INFLOW DESIGN FLOOD CONTROL PLAN

Transcription

1 INFLOW DESIGN FLOOD CONTROL PLAN CFR Bottom Ash Pond Big Sandy Plant Louisa, Kentucky October, 2016 Prepared for: Kentucky Power Big Sandy Plant Louisa, Kentucky Prepared by: American Electric Power Service Corporation 1 Riverside Plaza Columbus, OH GERS

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3 Table of CONTENTS 1.0 OBJECTIVE DESCRIPTION OF THE CCR UNIT INFLOW DESIGN FLOOD (a)(3) FLOOD CONTROL PLAN (c)... 1 ii

4 1.0 OBJECTIVE This report was prepared by AEP- Geotechnical Engineering Services (GES) section to fulfill requirements of CFR for the hydrologic and hydraulic evaluation of CCR surface impoundments. 2.0 DESCRIPTION OF THE CCR UNIT The Big Sandy Power Plant is located north of the City of Louisa, Lawrence County, Kentucky. It is owned and operated by Kentucky Power. The facility operates two surface impoundments for storing CCR called the Fly Ash Pond and the Bottom Ash Pond. This report deals with the inflow design flood for the Bottom Ash Pond. The Bottom Ash Pond is comprised of diked embankments on the East, West, South sides with the north side abutting the adjoining the hillside. The Bottom ash pond is split into north and south cells. The Bottom Ash Pond discharges into the Clearwater pond (north/south) which discharges into the Reclaim pond where water is pumped to the Fly Ash Pond. The combination of the Bottom Ash Pond, the Clearwater Pond and the Reclaim Pond are commonly referred to as the Bottom Ash Pond complex. The Big Sandy Power Plant has ceased burning coal and been refueled for natural gas. Bottom Ash pond will continue to remain in service as a wastewater pond. As such the 3.0 INFLOW DESIGN FLOOD (a)(3) The facility is classified as a Signficant Hazard Potential Dam. The Inflow Design Flood per this rule is the 1000-yr storm. AEP has identified the facility as a Class B moderate Hazard Facility under Kentucky Dam Safety regulations. The design event for a Class B facility in Kentucky is: P B = P x(PMP P 100 ) The 1000-year, 6-hr precipitation for the site is 5.5 inches. The resulting Class B Design event (P B ) is 13.6 inches. As such the Kentucky design flood is the controlling event for the facility. 4.0 FLOOD CONTROL PLAN (C) The watershed for the Bottom Ash Pond is limited to the crest of the perimeter dikes. A freeboard analysis of the Bottom Ash Pond Complex was performed by Stantec Consulting Services. The operation of the bottom ash pond complex is currently dependent on the ability to pump water to the Fly Ash Pond and can be controlled accordingly. The freeboard analysis by Stantec evaluates the pond complex in the event that the ability to pump to the Fly Ash Pond is loss. The freeboard analysis also looks at the capacity of the Bottom Ash Pond if the discharge to the Clearwater Pond is blocked or closed. The analysis from Stantec is included in Attachment A and provides the description of the spillway system, flood storage capacity, and maximum pool elevation based on the evaluated conditions. The evaluation is based on no outflow from the facility. The freeboard analysis shows that the facility has the capacity to manage the inflow design flood. 1

5 ATTACHMENT A

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7 Report of Freeboard Analysis AEP Big Sandy Power Plant / Unit 1-2 Bottom Ash Pond Louisa, Lawrence County, Kentucky Prepared for: American Electric Power 1 Riverside Plaza 22 nd Floor Columbus, Ohio September, 2016

8 REPORT OF FREEBOARD ANALYSIS AEP BIG SANDY POWER PLANT / UNIT 1-2 BOTTOM ASH POND LOUISA, LAWRENCE COUNTY, KENTUCKY ` Table of Contents 1.0 INTRODUCTION AND SUMMARY HYDROLOGY RESERVOIR ROUTING STAGE-STORAGE INFORMATION DAM EMBANKMENTS PRINCIPAL SPILLWAYS RESULTS... 7 BIBLIOGRAPHY AND REFERENCES... 8 Appendices Appendix A Appendix B Watershed Layout Hydraulic Model Input / Output i

9 REPORT OF FREEBOARD ANALYSIS AEP BIG SANDY POWER PLANT / UNIT 1-2 BOTTOM ASH POND LOUISA, LAWRENCE COUNTY, KENTUCKY 1.0 Introduction and Summary The Big Sandy Power Plant bottom ash pond network, owned and operated by American Electric Power (AEP) is located near Louisa, Kentucky along the western bank of the Big Sandy River. The bottom ash pond network currently serves as a settling facility for sluiced bottom ash produced at the plant. The pond network includes the North Bottom Ash Pond (NBAP), South Bottom Ash Pond (SBAP), North Clearwater Pond (NCWP), South Clearwater Pond (SCWP) and the Reclamation Pond (RP). In addition to the process flows from the plant, approximately 10.7 acres drain to the facility. The ponds are formed by natural grade to the north, east and west and a series of dikes that divide the ponds and form the southern boundary along the bank of the Big Sandy River. The Big Sandy bottom ash pond network dikes have been identified as a Significant Hazard structure according to the definitions established in the EPA Final CCR Rule at 40 CFR (Reference 1). The structure was also reviewed in relation to state regulatory requirements and meets the definition of a Moderate (Class B) facility according to the Kentucky Division of Water (KDOW) hazard classification system. As part of an evaluation of the dikes, Stantec Consulting Services Inc. (Stantec) has been contracted to perform a reservoir routing analysis to determine the freeboard above the inflow design flood for each pond. Stantec performed hydrologic calculations of the drainage area to determine the expected runoff and developed a hydraulic model to route the flows through the pond network. The results of the reservoir routing analysis indicate that the pond system as a network appears capable of passing the inflow design flood. 1

10 REPORT OF FREEBOARD ANALYSIS AEP BIG SANDY POWER PLANT / UNIT 1-2 BOTTOM ASH POND LOUISA, LAWRENCE COUNTY, KENTUCKY 2.0 Hydrology Due to the limited drainage area of the bottom ash pond network, much of it accounted for by the pond surface itself, a hydrologic model was not developed for the site. Instead, stormwater runoff was calculated directly using the curve number method (Reference 2). The site was divided into five sub-watersheds based on topographic data provided by AEP (Reference 3). The hydrologic properties of the sub-watersheds, including curve numbers, lag times and runoff depths were determined using the methodology outlined in TR-55 (Reference 4). A drawing of the watershed layout is provided in Appendix A. Hydrologic properties of the watershed are listed in Table 1. Table 1. Hydrologic Parameters and Runoff Results Sub-Watershed No. Area (acres) Curve Number Runoff Depth (in) Runoff Volume (ac-ft) NBAP SBAP NCWP SCWP RP The inflow design flood is determined based on the hazard rating of the facility. Stantec reviewed both the federal and state regulations and selected the controlling flood event based on whichever was greater. According to federal regulations, the inflow design flood for a Significant Hazard potential CCR surface impoundment is the 1000-year flood per the EPA Final CCR Rule (Reference 1). The 1000-year, 6-hour precipitation depth is 5.5 inches according to the National Oceanographic and Atmospheric Administration (NOAA) Precipitation Depth Frequency Server (Reference 5). The design rainfall event designated by KDOW s Engineering Memorandum No. 5 (Reference 6) was calculated for the Big Sandy bottom ash ponds based on the Class B Moderate Hazard classification. The design rainfall event designated by KDOW for the freeboard hydrograph for a Class B structure is described by Equation 1. Eq. 1 P.4 ( PMP ) P B P100 In this case, the design storm corresponds to 48.5 percent of the 6-hour Probable Maximum Precipitation (PMP) rainfall depth with a 6-hour Soil Conservation Service (SCS) Type B 2

11 REPORT OF FREEBOARD ANALYSIS AEP BIG SANDY POWER PLANT / UNIT 1-2 BOTTOM ASH POND LOUISA, LAWRENCE COUNTY, KENTUCKY Hydrology temporal distribution (Reference 7). Rainfall depths used in calculating the design rainfall event included a 6-hour PMP rainfall depth of 28.0 inches obtained from the National Weather Service (Reference 6) and a 6-hour 100-yr rainfall depth of 3.99 inches obtained from the National Weather Service Precipitation Frequency Data Server (Reference 5). The resulting design rainfall used in this analysis is 13.6 inches. Since the KDOW required inflow (13.6 inches) is greater than the Final EPA CCR Rule (5.5 inches), the KDOW designated design inflow standard will be used in this analysis. 3

12 REPORT OF FREEBOARD ANALYSIS AEP BIG SANDY POWER PLANT / UNIT 1-2 BOTTOM ASH POND LOUISA, LAWRENCE COUNTY, KENTUCKY 3.0 Reservoir Routing Following the development of runoff parameters, the subsequent flows were routed through the reservoir network. The North and South Bottom Ash Ponds, North and South Clearwater Ponds and the Reclamation Pond, principal spillway and embankment characteristics were input into an Environmental Protection Agency (EPA) Storm Water Management Model (SWMM) to perform the reservoir routing analyses. The Big Sandy Bottom Ash Pond network consists of a series of ponds with flexible operating parameters impacted by pumping, valve settings and spillway adjustments. Due to the variability of operations, two scenarios were reviewed for this analysis that represented the potential worst-case scenario for the dikes being evaluated. The scenarios were: Scenario 1 - Bottom Ash Ponds: This scenario included the evaluation of overtopping potential of the Bottom Ash Ponds if the outlet valves to the Clearwater Ponds were closed prior to the design storm event. This scenario would result in the greatest water surface elevation in the North and South Bottom Ash Ponds and a lower elevation in the Clearwater and Reclamation Ponds. Scenario 2 Clearwater and Reclamation Ponds: Under Scenario 2, the valves between the Bottom Ash Ponds and Clearwater Ponds are assumed fully open to allow the storm flows that drain to the Bottom Ash Ponds to flow freely to the Clearwater Ponds. This scenario would result in the greatest water surface elevation in the Clearwater and Reclamation Ponds and a lower elevation in the Bottom Ash Ponds. Under either of the scenarios listed above, additional assumptions regarding operation of the pond network were required for the analysis. Key assumptions included that no baseflow or process flows were being discharged into the ponds at the time of the design storm; no outlet flows were being discharged into the Big Sandy River from the Reclamation Ponds; and the static water surface elevations of the ponds at the time of the analysis were equal to or less than those provided by AEP on the basemapping for the site. Further discussion of the parameters input into the SWMM model is provided below. 3.1 STAGE-STORAGE INFORMATION The stage-storage information for the model was used in the determination of the water level in the reservoir. The reservoirs were assumed to have a fixed water surface elevation at the time of the storm event with only the depth above the fixed water surface elevation available for storage. The stage-storage data was calculated from 2001 topographic mapping provided by AEP (Reference 3). Table 2 lists the cumulative storage volume for a given elevation for each 4

13 REPORT OF FREEBOARD ANALYSIS AEP BIG SANDY POWER PLANT / UNIT 1-2 BOTTOM ASH POND LOUISA, LAWRENCE COUNTY, KENTUCKY Reservoir Routing reservoir. The lowest elevation for each pond represents the static water surface elevation assumed at the start of each model run. Table 2. Reservoir Stage-Storage Reservoir Name Elevation (feet) Storage (acre-feet) North Bottom Ash Pond South Bottom Ash Pond North Clearwater Pond South Clearwater Pond Reclamation Pond DAM EMBANKMENTS The Bottom Ash Pond Network is formed by a series of dikes that form the southern boundary of the network and divide each of the ponds. Appendix A shows each of the dikes and includes a label with a letter designation for use with this analysis. Dike A bounds the North and South Bottom Ash Ponds on all sides but the north and separates them from the North and South Clearwater Ponds. Dike B separates the North and South Clearwater Ponds from the Reclamation Pond. Finally, Dike C forms the southern boundary of the Clearwater and Reclamation Ponds. The 2-foot contour interval topographic data with spot elevations (Reference 2) provided by AEP was used to determine the elevations of the top of each dike. The crest of Dike A ranges between to 578 feet, Dike B ranges from to feet, and Dike C ranges from 566 to 576 feet. 5

14 REPORT OF FREEBOARD ANALYSIS AEP BIG SANDY POWER PLANT / UNIT 1-2 BOTTOM ASH POND LOUISA, LAWRENCE COUNTY, KENTUCKY Reservoir Routing 3.3 PRINCIPAL SPILLWAYS Principal spillway pipe dimensions were determined from original construction drawings for the pond system (Reference 8). These drawings did not contain details of the inlet control structures attached to the spillways; however, discussions with AEP indicate that the sluice gates connecting the North Clearwater Pond and the South Clearwater Pond to the Reclamation Pond no longer function and remain continuously open. The spillways were therefore modeled as unvalved 30-inch culverts with inlet losses at the entrance. Based on the model scenario, it was assumed that the spillways from the North Bottom Ash Pond and South Bottom Ash Pond to the North and South Clearwater Ponds were either fully open 24-inch culverts or completely closed. The Reclamation Pond at the downstream end of the system was modeled without an outlet, as directed by AEP. 6

15 REPORT OF FREEBOARD ANALYSIS AEP BIG SANDY POWER PLANT / UNIT 1-2 BOTTOM ASH POND LOUISA, LAWRENCE COUNTY, KENTUCKY Results 4.0 Results The reservoir routing model indicates that water surface elevations do not exceed the outer dike crests of the Bottom Ash Ponds (Dike A) or the Clearwater and Reclamation Ponds (Dike C) for either of the two modeled scenarios. The model indicates that Dike B, the embankment separating the Clearwater and Reclamation Ponds, is overtopped during the design event under Scenario 2; and the water levels between the ponds are nearly coincident. Table 3 summarizes the estimated peak water surface elevations and associated freeboard observed in each pond during the modeled storm events. Reservoir Name Table 3. Bounding Dike Reservoir Peak Water Surface Elevation Controlling Scenario Peak Water Surface Elevation (feet) Dike Minimum Crest Elevation (feet) Minimum Freeboard (feet) North Bottom Ash Pond A South Bottom Ash Pond A North Clearwater Pond* C South Clearwater Pond* C Reclamation Pond* C *Internally, Dike B with crest of overtops by and estimated 0.8 feet. The presented model results are dependant on the assumptions outlined in Section 3 of this report. Changes to the operation of the ponds that would result in differences to the assumed conditions including: adjustments of the normal water surface elevation, pond geometry, spillway structures, valving and pumping would require further analysis. 7

16 REPORT OF FREEBOARD ANALYSIS AEP BIG SANDY POWER PLANT / UNIT 1-2 BOTTOM ASH POND LOUISA, LAWRENCE COUNTY, KENTUCKY Bibliography and References Bibliography and References 1. U.S. Environmental Protection Agency (2015). Disposal of Coal Combustion Residuals from Electric Utilities, 40 CFR Section 257 (effective April 17, 2015). 2. U.S. Department of Agriculture, Soil Conservation Service (1985). Section 4: Hydrology. National Engineering Handbook 3. GeoOne Mapping Services (2001). Big Sandy 2 Foot Interval Aerial Survey. NAVD 88 / NAD83 KY North. 4. U.S. Department of Agriculture, Natural Resources Conservation Service (1986). Technical Release No. 55: Urban Hydrology for Small Watersheds, 2 nd Edition. 5. National Oceanic and Atmospheric Administration (2004). NOAA Atlas14: Precipitation- Frequency Atlas of the United States. National Weather Service, Silver Spring, Maryland. 6. Department for Natural Resources and Environmental Protection, Division of Water (1979). Engineering Memorandum No National Oceanic and Atmospheric Administration, Office of Hydrology, National Weather Service (1978). Hydrometeorlogical Report No. 51: Maximum Precipitation Estimates, United States East of the 105 th Meridian. 8. Kentucky Power Company (1968). Big Sandy Plant As-Built Drawing

17 Appendix A Watershed Layout

18 Stantec does not certify the accuracy of the data. This map is for reference only and should not be used for constructrion. Legend Drainage Area Pond Dike North Bottom Ash Pond North Clearwater Pond South Bottom Ash Pond Reclamation Pond Dike B South Clearwater Pond Dike C Dike A Geographic Information Systems Lebanon Rd., Cincinnati, OH Phone Fax Appendix A Watershed Layout

19 Appendix B Hydraulic Model Input/Output

20 [TITLE] Appendix_B_SWMM_Input_Scenario_1.txt [OPTIONS] FLOW_UNITS CFS INFILTRATION HORTON FLOW_ROUTING DYNWAVE START_DATE 01/01/2010 START_TIME 00:00:00 REPORT_START_DATE 01/01/2010 REPORT_START_TIME 00:00:00 END_DATE 01/01/2010 END_TIME 12:00:00 SWEEP_START 01/01 SWEEP_END 12/31 DRY_DAYS 0 REPORT_STEP 00:05:00 WET_STEP 00:15:00 DRY_STEP 01:00:00 ROUTING_STEP 0:00:10 ALLOW_PONDING NO INERTIAL_DAMPING PARTIAL VARIABLE_STEP 0.75 LENGTHENING_STEP 0 MIN_SURFAREA 0 NORMAL_FLOW_LIMITED BOTH SKIP_STEADY_STATE NO FORCE_MAIN_EQUATION H-W LINK_OFFSETS DEPTH MIN_SLOPE 0 [EVAPORATION] ;;Type Parameters ;; CONSTANT 0.0 [OUTFALLS] ;; Invert Outfall Stage/Table Tide ;;Name Elev. Type Time Series Gate ;; Dummy_Outlet 570 FREE NO [STORAGE] ;; Invert Max. Init. Storage Curve Ponded Evap. ;;Name Elev. Depth Depth Curve Params Area Frac. Infiltration Parameters ;; N_Bottom_Ash_Pond TABULAR NBAP 0 0 N_Clearwater_Pond TABULAR NCWP 0 0 S_Clearwater_Pond TABULAR SCWP 0 0 S_Bottom_Ash_Pond TABULAR SBAP 0 0 Reclaim_Pond TABULAR RP 0 0 [CONDUITS] ;; Inlet Outlet Manning Inlet Outlet Init. Max. ;;Name Node Node Length N Offset Page 1

21 Appendix_B_SWMM_Input_Scenario_1.txt Offset Flow Flow ;; NBAP-NCWP N_Bottom_Ash_Pond N_Clearwater_Pond SBAP-SCWP S_Bottom_Ash_Pond S_Clearwater_Pond SCWP-RP S_Clearwater_Pond Reclaim_Pond NCWP-RP N_Clearwater_Pond Reclaim_Pond Dummy_Outlet Reclaim_Pond Dummy_Outlet [XSECTIONS] ;;Link Shape Geom1 Geom2 Geom3 Geom4 Barrels ;; NBAP-NCWP CIRCULAR SBAP-SCWP CIRCULAR SCWP-RP CIRCULAR NCWP-RP CIRCULAR Dummy_Outlet CIRCULAR [LOSSES] ;;Link Inlet Outlet Average Flap Gate ;; NBAP-NCWP NO SBAP-SCWP NO SCWP-RP NO NCWP-RP NO [INFLOWS] ;; Param Units Scale Baseline Baseline ;;Node Parameter Time Series Type Factor Factor Value Pattern ;; N_Bottom_Ash_Pond FLOW NBAP FLOW N_Clearwater_Pond FLOW NCWP FLOW S_Clearwater_Pond FLOW SCWP FLOW S_Bottom_Ash_Pond FLOW SBAP FLOW Reclaim_Pond FLOW RP FLOW [CURVES] ;;Name Type X-Value Y-Value ;; NBAP Storage 0 0 NBAP NBAP NBAP Page 2

22 Appendix_B_SWMM_Input_Scenario_1.txt NBAP SBAP Storage 0 0 SBAP SBAP SBAP SBAP NCWP Storage 0 0 NCWP NCWP NCWP NCWP SCWP Storage 0 0 SCWP SCWP SCWP SCWP SCWP RP Storage 0 0 RP RP RP RP RP [TIMESERIES] ;;Name Date Time Value ;; NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP SBAP SBAP SBAP SBAP SBAP SBAP Page 3

23 Appendix_B_SWMM_Input_Scenario_1.txt SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP Page 4

24 Appendix_B_SWMM_Input_Scenario_1.txt SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP [REPORT] INPUT NO CONTROLS NO SUBCATCHMENTS ALL NODES ALL LINKS ALL [TAGS] [MAP] DIMENSIONS Units None [COORDINATES] ;;Node X-Coord Y-Coord ;; Dummy_Outlet N_Bottom_Ash_Pond N_Clearwater_Pond S_Clearwater_Pond S_Bottom_Ash_Pond Reclaim_Pond [VERTICES] ;;Link X-Coord Y-Coord ;; Page 5

25 Appendix_B_SWMM_Output_Scenario_1.txt EPA STORM WATER MANAGEMENT MODEL - VERSION 5.0 (Build ) ********************************************************* NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step. ********************************************************* **************** Analysis Options **************** Flow Units... CFS Process Models: Rainfall/Runoff... NO Snowmelt... NO Groundwater... NO Flow Routing... YES Water Quality... NO Flow Routing Method... DYNWAVE Starting Date... JAN :00:00 Ending Date... JAN :00:00 Antecedent Dry Days Report Time Step... 00:05:00 Routing Time Step sec ************************** Volume Volume Flow Routing Continuity acre-feet 10^6 gal ************************** Dry Weather Inflow Wet Weather Inflow Groundwater Inflow RDII Inflow External Inflow External Outflow Internal Outflow Storage Losses Initial Stored Volume Final Stored Volume Continuity Error (%) ************************* Highest Continuity Errors ************************* Node S_Clearwater_Pond (1.05%) *************************** Time-Step Critical Elements *************************** None ******************************** Highest Flow Instability Indexes ******************************** Link NCWP-RP (22) Link SCWP-RP (11) Page 1

26 Appendix_B_SWMM_Output_Scenario_1.txt ************************* Routing Time Step Summary ************************* Minimum Time Step : sec Average Time Step : sec Maximum Time Step : sec Percent in Steady State : 0.00 Average Iterations per Step : 2.25 ****************** Node Depth Summary ****************** Average Maximum Maximum Time of Max Depth Depth HGL Occurrence Node Type Feet Feet Feet days hr:min Dummy_Outlet OUTFALL :00 N_Bottom_Ash_Pond STORAGE :00 N_Clearwater_Pond STORAGE :10 S_Clearwater_Pond STORAGE :03 S_Bottom_Ash_Pond STORAGE :00 Reclaim_Pond STORAGE :06 ******************* Node InFlow Summary ******************* Maximum Maximum Lateral Total Lateral Total Time of Max Inflow Inflow Inflow Inflow Occurrence Volume Volume Node Type CFS CFS days hr:min 10^6 gal 10^6 gal Dummy_Outlet OUTFALL : N_Bottom_Ash_Pond STORAGE : N_Clearwater_Pond STORAGE : S_Clearwater_Pond STORAGE : S_Bottom_Ash_Pond STORAGE : Reclaim_Pond STORAGE : ********************** Node Surcharge Summary ********************** Page 2

27 Appendix_B_SWMM_Output_Scenario_1.txt Surcharging occurs when water rises above the top of the highest conduit Max. Height Min. Depth Hours Above Crown Below Rim Node Type Surcharged Feet Feet N_Bottom_Ash_Pond STORAGE N_Clearwater_Pond STORAGE S_Clearwater_Pond STORAGE S_Bottom_Ash_Pond STORAGE ********************* Node Flooding Summary ********************* No nodes were flooded. ********************** Storage Volume Summary ********************** Average Avg Maximum Max Time of Max Maximum Volume Pcnt Volume Pcnt Occurrence Outflow Storage Unit 1000 ft3 Full 1000 ft3 Full days hr:min CFS N_Bottom_Ash_Pond : N_Clearwater_Pond : S_Clearwater_Pond : S_Bottom_Ash_Pond : Reclaim_Pond : *********************** Outfall Loading Summary *********************** Flow Avg. Max. Total Freq. Flow Flow Volume Outfall Node Pcnt. CFS CFS 10^6 gal Dummy_Outlet System ******************** Page 3

28 Link Flow Summary ******************** Appendix_B_SWMM_Output_Scenario_1.txt Maximum Time of Max Maximum Max/ Max/ Flow Occurrence Velocity Full Full Link Type CFS days hr:min ft/sec Flow Depth NBAP-NCWP CONDUIT : SBAP-SCWP CONDUIT : SCWP-RP CONDUIT : NCWP-RP CONDUIT : Dummy_Outlet CONDUIT : *************************** Flow Classification Summary *************************** Adjusted --- Fraction of Time in Flow Class ---- Avg. Avg. /Actual Up Down Sub Sup Up Down Froude Flow Conduit Length Dry Dry Dry Crit Crit Crit Crit Number Change NBAP-NCWP SBAP-SCWP SCWP-RP NCWP-RP Dummy_Outlet ************************* Conduit Surcharge Summary ************************* Hours Hours Hours Full Above Full Capacity Conduit Both Ends Upstream Dnstream Normal Flow Limited NBAP-NCWP SBAP-SCWP SCWP-RP NCWP-RP Analysis begun on: Mon Mar 15 09:34: Analysis ended on: Mon Mar 15 09:34: Total elapsed time: < 1 sec Page 4

29 [TITLE] Appendix_B_SWMM_Input_Scenario_2.txt [OPTIONS] FLOW_UNITS CFS INFILTRATION HORTON FLOW_ROUTING DYNWAVE START_DATE 01/01/2010 START_TIME 00:00:00 REPORT_START_DATE 01/01/2010 REPORT_START_TIME 00:00:00 END_DATE 01/01/2010 END_TIME 12:00:00 SWEEP_START 01/01 SWEEP_END 12/31 DRY_DAYS 0 REPORT_STEP 00:05:00 WET_STEP 00:15:00 DRY_STEP 01:00:00 ROUTING_STEP 0:00:10 ALLOW_PONDING NO INERTIAL_DAMPING PARTIAL VARIABLE_STEP 0.75 LENGTHENING_STEP 0 MIN_SURFAREA 0 NORMAL_FLOW_LIMITED BOTH SKIP_STEADY_STATE NO FORCE_MAIN_EQUATION H-W LINK_OFFSETS DEPTH MIN_SLOPE 0 [EVAPORATION] ;;Type Parameters ;; CONSTANT 0.0 [OUTFALLS] ;; Invert Outfall Stage/Table Tide ;;Name Elev. Type Time Series Gate ;; Dummy_Outlet 570 FREE NO [STORAGE] ;; Invert Max. Init. Storage Curve Ponded Evap. ;;Name Elev. Depth Depth Curve Params Area Frac. Infiltration Parameters ;; N_Bottom_Ash_Pond TABULAR NBAP 0 0 N_Clearwater_Pond TABULAR NCWP 0 0 S_Clearwater_Pond TABULAR SCWP 0 0 S_Bottom_Ash_Pond TABULAR SBAP 0 0 Reclaim_Pond TABULAR RP 0 0 [CONDUITS] ;; Inlet Outlet Manning Inlet Outlet Init. Max. ;;Name Node Node Length N Offset Page 1

30 Appendix_B_SWMM_Input_Scenario_2.txt Offset Flow Flow ;; NBAP-NCWP N_Bottom_Ash_Pond N_Clearwater_Pond SBAP-SCWP S_Bottom_Ash_Pond S_Clearwater_Pond SCWP-RP S_Clearwater_Pond Reclaim_Pond NCWP-RP N_Clearwater_Pond Reclaim_Pond Dummy_Outlet Reclaim_Pond Dummy_Outlet [XSECTIONS] ;;Link Shape Geom1 Geom2 Geom3 Geom4 Barrels ;; NBAP-NCWP CIRCULAR SBAP-SCWP CIRCULAR SCWP-RP CIRCULAR NCWP-RP CIRCULAR Dummy_Outlet CIRCULAR [LOSSES] ;;Link Inlet Outlet Average Flap Gate ;; NBAP-NCWP NO SBAP-SCWP NO SCWP-RP NO NCWP-RP NO [INFLOWS] ;; Param Units Scale Baseline Baseline ;;Node Parameter Time Series Type Factor Factor Value Pattern ;; N_Bottom_Ash_Pond FLOW NBAP FLOW N_Clearwater_Pond FLOW NCWP FLOW S_Clearwater_Pond FLOW SCWP FLOW S_Bottom_Ash_Pond FLOW SBAP FLOW Reclaim_Pond FLOW RP FLOW [CURVES] ;;Name Type X-Value Y-Value ;; NBAP Storage 0 0 NBAP NBAP NBAP Page 2

31 Appendix_B_SWMM_Input_Scenario_2.txt NBAP SBAP Storage 0 0 SBAP SBAP SBAP SBAP NCWP Storage 0 0 NCWP NCWP NCWP NCWP SCWP Storage 0 0 SCWP SCWP SCWP SCWP SCWP RP Storage 0 0 RP RP RP RP RP [TIMESERIES] ;;Name Date Time Value ;; NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP NBAP SBAP SBAP SBAP SBAP SBAP SBAP Page 3

32 Appendix_B_SWMM_Input_Scenario_2.txt SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP SBAP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP NCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP Page 4

33 Appendix_B_SWMM_Input_Scenario_2.txt SCWP SCWP SCWP SCWP SCWP SCWP SCWP SCWP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP RP [REPORT] INPUT NO CONTROLS NO SUBCATCHMENTS ALL NODES ALL LINKS ALL [TAGS] [MAP] DIMENSIONS Units None [COORDINATES] ;;Node X-Coord Y-Coord ;; Dummy_Outlet N_Bottom_Ash_Pond N_Clearwater_Pond S_Clearwater_Pond S_Bottom_Ash_Pond Reclaim_Pond [VERTICES] ;;Link X-Coord Y-Coord ;; Page 5

34 Appendix_B_SWMM_Output_Scenario_2.txt EPA STORM WATER MANAGEMENT MODEL - VERSION 5.0 (Build ) ********************************************************* NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step. ********************************************************* **************** Analysis Options **************** Flow Units... CFS Process Models: Rainfall/Runoff... NO Snowmelt... NO Groundwater... NO Flow Routing... YES Water Quality... NO Flow Routing Method... DYNWAVE Starting Date... JAN :00:00 Ending Date... JAN :00:00 Antecedent Dry Days Report Time Step... 00:05:00 Routing Time Step sec ************************** Volume Volume Flow Routing Continuity acre-feet 10^6 gal ************************** Dry Weather Inflow Wet Weather Inflow Groundwater Inflow RDII Inflow External Inflow External Outflow Internal Outflow Storage Losses Initial Stored Volume Final Stored Volume Continuity Error (%) *************************** Time-Step Critical Elements *************************** Link NBAP-NCWP (47.05%) Link SBAP-SCWP (3.96%) ******************************** Highest Flow Instability Indexes ******************************** Link NCWP-RP (15) Link NBAP-NCWP (13) Link SBAP-SCWP (9) Link SCWP-RP (8) ************************* Routing Time Step Summary Page 1

35 Appendix_B_SWMM_Output_Scenario_2.txt ************************* Minimum Time Step : 5.00 sec Average Time Step : 8.64 sec Maximum Time Step : sec Percent in Steady State : 0.00 Average Iterations per Step : 2.17 ****************** Node Depth Summary ****************** Average Maximum Maximum Time of Max Depth Depth HGL Occurrence Node Type Feet Feet Feet days hr:min Dummy_Outlet OUTFALL :00 N_Bottom_Ash_Pond STORAGE :41 N_Clearwater_Pond STORAGE :00 S_Clearwater_Pond STORAGE :06 S_Bottom_Ash_Pond STORAGE :40 Reclaim_Pond STORAGE :02 ******************* Node InFlow Summary ******************* Maximum Maximum Lateral Total Lateral Total Time of Max Inflow Inflow Inflow Inflow Occurrence Volume Volume Node Type CFS CFS days hr:min 10^6 gal 10^6 gal Dummy_Outlet OUTFALL : N_Bottom_Ash_Pond STORAGE : N_Clearwater_Pond STORAGE : S_Clearwater_Pond STORAGE : S_Bottom_Ash_Pond STORAGE : Reclaim_Pond STORAGE : ********************** Node Surcharge Summary ********************** Surcharging occurs when water rises above the top of the highest conduit Page 2

36 Appendix_B_SWMM_Output_Scenario_2.txt Max. Height Min. Depth Hours Above Crown Below Rim Node Type Surcharged Feet Feet N_Bottom_Ash_Pond STORAGE S_Bottom_Ash_Pond STORAGE ********************* Node Flooding Summary ********************* No nodes were flooded. ********************** Storage Volume Summary ********************** Average Avg Maximum Max Time of Max Maximum Volume Pcnt Volume Pcnt Occurrence Outflow Storage Unit 1000 ft3 Full 1000 ft3 Full days hr:min CFS N_Bottom_Ash_Pond : N_Clearwater_Pond : S_Clearwater_Pond : S_Bottom_Ash_Pond : Reclaim_Pond : *********************** Outfall Loading Summary *********************** Flow Avg. Max. Total Freq. Flow Flow Volume Outfall Node Pcnt. CFS CFS 10^6 gal Dummy_Outlet System ******************** Link Flow Summary ******************** Maximum Time of Max Maximum Max/ Max/ Page 3

37 Appendix_B_SWMM_Output_Scenario_2.txt Flow Occurrence Velocity Full Full Link Type CFS days hr:min ft/sec Flow Depth NBAP-NCWP CONDUIT : SBAP-SCWP CONDUIT : SCWP-RP CONDUIT : NCWP-RP CONDUIT : Dummy_Outlet CONDUIT : *************************** Flow Classification Summary *************************** Adjusted --- Fraction of Time in Flow Class ---- Avg. Avg. /Actual Up Down Sub Sup Up Down Froude Flow Conduit Length Dry Dry Dry Crit Crit Crit Crit Number Change NBAP-NCWP SBAP-SCWP SCWP-RP NCWP-RP Dummy_Outlet ************************* Conduit Surcharge Summary ************************* Hours Hours Hours Full Above Full Capacity Conduit Both Ends Upstream Dnstream Normal Flow Limited SCWP-RP NCWP-RP Analysis begun on: Mon Mar 15 09:46: Analysis ended on: Mon Mar 15 09:46: Total elapsed time: < 1 sec Page 4