Site-Specific Green Infrastructure Projects

5. SITE-SPECIFIC GREEN INFRASTRUCTURE PROJECTS Green Infrastructure Design Process Concept Development Focus Area Concepts Preliminary Designs Permit-Level Designs

GREEN INFRASTRUCTURE What is Green Infrastructure?

Green Infrastructure (GI) refers to natural and man-made landscapes and practices that reduce stormwater runoff using vegetation, soils, and natural processes to manage water and create healthier urban and suburban environments. These practices capture, manage, and/or reuse rainfall close to where it falls, reducing stormwater runoff and keeping it out of drainage systems, combined sewer systems, and receiving waters.

Examples of natural green infrastructure include forests, meadows, and floodplains and land conservation strategies to preserve these features in a natural or undeveloped state. Examples of man-made green infrastructure include Green Stormwater Infrastructure (GSI) for managing

Green Stormwater Infrastructure (GSI)

stormwater runoff at the site or neighborhood scale, such as bioswales, rain gardens, green roofs, and rainwater harvesting, as well as other types of designed green infrastructure such as urban tree canopy, floodplain and riparian corridor restoration and conservation, and urban rewilding.

Bioretention Planters Parking Lot Bioretention

The Benefits of Green Infrastructure In addition to reducing runoff and improving water quality, green infrastructure has been shown to provide many other social and economic benefits as highlighted in the following graphic.

Infiltration basins

Bioretention systems

Bioretention & Walking Trails

Roadside Bioswales

Rain Gardens

Green Streets

Other Natural and Designed Green Infrastructure The multiple benefits of green infrastructure (Source: Carbon180).

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Riparian & Floodplain Restoration

Urban Tree Canopy

Small Urban Forests & Urban Rewilding

DESIGN PROCESS Introduction A stepwise approach was used to identify and develop designs for “high-impact” green infrastructure (GI) projects within the North Branch Park River subwatershed, which was identified in the 2010 North Branch Park River Watershed Management Plan as a focus for restoration and green infrastructure implementation. The focus area included targeted portions of the City of Hartford, the Town of West Hartford, and the Town of Bloomfield that contribute pollutant loadings to the North Branch Park River. High-impact projects are generally larger-scale projects capable of achieving substantial reductions in pollutant (fecal indicator bacteria, nutrients, and sediment) loads and runoff volumes, with other benefits including but not limited to CSO reduction, increased resilience to flooding and extreme heat, and community enhancement.

The following major goals guided the selection and design of green infrastructure strategies and projects within the North Branch Park River subwatershed: • Improve and protect water quality • Restore and protect the riparian corridor • Increase flood and community resilience • Provide healthy neighborhood amenities • Increase ecological and recreational connectivity

GSI practices that have been shown to be appropriate within the City of Hartford and other areas of the watershed based on cost, maintenance, and effectiveness were considered. These included various types of bioretention systems (bioswales, rain gardens, tree box systems), stormwater wetlands and ponds, subsurface detention/retention systems, rainwater harvesting, green roofs, and infiltration systems where soil and groundwater conditions allow.

Data Gathering and Review

• MDC and municipal storm, sanitary, and combined sewer system mapping • Public and institutional parcel information • Site data and mapping to help inform GI design including soil type, impervious areas, tree canopy, etc.

• Existing GSI or other stormwater treatment systems and planned stormwater retrofits to meet MS4 Permit impervious area reduction goals or other objectives • Ongoing and planning capital improvement projects.

Geographic information system (GIS) infrastructure and site data were compiled from available sources for the lower, developed North Branch Park River subwatersheds in Hartford, West Hartford, and Bloomfield. Data sources included the watershed municipalities, the Metropolitan District (MDC), Capitol Region Council of Governments, and statewide GIS data layers. The information gathered consisted of:

The design process built upon the site-specific green infrastructure concepts presented in the 2010 watershed management plan. The designs were also informed by the project-specific community engagement process, including feedback from the Project Partners, Project Advisory Committee, community members, and other stakeholders.

Green infrastructure projects that were considered as part of the design development process for the North Branch Park River included: • Green stormwater infrastructure (GSI) installations on public and institutional properties (parking lots, driveways, roofs, at existing outfalls, etc.)

• GSI within the municipal right-of-way (i.e., “Green Streets”) • Tree planting and enhancement of urban tree canopy • Riparian, stream, and floodplain restoration • Land conservation to protect or preserve land in a natural or undeveloped state • Walking paths and trails to connect restored riparian/floodplain areas, schools, institutional facilities, and landscapes.

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North Branch Park River Watershed green infrastructure design process

DESIGN PROCESS Project Screening and Selection

Green Infrastructure Concepts

Desktop Screening

Site and neighborhood scale green infrastructure concepts were developed for locations where field inventories and feedback from property owners suggest potential for effective green infrastructure implementation. These concepts provide a high-level vision for green infrastructure – parcel-based GSI, green streets, riparian and floodplain restoration, land conservation, etc. – within the North Branch Park River subwatershed. Plan view concept graphics were developed for the overall subwatershed to show the application of green infrastructure typologies or strategies at the subwatershed scale. More detailed concept graphics were developed at the site and neighborhood scale, organized into 13 different “focus areas.”

A desktop screening-level review was performed to identify potential green infrastructure opportunities on public sites, within the public right-of-way, on institutional properties, and at major outfalls within the project area. The screening process enabled the project team to systematically identify potential green infrastructure project sites that were not originally identified in the 2010 watershed management plan. The desktop screening made use of the mapping and GIS layers compiled in the data gathering and review process to identify sites within the project area with the strong potential for green infrastructure implementation. The screening-level review considered land ownership, physical site characteristics (soils infiltration potential and depth to groundwater), land use, impervious cover, storm drainage and combined sewer systems, and water quality impairments.

Preliminary and Permit-Level Designs Preliminary designs were developed for five (5) priority projects selected from the green infrastructure concepts. Project concepts

The desktop screening process identified approximately 90 parcels and locations for possible green infrastructure implementation projects. These were reviewed with the Project Partners and Project Advisory Committee, as well as through interviews with property owners (Hartford, West Hartford, Bloomfield, MDC, University of Hartford, and others), to assess potential support for green infrastructure projects on these sites.

Field Inventories Field inventories were conducted on December 14 and 15, 2023 of the approximately 90 sites identified from the desktop screening process.

The purpose of the field inventories was to confirm the physical feasibility of green infrastructure and to inform site selection and project designs. The site visits were used to confirm on-site and adjacent land use and development characteristics, impervious surfaces, drainage patterns, the presence of utilities, areas suitable for potential retrofits, and site constraints such as mapped lowpermeability soils or evidence of shallow groundwater or bedrock that could limit the feasibility of infiltration practices. Visual observations were recorded in a GIS-based field form.

Watershed field inventories conducted in December 2023

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that were advanced to preliminary design were selected based on feedback from the Project Partners, Project Advisory Committee and community engagement process. The preliminary designs include a preliminary layout plan, order of magnitude opinion of construction costs, required permits and approvals, and a brief design narrative.

Permit level designs were then developed for the three (3) highest priority green infrastructure projects selected from the preliminary design phase in collaboration with the Project Partners and Project Advisory Committee. Permit level designs are intended to support the local, state, and/or federal permitting process and include design drawings, an updated design narrative, updated cost estimates, and required permits and approvals.

The following sections present concept, preliminary, and permit-level designs for selected green infrastructure projects in the North Branch Park River subwatershed.

CONCEPT DEVELOPMENT FLOODPLAIN & RIPARIAN CORRIDOR The area along the North Branch Park River, which includes the floodplain, riparian area, and adjacent uplands, is a key integrating feature for green infrastructure.

Floodplain A floodplain is the area of land next to a river or stream that is susceptible to being inundated by floodwaters. Floodplains provide important social, economic and ecological functions such as floodwater storage and movement, groundwater recharge, water quality protection (trapping of sediment and nutrients), and wildlife and fish habitat. Floodplains are also places where people, human structures, and critical transportation infrastructure can be vulnerable to disruption and damage.

The regulatory floodplain, also referred to as the flood hazard area or zone, is the flood prone area adjacent to a river or stream defined by the return period of its inundation. For example, the 100-year floodplain corresponds to the area inundated by the flood with a return period of 100 years or a 1 percent chance of occurring in any given year (1 percent Annual Exceedance Probability).

The adjacent figure shows the 100-year and 500-year regulatory floodplains, as mapped by the Federal Emergency Management Agency (FEMA), for the North Branch Park River subwatershed.

WOODED WOODED FLOODPLAIN AND RIPARIAN AREA FLOODPLAIN

PARKING LOTS PARKING LOTS IN INFLOODPLAIN FLOODPLAIN

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CONCEPT DEVELOPMENT FLOODPLAIN & RIPARIAN CORRIDOR Riparian Area & Riparian Corridor Riparian areas are the transition zone between terrestrial and aquatic systems and typically include streambanks, floodplains, wetlands and other systems adjacent to rivers and streams. Riparian areas characteristically have high water tables and are subject to periodic flooding. Healthy riparian areas (i.e., characterized by stable, healthy vegetation) have high ecological diversity, can maintain or improve water quality, and have both recreational and economic benefits.

The riparian corridor encompasses riparian areas, as well as adjacent upland areas needed to protect or restore riparian function. For example, steep erodible slopes that could adversely affect the riparian area or the stream are included in the riparian corridor (see adjacent figure for steep slope areas along the North Branch Park River).

The management goal for riparian corridors is to maintain or restore the area to a vegetated condition to help filter pollutants and to protect riparian habitat and species. Mitigation measures can be located within the riparian corridor to protect water quality and riparian values.

WOODED FLOODPLAIN AND WOODED FLOODPLAIN AND RIPARIAN AREA RIPARIAN AREA

STEEP WOODED SLOPES

PARKING LOTS IN FLOODPLAIN AND PARKING LOTS IN RIPARIAN FLOODPLAIN AREA

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CONCEPT DEVELOPMENT FLOODPLAIN & RIPARIAN CORRIDOR DESIGN STRATEGIES Riparian & Floodplain Restoration Restore riparian areas and floodplains currently occupied by parking lots and other flood prone development to re-establish natural ecological system processes and functions (water quality, habitat, flood reduction, etc.). Restoration of these areas would involve converting portions of the existing parking lots to a more natural condition and function by removing the man-made infrastructure, removing non-native vegetation, amending the soils, and planting native trees and shrubs. Other modifications to the streambanks, riparian area, and floodplain may be warranted to re-connect the stream to its floodplain and restore lost hydrologic function and habitat.

LAND CONSERVATION OF FLOODPLAIN FLOODPLAIN, AND RIPARIAN RIPARIAN CORRIDOR, CORRIDOR,AND INCLUDING WOODED WOODED STEEPSTEEP SLOPES SLOPES

Land Conservation Protect or preserve land in a natural or undeveloped state through acquisition and/or conservation easement or other type of conservation restriction.

Target existing undeveloped parcels along riparian corridors and in headwater areas, as well as areas proposed for riparian and floodplain restoration.

Challenges • Loss of existing parking and future development potential • Voluntary cooperation of property owners • Strategies and incentives to reduce parking and other impervious cover such as shared parking, stormwater user fee and credit system, and structured parking

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RIPARIAN/FLOODPLAIN FLOODPLAIN RESTORATION OF RESTORATION OF EXISTING EXISTING PARKING LOTS PARKING LOTS

CONCEPT DEVELOPMENT

SUBSURFACE STORMWATER STORAGE

IMPERVIOUS SURFACES & POLLUTED RUNOFF DESIGN STRATEGIES Green Stormwater Infrastructure Retrofit existing impervious surfaces with bioswales, rain gardens, infiltration systems, green roofs, and other green stormwater infrastructure (GSI) practices.

Numerous GSI retrofit opportunities exist on public and institutional properties within the North Branch Park River subwatershed including parking lots, schoolyards, and along roads (green streets). Opportunities also exist for installation of larger subsurface storage and infiltration systems below athletic fields and parking lots.

Several areas of the watershed with combined sewers are slated for future sewer separation (e.g., Granby Street and Blue Hills neighborhood), creating the opportunity to incorporate GSI into the right-of-way (green streets) as part of the sewer separation and GSI treatment of new separated stormwater discharges that will serve these areas.

Challenges • Voluntary cooperation of property owners • Combined sewers in a large portion of the subwatershed. MDC currently prohibits the use of open-bottom stormwater infiltration systems in combined sewer areas due to concerns about groundwater potentially entering the combined sewer system through stormwater infiltration systems.

• Portions of the watershed are underlain by soils with low infiltration capacity (clay soils) and a high groundwater table, which are challenging site conditions for implementation of infiltration-based GSI. This underscores the importance of careful GSI selection and design.

• Strategies and incentives to reduce impervious cover such as stormwater user fee and credit system NORTH BRANCH PARK RIVER WATERSHED MANAGEMENT PLAN UPDATE | 41

GREEN STREETS

GREEN STORMWATER INFRASTRUCTURE IN PARKING LOTS

CONCEPT DEVELOPMENT IMPROVED ECOLOGICAL & RECREATIONAL CONNECTIVITY DESIGN STRATEGIES

EVALUATE RIVER CROSSING FOR REPLACEMENT

Walking Paths and Trails Create walking paths and trails within restored riparian/floodplain areas to connect area schools, institutional facilities, and landscapes to the river corridor and to the proposed Hartline multi-use trail.

Boardwalks could be used within the restored floodplain to elevate the walking paths above the flood elevation.

Existing sidewalks, as well as new side paths and bicycle lanes added along existing roads, could provide connections between the walking path/trail network and existing or proposed green spaces in the watershed. The proposed walking paths/trails and green streets can also serve as cooling corridors by providing shaded routes for walking and bicycling.

TRAIL CONNECTIONS

River & Stream Crossings There are numerous road crossings (culverts and bridges) of the North Branch Park River and its tributaries. These crossings have the potential to restrict wildlife (terrestrial and aquatic) passage, restrict flood flows and act as choke points for trees and debris, and contribute to erosion and degraded water quality. The road-stream crossings in the watershed should be evaluated for potential upgrade/replacement and related stream restoration.

Challenges • Voluntary cooperation of property owners • Public concern over proposed walking paths/ trails • Engineering and fluvial geomorphic evaluation of river and road-stream crossings NORTH BRANCH PARK RIVER WATERSHED MANAGEMENT PLAN UPDATE | 42

WALKING PATHS IN RESTORATION AREAS

SOUTH OF FARMINGTON AVENUE

FOCUS AREA CONCEPTS

NORTH BRANCH PARK RIVER CONDUIT ENTRANCE

GREEN STREETS (TYP)

CSO N-22 CSO N-30

HARRIET BEECHER STOWE CENTER

CLEMENS PLACE SIDE PATH

GREEN STORMWATER INFRASTRUCTURE (TYP)

GREEN ROOF (TYP) SHEPHERD PARK ELDERLY HOUSING

NORTH BRANCH PARK RIVER CONDUIT

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FARMINGTON AVENUE TO ASYLUM AVENUE

FOCUS AREA CONCEPTS

CONNECTICUT MUSEUM OF CULTURE AND HISTORY

CSO N-10

CSO N-9

CLASSICAL HIGH SCHOOL

CONNECTICUT COMMUNITY COLLEGES WALKING TRAILS / LOOP POLLINATOR GARDEN

SUBSURFACE STORMWATER STORAGE

FLOODPLAIN RESTORATION WITHIN EXISTING PARKING LOTS HARTFORD INTERNATIONAL UNIVERSITY FOR RELIGION AND PEACE

GREEN STORMWATER INFRASTRUCTURE (TYP)

GREEN STREETS (TYP)

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LAND CONSERVATION

ASYLUM AVENUE TO HOMESTEAD AVENUE

FOCUS AREA CONCEPTS

GREEN STREETS (TYP)

FLOODPLAIN RESTORATION WITHIN EXISTING PARKING LOTS

GOODWIN CIRCLE

WOODSIDE CIRCLE WALKING TRAILS / LOOP

POLLINATOR GARDEN

LAND CONSERVATION

CSO N-9

SUBSURFACE STORMWATER STORAGE CONNECTICUT MUSEUM OF CULTURE AND HISTORY

EVALUATE EXISTING STREAM CROSSING (TYP)

CLASSICAL HIGH SCHOOL

GSI GSI WITHIN WITHIN PARKING PARKING PARKING LOTS LOT LOT (TYP) (TYP) (TYP)

CONNECTICUT COMMUNITY COLLEGES

CSO N-9

WALKING TRAILS / LOOP

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FOCUS AREA CONCEPTS

HOMESTEAD AVENUE & GOODWIN’S WILD

EVALUATE EXISTING STREAM CROSSING (TYP)

GREEN STREETS IN FUTURE SEWER SEPARATION AREA (TYP)

PROPOSED SIDE PATH

EVERSOURCE ELECTRICAL SUBSTATION GREEN STORMWATER INFRASTRUCTURE WITH BROWNFIELD REDEVELOPMENT

FLOODPLAIN RESTORATION

LAND CONSERVATION

GREEN STREET SCARBOROUGH STREET

GOODWIN’S WILD (OLD GROWTH FOREST)

FUTURE HARTLINE MULTIUSE TRAIL

FLOODPLAIN RESTORATION WITH FUTURE SITE REDEVELOPMENT

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FOCUS AREA CONCEPTS

UPPER ALBANY NEIGHBORHOOD

GREEN STREETS IN FUTURE SEWER SEPARATION AREA (TYP)

HANDEL PERFORMING ARTS CENTER AT UNIVERSITY OF HARTFORD GSI WITHIN PARKING LOTS (TYP)

GSI WITHIN PARKING LOTS (TYP)

GREEN STORMWATER INFRASTRUCTURE WITH BROWNFIELD REDEVELOPMENT

FUTURE HARTLINE MULTIUSE TRAIL

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ALBANY BRANCH

FOCUS AREA CONCEPTS

NORTH OF ALBANY AVENUE & MARK TWAIN DRIVE WALKING TRAIL UNIVERSITY HIGH SCHOOL OF SCIENCE & ENGINEERING

GSI WITHIN UNIVERSITY HIGH SCHOOL PARKING LOT FLOODPLAIN RESTORATION OF UHART PARKING LOT

GSI TO TREAT FUTURE SEPARATE STORM DRAIN OUTFALL UNIVERSITY OF HARTFORD MAGNET SCHOOL

CSO N-2

GSI WITHIN PARKING LOTS (TYP)

ANNIE FISHER MONTESSORI MAGNET SCHOOL

LAND CONSERVATION

ONGOING PHASED REDEVELOPMENT WITH LID/GSI

FLOODPLAIN RESTORATION

GREEN STREET ALONG MARK TWAIN DRIVE FUTURE HARTLINE MULTI-USE TRAIL CSO N-4

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EVALUATE EXISTING RIVER CROSSING (TYP)

GSI TO TREAT FUTURE SEPARATE STORM DRAIN OUTFALL

FOCUS AREA CONCEPTS

CRONIN PLAYGROUND & BLUE HILLS NEIGHBORHOOD

LAND CONSERVATION – RIPARIAN AREA OF TRIBUTARY TO NORTH BRANCH PARK RIVER

GSI AT EXISTING STORM DRAIN OUTFALL (TYP)

GSI WITHIN PARKING LOTS (TYP)

GREEN STREETS IN FUTURE SEWER SEPARATION AREA (TYP)

SUBSURFACE STORAGE SYSTEM BENEATH ATHLETIC FIELDS TO MANAGE STORMWATER FROM FUTURE SEPARATE STORM DRAINAGE SYSTEM

LYME ST

GSI WITHIN PARKING LOT ISLANDS AND EDGES (TYP)

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FOCUS AREA CONCEPTS

UNIVERSITY OF HARTFORD – SOUTH GSI WITHIN PARKING LOT (TYP) EVALUATE EXISTING STREAM CROSSING (TYP)

WALKING TRAIL

GSI AT EXISTING STORM DRAIN OUTFALL (TYP)

FLOODPLAIN RESTORATION OF UHART PARKING LOT

GSI WITHIN PARKING LOT (TYP)

UNIVERSITY OF HARTFORD MAGNET SCHOOL

WATKINSON SCHOOL LAND CONSERVATION

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FOCUS AREA CONCEPTS

UNIVERSITY OF HARTFORD – NORTH

GREEN STREET (TYP)

FUTURE HARTLINE MULTI-USE TRAIL GSI WITHIN PARKING LOT (TYP)

GSI WITHIN PARKING LOT (TYP)

EVALUATE EXISTING STREAM CROSSING (TYP)

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ELIZABETH PARK

FOCUS AREA CONCEPTS

GREEN STREET (TYP)

ENHANCED POND BUFFER

ELIZABETH PARK POND

WALBRIDGE RD

GSI ALONG PARK ROADS ROADSAND ANDIN PARKING LOTS (TYP)

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ELIZABETH PARK EAST

ELIZABETH PARK ROSE GARDEN INTEGRATE GSI INTO FUTURE PARK IMPROVEMENTS CONSISTENT WITH UPDATED MASTER PLAN FOR ELIZABETH PARK EAST

FOCUS AREA CONCEPTS

BLOOMFIELD AVENUE AND SIMSBURY ROAD CORRIDOR – WEST HARTFORD PORTAGE ROAD AND SUNNY REACH DRIVE NEIGHBORHOOD

GREEN STREETS (TYP) HEBREW CENTER FOR HEALTH & REHABILITATION

GSI WITHIN PARKING LOTS (TYP) LAND CONSERVATION

NEW ENGLAND JEWISH ACADEMY

JEWISH COMMUNIY CENTER CAMPUS

GSI WITHIN PARKING LOTS (TYP) EVALUATE EXISTING STREAM CROSSING (TYP)

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BROOKDALE WEST HARTFORD

PORTAGE ROAD & SUNNY REACH DRIVE NEIGHBORHOOD – WEST HARTFORD

FOCUS AREA CONCEPTS

GREEN STREETS (TYP)

HEBREW CENTER FOR HEALTH & REHABILITATION

GSI WITHIN PARKING LOTS (TYP) EVALUATE EXISTING STREAM CROSSING (TYP)

LAND CONSERVATION

JEWISH COMMUNIY CENTER CAMPUS

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FOCUS AREA CONCEPTS

COPACO SHOPPING CENTER – BLOOMFIELD

GSI WITHIN PARKING LOTS (TYP)

LAND CONSERVATION

LOWE’S

GSI WITHIN PARKING LOTS (TYP)

THE HOME DEPOT

GREEN ROOFS (TYP)

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