Seepage and Stability Evaluation by cityofindepmo

Ash Pond Seepage and Stability Evaluation Independence Power & Light Blue Valley Power Station 21500 E. Truman Road Independence, Missouri

Aquaterra Project Number: 5828.10 October 17, 2012

Prepared For:

City of Independence Independence Power & Light 21500 E. Truman Road Independence, Missouri

AQUATERRA Environmental Solutions, Inc.

October 17, 2012 Mr. Joshua Buehre Environmental Program Specialist Independence Power & Light 21500 E. Truman Road Independence, MO 64051 Re:

Ash Pond Seepage and Stability Evaluation Blue Valley Power Station Aquaterra Project No. 5528.10

Dear Mr. Buehre: Aquaterra Environmental Solutions, Inc. (Aquaterra) is pleased to submit this report for engineering services related to the Blue Valley Power Station (BVPS) and its ash pond system. We understand the request for a Seepage and Stability Evaluation of the pond system is the result of a United States Environmental Protection Agency (EPA) evaluation1 of the BVPS Fly Ash and Bottom Ash ponds, as part of EPA’s ongoing national effort to review the management and structural integrity of coal combustion residuals (CCR) and their impoundments. We sincerely appreciate the opportunity to provide Independence Power & Light engineering services on this project. Should you have questions or comments on the report, please contact us at 913-681-0030. Sincerely, Aquaterra Environmental Solutions, Inc.

Patrick M. Goeke, P.E. Senior Project Manager

Doug Doerr, P.E. Principal

Specific Site Assessment for Blue Valley Power Station North and South Fly Ash Ponds, and Bottom Ash Pond, prepared for the U.S. Environmental Protection Agency by GEI Consultants, dated June 2011.

Aquaterra Environmental Solutions, Inc. • 7311 W. 130th Street, Suite 100 • Overland Park, Kansas 66213 • (913) 681-0030 • FAX (913) 681-0012

TABLE OF CONTENTS Page SECTION 1.0 – DISCUSSION ................................................................................................ 1 1.1 Report Summary ............................................................................................. 1 1.2 Background Information .................................................................................. 1 1.3 Historical Data Review and Work Plan Development ...................................... 2 1.4 Subsurface Exploration Program ..................................................................... 4 1.4.1 EC Logging Program ........................................................................... 4 1.4.2 Boring and Piezometer Program ......................................................... 5 1.5 Laboratory Testing Program ............................................................................ 7 1.6 Stability Analyses ............................................................................................ 7 1.6.1 Profiles ................................................................................................. 8 1.6.2 Material Properties ............................................................................... 9 1.6.3 Failure Analysis ................................................................................. 10 1.6.4 Results ............................................................................................... 12 1.7 Conclusions ................................................................................................... 13 General Comments ................................................................................................... 15 SECTION 2.0 – FIGURES .................................................................................................... 16 Figure 1 – Site Location Map .................................................................................... 17 Figure 2 – Site Aerial Photo ...................................................................................... 18 Figure 3 – EC and Boring Location Map ................................................................... 19 SECTION 3.0 – TABLES ...................................................................................................... 20 Table 3.1 - Piezometer Water Level Summary Table ............................................... 20 Table 3.2 - Geotechnical Laboratory Summary Table ............................................... 21 SECTION 4.0 – CONDUCTIVITY LOGS .............................................................................. 22 EC Location Map ....................................................................................................... 23 EC-1 ....................................................................................................................... 25 EC-2 ....................................................................................................................... 26 EC-3 ....................................................................................................................... 27 EC-4 ....................................................................................................................... 28 EC-5 ....................................................................................................................... 29 EC-6 ....................................................................................................................... 30 EC-7 ....................................................................................................................... 31 EC-8 ....................................................................................................................... 32

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TABLE OF CONTENTS Page SECTION 5.0 – DRILLING LOGS ........................................................................................ 33 Boring A1................................................................................................................... 34 Boring A2................................................................................................................... 36 Boring B1................................................................................................................... 38 Boring B2................................................................................................................... 40 Boring C1 .................................................................................................................. 41 Boring C2 .................................................................................................................. 43 SECTION 6.0 – LABORATORY TEST DATA...................................................................... 45 SECTION 7.0 – SLOPE STABILITY ANALYSES ................................................................ 51 SECTION A-A ........................................................................................................... 52 SECTION B-B ........................................................................................................... 57 SECTION C-C ........................................................................................................... 62 SECTION 8.0 – DOCUMENTATION .................................................................................... 67 APPENDIX 1 2012 Geotechnical Testing Data ........................................................ 69 APPENDIX 2 Slope Stability Results ....................................................................... 70 APPENDIX 3 Slope Stability References ................................................................. 71 APPENDIX 4 1977 South Ash Pond Geotechnical Data .......................................... 72

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ASH POND SEEPAGE AND STABILITY EVALUATION REPORT INDEPENDENCE POWER & LIGHT BLUE VALLEY POWER STATION INDEPENDENCE, MISSOURI DECEMBER 13, 2012

SECTION 1.0 – DISCUSSION 1.1

Report Summary

Aquaterra Environmental Solutions, Inc. (Aquaterra) has prepared this report summarizing the installation of boring and piezometers along critical cross sections of the North and South Fly Ash ponds at the Independence Power & Light (IPL) Blue Valley Power Station. The work was completed under contract with the City of Independence and conducted in accordance with the Request for Proposal and Aquaterra's proposal dated June 7, 2012. This report presents a comprehensive description of the historical data review, subsurface exploration, and slope stability analyses conducted at the North and South Fly Ash Ponds at the IPL Blue Valley Power Station. The facility is located at 21500 East Truman Road, in eastern Independence, Missouri. The location of the site is shown on Figures 1 and 2, Section 2. 1.2

Background Information

As part of an ongoing national effort by the United States Environmental Protection Agency (EPA) to review the management of coal combustion residuals (CCR) by assessing the structural integrity of CCR impoundments, GEI Consultants, Inc (GEI) prepared a report in June 2011 assessing the integrity of the North and South Fly Ash Ponds. The GEI findings were based on historical and visual data. The June 2011 GEI report, titled "Specific Site Assessment for Blue Valley Power Station North and South Fly Ash Ponds and Bottom Ash Pond" concluded "the dams and outlet works facilities associated with the impoundments at the Blue Valley Power Station were generally found to be in satisfactory condition. No visual signs of instability, erosion, or movement were observed. However, there are wet areas within a storm water drainage ditch that runs along the toe of the east dike of the North Fly Ash Pond. The wet areas may be due to standing water within the drainage ditch; however they could also be seepage from the toe of the dike. Further evaluation should be conducted to determine the source of water in the wet areas." Regarding the structural stability of the embankments, GEI concluded "Liquefaction potential at this site appears to be very low and is not considered a concern."

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Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

Regarding the adequacy of hydrologic/hydraulic safety, GEI concluded "Based on the current facility operations, recommended hazard classifications, and inflow design flood documents, each of the impoundments appear to have adequate capacity to store the regulatory design floods without overtopping the dikes. Regarding the structural stability of the embankments, GEI recommended: 

Seepage and stability analyses be performed to properly assess the stability of the dike,



Additional borings be performed prior to performing the analyses under the direction of the engineer performing the seepage and stability analysis, and



An Ash Pond Operation Manual be prepared and maintained.

In Enclosure 2 to EPA's letter dated July 28, 2011 to the City of Independence, EPA summarized the Blue Valley Power Station recommendations as follows: The following factors were the main considerations in determining the final rating of the impoundments at Blue Valley Power Station. • • • • • •

The dikes at each of the impoundments are low-hazard structures based on federal and state classifications. The impoundments were generally observed to be in good condition in the field assessment. Hydrologic analyses indicate the dikes at each pond can store the regulatory design flood without overtopping. Seepage and stability analyses of the dikes could not be located and should be performed. Maintenance, surveillance and operational procedures are considered adequate. An operation plan should be developed and maintained.

Based on the conclusions and recommendations in the GEI Consultants report and the letter from EPA, IPL responded to EPA with a scope of work for the implementation of a subsurface exploration and stability assessment of the embankments. 1.3

Historical Data Review and Work Plan Development

During the development of the proposal for the subsurface exploration, Aquaterra recommended use of electric conductivity (EC) logging in lieu of the cone penetrometer testing (CPT). This recommendation was based on our knowledge that during the 1977

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pond design phase, an extensive subsurface exploration program and stability analyses were conducted by Burns and McDonnell and construction of the ponds was most likely overseen by Burns and McDonnell personnel, as that was standard protocol. During the same period, the writer of the report was employed at Burns and McDonnell and completed a similar project at the Sibley Power Station using the same company protocols. Subsequently, IPL provided Aquaterra the results of the borings from the subsurface exploration, but did not have stability analyses documentation (nor knowledge if it had been performed). During the 1977 subsurface exploration, a total of 29 sample borings, 13 auger borings, and 16 hand auger borings were completed in the area of the south fly ash pond and the bottom ash pond located to the west of the fly ash pond. A total of 70 unconfined compression tests and four consolidation tests were performed on undisturbed Shelby tube samples from the borings. The results of the 1977 subsurface exploration program are presented in Section 8, Appendix 4. The GEI report indicated the 1988 design drawings for the North Fly Ash Pond noted that borings were performed in the vicinity of the proposed pond. However, the subsurface investigation report and/or boring logs could not be located. Aquaterra recommended use of the EC logging tool to demonstrate the embankment soils and foundation soils were consistent along the steepest embankment cross sections, where the lowest slope stability factor of safety is most likely to occur due to the combination of embankment height and slope. In Aquaterra's opinion, the correlation of soil conductivity to soil type is more accurate than the correlation of CPT reading to soil type. While CPT data does provide an assessment of soil strength, Aquaterra did not believe the high cost to mobilize CPT equipment to the site was cost effective, given the nature of the historical strength data at the site and the ability to obtain additional strength data in the planned borings. IPL provided Aquaterra a survey of the area. The survey was used to determine the embankment locations that had the steepest downstream slope and largest elevation change between the embankment crest and downstream toe. Based on the historical information and Aquaterra personnel's knowledge of the site, Aquaterra recommended the following subsurface exploration scope of work in our proposal and pre-exploration project meeting with IPL staff: 

Conduct eight EC probes along the east embankment of the South and North Fly Ash ponds, the north embankment of the South Fly Ash Pond, and south embankment of the North Fly Ash Pond.

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

Conduct two borings at three cross sections that represent the steepest cross sections on the east embankment of the South and North Fly Ash ponds and the south embankment of the North Fly Ash Pond.



Complete a boring at the embankment crest and embankment toe of each of the three cross sections and complete the borings with “temporary” piezometers to determine the phreatic surface in the embankment and foundation soils. A pair of nested piezometers was proposed for the two crest borings along the east embankments and a foundation piezometer at the toe of the three cross sections.



Based on the results of the EC probes and field borings, select representative samples of the embankment and foundation soils for geotechnical testing, including moisture, density, Atterberg limits, and strength testing.

EC logging and soil borings were not proposed at the Bottom Ash Pond because Aquaterra's engineer's evaluation of the bottom ash pond embankment height and downstream slope configuration were substantially lower than the North and South Fly Ash Ponds. Since these “driving” forces were considerably smaller than the critical profiles evaluated, the probability of a bottom ash embankment failure was unlikely to occur before a fly ash embankment failure. Therefore, if it can be shown that the fly ash embankments are suitably stable, the Bottom Ash embankments are even less critical. 1.4

Subsurface Exploration Program

1.4.1

EC Logging Program

On July 26, 2012, Aquaterra mobilized a Geoprobe® rig and EC logging equipment to the site to conduct EC probes along the fly ash pond embankments. The work was performed to classify the embankment and foundation soil types in the embankment areas most likely to have to the lowest slope stability factor of safety. Conductivity logs were obtained using Aquaterra’s Geoprobe model SC 400 Wenner EC probe and a Geoprobe model FC-5000 data logger. The EC probe was generally driven to a depth of 35 to 40 feet through the embankment and foundation soils. The data was transferred

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from the field computer and imported into a spreadsheet for plotting during the exploration program for analysis and to determine if modifications of the exploration work plan were necessary. The above graph presents the conductivity data for the eight locations. The locations of the EC probes are shown on Figure 3 in Section 4 together with the data and graphs. As shown on the conductivity graph to the right, the embankment and foundation soils generally consist of fine grained clays and silts to the depth explored. The conductivity probe was generally pushed to probe refusal, defined as the point where hammering presented a risk to the conductivity sensors in the probe. Probe refusal appears to have been in dense clays based on the subsequently completed boring logs. Based on the EC results, the embankment and foundation soils appeared to be consistent with depth and generally consistent along the embankments; therefore no changes were made to the planned cross section boring locations. 1.4.2

Boring and Piezometer Program

On July 27, 2012, Aquaterra's drilling subcontractor mobilized a CME 5500 rotary drill rig to the site to complete the six proposed borings. The borings were drilled using 3¼-inch inside diameter hollow stem augers. Soil samples were collected using Shelby tubes and split spoon samplers for geotechnical laboratory testing of the embankment and foundation soils and to prepare logs of the borings. Each sample was classified in the field and field pocket penetrometer readings were taken by Aquaterra's field geologist. The borings were drilled to depths of 17.5 to 32 feet. The three borings through the embankment were drilled to depths ranging from 30 to 32 feet, and the borings located at the toe of the embankment were drilled to depths ranging from 17.5 to 25 feet. With an ash pond embankment height of 19 to 22 feet, the borings through the embankment allowed for the collection of foundation soils samples to evaluate the strength gain of the foundation due to the consolidation of the soil under the embankment loading. The boring depths were designed to allow for new data to supplement the existing site data, and collection of the necessary soil samples for the laboratory testing program. Piezometers consisting of 1-inch diameter PVC pipe with 6 inches of field slotted screen were installed in selected borings. The piezometer screen sections were backfilled with approximately 1.5 to 2 feet of silica filter sand before a hydrated bentonite seal was placed over the sand. For nested piezometers, hydrated bentonite was placed to the planned depth of the second piezometer and the process was repeated. The crest wells were protected with a temporary flush mount well cover and the toe borings were terminated

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above the ground surface and flagged. The horizontal locations of the borings were surveyed by a licensed land surveyor using GPS equipment and the elevation of the top of the piezometer casings were determined by the survey using a total station. The piezometers were abandoned following collection of required water level data, due to State of Missouri temporary piezometer regulations. The boring logs are presented in Section 5 and the water levels are presented in Section 3, Table 3.1. The examination and testing of the soil samples indicates the embankment soils consist of similar fine grained clays throughout the embankment. No evidence of vegetative material was observed in the samples, indicating that proper topsoil stripping was likely performed as part of the embankment construction. No evidence of ash was observed in the samples, indicating the embankments were not likely constructed over fly ash or bottom ash. Bedrock was not encountered in the borings during this exploration or the 1977 exploration. The Missouri database that maintains boring logs from various sources includes several boring logs to the east of the facility that indicate the depth to the Pleasanton shale in the area is generally 75 feet. Following installation of the temporary piezometers, Aquaterra measured water levels in the piezometers on three occasions over a five-week period. Due to the fine grained soils making up the embankment and foundation materials, the piezometers were slow to stabilize. As shown in Table 3.1, due to the low permeability of the clay soils, the piezometers were slow to stabilize and the water levels continued to increase with time. The water levels from the last set of data, collected on September 7, 2012, are shown on the profiles presented on Figure 3, Section 2. As can be seen on the figure, at Profile A-A, the piezometer located in the was dry while the piezometer located under the embankment was lower than the water level in the piezometer located near the toe of the embankment. As the South Ash Pond is nearly filled with ash and the embankment is no longer acting as a water retention structure, embankment and foundation water levels lower than expected for a homogeneous water retention structure are not unexpected. At Profile C-C located in the North Ash Pond, the water level in the embankment piezometer is dry while the water level in the piezometer located in the foundation soils under the embankment is approximately the same elevation as the water level in the piezometer near the toe of the embankment. The water level in the embankment piezometer is lower than would be expected for the water level in a homogeneous water retention embankment. The lower water levels may be due to the water levels not having stabilized, but could be due to the presence of ash against the upstream face of the embankment or the low permeability of

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the clay embankment. The water levels at both Profile A-A and C-C indicate that water piping through the embankments is unlikely. Laboratory Testing Program Following completion of the boring program, Aquaterra's geotechnical engineer reviewed the boring logs, pocket penetrometer data, and available undisturbed soil samples to develop the laboratory testing program. The strength testing program was designed to determine the range of soil shear strength for the embankment and foundation soils at the site. Due to the cohesive nature of the soils, unconfined compression tests were used to determine the soil shear strength. Additional samples were held in reserve in the event that samples failed prematurely in the unconfined state and triaxial testing was necessary to obtain the necessary shear strength data. The results of the laboratory testing are presented in Table 3.2, Section 3 and on the boring logs in Section 5. The laboratory strength test report sheets are provided in Section 6. The geotechnical testing program consisted of 37 moisture content determinations, seven dry density determinations, six Atterberg limit determinations, and seven unconfined compression tests. The following table summarizes the range of test data for the embankment and foundation soils. Laboratory Test Moisture Content, % Dry Density, pcf Liquid Limits, % Plastic Index, % Unconfined Compressive Strength, psf

Embankment 17.8 - 27.9 99.1 - 103.0 45 - 58 37-24

Foundation 14.5 - 34.4 90.1 -103.2 43 - 73 20 - 48

947 - 3452

956 - 3656

pcf = pounds per cubic foot psf = pounds per square foot

1.5

Stability Analyses

Using the historic data and the data developed during the 2012 subsurface exploration, this section presents the engineering analysis performed to determine the static and seismic slope stability of the critical embankment sections that form the fly ash ponds at the facility, as requested in the July 28, 2011 EPA letter to the City of Independence.

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A review of the ash ponds and the site survey resulted in the identification of three embankment cross sections that represent the embankment areas having the combination of greatest height and steepest slope. The location of these worst case profiles are depicted on Figure 3, Section 2. The three cross sections were identified as Profile A-A, Profile B-B and Profile C-C. A profile was not selected for evaluation in the Bottom Ash Pond as the lesser height of the embankment and shallower grade of the downstream slope produce significantly lower “driving forces” compared to the same characteristics in the North and South Fly Ash Ponds. Based on this observation, the critical profiles are in the North and South Fly Ash Ponds. If these are determined to be suitably stable, then the Bottom Ash Ponds will also be considered stable. The soil properties and approximate stratigraphy in each profile were based on previous data developed during the original design of the facility and two additional borings that were completed during this evaluation. Each profile was cut perpendicular to the slope to provide accurate representations of the driving and resisting forces acting on critical slip surfaces. Deep global soil and ash waste mass analysis was performed as part of the scope of service. This analysis was performed using a 2-D general limit equilibrium (GLE) numerical model from Geoslope International's Geostudio 2007, Slope W™, Version 7.19, Build 5027. Graphical results of the slope stability analyses are included in Appendix 2, Section 8. The following sections describe the input parameters and considerations, results, and methodologies employed. 1.6.1

Profiles

Profile A-A is located on the east embankment of the South Fly Ash Pond. The profile is approximately 125 feet long, with approximately 15 feet of vertical relief. The section runs from northwest downhill to the southeast. The embankment soil consists of stiff, brown silty clay which is underlain by alluvial sediments that range from stiff, silty clay to stiff, clayey silt which extended to the bottom of the borings at elevations around 720 feet above mean sea level (msl). Profile B-B transects the embankments separating the North and South Fly Ash Ponds. It is about 150 feet long, with 20 feet of vertical relief. The portion of this profile that was evaluated forms the south embankment of the North Fly Ash Pond. The embankment soils consist of stiff to very stiff, brown silty clay. The alluvial soils located beneath the embankment consisted of moist, stiff, silty clay, and gradually transitioned to very silty clay and then clayey silt, and ultimately to clayey sand which was encountered below an approximate elevation of 734 feet msl.

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Profile C-C transects the eastern embankment of the North Fly Ash Pond. This profile covers about 150 feet of run with 15+ feet of vertical relief. The embankment soil consists of stiff to very stiff, silty to very silty, clay. These embankment soils were underlain by the alluvial soil sequence which was consistent with the other profiles. The uppermost soil was a silty clay that transitioned to clayey silt, then sandy clay and finally clay sand at an approximate elevation of 732 feet msl. Prior onsite deep borings performed by others indicated a soil depth of 64.5 feet below ground surface (bgs) (elevation 693 feet msl) with no indication of bedrock or why the boring stopped (AP-8). A nearby boring log from the Missouri well record database shows a depth of 75 feet to shale bedrock. Because of the uncertainty of the long term piezometric levels in the embankments, the analyses were performed using two different water levels: the measured water levels from the piezometers and a worst case (high water level) condition. The first set of stability analyses was performed using the measured water levels and a second set of stability analyses was performed using a water level higher than likely to be encountered in a homogeneous water retention embankment to provide a worst case analysis. 1.6.2

Material Properties

The material properties used as slope stability analysis input are summarized below in the input properties table, Material Layer Properties Input into the Slope W™ Stability Model Static Analysis. The strength of soil materials contained in these tables and the associated references are footnoted and literature references are provided in Appendix 3, Section 8. The strength properties of the soil layers that were modeled were developed for each particular layer using site specific test data derived from the samples obtained as part of the above described field work (where available). The soil samples were tested by Alpha Omega Geotechnical, Inc. 20122 as noted above. The strength parameters used in the model are noted on the Summary of Laboratory Testing provided in Section 3, Table 3.2. Of additional noteworthiness, a relatively soft layer was observed at the bottom of boring C1 at a depth of 28 to 30 feet bgs. The approximate unconfined shear strength (Qp) was observed to range from 500 to 1500 pounds per square foot (psf) in the field, with a laboratory Qp reported at 1000 psf. To be conservative, 500 psf was used in the Profile C-C modeling effort.

Alpha Omega Geotechnical Inc., "Summary of Laboratory Testing - Project #: 12-312E, 30 July 2012, 14 pgs.

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The unit weight property of the fly ash material used in modeling was developed using Kim et.al., (2005)3. The reported minimum range in ash waste dry density and the corresponding moisture contents resulted in a wet density of 92 pounds per cubic foot (pcf). This value was for mechanically compacted ash waste. Since ash waste in the subject ash ponds was reportedly sluiced into place, and reportedly received no mechanical compactive effort, Aquaterra believes that a unit weight of 92 pcf represents a conservatively high factor as a potential driving force in the slip surface evaluation. Since no information was available regarding the representative shear strength of the ash waste, Aquaterra assigned a nominal 1 psf cohesion and a 0° friction angle () (un-drained condition) to be conservative. Note that Kim et.al. reported a minimum  angle of 28°.

Material Layer Properties Input into the Slope W™ Stability Model Static Analysis Material Profile

Embankment Soil (A) Fly Ash Waste Dark Brown Silty Clay (B) Blue Gray Clay Silt (C) Gray Brown Silty Clay (D) Clayey Sand (E) Impenetrable Layer

Density

pcf

psf

126

125

3450

92 118 123 122* 123 131* 130 134* N/A

 Degrees

3250 950 1 1300 1250 1000 950 1000 750 250 3250 500 500 500 Impenetrable

0 0 0 0 0 0 0 0 0 0 0 0 0 0 Impenetrable

*Values derived from Huang 1983 Default source is Table 2.1

1.6.3

Failure Analysis

Each profile was analyzed for the static condition and the results of these analyses are provided in Section 7. Slope WTM 2007 solves two factor of safety (FOS) equations: one satisfying force equilibrium and one satisfying moment equilibrium. The stability process involves passing a slip surface through the earth mass and dividing the inscribed portion into vertical slices. The slip surface may be circular, composite (i.e., combination of circular and linear portions), or consist of any shape defined by a series of straight lines (i.e., fully specified slip surface). Slope WTM 2007 has undergone a rigorous validation and verification process, which can be accessed on the Geoslope International website (www.geo-slope.com). 3

Kim, B., Prezzi, M., and Salgado, R., “Geotechnical Properties for Fly and Bottom Ash Mixtures for Use in Highway Embankments” Journal of Geotechnical and Geoenvironmental Engineering, ASCE, July 2005 pgs. 914 – 924.

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The failure surface is divided into at least 30 vertical slices, and the individual slice forces and moments are computed using the methodologies discussed in this report. Four search routines including Auto Locate, Exit Entry, Block Specified, and Grid and Radius, were employed to identify the critical slip surface. Depending on the search routine, from 1,000 to more than 60,000 individual slip surfaces were screened to identify the most critical potential slip surface. After finding the critical slip surface by one of these methods, a segmental optimization iteration technique is applied to find a more critical solution. This iterative process is repeated from 2,000 to 20,000 times and with each method described above, the most critical optimized slip surface is presented to determine the most critical surface for the static profile analysis. This surface is the surface reported in the above table. Once the critical static slip surface was determined, a sensitivity analysis was performed by applying a seismic load to the initial static condition. This seismic load was varied from 0 to 1.0g in 0.01g increments, and the seismic acceleration for which a FOS of 1.00 was achieved was designated as the seismic acceleration at which permanent deformational yield would occur. This value is defined as the yield acceleration (Ay). If the maximum acceleration (Amax) which the slip surface would experience for the defined design event was less than the Ay, no permanent deformation will occur along the critical slip surface. Aquaterra retrieved peak ground acceleration seismic data from the USGS 2008 data set for a probability of exceedance (PE) of 10% over a period of 250 years, which coincides with the EPA's definition of a seismic impact zone when the resulting peak acceleration is 0.1g or greater. The site, which is located at Lat. 39o 6’ N, Long -94o 19’E, has a peak ground acceleration (Kp) of 0.054g. This is the peak acceleration in the bedrock beneath the site. Note that the site by definition is not in an EPA-defined seismic impact zone. The Missouri Dam and Reservoir Safety Council (MDRSC) regulations (1981)4 specify the procedure to be used in the State of Missouri to estimate the appropriate peak bedrock acceleration (Kp). The MDRSC-required design acceleration for earthquake design for dams and reservoirs is 25% of the Probable Maximum Acceleration (PMA) of bedrock, set for Environmental Class III dams with a dam with less than 50 feet of height. For sites located in Jackson County (Zone E), the PMA is 0.20g and the corresponding Kp is 0.05g (25% of 0.20g). Since the Kp established using the EPA Subtitle D methodology result (0.54g) is higher than the required Kp for the MDRSC, Aquaterra elected to use the Subtitle D value as a conservative factor. 4

Missouri Department of Natural Resources, Geological Survey and Resource Assessment Division, Dam and Reservoir Safety Program, “Dam Safety Publication No. 3, Rules and Regulations of the Missouri Dam and Reservoir Safety Council” 1981, pgs. 14-15 pp. 32

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To determine the maximum acceleration transmitted to the ground surface from the underlying bedrock for the design seismic event, Aquaterra used Seed (1982)5. Available information indicates the site is generally underlain by clays and silts to a depth of 50 to 60 feet, and sands of varying grain size to bedrock. The borings performed at the site during this evaluation encountered cohesive soils of relatively stiff consistency. While the soils appeared to increase in grain size with depth, no cohesionless soils were encountered within the depth of the relatively shallow borings performed for this evaluation. Therefore, Aquaterra made a conservative assumption and used the soil category of “Soft to Medium Clay with Sand” as the soil medium overlying bedrock, which provides maximum amplification of the peak ground acceleration from the bedrock to the surface. As a result, the estimate of the Amax at ground surface was determined to be 0.081g for the design PE of 10% over a period of 250 years, which exceeds the maximum bedrock acceleration required by the MDRSC regulations. 1.6.4

Results

Stability analysis results using the Morgenstern-Price stability modeling method are presented in the table below. The computed FOS for each critical slip surface case is shown below in the stability results table, Global Slope Stability Analysis (Geostudio SlopeWTM). Results indicate the embankments have FOSs that are suitable for the long term functional performance for which they were designed. As a means of comparison, the Rules and Regulations of the MDRSC require a FOS of 1.5 for the Steady seepage, full reservoir case. For the seismic case, the FOSs exceed the MDRSC required FOS of 1.0 for the Earthquake, steady seepage, full reservoir case. The graphic presentations of each case are presented in Section 7. In each case, the graphic depicts the weakest slip surface using the Morgenstern-Price Method as determined using an optimization routine that considers circular, non-circular, and block failure surfaces.

Seed, H.B., and Idriss, I.M., Ground Motions and Soil Liquefaction during Earthquakes, Earthquake Engineering Research Institute, Berkeley, CA. 134 pp, 1982, pg. 37, Figure 19.

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Global Slope Stability Analysis (GeoStudio SlopeWTM) Results

B-B

C-C

1.6

Current WL Condition High WL Condition Current WL Condition High WL Condition Current WL Condition High WL Condition

Method

Seismic – Peak Load Amax to Ay

0.081 g < 0.54 g

1.7 @ 2000 iterations (min)

A-A

Description

Morgenstern-Price with Optimization

Profile

Static Factor of Safety

No permanent deformation

0.081 g < 0.49 g

1.8

No permanent deformation

0.081 g < 0.69 g

2.4

No permanent deformation

0.081 g < 0.75 g

2.3

No permanent deformation

0.081 g < 0.19 g

1.8

No permanent deformation

0.081 g < 0.17 g

1.7

No permanent deformation

Seismic Factor of Safety @ 0.081g 1.4 1.4 2.1 2.0 1.5 1.4

Conclusions

Based upon the embankment slope stability analysis presented above, site observations and measurements, and laboratory testing, Aquaterra concludes the embankments are stable in both the static and seismic loading for the current and potential high piezometric surface conditions. The factors of safety (FOS) for the static loading condition for the current piezometric surface (noted as Current WL) ranges from 1.7 to 2.4 for the three profiles evaluated. These values are well above the normal minimum design threshold of 1.5. The FOS for the static loading condition for the potential high piezometric surface (noted as High WL) ranges from 1.7 to 2.3 for the three profiles evaluated. These values are well above the normal minimum design threshold of 1.5. The seismic loading condition was evaluated using two methodologies. The first method evaluated the change in FOS as a variable seismic load (which varied from 0.01g to 1.0g) was applied to the critical static slip surface. Using this method, the Ay was determined and ranged from 0.19g to 0.69g. Since the Amax for the site was 0.081g, the Ay in each case was well below the Amax and Aquaterra therefore concludes that in the event of a design seismic event for the current piezometric conditions, no permanent deformation would occur along the critical slip surface.

5528.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

The seismic loading condition was evaluated using the High WL as well. The High WL Ay was determined and ranged from 0.17g to 0.75g. Since the Amax for the site was 0.081g, the Ay in each case was well below the Amax and Aquaterra therefore concludes that in the event of a design seismic event for the High Piezometric conditions, no permanent deformation would occur along the critical slip surface. Further, each profile was evaluated for the specific design seismic load (Amax = 0.081g), the current piezometric (Current WL) condition, and the probable high piezometric surface (High WL) condition. The pseudo-static FOS for each profile was determined. The pseudo-static (seismic) FOS for the Current WL condition ranged from 1.4 to 2.1 for the critical slip surface in each profile, and from 1.4 to 2.0 for the High WL condition. The MDRSC regulations establish that a FOS of 1.0 is adequate for earthquake evaluation for a full reservoir. This requirement comports with and is significantly less than the High WL scenario, for which the pseudo-static FOS ranges from 1.4 to 2.0 as noted above. The static and seismic stability of the evaluated embankments are relatively insensitive to significant shifts in the piezometric surface as a review of the stability analysis results shows. Given this observation, there appears to be no substantive slope stability related use for long term monitoring of the piezometers that were installed for this evaluation. While these instruments, if left in place, would provide a local indication of the piezometric surface, and in turn would provide some indication of the potential for piping failure, a more practical and considerably more effective means of monitoring the potential for piping failure would be the initiation of periodic and regular visual observation of the toe of slope for seeps, standing water, varmint or vector burrowing, wet zone vegetation or the development of boggy soils. In the event that visual indicators are observed, preventative action can be implemented in a timely fashion to evaluate the cause and apply appropriate maintenance. Aquaterra is in the process of preparing an Operation Manual for IPL to use at the site that will require implementation of these observations.

5528.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

******* General Comments This report includes analysis of the available information, and does not reflect variations of subsurface stratigraphy which may occur between sampling locations. The extent of such variations may not become evident without further investigation or the completion of further remedial actions. Conclusions drawn by others from the results of this work should recognize the limitation of the methods used. This report is prepared in accordance with generally accepted environmental engineering practices, within the constraints of the client’s directives. It is intended for the exclusive use of the client for specific application to the assessed property. No guarantees, express or implied, are intended or made. *******

5528.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

SECTION 2.0 – FIGURES

5528.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

SECTION 3.0 – TABLES Table 3.1 - Piezometer Water Level Summary Table

9/7/2012

8/27/2012

7/31/2012

Date

Ground

Top of

Total

Surface

Casing Elev

Depth

Elev (MSL)

(MSL)

(feet)

A1a

765.33

765.00

13.51

A1b

765.33

765.00

747.51

Depth to

Water

Elevation

(feet)

(MSL)

751.82

dry

<751.82

29.02

736.31

dry

<736.31

748.18

25.77

721.74

6.35

741.83

750.15

750.90

15.35

734.80

2.75

748.15

C1a

768.33

768.00

12.32

756.01

dry

<756.01

C1b

768.33

768.00

30.49

737.84

16.68

751.32

C2 A1a

752.63 765.33

753.76 765.00

22.93 13.51

729.70 751.82

5.01 dry

748.75 <751.82

A1b

765.33

765.00

29.02

736.31

24.51

740.49

747.51

748.18

25.77

721.74

6.63

741.55

750.15

750.90

15.36

734.79

2.67

748.23

C1a

768.33

768.00

12.32

756.01

dry

<756.01

C1b

768.33

768.00

30.49

737.84

16.55

751.45

C2 A1a

752.63 765.33

753.76 765.00

22.93 13.51

729.70 751.82

4.04 dry

749.72 <751.82

A1b

765.33

765.00

29.02

736.31

22.72

742.28

747.51

748.18

25.77

721.74

1.86

746.32

750.15

750.90

15.36

734.79

2.28

748.62

C1a

768.33

768.00

12.32

756.01

dry

<756.01

C1b

768.33

768.00

30.49

737.84

16.46

751.54

752.63

753.76

22.93

729.70

3.10

750.66

Piezometer ID

5528.10/IPL Embankment Evaluation Report IPL Version

Screen Elev (MSL)

Aquaterra

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

Table 3.2 - Geotechnical Laboratory Summary Table

CL = low plastic clay, CH = high plastic clay, SC = sandy clay

5528.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

SECTION 4.0 – CONDUCTIVITY LOGS This section includes the eight conductivity logs completed during the subsurface exploration phase of the project.

5528.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

EC Location Map

5528.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

5528.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

Independence Power and Light Conductivity 0

IPL-1

-5

-10

Depth, Feet

-15

-20

-25

-30

-35

-40

Data collected 3/27/2012

100

150

200

250

300

350

400

Independence Power and Light Conductivity 0

ILP-2

-5

-10

Depth, Feet

-15

-20

-25

-30

-35

-40

Data collected 3/27/2012

100

150

200

250

300

350

400

Independence Power and Light Conductivity 0

100

0 IPL-3

-5

-10

Depth, Feet

-15

-20

-25

-30

-35

-40

Data collected 3/27/2012

150

200

250

300

350

400

Independence Power and Light Conductivity 0

IPL-4

-5

-10

Depth, Feet

-15

-20

-25

-30

-35

-40

Data collected 3/27/2012

100

150

200

250

300

350

400

Independence Power and Light Conductivity 0

IPL-5

-5

-10

Depth, Feet

-15

-20

-25

-30

-35

-40

Data collected 3/27/2012

100

150

200

250

300

350

400

Independence Power and Light Conductivity 0

IPL-6

-5

-10

Depth, Feet

-15

-20

-25

-30

-35

-40

Data collected 3/27/2012

100

150

200

250

300

350

400

Independence Power and Light Conductivity 0

IPL-7

-5

-10

Depth, Feet

-15

-20

-25

-30

-35

-40

Data collected 3/27/2012

100

150

200

250

300

350

400

Independence Power and Light Conductivity 0

IPL-8

-5

-10

Depth, Feet

-15

-20

-25

-30

-35

-40

Data collected 3/27/2012

100

150

200

250

300

350

400

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

SECTION 5.0 – DRILLING LOGS This section includes the drilling logs and well completion diagrams for the six borings completed as part of the subsurface exploration.

5528.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

AQUATERRA

LOG OF BORING NO.:

Environmental Solutions, Inc. 7311 West 130th, Overland Park, KS 66213 CLIENT: Independence Power & Light PROJECT NAME: IPL - Blue Valley Ash Ponds

Alpha - Omega Geotech, Inc. Mike Burdick DRILLING RIG: CME 5500

DRILLING CONTRACTOR:

DRILLER:

5528.10 PROJECT LOCATION: 21500 East Truman Road, Independence, MO 64056 PROJECT NUMBER:

BORING LOCATION:

DRILLING METHOD:

3.25"ID HSAs

SAMPLING METHOD:

Split Spoon - Shelby Tube ~8.5" 1" 7/27/2012 NA 751.77 - 751.77 Dry - 24.51 738.26 - 727.26

BORING DIAMETER:

East dike of South Fly Ash Pond

WELL DIAMETER: WELL COMPLETION:

PROJECT NO: GEOLOGIST: START DATE: START TIME:

5528.10 Adam Parris 07/27/12 FINISH DATE: 9:12 FINISH TIME:

SURFACE ELEVATION: TOC ELEVATION:

07/27/12 10:55

WATER LEVEL: WATER ELEVATION:

SAMPLE

BLOW

RECOVERY DEPTH

TYPE

DEPTH

NO.

IN INCHES IN FEET CLASS %M

USCS

DATE:

1-2.5

4-3-4

10.0

3-5

10.0

SHEET NUMBER

1 of 2

WELL CONSTRUCTION DETAILS MATERIAL:

PVC

DIAMETER:

WELL TOTAL DEPTH: 13.5 33 FT BGS SCREEN LENGTH:

0.5 0.5 FT

RISER LENGTH:

13 32 FT

TOP OF SCREEN:

13 32 FT BGS

BOTTOM OF SCREEN: 13.5 33 FT BGS SCREEN SLOT:

NA NA IN

TOP OF FILTER PACK:

12 31 FT BGS

TOP OF SEAL:

0.5 0.5 FT BGS

TYPE OF SEAL: TYPE OF FILTER PACK:

Bentonite Chips Silica Sand

NOTES AND WELL CONSTRUCTION

~18" road gravel

PP=2.5-3.5 TSF

20%

CLAY, Silty, brown, moist, stiff, medium plastic, some gravel

3 ST

8/27/2012

SOIL DESCRIPTION AND DRILLING CONDITIONS

1 SS

PP=3 TSF

4 5 6 7 8 9

PP=2.5 TSF

10 SS

9.5-11

2-3-4

16.0

19%

11 12 ST

12-14

16.0

22% CLAY, Silty, brown, moist, moderately stiff,

medium plastic 14 SS

14-15.5

3-4-5

16.0

28% CLAY, Very Silty, grayish brown, very moist,

PP=2.25 TSF DD= 103.0 pcf Limits (58,21,37 CH) Qu/2 = 3452 psf

******

PP=2-2.5 TSF

softer than previous, highly plastic 16 17 18 ~possible change to native soils 19 SS

19-20.5

2-3-5

LEGEND:

18.0

21% CLAY, Silty, brown, moist, stiff, medium plastic

SS - Split Spoon

DD - Dry Unit Weight P P - Pocket Penetrometer

ST - Shelby Tube HSA - Hollow Stem Augers

%M - Moisture Content Qu/2 - Shear Strength

PP=3.5-4 TSF

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: ACTUAL TRANSITIONS MAY BE GRADUAL.

AQUATERRA

LOG OF BORING NO.:

Environmental Solutions, Inc. 7311 West 130th, Overland Park, KS 66213 CLIENT: Independence Power & Light PROJECT NAME: IPL - Blue Valley Ash Ponds

GEOLOGIST: DATE: PROJECT NUMBER:

SAMPLER

SAMPLE

BLOW

RECOVERY DEPTH

USCS

TYPE

DEPTH

NO.

IN INCHES IN FEET CLASS %M

19-20.5

2-3-5

NOTES:

18.0 CLAY, Silty, brown, moist, stiff, medium plastic PP=3.5 TSF DD= 103.2 pcf Qu/2 = 3656

22%

21-23

2 of

Adam Parris 07/27/12 5528.10

SOIL DESCRIPTION AND DRILLING CONDITIONS

21 ST

SHEET NUMBER

13.0

22 23 CLAY, Very Silty, grayish brown, moist, soft, highly plastic

24 SS

24-25.5

1-2-3

18.0

25.5-27.5

24.0

PP=1.5 TSF

31%

26 27

CLAY, Very Silty, grayish brown, moist, very soft, PP=1.5 TSF highly plastic

28 29 SS

29-30.5

2-2-3

18.0

CLAY, Silty, brown, moist, stiffer than previous,

PP=1.75 TSF

medium plastic 31 32 33

******

Boring Terminated at 32.5'

34 35 36 37 38 39 40 41 42 43 44 45

LEGEND: SS - Split Spoon

DD - Dry Unit Weight P P - Pocket Penetrometer

ST - Shelby Tube HSA - Hollow Stem Augers

%M - Moisture Content Qu/2 - Shear Strength

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: ACTUAL TRANSITIONS MAY BE GRADUAL.

AQUATERRA

LOG OF BORING NO.:

Environmental Solutions, Inc. 7311 West 130th, Overland Park, KS 66213 CLIENT: Independence Power & Light PROJECT NAME: IPL - Blue Valley Ash Ponds PROJECT NUMBER: PROJECT LOCATION:

BORING LOCATION:

DRILLING CONTRACTOR: DRILLER: DRILLING RIG:

5528.10 21500 East Truman Road, Independence, MO 64056

5528.10 GEOLOGIST: Adam Parris START DATE: 07/30/12 FINISH DATE: START TIME: 13:05 FINISH TIME: PROJECT NO:

3.25"ID HSAs

SAMPLING METHOD:

Split Spoon - Shelby Tube ~8.5" 1" 7/30/2012 NA 734.95 6.63 728.32

WELL DIAMETER: WELL COMPLETION: SURFACE ELEVATION: TOC ELEVATION:

07/30/12 13:50

WATER LEVEL: WATER ELEVATION:

SAMPLE

BLOW

RECOVERY

DEPTH

TYPE

DEPTH

NO.

IN INCHES

IN FEET CLASS %M

Alpha - Omega Geotech, Inc. Mike Burdick CME 55

DRILLING METHOD:

BORING DIAMETER:

Toe of the East dike of the South Fly Ash Pond East of A1

USCS

DATE:

8/27/2012

SOIL DESCRIPTION AND DRILLING CONDITIONS

SHEET NUMBER

1 of 2

WELL CONSTRUCTION DETAILS MATERIAL: DIAMETER:

PVC 1 25.5

WELL TOTAL DEPTH: SCREEN LENGTH: RISER LENGTH: TOP OF SCREEN: BOTTOM OF SCREEN: SCREEN SLOT: TOP OF FILTER PACK: TOP OF SEAL: TYPE OF SEAL: TYPE OF FILTER PACK:

IN FT BGS

0.5 FT 25 FT 25 FT BGS 25.5 FT BGS 0.020 IN 24.5 FT BGS 0.5 FT BGS Bentonite Chips Silica Sand

NOTES AND WELL CONSTRUCTION

~organic matter 1 SS

1-2.5

3-3-4

10.0

22% CLAY, Very Silty, dark brown, dry, hard, trace

PP=4.5 TSF

organics, medium plastic 3 4 PP=1.25 TSF ST

4-6

12.0

31% CLAY, Very Silty, dark grayish brown, moist, stiff,

medium plastic 6

DD= 90.1 pcf Limits (73,25,48 CH) Qu/2 = 1295 psf

7 8 9 SS

9-10.5

2-2-3

18.0

33% CLAY, Silty, dark grayish brown, moist, stiff,

PP=1.5 TSF

medium plastic, trace organics 11 12 13 14 SS

14-15.5

2-3-3

18.0

31% CLAY, Very Silty, grayish brown, moist, stiff,

PP=2 TSF

medium plastic 16 17 18 19 PP=1.0 TSF CLAY, Sandy, grayish green, moist, stiff, 23.0 20 CL 28% medium plastic Limits (43,19,24 CL) THE STRATIFICATION LINES REPRESENT APPROXIMATE LEGEND: DD - Dry Unit Weight BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: ACTUAL P P - Pocket Penetrometer SS - Split Spoon TRANSITIONS MAY BE GRADUAL. ST - Shelby Tube %M - Moisture Content HSA - Hollow Stem Augers Qu/2 - Shear Strength ST

19-21

AQUATERRA

LOG OF BORING NO.:

Environmental Solutions, Inc. 7311 West 130th, Overland Park, KS 66213 CLIENT: Independence Power & Light PROJECT NAME: IPL - Blue Valley Ash Ponds

GEOLOGIST: DATE: PROJECT NUMBER:

SAMPLER

SAMPLE

BLOW

RECOVERY

DEPTH

TYPE

DEPTH

NO.

IN INCHES

IN FEET CLASS %M

USCS

19-21

23.0

SHEET NUMBER

Adam Parris 07/30/12 5528.10 NOTES:

SOIL DESCRIPTION AND DRILLING CONDITIONS 28% CLAY, Sandy, grayish green, moist, stiff,

2 of 2

medium plastic

DD= 96.0 pcf Qu/2 = 956 psf

22 SS

22-23.5

0-2-2

18.0

28% CLAY, Very Sandy, grayish blue green, very wet,

PP=0.75 TSF

soft, trace plasticity 24 SS

24-25.5

0-2-2

18.0

25 26

PP=0.75 TSF

31%

******

Boring Terminated at 25.5'

27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

LEGEND: SS - Split Spoon

DD - Dry Unit Weight P P - Pocket Penetrometer

ST - Shelby Tube %M - Moisture Content HSA - Hollow Stem Augers Qu/2 - Shear Strength

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: ACTUAL TRANSITIONS MAY BE GRADUAL.

AQUATERRA

LOG OF BORING NO.:

Environmental Solutions, Inc. 7311 West 130th, Overland Park, KS 66213 CLIENT: Independence Power & Light PROJECT NAME: IPL - Blue Valley Ash Ponds PROJECT NUMBER: PROJECT LOCATION:

BORING LOCATION:

DRILLING CONTRACTOR: DRILLER: DRILLING RIG:

5528.10 21500 East Truman Road, Independence, MO 64056

3.25"ID HSAs

SAMPLING METHOD:

Split Spoon - Shelby Tube ~8.5" NA NA NA NA NA NA

WELL DIAMETER: WELL COMPLETION:

5528.10 GEOLOGIST: Adam Parris START DATE: 07/27/12 FINISH DATE: START TIME: 11:20 FINISH TIME: PROJECT NO:

SURFACE ELEVATION: TOC ELEVATION:

07/27/12 12:30

WATER LEVEL: WATER ELEVATION:

SAMPLE

BLOW

RECOVERY

DEPTH

TYPE

DEPTH

NO.

IN INCHES

IN FEET CLASS %M

Alpha - Omega Geotech, Inc. Mike Burdick CME 5500

DRILLING METHOD:

BORING DIAMETER:

South dike of North Fly Ash Pond

USCS

DATE:

SOIL DESCRIPTION AND DRILLING CONDITIONS

SHEET NUMBER

1 of 2

WELL CONSTRUCTION DETAILS MATERIAL:

DIAMETER:

WELL TOTAL DEPTH:

FT BGS

SCREEN LENGTH:

NA NA NA NA NA NA NA

RISER LENGTH: TOP OF SCREEN: BOTTOM OF SCREEN: SCREEN SLOT: TOP OF FILTER PACK: TOP OF SEAL: TYPE OF SEAL:

TYPE OF FILTER PACK:

FT FT FT BGS FT BGS IN FT BGS FT BGS

NOTES AND WELL CONSTRUCTION

~18" road gravel

2 SS

1.5-3

3-6-6

18% CLAY, Silty, brown, dry, hard, medium plastic,

PP=5 TSF

some gravel

3 4 ST

4-4.5

PP=2.5 TSF

6" 5

4.5-6

4-5-5

18"

CLAY, Silty, brown, moist, very stiff, 20% medium plastic

PP=3.25 TSF

6 7 8 9 SS

9-10.5

2-3-5

18"

23%

11 12 13 14 SS

14-15.5

3-4-5

18.0

24% CLAY, Silty, grayish brown, very moist, stiff

highly plastic

PP=0-3.5 TSF (soft spot ~14.5')

16 17 18 ~possible change to native soils 19 SS

19-20.5

LEGEND: SS - Split Spoon

2-3-5

16.0

DD - Dry Unit Weight P P - Pocket Penetrometer

ST - Shelby Tube %M - Moisture Content HSA - Hollow Stem Augers Qu/2 - Shear Strength

21%

CLAY, Very Silty, grayish brown, moist, stiff, PP=3.5-4 TSF medium plastic, trace organics THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: ACTUAL TRANSITIONS MAY BE GRADUAL.

AQUATERRA

LOG OF BORING NO.:

Environmental Solutions, Inc. 7311 West 130th, Overland Park, KS 66213 Independence Power & Light CLIENT: IPL - Blue Valley Ash Ponds PROJECT NAME:

GEOLOGIST: DATE: PROJECT NUMBER:

SAMPLER

SAMPLE

BLOW

RECOVERY

DEPTH

TYPE

DEPTH

NO.

IN INCHES

IN FEET CLASS %M

USCS

19-20.5

2-3-5

16.0

SHEET NUMBER

2 of 2

Adam Parris 07/27/12 5528.10 NOTES:

SOIL DESCRIPTION AND DRILLING CONDITIONS 21% CLAY, Very Silty, grayish brown, moist, stiff,

medium plastic, trace organics

22 23 ~chunk of wood in split spoon 24 SS

24-25.5

1-2-3

14.0

24% CLAY, Very Silty, grayish brown, moist, medium,

PP=1 TSF

highly plastic 26 27 ~very wet, water on the auger 28 ST

28-30

28.0

CLAY, Very Silty, grayish brown, very moist,

PP=3.25 TSF

very soft, medium plastic 30 Boring Terminated at 30.0' 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

LEGEND: SS - Split Spoon

DD - Dry Unit Weight P P - Pocket Penetrometer

ST - Shelby Tube %M - Moisture Content HSA - Hollow Stem Augers Qu/2 - Shear Strength

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: ACTUAL TRANSITIONS MAY BE GRADUAL.

AQUATERRA

LOG OF BORING NO.:

Environmental Solutions, Inc. 7311 West 130th, Overland Park, KS 66213 CLIENT: Independence Power & Light PROJECT NAME: IPL - Blue Valley Ash Ponds PROJECT NUMBER: PROJECT LOCATION:

BORING LOCATION:

DRILLING CONTRACTOR: DRILLER: DRILLING RIG:

5528.10 21500 East Truman Road, Independence, MO 64056

5528.10 GEOLOGIST: Adam Parris START DATE: 07/30/12 FINISH DATE: START TIME: 14:30 FINISH TIME: PROJECT NO:

3.25"ID HSAs

SAMPLING METHOD:

Split Spoon - Shelby Tube ~8.5" 1" 7/30/2012 NA 738.11 2.67 735.44

WELL DIAMETER: WELL COMPLETION: SURFACE ELEVATION: TOC ELEVATION:

07/30/12 15:00

WATER LEVEL: WATER ELEVATION:

SAMPLE

BLOW

RECOVERY

DEPTH

TYPE

DEPTH

NO.

IN INCHES

IN FEET CLASS %M

Alpha - Omega Geotech, Inc. Mike Burdick CME 55

DRILLING METHOD:

BORING DIAMETER:

Between the North and South Fly Ash Ponds

USCS

DATE:

8/27/2012

SOIL DESCRIPTION AND DRILLING CONDITIONS

SHEET NUMBER

1 of 1

WELL CONSTRUCTION DETAILS

DIAMETER:

PVC 1

WELL TOTAL DEPTH:

MATERIAL:

SCREEN LENGTH: RISER LENGTH: TOP OF SCREEN: BOTTOM OF SCREEN: SCREEN SLOT: TOP OF FILTER PACK: TOP OF SEAL: TYPE OF SEAL: TYPE OF FILTER PACK:

IN FT BGS

0.5 FT 14.5 FT 14.5 FT BGS 15 FT BGS 0.020 IN 14 FT BGS 0.5 FT BGS Bentonite Chips Silica Sand

NOTES AND WELL CONSTRUCTION

~organic matter 1 SS

1-2.5

4-5-5

10.0

15% CLAY, Silty, brown, dry, hard, trace organics,

PP=4.5 TSF

medium plastic, iron oxide streaks 3 4 SS

4-5.5

2-2-4

18.0

25% CLAY, Silty, brown, moist, stiff, medium plastic,

PP=2 TSF

orange and gray mottles 6 7 8 9 ST

9-11

22.0

30% CLAY, Sandy, grayish green, very moist, stiff,

medium plastic 11

PP=1.75 TSF DD= 94.9 pcf Limits (44,24,20 CL) Qu/2 = 1283 psf

12 13 14 ST

14-16

30.0

CLAY, Very Sandy, grayish green, moist, stiff,

PP=2 TSF

******

medium plastic 16 SS

16-17.5

2-2-2

18.0

28% SAND, Clayey, grayish green blue, very wet,

trace plasticity Boring Terminated at 17.5'

PP=0.5 TSF

LEGEND: SS - Split Spoon

DD - Dry Unit Weight P P - Pocket Penetrometer

ST - Shelby Tube %M - Moisture Content HSA - Hollow Stem Augers Qu/2 - Shear Strength

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: ACTUAL TRANSITIONS MAY BE GRADUAL.

AQUATERRA

LOG OF BORING NO.:

Environmental Solutions, Inc. 7311 West 130th, Overland Park, KS 66213 CLIENT: Independence Power & Light PROJECT NAME: IPL - Blue Valley Ash Ponds

DRILLING CONTRACTOR: DRILLER: DRILLING RIG:

5528.10 21500 East Truman Road, Independence, MO 64056

PROJECT NUMBER: PROJECT LOCATION:

BORING LOCATION:

3.25"ID HSAs

SAMPLING METHOD:

Split Spoon - Shelby Tube ~8.5" 1" 7/30/2012 NA 754.72 - 754.72 12.14 - 16.55 742.58 - 738.17

WELL DIAMETER: WELL COMPLETION:

PROJECT NO: GEOLOGIST: START DATE: START TIME:

5528.10 Adam Parris 07/30/12 FINISH DATE: 8:45 FINISH TIME:

SURFACE ELEVATION: TOC ELEVATION:

07/30/12 9:45

WATER LEVEL: WATER ELEVATION:

SAMPLE

BLOW

RECOVERY DEPTH

TYPE

DEPTH

NO.

IN INCHES IN FEET CLASS %M

Alpha - Omega Geotech, Inc. Mike Burdick CME 55

DRILLING METHOD:

BORING DIAMETER:

East Dike of the North Fly Ash Pond

USCS

DATE:

8/27/2012

SOIL DESCRIPTION AND DRILLING CONDITIONS

SHEET NUMBER

1 of 2

WELL CONSTRUCTION DETAILS MATERIAL: DIAMETER: WELL TOTAL DEPTH:

PVC 1

12.5 30 FT BGS

SCREEN LENGTH:

0.5

RISER LENGTH:

30 FT

TOP OF SCREEN:

12 29.5 FT BGS

BOTTOM OF SCREEN:

12.5 30 FT BGS

SCREEN SLOT: TOP OF FILTER PACK:

NA NA IN 11.5 29 FT BGS

TOP OF SEAL:

0.5 0.5 FT BGS

TYPE OF SEAL:

Bentonite Chips

TYPE OF FILTER PACK:

Silica Sand

NOTES AND WELL CONSTRUCTION

~18" road gravel

1 2

CLAY, Very Silty, brown, moist, very stiff, medium plastic, some gravel

3 SS

2.5-4

2-2-2

12.0

PP=3 TSF

27%

4 PP=2.25 TSF ST

4-6

17.0

DD= 99.1 pcf Limits (45,21,24 CL) Qu/2 = 947 psf

6 7 8 9 ST

9-11

17.0

26% CLAY, Silty, brown, moist, stiff, medium plastic,

dark brown streaks 11

PP=1.25 TSF DD= 100.2 pcf Limits (48,19,29 CL) Qu/2 = 1159 psf

12 ~very wet, water on auger

******

* *

******

* ** *

13 14 SS

14-15.5

3-4-7

15.0

21% CLAY, Silty, brown to dark brown, moist, stiff,

PP=3 TSF

highly plastic 16 17

~very wet, water on auger

18 19 SS

19-20.5

2-3-4

LEGEND:

20.0

21% CLAY, Silty, brown, moist, stiff, medium plastic

SS - Split Spoon

DD - Dry Unit Weight P P - Pocket Penetrometer

ST - Shelby Tube HSA - Hollow Stem Augers

%M - Moisture Content Qu/2 - Shear Strength

PP=2 TSF

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: ACTUAL TRANSITIONS MAY BE GRADUAL.

AQUATERRA

LOG OF BORING NO.:

Environmental Solutions, Inc. 7311 West 130th, Overland Park, KS 66213 CLIENT: Independence Power & Light PROJECT NAME: IPL - Blue Valley Ash Ponds

GEOLOGIST: DATE: PROJECT NUMBER:

SAMPLER

SAMPLE

BLOW

RECOVERY DEPTH

USCS

TYPE

DEPTH

NO.

IN INCHES IN FEET CLASS %M

19-20.5

2-3-4

SHEET NUMBER

of 2

Adam Parris 07/30/12 5528.10 NOTES:

SOIL DESCRIPTION AND DRILLING CONDITIONS

20.0 21

CLAY, Silty, brown, moist, stiff, medium plastic

22 23 24 ST

24-26

15.0

CLAY, Very Silty, dark brown, moist, stiff,

PP=1.5 TSF

medium plastic 26 SS

26-27.5

2-2-3

18.0

26% CLAY, Silty, brown, very moist, stiff, highly plastic,

PP=1 TSF

gray sreaks 28 29 SS

28.5-30

1-2-2

18.0

0% CLAY, Silty, brown, very wet, soft, medium

PP=0.25-0.75 TSF

plastic 30

******

Boring Terminated at 30.0' 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

LEGEND: SS - Split Spoon

DD - Dry Unit Weight P P - Pocket Penetrometer

ST - Shelby Tube HSA - Hollow Stem Augers

%M - Moisture Content Qu/2 - Shear Strength

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: ACTUAL TRANSITIONS MAY BE GRADUAL.

AQUATERRA

LOG OF BORING NO.:

Environmental Solutions, Inc. 7311 West 130th, Overland Park, KS 66213 CLIENT: Independence Power & Light PROJECT NAME: IPL - Blue Valley Ash Ponds PROJECT NUMBER: PROJECT LOCATION:

BORING LOCATION:

DRILLING CONTRACTOR: DRILLER: DRILLING RIG:

5528.10 21500 East Truman Road, Independence, MO 64056

5528.10 GEOLOGIST: Adam Parris START DATE: 07/30/12 FINISH DATE: START TIME: 10:50 FINISH TIME:

3.25"ID HSAs

SAMPLING METHOD:

Split Spoon - Shelby Tube ~8.5" 1" 7/30/2012 NA 740.48 4.04 736.44

WELL DIAMETER: WELL COMPLETION:

PROJECT NO:

SURFACE ELEVATION: TOC ELEVATION:

07/30/12 11:15

WATER LEVEL: WATER ELEVATION:

SAMPLE

BLOW

RECOVERY

DEPTH

TYPE

DEPTH

NO.

IN INCHES

IN FEET CLASS %M

Alpha - Omega Geotech, Inc. Mike Burdick CME 55

DRILLING METHOD:

BORING DIAMETER:

Toe of the East dike of the North Fly Ash Pond East of C1

USCS

DATE:

8/27/2012

SOIL DESCRIPTION AND DRILLING CONDITIONS

SHEET NUMBER

1 of 2

WELL CONSTRUCTION DETAILS MATERIAL: DIAMETER: WELL TOTAL DEPTH: SCREEN LENGTH: RISER LENGTH: TOP OF SCREEN: BOTTOM OF SCREEN: SCREEN SLOT: TOP OF FILTER PACK: TOP OF SEAL: TYPE OF SEAL: TYPE OF FILTER PACK:

PVC 1 22.5

IN FT BGS

0.5 FT 22 FT 22 FT BGS 22.5 FT BGS 0.020 IN 21.5 FT BGS 0.5 FT BGS Bentonite Chips Silica Sand

NOTES AND WELL CONSTRUCTION

~organic matter 1 SS

1-2.5

5-6-6

14.0

18% CLAY, Very Silty, brown, dry, hard, some

PP=3 TSF

organics, medium plastic 3 SS

2.5-4

2-2-2

16.0 4 5

28% CLAY, Very Silty, brown, moist, stiff, medium

PP=2 TSF

plastic, trace organics 6 7 8 9 SS

9-10.5

2-2-3

16.0

27% CLAY, Very Silty, brown, moist, stiff, trace

PP=1.5 TSF

plasticity 11 12 13 14 SS

14-15.5

2-2-2

20.0

31% CLAY, Silty, grayish brown, very moist, soft,

PP=0.75 TSF

medium plastic 16 17 ~very wet, water on auger 18 19 ST

19-21

LEGEND: SS - Split Spoon

30.0

DD - Dry Unit Weight P P - Pocket Penetrometer

ST - Shelby Tube %M - Moisture Content HSA - Hollow Stem Augers Qu/2 - Shear Strength

CLAY, Sandy, grayish green, very moist, stiff, PP=1.25 TSF medium plastic THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: ACTUAL TRANSITIONS MAY BE GRADUAL.

AQUATERRA

LOG OF BORING NO.:

Environmental Solutions, Inc. 7311 West 130th, Overland Park, KS 66213 CLIENT: Independence Power & Light PROJECT NAME: IPL - Blue Valley Ash Ponds

GEOLOGIST: DATE: PROJECT NUMBER:

SAMPLER

SAMPLE

BLOW

RECOVERY

DEPTH

TYPE

DEPTH

NO.

IN INCHES

IN FEET CLASS %M

19-21

21-22.5

USCS

30.0

2-2-2

16.0

2 of 2

Adam Parris 07/30/12 5528.10 NOTES:

SOIL DESCRIPTION AND DRILLING CONDITIONS

CLAY, Sandy, grayish green, very moist, stiff, medium plastic

22% SAND, Clayey, fine grain, grayish blue green,

very wet 23

SHEET NUMBER

PP=0.5 TSF

* ** *

* *

* ** *

Boring Terminated at 22.5'

24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

LEGEND: SS - Split Spoon

DD - Dry Unit Weight P P - Pocket Penetrometer

ST - Shelby Tube %M - Moisture Content HSA - Hollow Stem Augers Qu/2 - Shear Strength

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: ACTUAL TRANSITIONS MAY BE GRADUAL.

* *

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

SECTION 6.0 – LABORATORY TEST DATA This section includes the laboratory data sheets for the samples analyzed as part of the subsurface exploration phase of the project.

5528.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

SECTION 7.0 – SLOPE STABILITY ANALYSES This section includes the printout from the slope stability analyses completed as part of the project.

4650.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

SECTION A-A

4650.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

SECTION B-B

4650.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

SECTION C-C

4650.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

Ash Pond Seepage and Stability Evaluation Report Independence Power & Light Blue Valley Power Station October 17, 2012

SECTION 8.0 – DOCUMENTATION

This section includes the following appendices: Appendix 1 – 2012 Geotechnical Testing Data Appendix 2 – Slope Stability Results Appendix 3 – Slope Stability References Appendix 4 – 1977 South Ash Pond Geotechnical Data

4650.10/IPL Embankment Evaluation Report IPL Version

Aquaterra

APPENDIX 1 2012 Geotechnical Testing Data

APPENDIX 2 Slope Stability Results

APPENDIX 3 Slope Stability References

Dam Safety Publication No.3

RULES AND REGULATIONS OF THE MISSOURI DAM AND RESERVOIR SAFETY COUNCIL

. DAM AND RESERVOIR SAFETY COUNCIL CHAIRMAN Mary Hagerty VICE-CHAIRMAN Dean E. Freeman MEMBERS Jeffrey Cawlfield John Boyer Zoretta Schoonover Barbara Adelman Richard Frueh

I r

MISSOURI DEPARTMENT OF NATURAL RESOURCES GEOLOGICAL SURVEY AND RESOURCE ASSESSMENT DIVISION Mimi R. Garstang, Director and State Geologist P.O. Box 250, Rolla, MO 65402-0250 (573) 368-2175

Legal Reference

Page Chapter 3 - Permit Requirements 11 11 11 11 12 12 12 12 12 12 12 12 16 16 16 16 16 16 17 17 17 17 17 17 17 17 18 19 19 19 20 21 21 22 22 22 22 22 22

General Information . General Requirements.. PermitApplication.. EnvironmentalClassification Qualityof Work Slope Stability

...

SeismicAnalysis- Liquefaction SeismicAnalysis- SlopeStability

10 CSR 22-3.010 10 CSR 22-3.020 10 CSR 22-3.020 (1) 10 CSR 22-3.020 (2) 10 CSR 22-3.020 (3) 10 CSR 22-3.020 (4)

10CSR22-3.020(5)

SpillwayDesignFlood RegistrationPermitRequirements ConventionalDams Inspection Maintenanceand Monitoring Rightof Entry Intentof Permit IndustrialWater RetentionDams Inspection.. Maintenanceand Monitoring Phased Construction Rightof Entry. Phased ConstructionSupervision SpecialPermitConsiderations Intentof Permit ConstructionPermitRequirements ConventionalDams InformationRequired Additional Information That May Be Required Rightof Entry IndustrialWater RetentionDams Considerationof PhasedConstruction Recordsand Supervisionof PhasedConstruction InformationRequired Additional Information That May Be Required Rightof Entry ChangedDrawings Safety PermitRequirements ConventionalDams.. IndustrialWater RetentionDams Rightof Entry

10 CSR 22-3.020 (6) 10 CSR 22-3.020 (7) 10 CSR 22-3.030 10 CSR 22-3.030 (1) 10 CSR 22-3.030 (1) (A) 10 CSR 22-3.030 (1) (B) 10 CSR 22-3.030 (1) (C) 10 CSR 22-3.030 (1) (D) 10 CSR 22-3.030 (2) 10 CSR 22-3.030 (2) (A) 10 CSR 22-3.030 (2) (B) 10 CSR 22-3.030 (2) (C) 10 CSR 22-3.030 (2) (D) 10 CSR 22-3.030 (2) (E) 10 CSR 22-3.030 (2) (F) 10 CSR 22-3.030 (2) (G) 10 CSR 22-3.040 10 CSR 22-3.040 (1) 10 CSR 22-3.040 (1) (A) 10 CSR 22-3.040 (1) (B) 10 CSR 22-3.040 (1) (C) 10 CSR 22-3.040 (2) 10 CSR 22-3.040 (2) (A) 10 CSR 22-3.040 (2) (B) 10 CSR 22-3.040 (2) (C) 10 CSR 22-3.040 (2) (D) 10 CSR 22-3.040 (2) (E) 10 CSR 22-3.040 (2) (F) 10 CSR 22-3.050 10 CSR 22-3.050 (1) 10 CSR 22-3.050 (2) 10 CSR 22-3.050 (3)

Chapter 4 - Action Taken by Council and Chief Engineer

23 23

EmergencyAction EnforcementOrders

10 CSR 22-4.010 10 CSR 22-4.020

Page

Legal Reference REVISED STATUTES OF MISSOURI

CHAPTER 236 - DAMS, MillS, AND ELECTRIC POWER

Definitions..

236.400, RSMo (1986)

25 25 25 25 25

Dam and Reservoir Safety Program Program Created Employment of Staff Employment of Chief Engineer Records

236.405, RSMo (1986) 236.405 (1), RSMo (1986) 236.405 (2), RSMo (1986) 236.405 (3), RSMo (1986) 236.405 (4), RSMo (1986)

25 25 25

Dam and Reservoir Safety Council Non-Partisan Council Created Council Composition, Structure, and Operation

236.410, RSMo (1986) 236.410 (1), RSMo (1986) 236.410 (2), RSMo (1986)

26 26 26 26 26

Council Duties and Powers Rules Adoption, Violations, and Hearings Hearings Criteria Issuing Permits and Delegating Authority Rules Adoption Criteria

236.415, RSMo (1986) 236.415 (1), RSMo (1986) 236.415 (2), RSMo (1986) 236.415 (3), RSMo (1986) 236.415 (4), RSMo (1986)

Required Inspections..

236.420, RSMo (1986)

27 27 27 27 27

Chief Engineer's Duties and Powers Recommend Rules Recommend Action on Permits Make Investigations Right of Entry

236.425, RSMo (1986) 236.425 (1), RSMo (1986) 236.425 (2), RSMo (1986) 236.425 (3), RSMo (1986) 236.425 (4), RSMo (1986)

Council Employment of Consultants

236.430, RSMo (1986)

27 27 27 27 28 28 28 28

Construction Permit Dam Owner Must Obtain Application Requirements Consulting with Chief Engineer Time Frame for Permit Action Application Rejection Agricultural Dam Exclusion Design by Conservation Agency Engineers

236.435, RSMo (1986) 236.435 (1), RSMo (1986) 236.435 (2), RSMo (1986) 236.435 (3), RSMo (1986) 236.435 (4), RSMo (1986) 236.435 (5), RSMo (1986) 236.435 (6), RSMo (1986) 236.435 (7), RSMo (1986)

28 28 28 28 28 28 29

Safety, Registration, and Construction Permit Notification of Construction Completed and Application for Safety Permit Safety Permit Procedures Registration Permit Procedures Additional Registration Permit Procedures

236.440, RSMo (1986) 236.440 (1), RSMo (1986) 236.440 (2), RSMo (1986) 236.440 (3), RSMo (1986) 236.440 (4), RSMo (1986)

ConditionalRegistrationPermits

236.440 (5), RSMo (1986) vii

Legal Reference

Page 29 29 29 29 29 29

Removal of Dam Under Construction Permit Safety Permits for Conservation Agency Engineered Dams Safety or Registration Permit Renewal Water Barrier Becomes Dam Violation for Lack of or Non-Compliance with Permit

236.440 (7), RSMo (1986) 236.440 (8), RSMo (1986) 236.440 (9), RSMo (1986) 236.440 (10), RSMo (1986)

29 29 30

Dam Condition Unsafe Suspend Permit and Require Repairs Violation for Failure to Act

236.445, RSMo (1986) 236.445 (1), RSMo (1986) 236.445 (2), RSMo (1986)

Abandoned Unsafe Dams

236.450, RSMo (1986)

Emergency Action Authorized

236.455, RSMo (1986)

Transfer of Ownership

236.460, RSMo (1986)

30 30 30 30 30 31 31 31

Industrial Water Retention Structures Additional Permit Requirements Enlargement Does Not Require New Permit Safety and Registration Permit with Enlargement Engineer Requirements Inspection for Permit Renewal Inspection by Chief Engineer Dams Regulated by Other Agencies

236.465, RSMo (1986) 236.465 (1), RSMo (1986) 236.465 (2), RSMo (1986) 236.465 (3), RSMo (1986) 236.465 (4), RSMo (1986) 236.465 (5), RSMo (1986) 236.465 (6), RSMo (1986) 236.465 (7), RSMo (1986)

31 31 31 31 31 31

Hearings Testimony, Recording,Availability Hearing Officer Powers and Duties Attendance Requirements for Rules Attendance Requirements for Other Matters Approval of Final Orders

236.470, RSMo (1986) 236.470 (1), RSMo (1986) 236.470 (2), RSMo (1986) 236.470 (3), RSMo (1986) 236.470 (4), RSMo (1986) 236.470 (5), RSMo (1986)

Immunity of Officers

236.475, RSMo (1986)

Judicial Review

236.480, RSMo (1986)

Water Rights Preserved

236.485, RSMo (1986)

Enforcement of Act

236.490, RSMo (1986)

32 32 32

Legal Actions Available Subpoena Powers.. Injunctive Relief and Penalties

236.495, RSMo (1986) 236.495 (1), RSMo (1986) 236.495 (2), RSMo (1986)

32 32 32 32 32

Penalties Willful Violation of Law Continued Violation Willful Obstruction or Resistance Willful Violation of Permit Requirements

236.500, RSMo (1986) 236.500 (1), RSMo (1986) 236.500 (2), RSMo (1986) 236.500 (3), RSMo (1986) 236.500 (4), RSMo (1986)

viii

236.440 (6), RSMo (1986)

INTRODUCTION The Dam and Reservoir Safety Council and the Dam and Reservoir Safety Program within the Missouri Department of Natural Resources were established by House Committee Substitute for House Bill 603 as passed by the first regular session of the 80thGeneral Assembly. The bill was signed by the governor and subsequently became law on September 28, 1979. This law is Sections 236.400 through 236.500 in the Revised Statutes of Missouri as printed in the 1986 Supplement. The Dam and Reservoir Safety Program was assigned to the Geological Survey and Resource Assessment Division within the Department of Natural Resources for administration. The Governor began appointment of the first Council during April of 1980. Employment of the Chief Engineer and initiation of recruitment for the additional authorized staff commenced in July 1980. A working Council with a quorum of four members had been appointed by September 1980. From September 1980 to August 1981 the Council, with help from the Chief Engineer and his staff, promulgated the first set of rules. These rules provide the information that is necessary in order to implement the law. These rules became effective on August 13, 1981 and are contained in the Code of State Regulations under Title 10, Division 22, Chapters 1 through 3.

In June 1984, the seventh member of the Council was appointed by the Governor, and the first full seven member council meeting was held in July 1984. From January 1984 to December 1984, the Council, with help from the Chief Engineer and his staff, made extensive revisions to the August 13, 1981 edition of the rules. These revisions became effective on January 1, 1985 and are contained in the Code of State Regulations under Title 10, Division 22, Chapters 1 through 4. The Council has taken action on four other occasions to make minor modifications to the rules. These revisions became effective on January 1, 1987; January 1, 1989; January 1, 1991; and June 9, 1994. The Dam and Reservoir Safety Council is a non-paid policy-making body appointed by the Governor with the consent of the Senate. Communication with the Council is normally handled through the paid staff, which is directed by the Chief Engineer. Questions, comments, requests, and other inquiries should be addressed to the Chief Engineer for action or referral to the Council. The Chief Engineer may be contacted at the following address or telephone number. Chief Engineer Dam & Reservoir Safety Program Missouri Department of Natural Resources PO Box 250 Rolla, MO 65402-0250 573/368-2175

TITLE 10 - DEPARTMENT OF NATURAL RESOURCES DIVISION 22 - DAM AND RESERVOIR SAFETY COUNCIL CHAPTER 3 - PERMIT REQUIREMENTS formation on dams in Missouri should address their inquiry to the chief engineer.

10 CSR 22-3.010 General Information PURPOSE: The purpose of this rule is to provide general information about permit requirements.

Auth: sections 236.400, 236.405, 236.415, 236.435, 236.440 and 236.465, RSMo (1986). Original rule filed April 14, 1981, effective August 13, 1981. Amended: Filed June 14, 1984, effective January 1, 1985.

(1) Requirements for existing or proposed dams and reservoirs must allow for variations in conditionsand materials from site to site. Therefore, this rule and rules 10 CSR 22-3.020 to 10CSR 22-3.050describe the minimum general requirements which are consistent with current engineering, geologic, construction, operation and maintenance practices, necessary to obtain permits from the Dam and Reservoir Safety Council.

10 CSR 22-3.020 General Requirements PURPOSE: The purpose of this rule is to itemize the basic requirements and standards that apply to all permits.

(1) The permit application must contain information required by the council and the chief engineer including, but not limited to, the following information: type of permit being applied for; name of owners; mailing address of owners; telephone number(s) of owners; name of dam; name of reservoir; coordinate location of the dam centerline at the maximum section; purposeor use of dam and reservoir; name, address and telephone number of the experienced professional engineer or agency engineer who has provided or will provide required technical assistance; and the downstream environment zone environmental class for the dam and reservoir. The owners must complete applicable investigations required in 10 CSR 22-3.020 to 10 CSR 22-3.050 before filing a permit application. All permit applications must be filed with the chief engineer at the address listed in 10 CSR 22-3.010 (4).

(2) These rules are not intended to define the only requirements for a dam and reservoirto complywith the law, or the only engineering, geologic and construction practices to be used in detailed site investigation or in the specific design and construction of individual dams. The detailed and specific information that outlines current and prudent engineering, geologic and construction practices is available in technical literature. Determinations by the Dam and Reservoir Safety Council, after hearing the recommendations of the chief engineer of the acceptability of a design and adequacy of plans, specifications and construction must, by necessity, be made on a case by case basis. Therefore, it is recommended that applicants unfamiliar with the way these rules are applied contact the councilor the chief engineer prior to commencing extensive work or plan development.

(2) The owner must provide a determination of an environmental class for each dam and reservoir. The method, data, and assumptions used by the owner to determine environmental class shall conform to practices reputable and in current use in the engineering, geologic and construction profession or the chief engineer may reject the owner's classification. If an owner chooses not to have this done by an experienced professional engineer or an agency engineer, the chief engineer will assign the dam and reservoir to environmental class I or he may assign the dam and reservoir to the appro-

(3) Adherence to the law does not guarantee the safety of any dam or reservoir or relieve the owner of any liability in the event of dam failure. (4) A permit application form along with a copy of the laws, rules, standards, and guidelines relating to dam and reservoir safety can be obtained free from the Department of Natural Resources, Geological Survey and ResourceAssessment Division, Dam Safety Program, PO Box 250, Rolla, MO 65402-0250. Persons seeking this and/or other in11

priate environmental class if he has justification to do so.

rock accelerations and earthquake intensities are listed in Table 4.

(3) The anticipated consequences of a dam failure with respect to public safety, life and property damage are important considerations in establishing acceptable methods for specific investigations and sites. Methods used in exploration, design, construction and maintenance must be in accordance with good engineering practices reputable and in current use in the engineering, geologic and construction professions.

(7) The required spillway design flood, which shall allow for flood storage in the reservoir, is to be derived by usingthe precipitationvalues given inTable5 and shall apply to both new and existing dams. Auth: sections 236.400, 236.405, 236.435, 236.440 and 236.465, RSMo (1986). Original rule filed April 14, 1981, effective August 13, 1981. Amended: Filed June 14, 1984, effective January 1, 1985.

(4) When the owner is applying for a construction permit, the required design factors of safetyfor slope stability for earth and rock conventional dams which are given in Table 1 shall be met. The required design factors of safety for concrete conventional dams are given in Table 2. The required design factors of safety for slope stability for industrial water retention dams are given in Table 3. Owners shall meet these requirements in the design of new dams prior to the issuance of the permit. Owners shall also meet these requirements when substantial changes are proposed to the height or slope of an existing conventional dam or structure prior to the issuance of the construction permit. (see following tables)

10 CSR 22-3.030 Registration Permit Requirements PURPOSE: The purpose of this rule is to itemize the requirements for a registration permit.

(1) In addition to the basic requirements for all permits listed in 10 CSR 22-3.020(1},(2},(3) and (7), the registration permit applicationfor a conventional dam and reservoir must include certification by an experienced professional engineer or an agency engineer that the dam and reservoir have been inspected in accordance with the law and that the owner has compliedwith the engineer's recommendations to correct observed defects and an inspection report, as required by the law. The engineer must further show that the spillway can safely pass the spillway design flood derived from Table 5 and submit a report describing the correction of all observed defects and the description of an operation and maintenance program to be followed while the registration permit is in effect. (A) The inspection of a dam and reservoir for a registration permit is intended to detect observable defects. The procedure to determine observable defects normally will be a surface examination by an experienced professionalengineer or an agency engineer. The inspection must include all surface examinations necessaryto determine if observable defects exist that affect the stability of the dam and reservoir or the adequacy of the spillway. Judgement of the structural stability and an evaluation of the spillway capacity must be made. Judgement shall be based upon the engineer's experience, training and knowledge of similar dams and in accordance with practicesreputableand in current use in the engineering, geologic and construction professions. 1. Observeddefectswhich may require correction, evaluated on the basis of current engineer-

(5) For new dams constructed wholly or partially of cohesionless materials (such as sands and silts) or having a foundation of cohesion less materials, earthquake loading may resultin the build-upof pore water pressures and a loss of strength. Engineers shall take this pore pressure increase and loss of strength into account when performing their stability analysis, but the degree to which liquefaction may affect the factor of safety for slope stability shall be left up to the engineer's best judgement. Bedrock accelerations and earthquake intensities are listed in Table 4. (6) New dams constructed wholly of cohesive materials (such as clays) and having a foundation of cohesive materials or bedrock, can be expected to withstand significant earthquake shaking if it can be shownthat other required design factors of safety for slopestabilityare met. Therefore,only newdams located in Bollinger, Butler, Cape Girardeau, Dunklin, Mississippi, New Madrid, Pemiscot, Ripley, Scott, Stoddard and Wayne counties must meet the requirements for slope stability during earthquake loading while dams located in other counties do not unless 10 CSR 22-3.020(5) applies to them. Bed12

TABLE 1

Required Design Factors of Safety for Slope Stability Earth and Rock ConventionalDams Factor of Safety

Loading Condition End of construction, full reservoir* Steady seepage, full reservoir* Steady seepage, maximum reservoir* Sudden drawdown, from full to empty reservoir (if applicable) Earthquake***, steady seepage, full reservoir* * ** ***

1.4 1.5 1.3 1.2 1.0

Full reservoir means water level is at the water storage elevation Maximum reservoir means water level is at maximum water level attained during the spillway design flood or at the dam crest elevation, whichever is lower. Earthquake loading will vary according to dam location in relation to seismic source zones and downstreamenvironmentalzones. SeeTable4.

TABLE2 Required Design Factors of Safety ConcreteConventionalDams Failure Mode

Loading Condition

Factor of Safety

Overturning

full reservoir* maximum reservoir**

1.5 1.3

Sliding

full reservoir* maximum reservoir**

1.5 1.3

Structural integrity

full reservoir* maximum reservoir**

1.5 1.3

Earthquake*** - any mode

full or maximum reservoir* & **

1.0

* ** ***

Full reservoir means water level is at the water storage elevation. Maximum reservoir means water level is at maximum level attained during the spillway design flood. Earthquake loading will vary according to dam location in relation to seismic source zones and downstream environmental zones. See Table 4.

TABLE 3 Required Design Factors of Safety for Slope Stability Industrial Water Retention Dams Factor of Safety

Loading Condition

1.4 1.3 1.0 1.5 1.3 1.0

Starter dam, end of construction, full reservoir* Any other stage of construction, full reservoir*, steady seepage Any other stage of construction, maximum reservoir**, steady seepage Completed dam, full reservoir*, steady seepage Completed dam, maximum reservoir**, steady seepage Earthquake***, steady seepage, full reservoir* * ** ***

Full reservoir means water level is at the water storage elevation. Maximum reservoir means water level is at maximum water level attained during the spillway design flood or at the dam crest elevation, whichever is lower. Earthquake loading will vary according to dam location in relation to seismic source zones and downstream environmental zones. See Table 4.

TABLE 4 Required Design Acceleration for Earthquake Design

Dam Type Conventional or Industrial

Industrial

Zone: PMA*: Intensity***: * ** ***

Special Descriptions

Stage of Construction

Environmental Class II III

New dams less than 50 feet in height

.75PMA*

.5PMA*

.25PMA*

New dams greater than 50 feet in height**

.75PMA*

.5PMA*

.4PMA*

Starter Dam

New Dams**

.5PMA*

.2PMA*

.1PMA*

After starter dam is finished and before final dam is completed

New Dams**

.75PMA*

.5PMA*

.2PMA*

Completed

A 0.31g IX-X

B 0.28g IX

C 0.26g VIII-IX

D 0.23g VIII

E 0.20g VII-VIII

F O.17g VII

PMA is Probable Maximum Acceleration of bedrock which is determined by the zones as a fraction of the acceleration of gravity (g-32.2fps2) for six zones in Missouri (See 10 CSR 22-1.010(40». See 10 CSR 22-2.020(3) for clarification. Modified Mercalli Intensity.

TABLE 4 (cont.) ZONE A Dunklin Mississippi New Madrid Pemiscot ZONE B Bollinger Butler Cape Girardeau Ripley Scott Stoddard Wayne ZONE C Carter Howell Iron Madison Oregon Perry Reynolds St. Francois Ste. Genevieve Shannon

Camden Carroll Cass Cedar Chariton Christian Clark Cole Cooper Dade Dallas Gasconade Greene Henry Hickory Howard Jackson Jasper Johnson Knox Laclede Lafayette Lawrence Lewis Lincoln

ZONE D Crawford Dent Douglas Franklin Jefferson Ozark Phelps Pulaski St. Louis St. Louis City Taney Texas Washington Wright ZONE E Audrain Barry Barton Bates Benton Boone Caldwell Callaway

Vernon Warren Webster

Linn Livingston McDonald Macon Maries Marion Miller Moniteau Monroe Montgomery Morgan Newton Osage Pettis Pike Polk Ralls Randolph Ray St. Charles St. Clair Saline Scotland Shelby Stone

ZONE F Adair Andrew Atchison Buchanan Clay Clinton Daviess Dekalb Gentry Grundy Harrison Holt Mercer Nodaway Platte Putnam Schuyler Sullivan Worth

TABLE 5 Required Spillway Design Flood Precipitation Values

Dam Type Conventional or Industrial

Industrial

* ** *** ****

Environmental Class III II

Special Descriptions

Any existing dam**

.75PMP*

.5PMP*

100 Yr****

New dams less than 50 feet in height**

.75PMP*

.5PMP*

100 Yr****

New dams greater than 50 feet in height**

.75PMP*

.5PMP*

100 Yr****

Starter Dam

Any

.5PMP*

.2PMP*

.1PMP*

After starter dam is finished and before final dam is completed

Any

.75PMP*

.5PMP*

.2PMP*

Stage of Construction Completed

PMP is Probable Maximum Precipitation. Existing dam means a dam which was completed byAugust 13, 1981 or which was started prior to August 13,1981 and completed byAugust 13, 1987. See 10 CSR 22-2.020(3) for clarification. 100Yr is the 1DO-year frequency rainfall event. 15

APPENDIX 4 1977 South Ash Pond Geotechnical Data