figure 2.7). A local developer is pursuing the redevelopment of an obsolete industrial site into a multi-family apartment building. The existing street (4th Street), scheduled for reconstruction by the City of Minneapolis, would be reconfigured within the existing 80-foot street right-of-way.

Shared The concept was based on the premise that runoff from the Boeser site would be managed in the adjacent street right-of-way, along with runoff from a future redevelopment parcel located across the street (see Figure 2.8).

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Stacked-Function The street concept envisions a high amenity street that accommodates pedestrians, bicycles and cars and includes space for outdoor gathering. The street concept artistically highlights and celebrates the movement of stormwater runoff down buildings and into aesthetically designed flow-through planters and rain gardens, which support new street vegetation and habitat. New street trees are installed in structural tree trenches overlaid with permeable pavers (see Figures 2.10 and 2.11).

Triple Bottom Line Benefits Economic: A comparison of the individual basis estimated costs (prepared under a side analysis not included in this reportâ&#x20AC;&#x2122;s scope [Boeser Site Stormwater Feasibility, MWMO]) to conceptual SSGI estimated costs indicated that SSGI results in net capital cost efficiencies overall. However, a cost recovery analysis revealed complexities, particularly when allocating costs based on contributing runoff volume (or impervious surface). The developer realized a disproportionate amount of savings relative to the City in the shared system, resulting in inequity. Environmental: Beyond the environmental benefits of stormwater management, the vegetated filtration basins and new street trees irrigated with harvested stormwater

provide numerous environmental benefits, such as habitat creation, urban heat island mitigation, and carbon sequestration. Social: The provision of stormwater supported vegetation in the street right-of-way improves livability by creating comfortable outdoor environments for walking and recreating. Increasing street activity strengthens the social fabric of the city and improves safety.

Public Art Public art concepts for the Boeser site focus on creating a sensory experience, a place for celebrating and interacting with water. Water could be taken from the rooftops through a kinetic sculpture that interacted with the flow of water, creating sound and reflecting light. The water would then fall into at-grade runnels- down steps, across sidewalks, and spill into the rain gardens (see Figures 2.9-2.10). Each runnel and spillway presents another opportunity to integrate public art.

Other Considerations This concept could be replicated along the length of the street reconstruction, which extends beyond the subject block. The existing street (4th Street) is a Municipal State Aid road which has specific design standards. The SSGI concept meets these standards.

Boeser Site

lrt green line

potential Development Sites

concept Sites

open Space candidate Site

watershed boundary Municipal boundary university of Minnesota

째

Boeser Site

Curfew Commons Site

Figure 2.7 Concept Sites Context Map

Figure 2.8 Boeser Site Conceptual Drainage Area

Strategic Stormwater Solutions for Transit-Oriented Development Final Report 29

Work Through the Details

Figure 2.9 Representative Public Art Concepts »» Top- Title, Source: To be inserted »» Bottom- Title, Source: To be inserted

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Figure 2.10 Boeser Concept Plan

Boeser Site

Figure 2.11 Boeser Concept: Illustrative Section Perspective

Strategic Stormwater Solutions for Transit-Oriented Development Final Report 31

Work through the Details

Curfew Commons Park Site The second site, known as Curfew Commons Park is located near the Green Line Westgate Station in Saint Paul (see Figure 2.7). The Station Area Plan envisions a new community park for this underserved neighborhood, which will experience housing and office-related redevelopment.

Shared The park concept is based on the premise that stormwater runoff from the adjacent multi-family redevelopment site and from the new streets is directed to the new park (see Figure 2.12). Those sharing the stormwater facility include the developer and various City Departments (Parks and Public Works).

Stacked-Function The concept depicts stormwater management within the park taking the form of filtration basins (see Figure 2.14). The basins are designed to provide quiet passive park uses when they are dry, which is a majority of the time. The basins surround a great lawn area. Art elements are designed to highlight runoff volumes resulting from varying rainfall events and to celebrate the movement of water when the basins overflow. The

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lawn incorporates an underground irrigation system that is fed with water that has passed through the filtration basins.

Triple Bottom Line Benefits Economic: Similar to the Boeser Site, a comparison of the individual basis estimated costs to conceptual SSGI estimated costs indicated that SSGI results in net capital cost efficiencies overall. However, a cost recovery analysis that allocated costs based on contributing runoff volume (or impervious surface) indicated the developer receiving a disproportionate amount of savings relative to the city in the shared system, resulting in inequity. The cost comparisons also indicated that operations and maintenance costs associated with green infrastructure exceed gray infrastructure operations and maintenance costs. By taking stormwater into a park facility, the City obtains a capital and maintenance funding source that will help finance the shared, stacked-function portion of park construction and maintenance. For a majority of the time, the stormwater facility

will be dry and will serve a recreational use, yet the funds used to construct and maintain the facility are derived by its stormwater function. While not empirically established through this study, discussions with the development community indicated that creation of new open spaces will make development parcels along the corridor more attractive to developers in comparison to other potential redevelopment parcels in the city that are not adjacent to open space. Developers prefer parcels adjacent to open spaces as they expect to receive higher returns on their investment through increased rents or unit sale prices. In turn, redevelopment of underperforming parcels increases the cityâ&#x20AC;&#x2122;s tax base. Environmental: Beyond the environmental benefits of stormwater management, the vegetated filtration basins in the park will introduce new habitat to the urban core. The conversion of pavement to vegetated surfaces will also help mitigate the urban heat island effect. Social: Using stormwater features to facilitate parkland development will provide needed open space amenities for an underserved area. The stormwater

Curfew Commons Park Site

supported irrigation of the great lawn, enhances the visual appeal and turf health for an area that is anticipated to receive heavy use. This will heighten livability by providing a place for exercise and recreation. Public Art: The intent of the FLUXion ≈ gARTens concept for Curfew Commons was to delight, educate and reinforce the triple bottom line benefits provided by SSGI. • Plantings could recall pre-European settlement plantings (most likely Oak Savanna habitat) and native materials could be used to help interpret and educate about the natural landscape and create a connection to the Mississippi river(see Figure 2.13).

Additional Considerations: The findings also indicated that runoff from smaller parcels currently not receiving treatment can be effectively included in SSGI projects. Finally, the investigation and resulting SAC discussion of findings suggested that the strongest benefit derived from SSGI implementation may be the community enhancements and associated improved livability, as these are key redevelopment outcomes desired Additional information on these conceptual designs can be found in Appendix F.

• Terraced retaining walls, seating elements, spillways, etc. could all incorporate public art and would be designed to enliven and animate water (see Figure 2.13). • Playground area located in the SW corner would be integrated into the larger concept of the park to celebrate water and teach children about different ecosystems.

Strategic Stormwater Solutions for Transit-Oriented Development Final Report 33

Work through the Details

A Streets B Park C New Development D Existing Residential (draining to new development) E Curfew St/Contributing Residential

Figure 2.12 Curfew Commons Conceptual Drainage Area

Figure 2.12 Representative Public Art Concepts »» Top Row- Title, Source: To be inserted »» Middle Row- Title, Source: To be inserted »» Bottom Row- Title, Source: To be inserted

34 Chapter Number

Curfew Commons Park Site

Figure 2.14 Curfew Commons Concept: Illustrative Plan

Strategic Stormwater Solutions for Transit-Oriented Development Final Report 35

Work through the Details

Figure 2.15 Curfew Commons Concept : Illustrative Section 36 Chapter Number

Curfew Commons Park Site

Figure 2.16 Curfew Commons Concept : Section Detail

Strategic Stormwater Solutions for Transit-Oriented Development Final Report 37

SSGI Implementation Chapter

While SSGI can be used to assist with the creation of TOD, the development of effective policies and implementation tools is critical to the successful implementation of SSGI.

Draft Policy Resolution The first step to implement SSGI is the development and adoption of a SSGI policy resolution. The initial policy resolution brought forward should highlight SSGI benefits and how its use can assist with the creation of the City’s adopted TOD vision. To increase policy makers’ comfort with its use and to refine implementation protocols, it is recommended that the resolution request authorization for pilot implementation of SSGI. SSGI policy resolutions can be brought forward to those agencies that influence or direct stormwater management implementation, primarily municipalities and MWOs. A policy resolution template can be found in Appendix G that can be tailored to each agency’s specific needs and circumstances.

Perform Pilot Studies Several pilot studies should be performed for the purpose of testing and refining the SSGI framework developed in this study. The use of pilot studies allows agencies to test the approach without making a longterm commitment to its implementation. The City will likely need to initiate the identification and selection of pilot sites in partnership with other stakeholder agencies and the development community.

38 Chapter Number

»»Draft Policy Resolution »»Perform Pilot Studies »»Revise Regulatory Framework

Pilot sites should be selected to test various SSGI • Development scales. • Approaches, such as green alleys, parks or parking. • Funding and cost recovery mechanisms. After a designated number of pilot sites have been implemented, monitored and evaluated, agencies can make the determination whether the approach provides desired TOD benefits. If SSGI is deemed feasible, modifications to implementation protocols identified through the pilot process should be incorporated into the SSGI framework. Another benefit of performing pilot studies is the creation of demonstration sites for others to see and learn from should SSGI be deemed feasible. If the pilot studies indicate that SSGI provides development benefits, another policy resolution authorizing the use of SSGI should be brought forward for adoption.

Revise Regulatory Framework While a majority of SSGI implementation recommendations address the development of an approach to define answers to logistic issues and thereby reducing risk, there are regulatory considerations as well. As noted previously, current stormwater regulations differ across the cities and WMOs. If elected/appointed officials choose to move

»»Institutionalize SSGI into Agency Processes »»Public Art Implementation beyond pilot studies into a long-term implementation mode, it will likely require modification of existing stormwater rules and local ordinances. Pertinent topics (not necessarily exhaustive) to scrutinize at a finer level of detail would include: • On-site management. The current CRWD rules require an applicant to follow a regimented series of stormwater compliance steps, the first being that stormwater must be managed on-site (Rule C.3(2) i). Both municipalities reflect that stormwater must be managed on-site (e.g. Minneapolis Chapter 54.70(1)a.1.; Saint Paul Chapters 69.504b and 63.319(a)). Minneapolis does have provisions for off-site stormwater management considerations but the wording indicates that provision is not to be used to circumvent on-site requirements. Flexibility would need to be incorporated into these processes to allow shared facilities when their use provides public benefit. • Encroachment. Cities of Saint Paul and Minneapolis both have requirements relating to encroachments into the right-of-way, which may potentially limit SSGI implementation. • Code consolidation. The City of Saint Paul has multiple locations for expressing stormwater management requirements. Any revisions would need to include all locations to ensure there are no conflicts or discord.

SSGI Implementation

• Green requirements. Cities of Saint Paul and Minneapolis have regulatory tools which, in certain circumstances, encourage the use of natural features and vegetation in stormwater management. (Minneapolis Chapter 54.70(3)ii; Saint Paul Chapters 63.319(b)1 and 66.344(b)5) These could be expanded or adapted to better support stacked-function green infrastructure implementation. Jurisdictional stormwater regulations need to be reviewed and modified to remove or clarify regulations that specifically prohibits or discourages SSGI implementation. Additionally, the City of Saint Paul has a charter prohibiting the diversion of park uses (Saint Paul Chapter 13.01.1). Through SAC discussions, it was determined that retrofitting SSGI into existing Green Line parks (within Saint Paul) would not be a high priority. Given that SSGI can be used as tool to assist with the development of new Saint Paul parks along the Green Line, its use should be strongly considered. Before this tool can be realized, Saint Paul will need to evaluate if changes are necessary to the existing charter to allow for the incorporation of SSGI in new parks along the Green Line. To that end, the city has already developed an official interdepartmental Cooperative Agreement that has been used to retrofit existing parks for large-scale stormwater runoff reduction. The “Green Line Parks and Commons” analysis being prepared by the Trust for Public Land may provide further clarification on this issue.

Institutionalize SSGI into Agency Processes The institutionalization of SSGI into agency processes is critical to its implementation. The feasibility of SSGI should be discussed between implementing agencies and developers early in the development process, before significant time or funds are invested in developing a traditional site plan. Traditional review procedures, such as site plan review, is too late in the development process to introduce SSGI discussions as developers have already invested time and funding into the plans being brought forward for agency review. Therefore, SSGI implementation may require modifications to existing agencies processes to allow for early discussion and evaluation.

SSGI may provide cost-efficient stormwater management for runoff from small parcels that otherwise would not receive treatment in the near future. Therefore, the development of a retrofit program that provides a process to initiate the SSGI feasibility discussion, evaluate opportunities and to identify potential funding mechanisms may be advantageous.

The implementation of SSGI is not limited to the redevelopment of individual parcels. There are a number of scenarios that could trigger SSGI feasibility discussions, such as: • Street reconstruction project • Replatting assembled land(s) • Construction project management permits

requiring

stormwater

• New public facility construction (e.g., schools, libraries, parks) • Development of a small area master plan or stormwater retrofit analysis Inserting SSGI feasibility discussions and evaluations to these agency processes is a key step in institutionalizing SSGI.

Strategic Stormwater Solutions for Transit-Oriented Development Final Report 39

SSGI Implementation

SSGI Assessment Tool Given that a number of factors must align in order to utilize SSGI, the determination whether SSGI is feasible needs to occur on a case-by-case basis. This study suggests that agency staff use an assessment tool to help evaluate whether SSGI would be appropriate. An assessment tool template, as shown in Figure 3.1, provides a series of questions that agency staff can ask early in the development process to assess whether SSGI is a tool that can be used to further the goal of TOD for the proposed project at hand. This tool is envisioned to be used by agency staff that first interact with the development community, as an early determination of feasibility is essential if SSGI is to be successfully implemented.

Decision-making Flowcharts and Matrices Numerous options exist for how SSGI can be implemented and funded. At times the multitude of options and complexity of funding options can appear to be overwhelming. To assist agency staff with the evaluation of funding options, a series of flow 40 Chapter Number

charts and matrices templates have been developed that articulate the various funding options currently available. The flowcharts are designed to lead agency staff through a series of questions and then provide funding alternatives based on answers provided. The matrices provide more detail about the opportunities and constraints associated with the various funding options. Additional information on these tools can be found in Appendix G.

Pilot Project Educational and Outreach Materials Educational and outreach materials should be utilized to inform Green Line development stakeholders about potential pilot opportunities, if a community is interested in advancing SSGI approaches. The audience primarily would involve developers, but also could help inform elected/appointed officials about TOD benefits that can be achieved through SSGI pilot projects. The materials help provide a consistent message about current stormwater challenges, the intent of SSGI and the potential opportunity, given that SSGI use is not formally adopted. Education and outreach materials may be useful when a developer begins initial dialogue with the city, a Green Line neighborhood group, or other early stages of property redevelopment. The materials can be complimentary to existing resources such as Saint Paul’s “TOD Guidebook for the Central Corridor. “ At a minimum, the outreach materials can help encourage and foster site designs that more creatively incorporate natural vegetation into stormwater management. A sample brochure can be found in Appendix G.

Public Art Implementation The implementation of the ‘FLUXion ≈ gARTens’ concept along the Central Corridor is contingent upon establishing community buy-in and support for the concept, along with the commitment from an arts organization to facilitate and coordinate its implementation. Similar to SSGI, educational and outreach materials need to be developed to inform the community about the stacked-function benefits that FLUXion ≈ gARTens can provide to the Green Line and surrounding community and to develop community support for voluntary implementation. With the City’s adoption of the public art ordinance in 2009, a mechanism is in place to implement artworks into public projects. Yet, in order for FLUXion ≈ gARTens to be successfully implemented, gardens in the network must be implemented beyond public projects. The development community must see the value FLUXion ≈ gARTens will provide for their properties and want to participate using their own funds or through a competitive grant process. Finally, an arts organization must also find value in the concept and volunteer to market, find funding, and oversee its implementation. In addition to traditional arts funding foundations and existing arts grant programs, the stacked-function of FLUXion ≈ gARTens (i.e., stormwater or plant identification, stormwater education, and urban agriculture) may open up other potential construction and maintenance funding sources such as health improvement grants, job training programs, MWOs, or educational institutions. Additional information on public art implementation tools can be found in Appendix H.

Implementation Tools

Strategic Stormwater Solutions for Transit-Oriented Development Final Report 41

Findings & Conclusion

Chapter

The Green Line has established a remarkable precedent with respect to implementing green infrastructure via the extensive tree trench system and other practices. This provides a critical fulcrum to leverage additional green infrastructure investment to achieve a vibrant corridor. In highly urban corridor, SSGI represents a balancing of risk, roles, and responsibilities (particularly for city departments) in the context of broader triple-bottom line benefits. Leadership from elected/appointed officials will be necessary to effectively support and advance with this strategic stormwater solution initiative. This may involve adopting resolutions, sponsoring code modifications, or other similar actions.

»»Flexibility Supports Vision »»Define a Process »»Development Scale is Important

Yet, there are key events such as the construction of major infrastructure projects like light rail transit that trigger concentrated redevelopment where sharing of stormwater facilities may be feasible and conducive to the creation of desired TOD. This is of particular importance for small, space-constrained, urban redevelopment parcels where numerous programmatic requirements are competing for valuable space. In these situations, flexibility should be provided in the current stormwater management approach to allow for SSGI implementation, if doing so would be beneficial to the City/WMO for purpose of achieving the community’s corridor vision of a green, vibrant, sustainable neighborhood.

Define a Process SSGI can be successfully implemented, but will likely involve a case-by-case approach. Therefore, processes – such as decision trees or screening methods – must be put in place to assess its feasibility early in the development process. Tools such as flowcharts identifying necessary incremental commitments must also be in place to assist agency staff and developers to efficiently structure a SSGI approach that creates a balanced approach for funding and risk management. These processes and tools must be general enough

»»Potential for Financial Balance »»Be Opportunistic

to work across a variety of possible development scenarios while acknowledging many stakeholders may potentially participate. The SSGI Assessment Tool (in combination with an outreach brochure) is essential to establish a structured dialogue to identify where a potential project may be feasible, while also maintaining baseline expectations for stormwater management.

Development Scale is Important While there are likely more, this study identified four SSGI approaches (Parks, Parking, Alleys, and Street Right-of-way) that successfully provide triple bottom line benefits supportive of TOD. In addition, the study indicated that several of these approaches lent themselves more strongly to a particular scale of development. For example, while green alleys can be incorporated into all scales of development, this approach is a more viable option for use with small scale development projects than the parks approach. Likewise, a structured parking approach is better aligned with an urban village development scale. Figure 4.1 highlights the applicability of the four SSGI approaches to different development scales.

Findings & Conclusion

Potential for Financial Balance Government units have broad authority and multiple options to raise revenue for SSGI costs. This will likely require significant political leadership. Yet a financially “neutral” funding source is preferable, rather than sequestering funds solely from one municipal department. Regardless of funding source, compared to estimated costs for stormwater facilities on an individual parcel basis, SSGI estimated costs result in net capital cost efficiencies overall. However, a cost recovery analysis that allocated costs based on contributing runoff volume (or impervious surface) resulted in private developments receiving a disproportionate amount of the savings relative to the city, resulting in inequity. This allocation method is one possibility; there may be other suitable allocation methods, depending on how SSGI is approached.

Therefore, careful consideration must be given when determining funding sources and developing cost recovery approaches for SSGI to ensure a balanced distribution of costs and benefits. Specifically SSGI implementation will place a significant emphasis on the use of Development Agreements to establish acceptable requirements, fees, noncompliance recourses, and other practicalities.

Be Opportunistic Runoff from untreated, small parcels that otherwise would not redevelop (i.e., receive stormwater management) in the near future can be effectively included in SSGI projects. SSGI provides an approach to opportunistically realize “excess capacity” in stormwater treatment in a cost effective manner. By casting a wide net on how much drainage area is potentially included in a SSGI project, larger gains in water quality can be attained with minimal additional cost. This is very useful in a corridor where overall redevelopment is very incremental (especially small sites) and public land control is very limited. As well, excess treatment capacity potentially can be a brokered commodity. This may warrant the discussion or development of a retrofit program to capitalize on these opportunities when they arise.

Figure 4.1 Possible SSGI Implementation Approaches Strategic Stormwater Solutions for Transit-Oriented Development Final Report 43

October 2, 2013 Board Meeting V. Action Item A) Approve Minutes of September 18, 2013 DRAFT Regular Board Meeting (Sylvander)

Regular Meeting of the Capitol Region Watershed District (CRWD) Board of Managers, for Wednesday, September 18, 2013 6:00 p.m. at the office of the CRWD, 1410 Energy Park Drive, Suite 4, St. Paul, Minnesota. REGULAR MEETING I.

Call to Order of Regular Meeting (President Joe Collins) A) Attendance Joe Collins Mary Texer Mike Thienes Shirley Reider Seitu Jones

Others Present Mark Doneux, CRWD Michelle Sylvander, CRWD Elizabeth Beckman, CRWD Bob Fossum, CRWD Forrest Kelley, CRWD

Public Attendees Christine Baumler, Artist in Residence Marlys Mandaville, Intern with McCalester College Bill Barton, CAC Member

Review, Amendments and Approval of the Agenda

President Collins asked for additions or changes to the agenda. There were no changes. Motion 13-167: Approve the September 18, 2013 Agenda with no changes. Texer/Reider Unanimously approved II.

Public Comments â&#x20AC;&#x201C; For Items not on the Agenda There were no public comments.

III.

Permit Applications and Program Updates A)

Permit # 13-018 Prince Street â&#x20AC;&#x201C; Stormwater Management (Kelley)

Mr. Kelley, reviewed Permit #13-018 Prince Street Construction. The applicant is the St. Paul Public Works. The permit is for reconstruction of Prince Street and connecting roads in Lowertown from Broadway to 4th Street. The applicable rule is Flood Control (Rule D). This project has 2.75 Acres of disturbed area and no impervious surface. Motion 13-168: Approve variance from Rule D for 32,900 cubic feet of floodplain fill. Reider/Jones Unanimously approved

Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District

Motion 13-169: Approve Permit with 2 Conditions: 1. Provide an updated cross section of the brick paver parking area. 2. Submit a copy of the NPDES permit. Reider/Jones Unanimously approved Motion 13-170: Approve withdrawal of 7,303 cf from the Public Works Volume Bank Reider/Texer Unanimously approved B)

Permit # 13-023 University of St. Catherine Dew Drop Pond Project (Kelley)

Mr. Kelley, reviewed Permit #13-023 University of St. Catherine Dew Drop Pond Project. The applicant is St. Catherine University. The permit is for the removal of accumulated sediment and invasive cattails from the Dew Drop Pond at St. Catherine University. The applicable rule is Erosion Control (Rule F). This project has 3.35 Acres of disturbed area and no impervious surface. Motion 13-171: Approve with two conditions 1. 2.

Provide a copy of the Minnesota Wetland Conservation Act determination. Provide a copy of the NPDES permit

Reider/Jones Unanimously approved Manager Texer asked if we have received plans for dewatering and disposal. Mr. Kelley replied yes, we have received and reviewed the plans. C)

Permit Program/Rules Update (Kelley)

There will be four permit applications at the October 2nd meeting. IV.

Special Reports A)

Hydropolis, Christine Baumler

Ms. Beckman introduced Ms. Christine Baumler the Artist in Residence for Capitol Region Watershed District. Ms. Baumler reviewed pictures of the aesthetic metal work around rain gardens that were redesigned by Lisa Elias. Ms. Baumler explained Hydropolis, the concept of a city designed primarily around the quality of water and social solutions. The watershed district is much like a hydropolis. Ms. Baumler shared she was able to obtain a grant and bring Buster Simpson as a keynote speaker to the L.I.D. symposium. Ms. Baumler also shared pictures from the L.I.D. symposium boat tour. Ms. Baumler reviewed upcoming projects such as the Central High School design and opportunities that are available to create urban games or community conversation boards. President Collins commented that he like the metal work around the BMP’s. Ms. Texer shared her concerns of an urban game such as “Bad Cat” that could bring negative attention to cats. The board thanked Ms. Baumler for her time and efforts. Ms. Baumler thanked the board for the opportunity to work with the District. Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District

15th Anniversary of Capitol Region Watershed District

Administrator Doneux, shared a presentation of early projects of the Capitol Region Watershed District. The presentation included many pictures of past and present Board members and staff. The Board and staff were able to reflect on the memories of several past Board members and staff. The presentation was a 15 year historical review of the progress made in the Capitol Region Watershed District. V.

Action Items A) AR: Approve Minutes of the September 4, 2013 Regular Meeting (Sylvander)

Motion 13-172: Approve Minutes of the September 4, 2013 Regular Meeting as amended. Jones/Texer Unanimously approved B)

AR: Approve Accounts Payable/Receivables for August 2013 (Sylvander)

Motion 13-173: Approve the Accounts Payable/Receivables for August 2013. Thienes/Reider Unanimously approved C)

AR: Authorize 2014 Partner Grant Solicitation (Beckman)

Ms. Beckman reviewed the 2014 Partner Grant Solicitations. At the December 5, 2012 meeting Board Managers authorized staff to propose changes to CRWD Grant programs to improve and streamline the grant application, approval and administrative process. Changes to the Partner Grant Program have not yet been made so staff proposes to solicit proposals from potential 2014 grantees using the application and process from previous years. Partner Grants are made to organizations, schools, businesses and other entities and range from $2,000 to $20,000 for clean water education and outreach projects. The 2014 budget for Partner Grants is $60,000. Motion 13-174: Authorize staff to distribute the CRWD 2014 Partner Grant application to organizations and other entities and proceed with the grant approval process according to the proposed timeline.. Texer/Jones Unanimously approved VI.

Unfinished Business A.

Villa Park Wetland Restoration Project Update (Fossum)

Mr. Fossum gave an update on the Villa Park Wetland Restoration Project. The project is moving along very well and is expected to be completed by the October 1st deadline. B.

Trout Brook Nature Sanctuary Update (Fossum)

Mr. Fossum gave an update on the Trout Brook Nature Sanctuary. The construction of this project started a couple of weeks ago. Mr. Fossum noted that at this time they are grading, and it is a very complicated project Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District

because there are areas of contamination. The buildings at Jackson and Maryland will be demolished and construction will be more noticeable. C.

Curtiss Pond Feasibility Study Update (Fossum)

Mr. Fossum gave an update on the Curtiss Pond Feasibility Study. Mr. Fossum and Board Administrator Doneux attended the Falcon Height City Council Meeting on September 11th, 2013. At the meeting, Mr. Fossum presented the updated feasibility study and was able to address many questions. The project was well received from neighbors and City Council members. The feasibility study will be presented to the Board again in October for formal adoption. The City Administrator will be reviewing the feasibility plans with the City Council for approval as well. VII.

General Information A. CAC Update and identify a Board Member Attendee for October 9th CAC Meeting

Manager Reider gave an update on the September 11th CAC meeting. The attendance of the CAC meetings has been down. The discussion started with how to increase attendance and membership. Ms. Reider reflected on a time when she was a member of the CAC and members brought project ideas to the meetings. Ms. Reider suggested that perhaps the role of the CAC needs to be reevaluated. President Collins, noted that we have CAC members with great expertise and asked what the CAC members can gain from being on the CAC? Ms. Texer suggested that purpose of the CAC be reestablished and give them some type of role where they can take ownership of it. Mr. Thienes suggested getting the CAC to be involved in the rating process of grants and increase their involvement in projects. Administrator Doneux suggested a joint meeting in November where the Board of Managers and the CAC can meet and discuss, what is of the most interest to them. B.

Administrator’s Report

Administrator Approved or Executed Agreements Change order No. 4 to construction agreement with Frattalone Companies, Inc. for the Villa Park Restoration Project. Increase cost by $4,500 for a total cost of $1,205,432.90. General updates including recent and upcoming meetings and events Elizabeth Beckman gave a presentation on the Como Lake Knowledge, Attitudes and Practices (KAP) study and work with Como Lake Neighbor Network at the seventh annual Clean Water Summit September 12, 2013. CRWD Staff will be participating in the Water Environment Federation Technical Conference, Stormwater Congress in Chicago, October 5 – 9 and the Minnesota Water Resources Conference in Saint Paul, October 15 – 16. Below is a list of presentations that involve CRWD staff or projects. 1)

Upcoming events and meetings a) Next Board Meeting is Wednesday, October 2, 2013 at 6:00 pm. b) Next CAC Meeting is Wednesday October 16, 2013 from 7:00-9:00 pm.

Project Updates a) Villa Park Wetland Restoration Project Dredging at Villa Park is almost complete. b) TBI – Cayuga Relocation Project Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District

Connections for the new segment of TBI to the existing sections continues and will be completed in early October. VIII. Next Meeting A) Wednesday, October 2, 2013 Meeting Agenda Review IX.

Adjournment

Motion 13-175: Adjournment of the September 18, 2013 regular Board Meeting at 7:45 p.m. Thienes/Texer Unanimously Approved Respectfully submitted, Michelle Sylvander

Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District

October 2, 2013 V. Action Items B) Authorize 2014 Special Grant Agreements (Zwonitzer)

DATE: TO: FROM: RE:

September 23rd, 2013 CRWD Board of Managers Nate Zwonitzer, Urban BMP Specialist 2014 Special Grant Agreements

Background On September 4th the CRWD Board awarded $510,000 between five applicants for the 2014 Special Grants. Award notices have been sent to recipients and staff are in the process of putting together grant agreements. Issues The following table outlines the projects and the approved funding level. Applicant

Project

Total Award

Agreement Notes

2 separate agreements, BROWNstone = $44,000 $65,000 Central Exchange = $21,000

Model Cities

BROWNstone & Central Exchange

St. Paul

Lowertown Ballpark

Agreement with St. Paul $225,000 Parks

Stormwater Retrofits Stormwater Retrofits

CRWD will manage, no $50,000 grant agreement needed $110,000 Agreement with school

Central High School Great River School Episcopal Homes Total

Treatment beyond permit requirement

$60,000 Agreement with Owners $510,000

Since the Model Cities project is taking place on two sites, we will do a separate agreement for each site. CRWD has managed the Central High School project to this point and will continue to do so. The $50,000 allocated to the project will be coordinated by CRWD staff so no agreement is needed with the school. All projects will only receive funding for elements approved by the CRWD Board. Action Requested Approve 2014 special grant agreements and authorize Board President and District Administrator to execute agreements pending approval of Assistant Ramsey County Attorney. Enclosures: Draft 2014 Special Grants Agreement. \\CRWDC01\Company\06 Projects\Special Grants\2014\Bd Memo 2014 Special Grants Agreements 10-02-2013.docx

Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District.

October 2, 2013 Board Meeting V. Action Items, C) Curtiss Pond Improvement Project Update

DATE: TO: FROM: SUBJECT:

September 25, 2013 CRWD Board of Managers Bob Fossum, Water Resource Project Manager Curtis Pond Improvement Project, Feasibility Study

(Fossum)

Background At the February 6, 2013 Board meeting the Managers reviewed the Curtiss Pond Improvement Project Feasibility Study. The study recommended a project to increase infiltration in the pond (alternative 2). This recommendation was contingent on confirming the assumed infiltration rate and groundwater levels. In March 2013, the Managers approved additional geotechnical investigation into the soils in the park. Also in May 2013, the District installed monitoring equipment to document the water level fluctuations in the pond and in groundwater. At the September 4th Board meeting, the Managers reviewed the revised Feasibility Study and provided comments to staff. Issues District staff presented the draft Curtiss Pond Improvement Project Feasibility Study at a public meeting for the project held in conjunction with the City of Falcon Heights Council meeting on September 11, 2013. Several questions and comments were received and in general there was support for the project as recommended in the Study. No changes to the study have been made since it was last reviewed by the Managers on September 4th. Requested Action Approve Curtiss Pond Improvement Project Feasibility Study and direct staff to develop the appropriate cooperative agreements to complete the project. enc:

Curtiss Pond Improvement Project, Feasibility Study, dated August 28, 2013

W:\06 Projects\Curtis Field\Feasibility Study\Board Memo Curtiss Pond 09-25-13.docx

Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District

2013 Curtiss Pond Improvement Project Feasibility Study

Greg Bowles Houston Engineering, Inc. 8/28/2013

1 TABLE OF CONTENTS

Table of Contents .......................................................................................................... 1 1

Introduction ............................................................................................................. 3

PROJECT GOALS AND OBJECTIVES .............................................................................. 3

2.1

Project Goal ................................................................................................................. 3

2.2

Technical Objectives................................................................................................... 3

Background of Curtiss Pond .................................................................................. 4 3.1

Summary of Curtiss Pond Historic Developments ................................................... 4

3.2

Wetland Conservation Act Determination ................................................................. 5

3.3

Review of Geotechnical Evaluations ......................................................................... 5

3.3.1

Geotechnical Evaluation Completed as Part of This Study in September, 2012 .................... 6

3.3.2

Additional Geotechnical Evaluation Completed as Part of this Study in May, 2013 ............... 7

3.4

Methods ................................................................................................................... 9 4.1

Define the Problem...................................................................................................... 9

4.1.1

LACK OF INFILTRATION CAPACITY .................................................................................... 9

4.1.2

FLOODING .......................................................................................................................... 10

4.2

Monitoring data and infiltration analysis ................................................................... 7

HYDROLOGY AND HYDRAULICS MODEL DEVELOPMENT ..........................11

4.2.1

MODEL NETW ORK ........................................................................................................... 11

4.2.2

HYDROLOGY ..................................................................................................................... 12

4.2.3

MODEL VERIFICATION ................................................................................................... 12

4.2.4

EXISTING CONDITIONS MODELING .......................................................................... 13

Alternatives Analysis ............................................................................................ 15 5.1

Alternative 1 – Do Nothing (Existing Conditions) Alternative .................................16

5.2

Alternative 2 – Maximize Curtiss Pond Infiltration Alternative................................16

5.3

Alternative 3 - Storage And Curtiss Pond Infiltration BMP Alternative ..17

5.4

Alternative 4 - Storage BMP Alternative ..........................................................18 Houston Engineering, Inc.

5.5

Alternative 5A – Storage & Curtiss Pond Drawdown BMP Alternative...................20

5.6

Alternative 5B – Storage & Curtiss Pond Drawdown BMP Alternative ...21

5.7

Other BMP Options Considered ................................................................................22

5.8

Summary Of Results ..............................................................................................23

COST AND BENEFIT ANALYSIS ..................................................................... 25 6.1

Preliminary Opinion Of Probable Cost .............................................................25

6.2

Feasibility Of The Alternatives ...........................................................................27

RECOMMENDATIONS ....................................................................................... 29 FIGURES: Figure 1- Project Location Figure 2- Geotechnical Boring Location Map Figure 2A- Profile of Curtiss Pond

Figure 2B- Trends in Infiltration

Figure 3- Drainage Areas Fully or Partially Contributing to Curtiss Pond Figure 4- LiDAR and Survey Elevation Contours Figure 5- Estimated Existing Conditions High Water Levels Figure 6- Alternative 2 Figure 7- Alternative 3 Figure 8- Alternative 4 Figure 9- Alternative 5A Figure 10- Alternative 5B Figure 11- Other BMP Options Considered

APPENDIX A: List of Existing Documents Reviewed APPENDIX B: Details on WCA Determination APPENDIX C: Geotechnical History

Houston Engineering, Inc.

3 1

INTRODUCTION

Curtiss Field Park is a neighborhood park located within the City of Falcon Heights along the east side of Snelling Avenue North between Idaho Avenue and Iowa Avenue (see Figure 1). During the summer, residents of Falcon Heights enjoy the use of the parkâ&#x20AC;&#x2122;s baseball field, basketball courts, playground, walking trail, and the park building. Within Curtiss Field Park is a small landlocked stormwater pond called Curtiss Pond that collects direct runoff from approximately 22 acres of residential neighborhood, commercial property, and portions of Snelling Avenue. Curtiss Pond has a history of flooding, which limits the use of the park, damages park infrastructure, and presents a safety concern for the City. The Capitol Region Watershed District (CRWD) retained Houston Engineering, Inc. (HEI) to complete a feasibility analysis that investigates the costs and benefits of a range of possible alternative improvements to reduce the risk of flooding.

2 2.1

PROJECT GOALS AND OBJECTIVES PROJECT GOAL

A narrative project goal describes the desired outcomes for a project. A concept must be able to attain the project goal to be considered feasible. The goal of this project is to develop and evaluate a range of possible concepts that present feasible improvements to minimize the risk of flood damage to park infrastructure and adjacent property, while improving the function of Curtiss Pond as an infiltration basin.

2.2

TECHNICAL OBJECTIVES

One or more technical objectives are needed to support the project goal. The technical objectives represent various attributes or project characteristics that collectively describe specific technical requirements. A concept failing to meet one or more technical objectives is considered incapable of achieving the project goal. The following technical objectives have been selected to support the project goal: 1. Maximize the volume of water infiltrated by Curtiss Pond, based on the current site conditions, while recognizing how the pond was designed and constructed. 2. Avoid flood damage to the park building and adjacent homes as follows: a. 10-yr return period, 24-hour storm event for park building; and b. 100-yr return period, 24-hour storm event for adjacent homes.

Houston Engineering, Inc.

SNE A Roseville

LARPENTEUR AVE W

Falcon Heights

Ramsey

Hennepin

ARONA ST

Project Location

Capitol Region Watershed District Curtiss Pond

Maplewood

St. Paul

Project Location Overview

CALIFORNIA AVE W

Dakota

HOLLYWOOD CT

Legend Curtiss Field Park Boundary (Met. Council)

Curtiss Field Park

SNELLING DR N

ARONA AVE N

Curtiss Pond

SNELLING A VE N

PASCAL ST N

IDAHO AVE W

IOWA AVE W

HOYT AVE W

SGROVE ST

OPER ST N

HOLTON ST

SIMPSON ST

MURPHY AVE

ARONA ST

ASBURY ST

125

250

500 Feet

Source: MN DOT Imagery: 2009 Ramsey County Aerials Figure 1 Project Location Scale: AS SHOWN

Drawn by: SMW

Checked by:

Project No.: 6475-008

Date: 8/15/2013

Sheet: 1 of 1

4 3. Reduce the number of days the park cannot be used during the summer months by reducing the amount of time land is flooded, specifically following the 10-year, 24-hour storm event. The project goal and technical objectives were developed based upon discussions with CRWD staff. Because the project goal and technical objectives are used as the basis for determining whether a design concept is feasible, modifying them can potentially alter the Engineer’s recommendations relative to a “preferred alternative.”

REPORT USE The purpose of this report is to provide sufficient information based on the project goal and technical objectives to select a preferred alternative for implementation. The level of technical analysis is completed at a “feasibility level”. This means sufficient engineering analysis is completed for the range of design concepts (alternatives) to evaluate and size the various project features (based on hydrologic design), evaluate the benefits, estimate the quantities, and develop Preliminary Opinion of Probable Costs. The analysis typically uses readily available information. The recommendations should be considered preliminary and may be dependent upon additional technical information obtained prior to the completion of final design and construction documents.

BACKGROUND OF CURTISS POND

In order to develop a sound solution to the infiltration and flooding problems associated with Curtiss Pond, it is critical to have a thorough understanding of the pond’s history and past performance, including its construction, subsequent modifications, and previous geotechnical evaluations. Several documents (listed in Appendix A) were gathered and reviewed primarily to understand the history of the pond, including specific measures or features constructed to improve performance.

3.1

SUMMARY OF CURTISS POND HISTORIC DEVELOPMENTS

Curtiss Pond was originally constructed sometime prior to 1991, based on historic aerial photography (note: we are not aware of the existence of any plans for the original pond construction). Due to frequent flooding of the park and resulting concerns that the infiltration basin was not functioning properly, the 1 pond was rehabilitated in June, 2004. According to the feasibility study, the rehabilitation was designed with a live storage capacity large enough to hold the volume of runoff generated from the 1-year return period, 24-hour rainfall event. The pond bottom was lowered 4 feet from elevation 926.0 to elevation

Feasibility Report Curtiss Field Park Pond, Short Elliot Hendrickson, Inc., October 2002

Houston Engineering, Inc.

5 2

922.0 (NAVD 1988 ) in order to cut through a layer of impermeable soil, then filled with sand up to elevation 926.0. Subsequent to construction, a 2.46-inch rainfall event occurred, and the pond partially filled with sediment, presumably due to failure to establish vegetative cover. Sediment was removed on September 29, 2004. A double ring infiltrometer test was conducted in the sand layer on September 30, 2004, a procedure that requires that the pond be dry. Therefore, it is assumed that the pond was successfully infiltrating subsequent to this cleanout procedure. However, since this most recent rehabilitation of Curtiss Pond in 2004, the park has flooded during several separate storm events. The only quantifiable high water mark was provided in a photograph of a high water line on the park building taken on October 7, 2005. This was two days after a 4.89-inch storm event (occurring within 28 hours), as measured at the Minneapolis International Airport (National Weather Service). Based on the photograph, a high water line elevation was estimated to be 938.39.

3.2

WETLAND CONSERVATION ACT DETERMINATION

As part of the historic background review, a Wetland Conservation Act (WCA) determination was completed to identify whether Curtiss Pond is considered a wetland under WCA regulation. The details of this determination are included in Appendix B. This determination is needed when considering improvement alternatives for the pond. WCA regulations may restrict the proposed improvements if the pond is considered a jurisdictional wetland. Based on the permitting research, National Wetland Inventory (NWI), Ramsey County Soil Survey data and the review of historic aerial photography, it is concluded that this basin would be considered an â&#x20AC;&#x153;incidental wetlandâ&#x20AC;? as defined in WCA and therefore not within the scope of regulation under WCA.

3.3

REVIEW OF GEOTECHNICAL EVALUATIONS

A review of historic aerial photographs of Curtiss Pond revealed that the pond has had standing water in the following years: 2004, 2006, 2008, 2009, 2010, and 2011 (those years with available aerial photographs), indicating poor infiltration performance, at least through the bottom of the pond. In an attempt to identify the reason for the infiltration problems, several prior geotechnical evaluations and data were reviewed, which are listed and described in detail in Appendix C. Figure 2 shows the locations of these geotechnical borings and infiltration tests locations. Figure 2A provides a profile of Curtiss Pond and adjacent Snelling Avenue and Curtiss Field that will help in understanding the existing pond and ground elevations.

Note all elevations in this report are stated in 1988 datum

Houston Engineering, Inc.

Capitol Region Watershed District Curtiss Pond B-1 B-1

B-2

Legend SB-9

Boring from AET Dated September 7, 2012*

PZ-6A

#2 A

B-6

HB-2

Hand Borings From HEI November 8, 2012

Borings from by AET Report Dated December 3, 2001* Borings from AET Report Dated April, 1991*

Borings from AET Report Dated March 13, 2001* Borings from AET Report Dated May 24, 2013

B-5

Borings from AET Report Dated October 3, 2000* Double Ring Infiltration Test from AET Dated September 30, 2004*

B-2

*Approximate Locations Shown.

1 #3

#1 B

B-4

HB-1

0 B-3 B-3

100 Feet

Source: MN DOT Imagery: 2009 Ramsey County Aerials Figure 2 Geotechnical Boring Location Map Scale: AS SHOWN

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S:\6475-003 Capital Region WD Curtiss Pond\CAD\6475003_BASE.dwg -Exhibit-Save_Date:1/28/2013 2:55 PM-Plot_Date:1/28/2013 3:10 PM-(gbowles)

Capitol Region Watershed District Curtiss Pond

Figure 2A Profile of Curtiss Pond AS SHOWN DJL GSB 6475-003 01-25-13 1 of 1

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6 The reports provide information important to understanding pond function, giving evidence of potential construction-related issues, and giving some indication about the relevance of groundwater in pond function. This information was used to estimate the elevation of groundwater beneath the pond. Typically, infiltration BMPs are designed so that the elevation of the bottom of the infiltration BMP is separated from groundwater by a minimum of 3 feet. Suitable soils are also necessary for infiltration to occur. Tight soils or fine alluvium such as clays exhibit slow infiltration rates. Sands or coarse alluvium with high infiltration rates are preferable. The estimated infiltration rate is used in the modeling analysis and is a critical assumption when considering pond function and the feasibility of the alternatives. The following paragraphs summarize relevant information contained within these geotechnical reports. Five previous geotechnical evaluations and an infiltration test were provided by the City of Falcon Heights. Two of the evaluations were completed within the field of Curtiss Field Park for use in constructing the 1991 park building and for use during the 2013 Street and Curtiss Pond Improvements Project. The remaining evaluations and infiltration tests were completed for use in evaluating the soils within or directly adjacent to Curtiss Pond to determine the reasons for poor infiltration performance. The results of the geotechnical evaluations completed within Curtiss Field Park ball field generally indicate that the upper 5 feet of soil is fill material consisting of a mixture of clay, sand, silt, and organic soil. Fill material generally will not provide a consistent infiltration rate. Soil below this fill layer consists of organic to lean clay at an approximate depth of 9.5 feet. Below 9.5 feet, the soils are mainly sand with silt and may provide opportunity for infiltration. Prior to the 2004 pond improvements, a geotechnical evaluation was completed within the bottom of the pond that indicates a 3 foot layer of clay, sand, and organic soil followed by a layer of sand with silt/gravel. The 2004 pond improvements removed this 3 foot layer and replaced it with 4 feet of select granular (sand) to increase the infiltration performance. A lean clay layer located approximately 3 feet under this select granular material was also noted in the boring log, which may restrict infiltration capacity. Based on this boring log, the soils below the fine alluvium or confining layers (clay) appear to be conducive for supporting infiltration at an estimated rate of 0.6 in/hr.

3.3.1 GEOTECHNICAL EVALUATION COMPLETED AS PART OF THIS STUDY IN SEPTEMBER, 2012 HEI completed two hand borings around the perimeter of the edge of the pond as shown in Figure 2. The logs for these two hand borings are included in Appendix C. Hand boring 1 and 2 were located on the southeast side and the northwest side of the pond, respectively. Hand borings 1 and 2 were completed approximately 5 feet from the edge of water of the pond to a depth of 6.8 feet and 13 feet, respectively. Standing water was only observed in Boring 1 at 3.5 feet of depth, or at elevation 929.78. This is approximately 2 feet below a November 8, 2012 surveyed elevation of the water level in the pond of 931.7 (conducted by the City of Falcon Heights). Standing water was not observed in Boring 2. Soils identified in Boring 1 include silty sand from 0 to 2 feet, lean clay from 2 to 3.3 feet, clayey sand mixture with organics and gravel from 3.3 to 5.8 feet, and lean/organic clay from 5.8 to 6.8 feet. Soils identified within Boring 1 consisted entirely of fill material. Soil identified in Boring 2 include sand from 0 to 0.8 feet,

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7 silty loam from 0.8 to 4 feet, sand from 4 to 8.5 feet, and silty loam from 8.5 to 13 feet of depth. Based on the results of these two borings, it appears the bottom layer of clay within Boring 1 is creating a confining layer that restricts the infiltration. However, Boring 2 was dry to 13 feet of depth, indicating that infiltration is feasible below the bottom of the pond. Typical infiltration rates for a silty sand or sandy loam varies from 0.6 in/hr. to 0.8 in/hr., respectively.

3.3.2 ADDITIONAL GEOTECHNICAL EVALUATION COMPLETED AS PART OF THIS STUDY IN MAY, 2013 As part of the feasibility study, it was recommended that additional soil borings be completed and piezometers installed to better define the infiltration rate of the soil and the depth to groundwater to reduce the risk of failure of alternatives requiring infiltration. CRWD hired American Engineering Testing, Inc. (AET) to complete six additional soil borings and install one piezometer as shown in Figure 2. On May 24, 2013, AET completed five hollow-stem auger borings and one monitoring well around the perimeter of Curtiss Pond that ranged in depth from 22 feet to 31 feet. They also completed one hollowstem auger near home plate of the ball field within the park to a depth of 50 feet. Soil borings indicate a general geologic soil profile of 4 to 8 feet of fill, overlying 7 to 10 feet of fine alluvium or topsoil, overlying coarse alluvium from 10 to greater than 42 feet. The fill consists of lean clay and clayey sand. Fine alluvium and topsoil consist of lean to organic clay. The coarse alluvium consists predominantly of layers of sand and sand with silt and extends from elevation 925.0 to at least elevation 885.2. Groundwater was only encountered during drilling in two of the six borings at a depth of 20.3 (919.5) and 13 feet (921.8) within the coarse alluvium sand deposit. The monitoring well was installed along the east edge of the pond to measure relative groundwater elevation. Water elevations within the well were initially measured at 916.5 and eventually dropped after 23 day to 912.0. Groundwater was not encountered in two borings that were completed to a depth of 31 feet and 50 feet. Groundwater direction of flow was not determined during the soil or monitoring analysis. As part of the geotechnical analysis, grain size analysis and hydraulic calculations using the KozenyCarmen equation were completed on 16 soil samples within the course alluvium layer. The results indicate hydraulic conductivity values range from 5.5 inches per hour to 46.2 inches per hour. In summary, the geotechnical analysis recommends extending the proposed infiltration practices down through the fill and terminating in the coarse alluvium layer. The analysis also indicates that groundwater may be perched within the coarse alluvium and likely comes from the infiltration of the pond water through preferential pathways within the sediment deposits and existing fill at the bottom of the pond.

3.4

MONITORING DATA AND INFILTRATION ANALYSIS

As part of the feasibility study, it was recommended that monitoring equipment be installed in Curtiss Pond and in monitoring wells pond-adjacent to better define the existing infiltration rate, bounce of the pond, and groundwater elevation. CRWD installed monitoring equipment within Curtiss Pond and within one monitoring well located along the east side of the pond. This equipment has been recording surface water and groundwater elevations since May 7, 2013. Monitoring and precipitation data from May 7, 2013 Houston Engineering, Inc.

8 until July 2, 2013 was used to analyze the infiltration rate and determine the amount of groundwater fluctuation. Precipitation data from the University of Minnesotaâ&#x20AC;&#x2122;s St. Paul campus was also used in this analysis. Figure 2B shows the data and established infiltration rate trend lines. Trend lines were established that represent existing infiltration rates above and below the 932.0 elevation of Curtiss Pond. The 932.0 elevation represents the approximate normal water elevation of Curtiss Pond during the monitoring period. Three trend lines above and two below the 932.0 elevation were analyzed. Infiltration rates above the 932.0 elevation ranged from 0.34 to 0.48 inches per hour with an average infiltration rate of 0.40 inches per hour. Infiltration rate below the 932.0 elevation ranged from 0.11 to 0.15 inches per hour with an average infiltration rate of 0.13 inches per hour. Monitoring data within monitoring well 6A indicates the groundwater elevation is between elevations 911.3 to 912.6. The data shows that surface water fluctuation within Curtiss Pond has a slight change in the groundwater elevation within the monitoring well. As the pond surface water elevation increases, so does the groundwater elevation. This may be an indicator that groundwater may be perched in some areas and not infiltrating vertically downward. Figure 2B - Trends in Infiltration

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9 4 4.1

METHODS DEFINE THE PROBLEM

Based on a review of the existing reports and geotechnical information, this portion of the feasibility report presents a forensic analysis of probable reasons for the lack of infiltration within Curtiss Pond, as well as reasons for the flooding problems.

4.1.1 LACK OF INFILTRATION CAPACITY A November 8, 2012 topographic survey conducted by City of Falcon Heights indicated a water depth of 5.7 feet in the pond, above elevation 926.0 (931.7). Because the survey followed a dry period (only 1.75 inches of rain as identified by the St. Paul University Farm precipitation records for all of October and November leading up to the date of the survey), this information leads to the assumption that during the summer of 2012, very little infiltration was occurring through the bottom of the pond. The largest losses of water during these fall months are caused by evaporation from the pond surface and infiltration into the ground (since there is no surface outflow). Evaporation during these months is typically quite low. For example, the Minnesota Hydrology Manual shows mean October and November rates of 3.0-inches and 1.25-inches for shallow lakes and reservoirs, respectively. Therefore, some lowering of the water surface elevation because of evaporation is expected. However, if infiltration occurred at a rate representative of the soils beneath the pond, the pond should be dry. Additional soil borings, monitoring data, and analysis completed as part of this feasibility study recommends extending the infiltration practices down through the fill and terminating in the coarse alluvium layer beginning at elevation 925.0. Monitoring data indicates the groundwater elevation is between elevations 911.3 to 912.6. Based on this data, Curtiss Pond should infiltrate until dry at elevation 926.0, which is the bottom elevation of the pond. It is not exactly known why infiltration is not occurring through the bottom of Curtiss Pond, but there are three potential factors: sediment build-up, infiltration capacity of soils, and construction methods used during pond rehabilitation projects. 1) Sediment Build-up Curtiss Pond has no pre-treatment, which is normally a necessary component to keep an infiltration basin functioning properly. Pre-treatment typically consists of installing sump basins or manholes, vegetated swales, or a sediment forebay to keep sediment. This can potentially seal the pond bottom and reduce the infiltration rate from reaching the pond. The watershed is comprised primarily of residential land use, but also contains approximately 1,160 feet of Snelling Avenue (four lanes of traffic) and its corresponding service road, from which runoff is directly conveyed to Curtiss Pond. Winter sanding of roads can be a significant contributor to clogging problems in an infiltration basin. No matter the corrective action selected to restore infiltration in Curtiss Pond, pre-treatment providing sediment removal will be necessary to maintain infiltration capacity into the future.

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10 2) Soils Soils below the pond are characterized by completing borings. The type of material is classified according to depth below the ground surface. Soil type varies not only with depth, but horizontally under the pond. For the sake of practicality, rarely is the boring densities sufficient to fully understand subsurface conditions in fill soils, and in this case the variability of infiltration rates under the pond. Consequently, the Engineer must rely on a few borings to infer subsurface conditions and the infiltration rate. Geotechnical evaluations indicate the soil within and adjacent to Curtiss Pond vary in type from a poorly graded sand to a lean clay that can lead to differences in infiltration rates and perched groundwater table. Infiltration rates are expected to range from 1.6 inch per hour for poorly graded sand to <0.2 inch per hour for lean clay. Based on the reviewed documents and verbal confirmation from the City that the pond has not been cleaned since 2004, we have assumed the sand layer at the bottom of the pond is either plugged with sediment, or the infiltration capacity is being restricted by confining layers directly below the pond bottom restricting the vertical hydraulic conductivity. To confirm this assumption (that infiltration will occur at elevation 922), we recommend additional infiltration testing either by double ring infiltrometer or infiltration test pits at elevation 922.0. This infiltration test could be completed alongside the standing water within the pond or at the bottom of the pond if the standing water is removed. 3) Pond Improvements Curtis Pond improvements were completed in 2004 and involved increasing the size and depth of the pond. As part of the improvements, a 4 foot thick layer of select granular material was installed in the bottom of the pond from elevation 922 to 926. The intent was to remove the less permeable soil at the bottom of the pond and replace it with select granular material to promote infiltration at the bottom of the pond. During these construction activities, it is possible that soils under the select granular material may have been compacted, reducing the rate of infiltration at the pond bottom. It was also noted in the boring logs from 2001, that a lean clay layer is located approximately 3 feet under the select granular material. This may also be restricting the infiltration rate of Curtiss Pond.

4.1.2 FLOODING Curtiss Pond has no outlet and relies on infiltration to lower water levels in order to accommodate runoff volume. The pond was redesigned during the 2004 rehabilitation to hold a 1-year return period, 24-hour

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11 3

rainfall event. Due to lack of infiltration and storage capacity, the park, park building and nearby homes are at risk for flooding.

4.2

HYDROLOGY AND HYDRAULICS MODEL DEVELOPMENT

A HydroCAD hydrology and hydraulic model was developed as a tool to understand and analyze the existing conditions of Curtiss Pond, as well as the benefits provided by alternatives to alleviate the infiltration and flooding problems. The model was used to estimate peak water elevations, runoff volumes, and subsequent drawdown times of the pond for the 2-year, 10-year, and 100-year, 24 hour storm events (return periods). Models results were then compared to the technical objectives to evaluate the ability of an alternative to achieve the project goal.

4.2.1 MODEL NETWORK To delineate drainage areas contributing runoff to Curtiss Pond, high resolution topographic data, collected using LiDAR, and City storm sewer information was used. Figure 3 shows the drainage areas used in the model. Storm sewers located along Arona Avenue were assumed to capture the runoff from Drainage Areas 3, 4, 5, 6, and 7. It was also assumed they be sized for a 10-year storm event. To estimate the total probable inflow to Curtiss Pond, the capacity of each catch basin, storage in intersections above catch basins, and the overflow elevations occurring along the center lines of Arona Avenue, Idaho Avenue West, and Iowa Avenue West, were incorporated into hydraulic model. Table 1 lists the drainage areas analyzed, along with their corresponding surface area and level of contribution to inflow to Curtiss Pond.

Table 1: Runoff Contribution from Arona Avenue (Drainage Areas 3, 4, 5, 6, and 7) Drainage Area

1 2

Area (acres) 22.0 3.4

1.0

4 5 6 7

7.2 0.3 0.8 3.6

Contribution to Curtiss Pond All runoff volume Volume which is not infiltrated in on-site basin Partially Contributes at 2-year storm events and greater when catch basins and/or storm sewer capacity exceeded

Feasibility Report Curtiss Field Park Pond, Short Elliot Hendrickson, Inc., October 2002

Houston Engineering, Inc.

Capitol Region Watershed District Curtiss Pond

ARONA ST

LARPENTEUR AVE W

D.A. 2 D.A. 3

CALIFORNIA AVE W

D.A. 4

Falcon Heights Catch Basins Subwatersheds Ponding in Intersections

HOLLYWOOD CT

St. Paul Storm Sewer Pipes Falcon Heights Storm Sewer Manholes Falcon Heights Storm Sewer Pipes

IDAHO AVE W

D.A. 5 D.A. 7

ARONA AVE N

Area(in Acres)

DA 1

DA 2

3.4

DA 3

1.0

DA 4

7.2

DA 5

0.3

DA 6

0.8

DA 7

3.6

D.A. 4 D.A. 3

D.A. 5

D.A. 6

D.A. 7

HOLTON ST

IDAHO AVE W

IDAHO AVE W ARONA AVE N

ARONA ST

ASBURY ST

D.A. 1

Drainage Area

ARONA ST

Direction of road overflow when catch basin or storm sewer capacity exceeded.

HOYT AVE W

Drainage Area Outlets

IOWA AVE W

SIMPSON ST

SNELLING DR N

SNELLING AV EN

D.A. 1

HY AVE

PASCAL ST N

D.A. 6

125

250

500 Feet

Source: MN DOT, City of Falcon Heights, City of St. Paul Imagery: 2009 Ramsey County Aerials Figure 3 Drainage Areas Fully or Partially Contributing to Curtiss Pond Scale: AS SHOWN

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12 The elevation-volume curve for Curtiss Pond was estimated from a November 8, 2012 City survey of the pond bottom and LiDAR elevation data. The 4-foot sand layer at the bottom of the pond, located between elevations 922.0 and 926.0, was included in the model, with the assumption of having 30% voids. Therefore, when dry, some water volume is stored in the sand. The first phase of Town Square Development, located to the north of Curtiss Pond, was constructed in 2003. The hydrology and model geometry for that portion of the model was adopted from the construction plans, including an infiltration rate of 1.44 inches per hour in its on-site stormwater treatment facility.

4.2.2 HYDROLOGY To estimate runoff volume generated from the subwatersheds for single rainfall events, the NRCS curve number method was used. Composite curve numbers were developed for each subwatershed with 4 guidance from the Minnesota Hydrology Guide, which provides tables of curve numbers based on land 5 use and the NRCS hydrologic soil group. The Soil Map for Ramsey County indicated that the soil in the area is dominated by the Waukegan complex, which is associated with Hydrologic Soil Group B. Land use for the watershed was determined by reviewing aerial images. Residential areas where characterized by assuming Âź acre lots, and were assigned a curve number of 75, in accordance with the Minnesota Hydrology Guide. The roadway surface of Snelling Avenue was assigned a curve number of 98, and open areas were assigned a curve number of 61. Rainfall depths for the 2-, 10-, and 100-year, 24-hour events of 2.73, 4.00, and 6.24 inches respectively, 6 were adopted from the Rainfall Frequency Atlas of The Midwest (Bulletin 71).

4.2.3 MODEL VERIFICATION Model performance was verified using an actual (observed) storm event of 4.89 inches of rainfall, which th occurred on October 4 and 5th, 2005 over a 28 hour duration at the St. Paul Minneapolis airport. The model was verified by comparing the model estimated maximum elevation to the inundation elevation on the Park building shown on and derived from on October 7, 2005 photograph (estimated at elevation 938.39 â&#x20AC;&#x201C; see Figure 4). Because this rainfall event occurred one year following the improvements of Curtiss Pond, full infiltration of the sand layer and no standing water at the beginning of the event was

Hydrology Guide for Minnesota, US Department of Agriculture and the Soil Conservation Service, 1993. Web Soil Survey, National Cooperative Soil Survey, Natural Resources Conservation Service, USDA. 6 Rainfall Frequency Atlas of The Midwest (Bulletin 71) by Floyd A. Huff and James R. Angel (1992). 5

Houston Engineering, Inc.

1 94

947

3 94 944

940

945

Capitol Region Watershed District Curtiss Pond

942

939 945

937 5

941

927 928

926

934

942

947

932

1543 Iowa Ave Basement Window Elevation of 940.47 (NAVD 88)

948

5 93 929

927 928

934

930

939

929 926

938

942

943

940

944

947

October 7, 2005 High Water Mark @ Approximately 938.39

936

1 Foot Contours Created from LIDAR and Survey Data

946

Park Building Low Entry Elevation (Door) of 937.0 (NAVD 88)

943

939

931 930

931

Legend

932

936

933

941

938

937

942

946

943

942

941

937

933

7 93

941

944

942

943 943

943

942

100 Feet

Source: MN DOT Imagery: 2009 Ramsey County Aerials

940 941

3 94

Figure 4 LIDAR and Survey Elevation Contours

947

948

943

1546 Iowa Ave Elevation of Tuck-Under Garage @ 939.02 (NAVD 88)

940

942

939

941

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13 assumed. A double ring infiltrometer test conducted in the sand layer of the pond on September 30, 2004, 7 resulted in an infiltration rate of 1.4 inches per hour. However, the limiting infiltration rate will occur through existing soil at the bottom and side slopes of the pond, and therefore an infiltration rate of 0.6 inches/hour was assumed in this analysis, based on recommendations for Hydrologic Group B soils in the 8 MPCA Stormwater Manual. This infiltration rate was applied at elevation 922.0 (bottom of sand layer up to elevation 936.0. The high water elevation resulting from the model was 938.12. The difference in elevation between the estimated October 7, 2005 high water level and the model is therefore 0.27 feet. Because the high water level was estimated from a photograph and not actually surveyed or measured, the results of the model verification are considered acceptable enough to warrant the use of the model use for the purposes of this project, and that a model calibration would provide no further benefit. The similarity between the observed and modeled high water elevations also affirms the assumption made in the model that the pond was indeed infiltrating at the time of the October 4-5, 2005 storm event. An infiltration rate of 0.6 inches/hour is a conservative assumption that results in slightly higher peak storm event (2-year, 10-year, 100-year) elevations and longer inundation times to the park than if an infiltration rate of 1.4 inches/hour was modeled. Observed inundation times for Curtiss Field from CRWD and the City of Falcon Heights indicated an infiltration rate higher than 0.6 inches/hour but less than 1.4 inches/hour. Further analysis and discussion on infiltration rate is presented in the Section 5.6 and in Table 8.

4.2.4 EXISTING CONDITIONS MODELING The HydroCAD model was modified to reflect existing pond conditions, specifically the reduced ability to infiltrate water. The results of the modeling were used as a base condition to compare alternative solutions to the problems of infiltration and flooding. As noted in Section 4.1.1, a November 8, 2012 survey conducted by the City indicated a water level of elevation 931.7. Because the survey followed a dry period, we assumed under existing conditions that there is no infiltration occurring through the bottom of the pond. We further assumed that infiltration through the sides of the pond above elevation 931.7 must be occurring since there is no other outlet from the pond, the pond was not full, and the evaporation rate is low. The model was adjusted to allow for infiltration only above elevation 931.7, and an infiltration rate of 0.6 inches/hour was assumed, which is based on recommendations for Hydrologic Group B soils in the

7 8

Infiltrometer test conducted on September 30, 2004, by American Engineering Testing, Inc. The Minnesota Stormwater Manual, Minnesota Pollution Control Agency, Version2, January 2008.

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14 9

MPCA Stormwater Manual. It was also assumed that the pond starting elevation is at 931.7 at the beginning of the various modeled storm events. Peak surface water elevations and inundation periods were then estimated using the model for the 2-year, 10-year, 100-year, 24 hour storm events as shown in Table 2. For the purpose of this project, the inundation period is defined as the time water surface elevation is above elevation 934.5, which is the water elevation which allows full use of the park for recreation.

Table 2: Model Results for Existing Conditions 24-hour

Peak

Inundation Time

Storm

Water

of Park

Event

Elevation

(days)

2-year (2.73-inch)

935.9

2.8

10-year (4.00-inch)

937.9

5.9

100-year (6.24-inch)

940.6

12.6

Notes: 1. 2. 3. 4.

Highest elevation before losing use of park is 934.5 Lowest entry of park building is 937.0 Lowest opening of nearby home is 940.47 Lowest nearby garage floor is 939.02

The existing conditions modeling results show that even in the 2-year, 24-hour rainfall event, a substantial portion of the park is temporarily flooded as the peak water surface peaks at an elevation of 935.9. The results of the existing conditions modeling also shows that the park building, which has a low entry elevation of 937.0 as measured at the base of the door, is flooded in both the 10-year and 100-year storm events. 10

According to an HEI survey, a home just to the east of the park (1543 Iowa Avenue) has a surveyed basement window elevation of 940.47 and therefore would be affected by a 100-year, 24-hour storm event (see Figure 5). Another home located east of the park, but south of Iowa Avenue (1546 Iowa Avenue) has a low entry elevation of 939.02 as measured at the garage floor. However, this home is a

The Minnesota Stormwater Manual, Minnesota Pollution Control Agency, Version2, January 2008. Houston Engineering, Inc. Survey conducted on January 8, 2013.

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948

Capitol Region Watershed District Curtiss Pond

941 7

946

940

945 944 943

938

942

939 937

929 932

941 939 936 933

Park Building Low Entry Elevation (Door) of 937.0 (NAVD 88)

Legend 1 Foot Contours Created from LIDAR and Survey Data 2-Year Approximate HWL @ 935.9 941

10-Year Approximate @ 937.9

931 927

926

October 7, 2005 High Water Mark @ Approximately 938.39

937

100-Year Approximate HWL @ 940.6

937

936

933

934

1543 Iowa Ave Basement Window Elevation of 940.47 (NAVD 88)

940

943

944

945

946

947

928 935

930

0 948

938

100 Feet

941

Source: MN DOT Imagery: 2009 Ramsey County Aerials

940 939

944

942 943

943

942

1546 Iowa Ave Elevation of Tuck-Under Garage @ 939.02 (NAVD 88)

948

Figure 5 Estimated Existing Conditions High Water Levels

942

Scale: AS SHOWN

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Date: 8/15/2013

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15 split-level tuck-under style, and without going inside the home we are unsure what the lowest opening is to the living quarters. The existing conditions model was also used to determine the runoff volume contribution to Curtiss Pond from Drainage Areas 3, 4, 5, 6, and 7 (see Figure 3). As shown in Table 3, these drainage areas partially contribute runoff to Curtiss Pond via the intersection of Arona Avenue and Idaho Avenue when the catch basin capacities are exceeded and water reaches an elevation which results in flow westerly to the park. In each modeled storm event, these drainage areas only contribute between 5-15% of the total runoff volume entering Curtiss pond. These results are important when considering potential placement of BMPs throughout the watershed, as placement would be strategic to capture the water.

Table 3: Runoff Contribution to Curtiss Pond from Arona and Idaho Avenue Intersection for the 2-, 10-, and 100-year, 24-hour storm events Drainage Area

Runoff to Curtiss Pond (Acre-Feet) 2-year

10-year

100-year

1.82

3.60

7.14

0.09

0.38

0.96

3, 4, 5, 6, and 7

0.09

0.41

1.32

Total

2.0

4.39

9.42

These results suggest that if BMPs are placed in the area contributing runoff to Curtiss Pond, they should be preferentially placed within Drainage Area 1, as this area contributes the largest percentage of the runoff volume for the 2-year, 24-hour return period event.

ALTERNATIVES ANALYSI S

Five alternatives were evaluated as potential solutions to the flooding problem and improve infiltration: Alternative 1: Do Nothing (Existing Conditions) Alternative Alternative 2: Maximize Curtiss Pond Infiltration Alternative Alternative 3: Storage and Curtiss Pond Infiltration BMP Alternative Alternative 4: Storage BMP Alternative Alternative 5: Storage and Curtiss Pond Drawdown BMP Alternative These alternatives are intended to correlate with and represent the range of potential BMP types, which the CRWD may consider using to address the flooding problem. For example, Alternative 2 assumes solely using infiltration BMPs, while Alternative 4 assumes relying solely on additional storage. Alternative 3 and 5 represent using a combination of storage and infiltration enhancements to achieve the

Houston Engineering, Inc.

16 technical objectives. An alternative incapable of achieving the technical objectives presented in Section 2 is considered infeasible.

ALTERNATIVE 1 – DO NOTHING (EXISTING CONDITIONS) ALTERNATIVE

5.1

The Do Nothing alternative assumes no future changes in the intensity of development within the area contributing runoff to Curtiss Park Pond, and no change in the infiltration rate or amount of storage. Peak water surface elevations and drawdown times (time needed for park to be fully usable) for this alternative are shown in Table 2. This alternative is presented primarily for comparison purposes. The Do Nothing alternative represents conditions within Curtiss Pond where water infiltrates only above elevation 931.7. The modeling results show that even for the 2-year event, a substantial portion of the park will continue to be temporarily flooded for more than 48 hours until infiltration through the sides of the pond (above 931.7) draws the water down. The Do Nothing alternative results in continued flooding of the park and park building for both the 10-year and 100-year storm events, and one neighboring home and one garage to flood in the 100-year storm event. Drawdown times following storm events will not decrease from present, and therefore the time the park is available for use will not be increased from what is shown in Table 2. This alternative does not meet the project objectives.

ALTERNATIVE 2 – MAXIMIZE CURTISS POND INFILTRATION ALTERNATIVE

5.2

Alternative 2 is solely focused on maximizing infiltration within or adjacent to Curtiss Pond. Alternative 2 contemplates dredging sediment accumulated since the last pond improvements in June, 2004 and the installation of a rock infiltration trench along the west edge of the pond to enhance infiltration along the side of the pond (see Figure 6). Sediment would need to be removed to the top of the sand layer. This alternative assumes infiltration capacity is fully restored to the 4-foot sand layer at elevation 926.0, as well as infiltration into the natural soils at elevation 922.0 at a rate of 0.6 inches per hour. Water surface peak elevations and inundation times resulting from the modeling analysis are summarized in Table 4 for 2year, 10-year, and 100-year storm events.

Table 4: Model Results for Alternative 2 – Maximize Curtiss Pond Infiltration. Peak

Inundation Time

Storm

Water

of Park

Event

Elevation

(days)

2-year (2.73-inch)

933.8

0.0

10-year (4.00-inch)

936.9

2.7

100-year (6.24-inch)

940.1

7.6

Notes: 1. 2. 3. 4.

Highest elevation before losing use of park is 934.5 Lowest entry of park building is 937.0 Lowest opening of nearby home is 940.47 Lowest nearby garage floor is 939.02

Houston Engineering, Inc.

948

6 94

945

942

947

949

Capitol Region Watershed District Curtiss Pond

944 941

943

947

946

940 939 938 936

943

Legend

941

945

Curtiss Pond

100-Year Approximate HWL @ 940.1 1 Foot Contours Created from LIDAR and Survey Data

947

940

Inflitration Trench Pond Cleanout Enhancement

945

942

937

948

Pretreatment Device

944

939

927 930

936

931

6 92

St Paul Storm Sewer Pipes Storm Sewer Manholes Falcon Heights Storm Sewer Line

937

935

929 3 93 936

1543 Iowa Ave Basement Window Elevation of 940.47 (NAVD 88)

938

941

939

10-Year Approximate @ 936.9

October 7, 2005 High Water Mark @ Approximately 938.39

934 932

937

943

942

928

940

2-Year Approximate HWL @ 933.8

Park Building Low Entry Elevation (Door) of 937.0 (NAVD 88)

940

1 94

941

100 Feet

948

0 942

942

Source: MN DOT Imagery: 2009 Ramsey County Aerials 947

943

944

1546 Iowa Ave Elevation of Tuck-Under Garage @ 939.02 (NAVD 88)

Figure 6 Alternative 2 Scale: AS SHOWN

Drawn by:

Checked by:

Project No.: 6475-008

Date: 8/15/2013

Sheet: 1 of 1

17 Alternative 2 achieves the technical objective of eliminating flooding of the park building for the 10-year, 24-hour duration event, though there is no margin of safety because of the lack of a freeboard to the low opening elevation. Although not considered a technical objective, the park building would continue to be inundated for the 100-year, 24-hour design event. This alternative achieves the technical objective for flood prevention of adjacent residential homes. The model suggests that the maximum elevation for the 100-year, 24-hour precipitation event would be reduced by 0.5-feet compared to existing conditions and the home at 1543 Iowa Avenue would not flood. The modeling results also show that the garage of 1546 Iowa Avenue will also continue to be at risk of flooding for the 100-year, 24-hour precipitation event This alternative achieves the technical objective related to park use. A substantive improvement in park usability characterized by the number of days of potential park use for typical conditions (i.e., the 2-year, 24-hour flood event) is expected. Increasing the infiltration rate to 0.6 inches per hour throughout the whole pond significantly decreases drawdown times. The park no longer floods during the 2-year storm event and in the 10-year storm event, the park would be available for use in a little over two days. This alternative could only be maintained if the improvements are combined with the installation of pretreatment facilities for the removal of sediment. Due to lack of space for stormwater pre-treatment, a hydrodynamic separator is recommended at each of the three stormwater inlet manholes to the pond. These are included in the Preliminary Opinion of Probable Cost for this alternative.

5.3

ALTERNATIVE 3 - STORAGE AND CURTISS POND INFILTRATION BMP ALTERNATIVE

In addition to improving infiltration capacity in Curtiss Pond, Alternative 3 includes additional storage to assist in alleviating flooding of the park, park building, and adjacent homes. The modeling completed for this alternative assumes the improvements to infiltration described in Alternative 2 are constructed and pre-treatment facilities are installed, resulting in an infiltration rate through the sides and bottom of the pond (below the 4-foot sand layer) of 0.6 inches per hour. Alternative 3 includes two storage options: Alternative 3A and Alternative 3B. Alternative 3A includes constructing an estimated 1.2 acre-feet of additional storage (in addition to the existing pond live storage) underground within the ball field area of the park, which is the estimated maximum feasible underground storage available based on park size and elevations (see Figure 7). The storage feature would be comprised of 30, 150-foot long, 36-inch diameter perforated pipes, embedded in gravel and equipped with a separator row for removal of TSS coming from Idaho and Iowa Avenue. The underground infiltration system would not be hydraulically connected to the pond. Alternative 3B includes the same total storage volume as 3A, but would include lowering the ball field area approximately 1 foot to provide surface storage and a reduction in the amount of underground storage required under the ball field. This alternative is less costly than providing the entire storage underground, but it will increase the frequency of flooding of the ball field.

Houston Engineering, Inc.

945

950

946

947

943

949

94 6

948

945

Capitol Region Watershed District Curtiss Pond

945

944

947

Legend

939 940 937 6 93

946

Pond Cleanout Enhancement Pretreatment Device

947

934

943

St. Paul Storm Sewer Pipes Storm Sewer Manholes

941

945

933

931

930

Falcon Heights Storm Sewer Line

948

937 927

935

940

Inflitration Trench

944

942

1 Foot Contours Created from LIDAR and Survey Data

Underground Storage

946

939

940 94

1543 Iowa Ave Basement Window Elevation of 940.47 (NAVD 88)

1 94

948

944 2

941 94

947

1546 Iowa Ave Elevation of Tuck-Under Garage @ 939.02 (NAVD 88) 944

944

945

100-Year Approximate HWL @ 939.3

944

10-Year Approximate @ 935.2

October 7, 2005 High Water Mark @ Approximately 938.39

928

938

943 941

935

Curtiss Pond

929 932 936

2-Year Approximate HWL @ 931.7

Park Building Low Entry Elevation (Door) of 937.0 (NAVD 88)

944

943

942

25 50

100 Feet

Source: MN DOT Imagery: 2009 Ramsey County Aerials Figure 7 Alternative 3 Scale: AS SHOWN

Drawn by:

Checked by:

Project No.: 6475-008

Date: 8/15/2013

Sheet: 1 of 1

18 Alternative 3 achieves the technical objective of eliminating flooding of the park building for the 10-year, 24-hour duration event and provides a larger margin of safety than Alternative 2 for the freeboard to the low door opening elevation. Although not considered a technical objective, the park building would continue to be inundated for the 100-year, 24-hour design event. This alternative achieves the technical objective for flood prevention of adjacent residential homes. The model suggests that the maximum elevation for the 100-year, 24-hour precipitation event would be reduced by 1.3-feet compared to existing conditions (i.e., the flood risk is reduced) and the home located just to the east of the park at 1543 Iowa Avenue would not flood for this rainfall event. However, the modeling results also indicate that the garage of 1546 Iowa Avenue will continue to be at risk of flooding. This alternative achieves the technical objective related to park use. A substantive improvement in park usability characterized by the number of days of potential park use for typical conditions (i.e., the 2-year, 24-hour flood event) is expected. Maximum water surface elevations and inundation times resulting from the modeling analysis for Alternative 3 are summarized in Table 5 for 2-year, 10-year, 100-year storm events.

Table 5: Model Results for Alternative 3 â&#x20AC;&#x201C;Storage and Curtiss Pond Infiltration BMP Alternative. Peak

Inundation Time

Storm

Water

of Park

Event

Elevation

(days)

2-year (2.73-inch)

931. 7

0.0

10-year (4.00-inch)

935.2

0.9

100-year (6.24-inch)

939.3

7.3

Notes: 1. 2. 3. 4.

5.4

Highest elevation before losing use of park is 934.5 Lowest entry of park building is 937.0 Lowest opening of nearby home is 940.47 Lowest nearby garage floor is 939.02

ALTERNATIVE 4 - STORAGE BMP ALTERNATIVE

The Storage BMP Alternative assumes only storage as a means to reduce the peak elevation within the pond (see Figure 8). Alternative 4 includes one of two storage options: Alternative 4A and Alternative 4B. Alternatives 4A and 4B include the same additional storage and pre-treatment as described in Alternative 3 to assist in alleviating the flooding of the park, park building, and adjacent homes. However, it does not include any improvements to the infiltration capacity in Curtiss Pond. Alternative 4A includes constructing an estimated 1.2 acre-feet of additional storage (in addition to the pond live storage) underground within the ball field area of the park, which is the estimated maximum feasible underground storage available based on park size and elevations. The storage feature would be comprised of 30, 150-foot long, 36-inch

Houston Engineering, Inc.

943

944

949

947

949

944

945

948

Capitol Region Watershed District Curtiss Pond

94 2

947

941

943 94

946

2-Year Approximate HWL @ 932.9

Park Building Low Entry Elevation (Door) of 937.0 (NAVD 88)

941

10-Year Approximate @ 936.2

October 7, 2005 High Water Mark @ Approximately 938.39

944 943

Curtiss Pond

Legend

942

1 93

100-Year Approximate HWL @ 939.8 1 Foot Contours Created from LIDAR and Survey Data

932 927

Pretreatment Device Underground Storage

938

939

St. Paul Storm Sewer Pipes

Storm Sewer Manholes

942

941

940

8 93

934

930

1543 Iowa Ave Basement Window Elevation of 940.47 (NAVD 88)

94 4

943

1546 Iowa Ave Elevation of Tuck-Under Garage @ 939.02 (NAVD 88) 943

100 Feet

Figure 8 Alternative 4

942

948

942

Source: MN DOT Imagery: 2009 Ramsey County Aerials

940

947 6 94

933

928 93

937

936

929

939

937

942

Falcon Heights Storm Sewer Line

Scale: AS SHOWN

Drawn by:

Checked by:

Project No.: 6475-008

Date: 8/15/2013

Sheet: 1 of 1

19 diameter pipes, embedded in gravel and would include a separator row for removal of TSS coming from Idaho and Iowa Avenue. Alternative 4B includes the same total storage volume as 4A, but would include lowering the ball field area approximately 1 foot to provide surface storage and a reduction in the amount of underground storage required under the ball field. This alternative may be less costly than providing the entire storage underground, but it will increase the frequency of flooding of the ball field. This alternative includes pre-treatment (sediment removal) of the stormwater runoff and anticipates maintaining the existing infiltration above elevation 931.7. The modeling for this alternative assumes infiltration at a rate of 0.6 inches per hour above elevation 931.7. Table 6 summarizes peak elevations and drawdown times resulting from the modeling analysis for Alternative 4 for 2-year, 10-year, and 100-year storm events.

Table 6: Model Results for Alternative 4 â&#x20AC;&#x201C; Storage BMP Alternative Peak

Inundation Time

Storm

Water

of Park

Event

Elevation

(days)

2-year (2.73-inch)

932.9

0.0

10-year (4.00-inch)

936.2

2.7

100-year (6.24-inch)

939.8

11.4

Notes: 1. 2. 3. 4.

Highest elevation before losing use of park is 934.5 Lowest entry of park building is 937.0 Lowest opening of nearby home is 940.47 Lowest nearby garage floor is 939.02

It is anticipated that the implementation of Alternative 4 would result in the park building remaining dry in the 10-year event, and the surrounding homes remaining dry up to the 100-year storm event. However, at an elevation of 939.02, the garage at 1546 Iowa Avenue will continue to be at risk of flooding in the 100year storm event. Alternative 4 achieves the technical objective of eliminating flooding of the park building for the 10-year, 24-hour duration event. It provides a larger margin of safety than Alternative 2, but less than Alternative 3 for the freeboard to the low door opening elevation. Although not considered a technical objective, the park building would continue to be inundated for the 100-year, 24-hour design event. This alternative achieves the technical objective for flood prevention of adjacent residential homes. The model suggests that the maximum elevation for the 100-year, 24-hour precipitation event would be reduced by 0.8-feet compared to existing conditions (i.e. the flood risk is reduced) and that the basement of the home located just to the east of the park at 1543 Iowa Avenue would not flood. However, the modeling results also show that the garage of 1546 Iowa Avenue will continue to be at risk of flooding.

Houston Engineering, Inc.

20 This alternative achieves the technical objective related to park use. A substantive improvement in park usability characterized by the number of days of potential park use for typical conditions (i.e., the 2-year, 24-hour flood event) is expected. Alternative 4 assumes no improvements to infiltration in Curtiss Field Pond, and therefore inundation times are not as low as in Alternative 3, though still improved from existing conditions.

5.5

ALTERNATIVE 5A â&#x20AC;&#x201C; STORAGE AND CURTISS POND DRAW DOWN BMP ALTERNATIVE

Alternative 5A provides additional storage and infiltration capacity from an underground infiltration system and by lowering the park 1 foot (935.5 to 934.5) to assist in alleviating flooding of the park, park building, and adjacent homes. The modeling completed for this alternative assumes improvements to infiltration are provided by the underground system and that pre-treatment facilities are installed, resulting in an infiltration rate within the underground system of 0.6 inches per hour. This alternative assumes that infiltration practices within the underground system are functioning and that the pond is dry at the start of a storm event. This alternative does not include dredging of pond sediment as proposed in Alternatives 2 and 3. However, it does include making a hydraulic connection between the pond and the underground system to draw down the water level of the pond to a dry condition. Alternative 5A includes constructing an estimated 0.68 acre-feet of additional storage (in addition to the existing pond live storage) with the underground system and the lowering the ball field by 1 foot (see Figure 9). The underground system would be comprised of one, 150-foot long, 120-inch diameter perforated pipe, embedded in gravel. This would be located along the east edge of the pond, and these dimensions are the estimated maximum feasible diameter and length underground system available to be installed in this location. The bottom of the underground system would be at elevation 922.0 which is the bottom of the existing sand layer of the pond. As part of the underground system, a hydraulic connection between the pond and the underground system would be created to allow for water from the pond to fill the underground system. This alternative would also include lowering the ball field area approximately 1 foot from 935.5 to 934.5 and regrading to provide positive drainage to the pond. The storage provided by lowering the ball field area would be approximately 0.34 acre-feet of the 0.68 acre-feet. Providing surface storage is less costly than providing the entire storage underground, but it will increase the frequency of flooding of the ball field within the park. Alternative 5A achieves the technical objective of eliminating flooding of the park building for the 10-year, 24-hour duration event, and provides a larger margin of safety than Alternative 2 for the freeboard to the low door opening elevation. The inundation period for this alternative during the 100-year, 24 hour storm event is less than shown for alternatives 2, 3, and 4. Although not considered a technical objective, the park building would continue to be inundated for the 100-year, 24-hour design event. This alternative achieves the technical objective for flood prevention of adjacent residential homes. The model suggests that the maximum elevation for the 100-year, 24-hour precipitation event would be reduced by 0.9-feet compared to existing conditions (i.e. the flood risk is reduced) and the home located

Houston Engineering, Inc.

948

6 94

945

942

947

949

Capitol Region Watershed District Curtiss Pond

944 941

943

947

946

1542 Idaho Ave Basement Window Elevation of 942.50 (NAVD 88)

940 939 938 936

943

Legend

941

945

Curtiss Pond

1 Foot Contours Created from LIDAR and Survey Data

947

940

939

10 ft. Wide & 150 ft. Long Infiltration Trench

948

944

Pretreatment Device

942

937

945

927 930

936

931

Ball Field Area to be Lowered One Foot St Paul Storm Sewer Pipes

Falcon Heights Storm Sewer Line 937

935

100-Year Approximate HWL @ 939.7

Storm Sewer Manholes

929 3 93 936

1543 Iowa Ave Basement Window Elevation of 940.47 (NAVD 88)

938

941

939

10-Year Approximate @ 936.1

October 7, 2005 High Water Mark @ Approximately 938.39

934 932

937

943

942

928

940

2-Year Approximate HWL @ 932.7

Park Building Low Entry Elevation (Door) of 937.0 (NAVD 88)

940

1 94

941

100 Feet

948

0 942

942

Source: MN DOT Imagery: 2009 Ramsey County Aerials 947

943

944

1546 Iowa Ave Elevation of Tuck-Under Garage @ 939.02 (NAVD 88)

Figure 9 Alternative 5A Scale: AS SHOWN

Drawn by: SW

Checked by: GB

Project No.: 6475-008

Date: 8/15/2013

Sheet: 1 of 1

21 just to the east of the park at 1543 Iowa Avenue would not flood for this rainfall event. However, the modeling results also indicate that the garage of 1546 Iowa Avenue will continue to be at risk of flooding. This alternative achieves the technical objective related to park use. A substantive improvement in park usability characterized by the number of days of potential park use for typical conditions (i.e. the 2-year, 24-hour flood event) is expected. Maximum water surface elevations and inundation times resulting from the modeling analysis for Alternative 5A are summarized in Table 7 for 2-year, 10-year, and 100-year storm events.

Table 7: Model Results for Alternative 5A â&#x20AC;&#x201C;Storage and Curtiss Pond Drawdown BMP Alternative. Peak

Inundation Time

Storm

Water

of Park

Event

Elevation

(days)

2-year (2.73-inch)

932.7

0.0

10-year (4.00-inch)

936.2

1.8

100-year (6.24-inch)

939.7

6.4

Notes: 1. 2. 3. 4.

5.6

Highest elevation before losing use of park is 934.5 Lowest entry of park building is 937.0 Lowest opening of nearby home is 940.47 Lowest nearby garage floor is 939.02

ALTERNATIVE 5B â&#x20AC;&#x201C; STORAGE AND CURTISS POND DRAW DOWN BMP ALTERNATIVE

Alternative 5B is essentially the same as Alternative 5A, except the underground infiltration system would have a 250-foot total length that would only extend under the ball field within the park. Alternative 5B includes constructing an estimated 0.91 acre-feet of additional storage (in addition to the existing pond live storage) with the underground system and the lowering of the ball field by 1 foot (see Figure 10). The 250-foot long underground storage feature would be comprised of two, 125-foot long, 120-inch diameter perforated pipes, embedded in gravel under the ball field. The bottom of the underground system would be at elevation 922.0, which is the bottom of the existing sand layer of the pond. As part of the underground system, a hydraulic connection between the pond and the underground system would be created that would allow for water from the pond to fill the underground system. This alternative also includes lowering the ball field area approximately 1 foot from 935.5 to 934.5 and regrading to provide positive drainage to the pond. The storage provided by lowering the ball field area would be approximately 0.34 acre-feet of the 0.91 acre-feet. Alternative 5B achieves the technical objective of eliminating flooding of the park building for the 10-year, 24-hour duration event, and provides a larger margin of safety than all other alternatives, except 3, for the freeboard to the low door opening elevation. The inundation period for this alternative during the 100-

Houston Engineering, Inc.

947

949

Capitol Region Watershed District Curtiss Pond

94 6

948

947

944

946

1542 Idaho Ave Basement Window Elevation of 942.50 (NAVD 88)

0 5 94

942

930

20 ft. Wide & 125 ft. Long Infiltration Trench

948

927 931 935

Pretreatment Device Ball Field Area to be Lowered One Foot St Paul Storm Sewer Pipes

944

942

1 Foot Contours Created from LIDAR and Survey Data

936

928 938

929 932 936

Storm Sewer Manholes

94 6

940

100-Year Approximate HWL @ 939.6 October 7, 2005 High Water Mark @ Approximately 938.39

933

10-Year Approximate @ 935.9

947

Curtiss Pond

2-Year Approximate HWL @ 932.0

Park Building Low Entry Elevation (Door) of 937.0 (NAVD 88)

943

934

939

941

Legend

1543 Iowa Ave Basement Window Elevation of 940.47 (NAVD 88)

940

942

948

939 941

940

945

941

Falcon Heights Storm Sewer Line

943

944

120 Feet

Source: MN DOT Imagery: 2009 Ramsey County Aerials

94 6

944

944 944

945

943

945

943

1546 Iowa Ave Elevation of Tuck-Under Garage @ 939.02 (NAVD 88)

Figure 10 Alternative 5B Scale: AS SHOWN

Drawn by: SW

Checked by: GB

Project No.: 6475-008

Date: 8/15/2013

Sheet: 1 of 1

22 year, 24 hour storm event is the least in comparison to all proposed alternatives. Although not considered a technical objective, the park building would continue to be inundated for the 100-year, 24-hour design event. This alternative achieves the technical objective for flood prevention of adjacent residential homes. The model suggests that the maximum elevation for the 100-year, 24-hour precipitation event would be reduced by 1.0-foot compared to existing conditions (i.e. the flood risk is reduced) and the home located just to the east of the park at 1543 Iowa Avenue would not flood for this rainfall event. However, the modeling results also indicate that the garage of 1546 Iowa Avenue will continue to be at risk of flooding. This alternative achieves the technical objective related to park use. A substantive improvement in park usability characterized by the number of days of potential park use for typical conditions (i.e. the 2-year, 24-hour flood event) is expected. Maximum water surface elevations and inundation times resulting from the modeling analysis for Alternative 5B are summarized in Table 8 for 2-year, 10-year, and 100-year storm events.

Table 8: Model Results for Alternative 5B –Storage and Curtiss Pond Draw Down BMP Alternative. Peak

Inundation Time

Storm

Water

of Park

Event

Elevation

(days)

2-year (2.73-inch)

932.0

0.0

10-year (4.00-inch)

935.9

1.5

100-year (6.24-inch)

939.6

5.8

Notes: 1. Highest elevation before losing use of park is 934.5 2. Lowest entry of park building is 937.0 3. Lowest opening of nearby home is 940.47 Lowest nearby garage floor is 939.02

5.7

OTHER BMP OPTIONS CONSIDERED

Other BMP options (see Figure 11) considered rather than providing storage within the park include:  Raingardens within the boulevard along Idaho and Iowa Avenue;  Infiltration/Filtration BMP between Snelling Drive and Snelling Avenue;  Underground storage under Idaho and Iowa Avenue; and  Town Square pond clean out and infiltration improvements. The rain gardens within the boulevard would need to be constructed between the back of curb and the sidewalk in areas without trees or driveways. This limits the size and volume of the rain gardens and does not make this BMP a good choice for reducing the flood elevation of the park. Each raingarden would provide approximately 20 cubic feet of storage capacity.

Houston Engineering, Inc.

Capitol Region Watershed District Curtiss Pond Town Square

Legend Inflitration/Flitration BMP Pond Cleanout Enhancement Rain Garden Within the Street Boulevard

Curtiss Pond

Underground Storage

100

200 Feet

Source: MN DOT Imagery: 2009 Ramsey County Aerials Figure 11 Other BMP Options Considered Scale: AS SHOWN

Drawn by:

Checked by:

Project No.: 6475-008

Date: 8/15/2013

Sheet: 1 of 1

23 The area located between Snelling Avenue and Snelling Drive is currently being used for pre-treatment of stormwater from Snelling Drive. To enlarge this BMP for infiltration/filtration would require removal of a number of mature trees and does not make the BMP a good choice. However, it may make sense to use this area as it exists by adding additional curb cuts to collect stormwater runoff from Snelling Avenue prior to Curtiss Pond. The infiltration/filtration BMP would provide approximately 120 cubic feet of storage capacity. Underground storage under Idaho and Iowa Avenues would need to be installed within a narrow corridor between the sanitary sewer and the small utilities within the boulevard. This option would be costly and would not provide sufficient storage capacity (approximately 0.2 acre-feet). The Town Square pond is an undersized pond located between Curtiss Pond and Town Square Development. The Town Square pond would provide approximately 130 cubic feet of storage capacity. None of the BMP options mentioned are large enough to provide sufficient storage to measurably reduce the amount of water reaching Curtiss Pond.

5.8

SUMMARY OF RESULTS

For comparison, Table 9 provides a summary of the peak water surface elevations and inundation times for each Alternative for the 2-yr, 10-yr, and 100-yr rainfall events. As previously noted, the key flooding elevations of Curtiss Field Park include:   

Ball field area of park at 934.5 (elevation at which park is dry and useable); Lowest entry of park building at 937.0; and Lowest entry of adjacent homes at 940.47 (lowest garage entry at 939.02).

Table 9: Summary of Model Results for Alternatives 1, 2, 3, 4, 5A, and 5B (Using an Infiltration Rate of 0.6 inches/hour) Alternative 1

Alternative 2

Do Nothing (Existing Conditions) Alternative

Maximize Curtiss Pond Infiltration Alternative Inundation Peak Time of Water Park

Alternative 3 Storage and Curtiss Pond Infiltration BMP Alternative Inundation Peak Time of Water Park

Alternative 4

Storage BMP Alternative Inundation Time of Peak Water Park

Storm

Peak Water

Inundation Time of Park

Event

Elevation

(days)

Elevation

(days)

Elevation

(days)

Elevation

(days)

2-year

935.9

2.8

933.8

0.0

931.7

0.0

932.9

0.0

10-year

937.9

5.9

936.9

2.7

935.2

0.9

936.2

2.7

100-year

940.6

12.6

940.1

7.6

939.3

7.3

939.8

11.4

Houston Engineering, Inc.

Alternative 5A Storage and Curtiss Pond Draw Down BMP Alternative

Alternative 5B Storage and Curtiss Pond Draw Down BMP Alternative Inundation Time of Peak Water Park

Storm

Peak Water

Inundation Time of Park

Event

Elevation

(days)

Elevation

(days)

2-year

932.7

0.0

932.0

0.0

10-year

936.2

1.8

935.9

1.5

100-year

939.7

6.4

939.6

5.7

These results show that Alternative 1 does not meet any of the technical objectives and project goals and should not be considered. Alternative 2 achieves all the technical objectives, though it provides little margin of safety between the 10-year high water level and the low opening on the park building. Alternative 3 achieves all technical objectives and the project goals. Note that none of the alternatives will provide 100-year protection to the garage at 1546 Iowa Avenue. Alternative 4 does not achieve the technical objective of maximizing infiltration within Curtiss Pond. However, it does meet other objectives, with the exception of the protection of the garage/home at 1546 Iowa Avenue. Alternatives 5A and 5B achieve all technical objectives and the project goals. Based on the results, the technical objectives proposed appear to be realistic and achievable by a majority of the alternatives. The infiltration rate used within the model is a critical assumption, so sensitivity analysis was completed to see how it affects the peak storm event elevations and inundation times. Based on discussions with CRWD staff, the inundation durations for the existing conditions model are longer than typically observed. Therefore, additional modeling was completed using an infiltration rate of 1.4 inches/hour, based on the results of the double ring infiltrometer tests. The results as shown in Table 10 indicate a decrease in peak elevations ranging from 0.2 to 0.7 feet and a larger decrease in inundation times ranging from no change to 7.6 hours, compared to using a rate of 0.6 inches/hour. It is our understanding that these inundation times closely match the observation made by CRWD and City of Falcon Heights staff after a storm event.

Table 10: Summary of Model Results for Alternatives 1, 2, 3, 4, 5A and 5B (Using an Infiltration Rate of 1.4 inches/hour) Alternative 1

Alternative 2

Do Nothing (Existing Conditions) Alternative

Maximize Curtiss Pond Infiltration Alternative Inundation Peak Time of Water Park Elevation (days)

Alternative 3 Storage and Curtiss Pond Infiltration BMP Alternative Inundation Peak Time of Water Park Elevation (days)

Alternative 4 Storage BMP Alternative Inundation Peak Time of Water Park Elevation (days)

Storm Event

Peak Water Elevation

Inundation Time of Park (days)

2-year

935.6

0.9

933.1

0.0

931.2

0.0

932.5

0.0

10-year

937.6

2.1

936.4

1.1

934.4

0.0

935.8

0.9

100year

940.4

5.0

939.7

3.2

939.0

3.0

939.5

4.2

Houston Engineering, Inc.

Alternative 5A Storage and Curtiss Pond Draw Down BMP Alternative

Alternative 5B Storage and Curtiss Pond Draw Down BMP Alternative Inundation Time of Peak Water Park

Storm

Peak Water

Inundation Time of Park

Event

Elevation

(days)

Elevation

(days)

2-year

932.0

0.0

931.2

0.0

10-year

935.6

0.8

935.3

0.7

100-year

939.3

2.7

939.2

2.4

Based on the results of this sensitivity analysis, an increase in the infiltration rate would result in a larger decrease in inundation time of the park and a smaller decrease the peak water elevations.

6 6.1

COST AND BENEFIT ANALYSIS PRELIMINARY OPINION OF PROBABLE COST

A planning-level Preliminary Opinion of Probable Construction Cost (POPCC) is provided for each alternative for the Curtiss Pond Improvement Project. This feasibility level POPCC is intended to help in the decision-making process when selecting an alternative, and should not be used as the actual cost of project construction. The POPCC of each alternative includes the following: a cost for the installation of proposed BMPs; grading and restoration of park and ball field; engineering design cost including survey, design, plans, specifications, and project management; engineering construction administration including bidding, selection of contractor, construction surveying, construction observation, payment processing, and asbuilt survey; annual BMP maintenance (as a footnote). The POPCC does not include testing and disposal of contaminated soils. Due to the feasibility level of POPCC, a 25% contingency is added to the total cost (rather than the construction cost only). Alternative #1 â&#x20AC;&#x201C; Do Nothing Alternative No direct cost associated with doing nothing. There will potentially be recurring monetary costs due to repetitive repair of the park building, flooding damage to homes and park lands, and recurring social costs of reduced use of the park. Alternative #2 â&#x20AC;&#x201C; Maximize Curtiss Pond Infiltration Alternative Install Infiltration Enhancement Options*

182,000

Dredge Accumulated Pond Sediment below Water Line

37,000

Engineering Design

35,000

Engineering Construction Administration/Inspection

10,000

Houston Engineering, Inc.

26 Contingency (25%)

66,000

TOTAL OPINION OF PROBABLE CONSTRUCTION COST (Rounded to nearest thousand dollars)

330,000

*Cost of installation of a rock infiltration trench and 3 hydrodynamic separator pre-treatment units (separators=$126,000). Note: 1. Annual maintenance would include removal of sediment from the hydrodynamic separator, as needed, based on sediment loading. Estimated annual maintenance cost = $3,000. 2. This estimate does not include costs for testing or disposal of contaminated soils.

Alternative #3 – Storage and Curtiss Pond Infiltration BMP Alternative Alternative=>

Install Infiltration Enhancement Options*

98,000

Dredge Pond Sediment below Water Line

37,000

Install Additional Storage BMPS**

385,000

257,000****

Grading and Restoration of Ball Field***

11,000

21,000

Engineering Design

80,000

Construction Administration/Inspection

20,000

Contingency (25%)

158,000

154,000

TOTAL OPINION OF PROBABLE CONSTRUCTION COST (Rounded to nearest thousand dollars)

789,000

641,000

*Cost of installation of a rock infiltration trench and one hydrodynamic separator (separator cost =$42,000). **Cost of installation of underground storage within park. ***Cost includes restoring ball field with sod. ****Assume cost of installation of “Install of Additional Storage BMPs” would be reduced by approximately 1/3. Note: 1. Annual maintenance would include removal of sediment from the hydrodynamic separator and separator row, as needed, based on sediment loading. Estimated annual maintenance cost = $7,500. 2. This estimate does not include costs for testing or disposal of contaminated soils.

Alternative #4 –Storage BMP Alternative Alternative=>

Hydrodynamic Separator

42,000

Install Additional Storage BMPS*

$ 385,000

257,000***

Grading and Restoration of Ball Field**

11,000

21,000

Engineering Design

40,000

Houston Engineering, Inc.

27 Construction Administration/Inspection

10,000

Contingency (25%)

122,000

93,000

TOTAL OPINION OF PROBABLE CONSTRUCTION COST (Rounded to nearest thousand dollars)

610,000

463,000

*Cost of installation of underground storage within park. **Cost includes restoring ball field with sod. *** Assume cost of installation of “Install of Additional Storage BMPs” would be reduced by approximately 1/3. Note: 1. Annual maintenance would include removal of sediment from the hydrodynamic separator and separator row, as needed, based on sediment loading. Estimated annual maintenance cost = $7,500.

Alternative #5 – Storage and Curtiss Pond Draw Down BMP Alternative Alternative=>

Hydrodynamic Separator*

126,000

Install Additional Storage BMPS

$ 123,000**

182,000***

Grading and Restoration of Ball Field****

11,000

21,000

Engineering Design

80,000

Construction Administration/Inspection

20,000

Contingency (25%)

90,000

107,000

TOTAL OPINION OF PROBABLE CONSTRUCTION COST (Rounded to nearest thousand dollars)

450,000

536,000

*Cost of installation of three hydrodynamic separators (separator cost =$42,000 each). **Cost of installation of 150 foot long, 120 inch diameter underground storage along the pond and removal of one foot of soil within park. *** Cost of installation of 250 foot long, 120 inch diameter underground storage within the park and removal of one foot of soil within park. ****Cost includes restoring ball field with sod. Note: 1. Annual maintenance would include removal of sediment from the hydrodynamic separator and separator row, as needed, based on sediment loading. Estimated annual maintenance cost = $7,500.

6.2

FEASIBILITY OF THE ALTERNATIVES

The feasibility of each alternative, based on the ability to achieve each of the technical objectives and therefore the project goal, are presented in Table 11 with the associated POPCC. The technical objectives include maximizing the use of infiltration, eliminating flooding of the park building and nearby homes for the 10-year, 24-hour, and 100-year, 24-hour return period events, and increasing the

Houston Engineering, Inc.

28 frequency of park’s recreational use. Because Curtiss Field Pond has no outlet, pollutants will not leave the park and affect downstream water resources. Water quality improvements are therefore assessed in terms of the extent to which sediment is removed through the installation of pre-treatment facilities prior to entering Curtiss Pond in order to prevent premature reduction in infiltration capacity.

Table 11: Comparison of Preliminary Opinion of Probable Construction Cost, Technical Objectives and Pollutant Reduction for the Alternatives* Alternative

1 Do Nothing 2 Maximize Infiltration 3A Storage and Infiltration 3B Storage and Infiltration 4A Storage BMP 4B Storage BMP 5A Storage and Draw Down 5B Storage and Draw Down

Preliminary Opinion of Probable Construction Cost

Level of Protection Technical Objective Maximize Infiltration

< 10-year (937.9)

Lowest Adjacent Home (940.47)*** < 100-year (940.6)

$330,000

Yes

≈ 10-year (936.9)

< 100-year (940.1)

2.7

Yes

$789,000

Yes

> 10-year (935.2)

> 100-year (939.3)

0.9

Yes

$641,000

Yes

> 10-year (935.2)

> 100-year (939.3)

0.9

Yes

$610,000

> 100-year (939.8) > 100-year (939.8)

2.7

$463,000

> 10-year (936.2) > 10-year (936.2)

2.7

$450,000

Yes

> 10-year (936.2)

> 100-year (939.7)

1.8

Yes

$536,000

Yes

> 10-year (935.9)

> 100-year (939.6)

1.5

Yes

Park** Building (937.0)

Inundation Time of Park (10-yr) (0.6 in/hr)

Achieves Technical Objectives?

5.9

* This table assumes an infiltration rate of 0.6 inches/hour. The use of 1.4 inches/hour would slightly lower the shown elevations and decrease the inundation time (see Table 10). ** The Park Building would have a level of flood protection less than the 10-year for Alternative 1, equal to the 10-year for Alternative 2 and greater than the 10-year for all remaining alternatives. *** Note that lowest garage opening at is elevation 939.02

Alternative 1 fails to meet any of the technical objectives and therefore, the project goal. Alternative 2 is the least expensive of the “build something” alternatives. This alternative protects the park building from flooding during the 10-year event and reduces the inundation duration within the park. Alternative 2 also achieves the technical objective of providing 100-year flood protection for the adjacent homes. Alternative 3 (both 3A and 3B) meets all the technical objectives and therefore the project goal, but is the most costly

Houston Engineering, Inc.

29 alternative because of the construction of a storage feature next to the pond. Alternative 4 (both 4A and 4B) is less expensive than Alternative 3 but fails to fully meet the technical objective related to maximizing infiltration and therefore the project goal. No improvements to current infiltration capacity within Curtiss Pond would be implemented with Alternatives 4. Alternatives 5A and 5B meet all technical objectives and therefore the project goal, and are not the most costly alternatives. No improvements to current infiltration capacity within Curtiss Pond would be implemented with Alternatives 5A and 5B. However, a hydraulic connection from Curtiss Pond to an underground infiltration system will be completed as an infiltration enhancement. Some caveats relative to the feasibility of the alternatives are warranted. For example, the Alternative 4 (Storage BMP) is considered not feasible solely because the technical objectives defining the project goal included maximizing infiltration. However, this alternative is successful in achieving the necessary reductions in flooding and is less costly than Alternative 3. Alternative 2 (Maximize Infiltration) is feasible, as it achieves each of the technical objectives. However, there is little “margin of safety” associated with this alternative, as the water surface elevations estimated by the model are very close to the damage elevations for the park building and nearby homes. One means of providing the protection to the park building is to construct a low berm around the facility or raising the building. Curtiss Pond’s history includes several previous seemingly failed attempts to achieve infiltration. The soil borings show highly variable subsurface conditions and the specific location of the confining layers are unknown. In the absence of additional information to ensure suitable subsurface conditions for infiltration, there is considerable risk associated with any alternative (Alternatives 2 and 3) that involves enhancing infiltration within Curtiss Pond because implementation feasibility is unknown. Although Alternative 3 is the most costly alternative, it also includes the greater “margin of safety” and has less implementation risk. This alternative achieves the technical objectives related to flooding and maximizing infiltration. Creating the necessary storage is essentially “more certain” than just relying on the ability to infiltrate. Alternative 4 (both 4A and 4B) is less expensive than Alternatives 3A and 3B but fails to fully meet the technical objective related to maximizing infiltration and therefore the project goal. Alternatives 5A and 5B are not the most expensive alternatives and provide a level of protection similar to Alternative 4. These alternatives provide additional flood storage and infiltration area under the park, instead of enhancing infiltration within Curtiss Pond, and have a lower implementation risk than other alternatives. It is important to note that all proposed alternatives involve enhancing infiltration within the pond or under the park. Since not all subsurface conditions are known, there will always be some level of risk associated with achieving infiltration. This should be considered by the Board of Managers when selecting the preferred alternative.

RECOMMENDATIONS

Curtiss Pond, as originally conceived, was intended to not only infiltrate stormwater runoff from its watershed, but to provide flood control for Curtiss Field Park, the park building, and the surrounding Houston Engineering, Inc.

30 homes. Curtiss Pond was rehabilitated in 2004 with a live storage capacity large enough to hold the volume of runoff generated for the 1-year return period, 24-hour rainfall event, so repeated flood problems throughout the years are not surprising. Most BMPs intended to reduce flooding are designed for the 100year return period event. Maintaining infiltration through the bottom of Curtiss Pond, necessary to lower water levels between storm events and provide sufficient flood storage, has been problematic. There have been numerous geotechnical analyses completed to determine the reasons for the lack of infiltration, but none have successfully identified the problem: “Why doesn’t Curtiss Pond infiltrate?” Explanations for this lack of infiltration could include sediment buildup within the pond, compaction of sediment during the construction process, or confining layers directly below the pond bottom restricting the vertical hydraulic conductivity. The most recent soil borings and grain size analyses indicate the coarse alluvium soil layer has a potential infiltration rate ranging from 5.5 inches per hour to 46.2 inches per hour. These soil borings and the monitoring well data collected by CRWD indicate that groundwater near the pond may be perched within the coarse alluvium at approximately elevation 912.0 and likely comes from the infiltration of the pond water through preferential pathways within the sediment deposits and existing fill at or below the bottom of the pond. However, soil borings also indicate there is no groundwater to a depth of 50 feet (885.8), indicating that as long as groundwater can pass through these confining layers, there is a potential to draw down Curtiss Pond. Four main alternatives were evaluated as potential solutions to the flooding problem and to improve infiltration: Alternative 1: Do Nothing (Existing Conditions) Alternative Alternative 2: Maximize Curtiss Pond Infiltration Alternative (pond cleanout, rock infiltration trench alongside of pond, pre-treatment device) Alternative 3: Storage and Curtiss Pond Infiltration BMP Alternative  

Alternative 3A (pond cleanout, rock trench alongside of pond, 150-foot long, 120-foot wide, 36-inch diameter underground infiltration storage feature in the park, pre-treatment device) Alternative 3B (pond cleanout, rock trench alongside of pond, lowering the park by one foot to reduce the size of the 150-foot long, 120-foot wide, 36-inch diameter underground storage feature in the park, pre-treatment device)

Alternative 4: Storage BMP Alternative  

Alternative 4A (150-foot long, 120-foot wide, 36-inch diameter underground storage system within the park, pretreatment device) Alternative 4B (lowering the park by one foot to reduce the size of the 150-foot long, 120-foot wide, 36-inch diameter underground storage system within the park, pre-treatment device)

Alternative 5: Storage and Curtiss Pond Draw Down BMP Alternative

Houston Engineering, Inc.

31 ď&#x192;&#x2DC; ď&#x192;&#x2DC;

Alternative 5A (150-foot, 120-inch diameter underground infiltration system alongside of pond, hydraulic connection to pond, lowering the park one foot, pre-treatment device) Alternative 5B (250-foot, 120-inch diameter underground infiltration system within the park, hydraulic connection to pond, lowering the park one foot, pre-treatment device)

Alternative 1 is the same as the existing conditions of Curtiss Pond. Alternative 2 maximizes infiltration by cleaning out the accumulated pond sediment, installing a rock infiltration trench along the side of the pond and pretreatment devices. Alternative 3 maximizes infiltration by installing additional underground infiltration and flood storage within the park and pretreatment devices. Alternative 4 only includes the installation of underground storage within the ball field and pre-treatment devices. Alternatives 5A and 5B provide a hydraulic connection to Curtiss Pond and underground infiltration and flood storage within the park and pre-treatment devices. Recommendation The additional field work completed in 2013 suggests that infiltration improvements are feasible for Curtiss Pond, though they come with some risk of failure even with the additional soil and monitoring information collected. The biggest unknown is the location of these subsurface confining soil layers within the coarse alluvium material that are creating a perched water condition and limiting hydraulic conductivity. Our recommendation to lower the risk of failure is to choose an alternative that increases the footprint of the infiltration area and does not rely on infiltration enhancement only within the pond. Given the aforementioned reasons, our recommendation would be to consider Alternative 5B. This alternative meets the project goals and technical objectives, is less costly than Alternatives 3A and 3B, and would not rely on enhancing infiltration within the bottom of the pond. In comparison to Alternative 5A, the unit cost of underground storage volume is less for Alternative 5B, making it a better value. The proposed infiltration features of Alternative 2 do not provide as much infiltration area as Alternatives 5A or 5B, however if the increased level of risk of failure is acceptable, Alternative 2 is recommended. Alternative 2 is the least costly alternative that meets the project goals and technical objectives. If Alternative 2 is chosen, HEI would strongly recommend additional analyses be completed prior to construction to fully understand why Curtiss Pond doesnâ&#x20AC;&#x2122;t infiltrate.

Houston Engineering, Inc.

APPENDIX A List of Existing Documents Reviewed

The following existing documents and data were gathered and reviewed primarily to understand the history of the pond, previous efforts to improve performance and specific measures or features constructed to improve performance. 1. Historic aerial photography. 2. Feasibility Report Curtiss Field Park Pond, Short Elliot Hendrickson, Inc., October 2002. 3. Town Square Grading and Stormwater Drainage Plan and Utility Plan dated March 4, 2003. 4. Curtiss Field Park Pond Improvements Construction Plans, Howard R. Company, March 2004. 5. Curtiss Field Pond Construction Memorandum, Howard R. Green Company, February 5, 2005. 6. Street utilities provided by the City. 7. Ramsey County LiDAR. 8. Monitoring data provided by the CRWD.

APPENDIX B Details on WCA Determination Historic aerial photography was reviewed to gather information to make a determination of the historic nature of Curtiss Pond, including its status under the state WCA. Historic aerial photography from the following years was observed: 1923, 1940, 1953, 1957, 1964, 1970 and 1991. Based on the photography, sometime between the years of 1970 and 1991 the pond appears to have been excavated from upland, most likely for the purposes of stormwater retention or wildlife habitat within the park. Prior to the 1991 photo, no indications of wetland signatures were observed. It appears the site’s history includes agriculture or open space surrounded by residential housing in 1923 and 1940, and in 1953 the site is well surrounded by housing and what appears to be an ice skating rink in the park. The 1957, 1964 and 1970 photos indicate that the site was a dry open space or park area. The National Wetland Inventory (NWI) indicates no wetland basins within the park area, and the Ramsey County Soil Survey has mapped the site as Urban land – Waukegan complex, which is not listed as a hydric soil in Ramsey County. Additionally, the permitting files of the CRWD and the City of Falcon Heights were reviewed to locate any wetland or stormwater permitting details regarding the Curtiss Pond. Neither agency had any permitting details regarding the pond. Based on the permitting research, NWI, Ramsey County Soil Survey data and the review of historic aerial photography, it is concluded that this basin would be considered an “incidental wetland” as defined in WCA (…”include drainage ditches, impoundments, or excavations construction in non-wetlands solely for the purposes of effluent treatment, containment of waste material, stormwater retention or detention, drainage, soil and water conservation practices, and water quality improvements not as part of a wetland replacement process…”), and therefore not within the scope of regulation under WCA.

APPENDIX C Geotechnical History Two borings were completed in the 1991 evaluation to a depth of 16 feet. These borings were taken on the east and north side of the existing park building. Soils identified within the boring generally consisted of a mixture of clay, sand, and organic soil to a depth of 8 feet, as well as poorly graded sand with silt from 8 to 16 feet of depth. In both borings, soils from a depth of 0 to 4.5 were determined to be fill. Water level was identified in one boring at 12.7 feet of depth. It is likely that this is the static water level. In 2000, two borings were advanced by hand to a depth of 2 feet below the pond bottom. At the time of the borings, about 3 feet of standing water was present within the pond. The boring identified organic sediment, leaves, silty sand, and lean clay. After the previous hand borings, it was recommended that additional deeper boring be completed to determine if clean sand was present below the low permeability soil of the pond bottom. In March 2001, two borings were completed through 3 feet of ice and water to a depth of 10 and 19 feet below the ice surface. A mixture of clay, sand, and organic soil (fill) was identified from 0 to 6 feet of depth in both borings. A mixture of sand, silt, gravel, and paper (fill) were identified in boring A from 6 to 10 feet of depth. Boring B consisted of sand with silt/gravel from 6 to 12 feet of depth, then 1 foot layer of lean clay from 12 to 13 feet of depth. Sand with silt and gravelly sand was identified from 13 to 18 feet. As part of the 2002 feasibility report, three additional borings were completed around the perimeter of Curtiss Pond and extend to depths of 8 to 25 feet below existing grades. Boring B-1 was completed on the north side of the pond along Idaho Avenue. Soils consisted of a mixture of clay, sand, silt, and a little gravel (fill) from 0 to17 feet and sand with silt from 17 to 24 feet of depth. Boring B-2 was completed between the pond and Snelling Avenue to a depth of 7 feet. Soils consisted of 4 feet of silt, clay, and sand (fill) above 3 feet of organic and lean clay. B-3 was completed on the south side of the pond to a depth of 21 feet. Soils consist of 5 feet of clayey sand and lean clay above 16 feet of sand mixed with a little gravel and cobbles. During the 2004 Curtiss Pond improvements, 4 feet of select granular soil was placed in the bottom of and pond from elevation 922 to 926 to facilitate infiltration. A sieve analysis of the select granular soil confirms that it meets MnDOT 3149.2B2 specifications for gradation. Following the improvements of the pond, a double ring infiltrometer test was complete in three locations in the bottom of the pond within the select granular soil. Test results indicated an infiltration rate of 1.4 in/hr can be used for the select granular soil. As part of the 2013 street and Curtiss Field Park Improvements, the City of Falcon Heights completed 1 boring to the north of the existing park building on September 7, 2012. This boring was completed to a depth of 21 feet and shows a temporary water level at 11.8 and 20.5 feet. These water levels were measured at different casing depth intervals during the drilling process and most likely do not represent static water level within boring. Soils identified within the boring generally consisted of a silty sand from 0 to 5.5 feet, organic and lean clay from 5.5 to 9.5 feet, and sand with silt/gravel from 9.5 to 21 feet of depth. Soils from a depth of 0 to 5.5 were determined to be filled in the boring.

1. Report of Geotechnical Exploration and Review for Park Building Idaho/Snelling Park, American Engineering Testing, Inc., April 24, 1991. 2. Geotechnical borings, American Engineering Testing, Inc., October 3, 2000. 3. Geotechnical borings, American Engineering Testing, Inc., March 13, 2001. 4. Geotechnical borings for the Feasibility Report, American Engineering Testing, Inc., December 3, 2001. 5. Sieve Analysis of Curtiss Pond Select Granular, American Engineering Testing, Inc., June 10, 2004. 6. Double Ring Infiltrometer Test Results, American Engineering Testing, Inc., October 18, 2004. 7. Subsurface boring log for the 2013 Street/Alley and Curtiss Pond Improvements, American Engineering Testing, Inc., September 7, 2012. 8. Hand auger borings, Houston Engineering, Inc., November 8, 2012. 9. Geotechnical borings, American Engineering Testing, Inc., May 24, 2013.

October 2, 2013 V. Action Items D) Authorize 2014 CWF Grant Applications (Zwonitzer) DATE: TO: FROM: RE:

September 26th, 2013 CRWD Board of Managers Nate Zwonitzer, Urban BMP Specialist 2014 Clean Water Fund Applications

Background Currently the Board of Water and Soil Resources (BWSR) is requesting proposals for the FY2014 Clean Water Fund (CWF) competitive grant program. A total of $17,345,000 is available through a variety of funds, the most applicable for CRWD being the BWSR Projects and Practices fund ($8.5 million). This fund requires a match of 25% of the grant request. Issues Staff would like to submit grant applications for Central High School and Upper Villa Park Volume Reduction and Stormwater Reuse Project. Project summaries and cost estimates are below. Central High School The Central High School project includes design finalization and construction of the stormwater components identified in the retrofit concept plan funded by CRWD. The project received $50,000 in 2014 Special Grant funds to be used for design finalization and grant match. An additional $30,000 could be applied to the project from the Special Grant contingency fund to provide the entire $80,000 match requirement needed to fully fund design and construction of all three phases (stormwater elements only). Design finalization would likely take place in 2014 with construction occurring in 2015. Anticipated project budget Project Areas Stormwater Elements Design/Construction mgmt. $72,000 Phase 1 (Plaza/Entry) $102,000 Phase 2 (West Parking Lot) $164,000 Phase 3 (East Side of Building) $62,000 Total $400,000

Grant Request Match Required $57,600 $14,400 $81,600 $20,400 $131,200 $32,800 $49,600 $12,400 $320,000 $80,000

Upper Villa Park Volume Reduction and Stormwater Reuse Project Through a subwatershed analysis completed by SRF in January, 2013, a volume reduction BMP opportunity was identified at the Upper Villa Park softball field behind the B-Dale Club. The project will result in significant volume reduction to Villa Park as well as a reduction of 45 lbs./yr in phosphorous. The initial work plan and project budget committed $275,000 of CRWD funds to match the $275,000 Clean Water Partnership grant awarded to CRWD for identification, design, and construction of volume reduction practices in the Lake McCarrons subwatershed. The City of Roseville Parks and Public Works Departments will also dedicate funds to the project, but the total amount has not been determined at this time.

Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District.

The preliminary engineerâ&#x20AC;&#x2122;s cost estimate for construction, not including a reuse system, is $810,000. CRWD estimates the total construction costs to approach $1,000,000. In order to fill the $450,000 funding gap, staff propose submitting a grant request of $360,000 and committing $90,000 as match funds for the BWSR CWF application.

Upper Villa Park Funding Funding Source Grant MPCA CWP BWSR CWF

CRWD/Roseville

MPCA

BWSR

Total Funding

$ $

275,000 $ 90,000 $

275,000 $ $

$ 360,000 $

550,000 450,000

Total $

365,000 $

275,000 $

360,000 $

1,000,000

Action Requested 1. Approve the use of 2014 special grant contingency funds totaling $30,000 as match for the Central High School Clean Water Fund grant application. 2. Authorize staff to apply for a $320,000 grant through the BWSR Clean Water Funds for the Central High School project using $80,000 in special grant funds as match. 3. Authorize staff to apply for a $360,000 grant through the BWSR Clean Water Funds for the Upper Villa Park Volume Reduction and Stormwater Reuse project using $90,000 in dedicated project funds as match. Relevant Links: BWSR Clean Water Fund RFP http://www.bwsr.state.mn.us/grants/apply/FY14/CWF_FY14_RFP_final.pdf \\CRwDC01\company\08 Orgs-Cities-Agencies\SPPS\Central High School\2014 CWF Application\Bd Memo 2014 CWF Grants Applications 10-022013.docx

October 2, 2013 VI. Unfinished Business D) CAC Update (Doneux)

DATE: TO: FROM: RE:

September 27, 2013 CRWD Board of Managers Mark Doneux, Administrator CAC Update

Background The CAC has had a drop off in attendance in 2013. This drop in attendance has prompted the Co-Chair, Gwen Willems, Manager Reider and I to discuss ideas to reinvigorate the committee. The Board also had a general discussion on this topic at the September 18th Board meeting. Issues At the October 9th CAC meeting, former State Senator Ellen Anderson will facilitate a discussion on ways to reinvigorate the committee. I have attached a draft agenda for your information. As part of that discussion the Board felt that it would be beneficial to provide input on ways to provide a clearer role and responsibilities for the CAC. I have provided a list of ideas below to generate discussion with the Board of Managers. Some of these ideas are already being acted upon by the CAC. 1) Review and comment on the annual work plan budget. 2) Review and comment on annual report. 3) Review and comment on Watershed Management Plan updates, amendments or Lake Management Plans. 4) Review and make recommendations on grant awards (determine which grants are appropriate) 5) Review and make recommendations on award nominations and winners (develop award program) 6) Review and comment on Rule revisions 7) Provide volunteer support for District outreach events 8) Participate on consultant selection committees (may be difficult) 9) Represent the District on community planning committees (ie POPS, Park Master Planning, Small Area Planning, Great River Passage, etc) 10) Provide Citizen monitoring of water resources (where feasible and appropriate) Action Requested Review and provide feedback on ways and methods to reinvigorate the Citizen’s Advisory Committee. enc:

Draft October 9, 2013 Citizen’s Advisory Committee Agenda March 1, 2006 Presentation” Key Elements for an Active Citizen’s Advisory Committee”

W:\04 Board of Managers\Board Memo Ideas for CAC 9-27-13.docx

Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District.

Citizen’s Advisory Committee 7:00 PM, Wednesday, October 9, 2013 - Capitol Region Watershed District Office Agenda 7:00

Welcome, Announcements and Updates – Introductions

7:05

II)

Public Comment for issues not on the Agenda (3 minutes per person)

7:08

III)

Approval of the Agenda

7:09

IV)

Approval of Minutes

Materials Enclosed

Approval of the August 14, 2013 Minutes 7:10 V)

Discussion of Strengthening the Role of the Citizen’s Advisory Committee A) B) C) D) E) F) G)

Overview and approval of Discussion process, introduction of Facilitator, Ellen Anderson Overview of CAC and its initial role to date Discuss strengths and weaknesses of CAC's current role, structure, meetings, processes Brainstorm potential changes and new roles Rank top choices from brainstormed ideas, discuss further as needed Develop plan to share concepts with Board of Managers Discuss potential changes to our meetings, i.e. length, time/day, room/seating arrangement, etc.

8:45

VI)

CAC Observer and Board of Managers Update

8:55

VII)

Discussion A) B) E) G)

9:00

New & Old Issues CAC Observer for October 16th and November 6th Board of Managers Meeting November 13, 2013 CAC Agenda Overview Electronic CAC Packets

VIII) Adjourn

Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District.

9/27/2013

Key Elements for an Active Citizen’s Advisory Committee Mark Doneux, Administrator Capitol Region Watershed District Washington County Water Consortium March 1, 2006 Stillwater, MN

Key Elements for an Active CAC Principals for Public Participation CRWD CAC Role and Work Plan Benefits and Challenges of Active CAC

9/27/2013

Principles of Public Participation Citizens will voluntarily participate in a community activity when they: See positive benefits to be gained. See some aspect of their way-of-life threatened. Have an organizational structure to express their interests. Feel committed to be supportive of the activity. Have better knowledge of an issue or situation. Feel comfortable in the group.

Principles of Public Participation Citizen participation can be improved by: Organizing and identifying appropriate groups receptive to citizen input. Helping citizens find positive ways to respond to threatening situations. Stressing obligations for community improvement. Provide citizens with better knowledge on issues and opportunities. Helping participants feel comfortable within the development group.

9/27/2013

Short List (write this down)

Impacted or threatened way of life Critical Mass Make a difference Educate

CRWD CAC Role & Work Plan

Advisory Role for the Board (50%)

Topics for CAC Advisory Role

Annual Workplan Annual Budget/Levy Watershed Plan/Amendments Rules Education and Outreach Program By-laws Any Major Project

9/27/2013

CRWD CAC Role & Work Plan

Methods of providing advice to the Board

Motion supporting/not supporting specific action or policy. Motion should provide committee supported list of changes or recommendations. Function more like a planning commission does for a City Council.

CRWD CAC Role & Work Plan

Project Involvement for the CAC (25%)

Development of Education and Outreach Workplan. Directly assist with the implementation of the Education and Outreach Workplan. Serve on select committees as recommended by the Board (ie. Trout Brook Alignment). Make recommendation regarding Stewardship Grants. Create subcommittees for topics with a small but intense interest group. Create better link between CAC members and their local District Councils. Be the “Eyes and Ears” of the District.

9/27/2013

CRWD CAC Role & Work Plan

Keep the CAC Informed (25%)

Keep the CAC informed of all major activities. Provide regular updates for ongoing projects. Regularly provide in-house and outside speakers on current topics in water resource management. Use the CAC meetings as a forum for speakers that may not fit into a Board Agenda.

Benefits and Challenges Benefits

Democracy requires Citizen Input Alternative view points Constructive criticism Litmus test for new ideas

Challenges Time & $ Managing tension between Board & CAC Balance Committee vs Individual Ideas

DATE: TO: FROM: RE:

September 26, 2013 CRWD Board of Managers and Staff Mark Doneux, Administrator October 2, 2013 Administrator’s Report

Administrator Approved or Executed Agreements Stewardship Grant Agreement with Twin Cities German Immersion School for construction of stormwater features including infiltration, rain gardens and permeable outdoor learning area. – Not to exceed $10,000.00 Work Order No. 5, Amendment No. 1 to Consultant Services Agreement with Barr Engineering for the Trout Brook Storm Sewer Interceptor to increase the cost of general engineering services from $15,000 to $30,000. Amendment No. 1 to Consultant Services Agreement with Barr Engineering for the CCLRT Green Infrastructure Practices to increase the cost of general engineering services from $5,000 to $7,000. Amendment No. 2 to Consultant Services Agreement with Emmons Olivier Resources, Inc. for the Como Park Regional Pond Improvement Project to extend the completion date to December 31, 2013. General updates including recent and upcoming meetings and events On Thursday, September 26, 2013 Mark Doneux presented at the Ramsey County State of the Waters Conference held at the Ramsey Conservation District office. Lake McCarron’s Shoreline Residents Meeting, 6:00 PM, Thursday, October 3rd, Roseville City Hall Council Chambers. CRWD Staff will be participating in the Water Environment Federation Technical Conference, Stormwater Congress in Chicago, October 5 – 9 and the Minnesota Water Resources Conference in Saint Paul, October 15 – 16. Below is a list of presentations that involve CRWD staff or projects. Stormwater Congress, WEF TEC October 5 – 9, 2013 McCormick Place South Chicago, Illinois Date Tuesday, October 8, 2013 Wednesday, October 9, 2013

Session Technical Session 316: Green Infrastructure Case Studies and Performance Assessment Session 515: Stormwater Maintenance

Presentation Title Green Infrastructure for the Central Corridor Light Rail Transit Project Quantifying Gross Solids and Phosphorus Loads Captured by Stormwater BMP Pretreatment Devices

Speakers Forrest Kelley Bob Fossum

Minnesota Water Resources Conference October 15 – 16, 2013 Saint Paul River Centre 175 West Kellogg Boulevard Saint Paul, MN Date Tuesday, October 15, 2013

Time 10:00 – 11:30 AM

Presentation Title Catalyzing Green Infrastructure and Redevelopment in an UltraUrban TOD Corridor

Speaker Wes Saunders Pearce, City of Saint Paul Joni Giese and David Filipiak, SRF Consulting Group

Tuesday, October 15, 2013

10:00 – 11:30 AM

Permeable Alley Pilot Project in Saint Paul, Minnesota

Dan Edgerton, Stantec, Inc. Wes Saunders-Pearce, City of Saint Paul

Tuesday, October 15, 2013

11:15 AM – 12:45 PM

Jim Herbert and Nathan Campeau, Barr Engineering Company Anna Eleria, CRWD

Wednesday, October 16, 2013

10:00 – 11:30 AM

Fast-Track Project Relies on Detailed Planning and Extensive Coordination with Numerous Entities to Install Box Culvert Beneath BNSF Tracks within 30 Hours Stormwater Pond Dredging Using Hydraulic Dredging and Geotextile Tubes

Ted Shannon and Peter Berrini, HDR Engineering, Inc. Anna Eleria and Bob Fossum, CRWD

Upcoming events and meetings a) Next Board Meeting is Wednesday, October 16, 2013 at 6:00 pm. b) Next CAC Meeting is Wednesday October 9, 2013 from 7:00-9:00 pm. c) Lake McCarrons Meeting – Thursday, October 3, 2013 from 6:00 – 8:00 pm at Roseville City Hall. d) MAWD Annual Meeting and Trade Show, December 5-7, 2013, Arrowwood Resort, Alexandria. The Villa Park Wetland Restoration Project is one of the featured presentations at this conference.

Project Updates a) Villa Park Wetland Restoration Project Dredging at Villa Park is almost complete. b) TBI – Cayuga Relocation Project Connections for the new segment of TBI to the existing sections continues and will be completed in by October 7th.

W:\04 Board of Managers\Correspondence\Administrator's Report 2013\Administrator's Report 10-2-13.docx

Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District.