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HomeMy WebLinkAboutSURRY-099 Final ReportDAM HYDRAULIC CAPACITY ASSESSMENT REPORT (DRAFT) JOHNSON SWINE WASTE LAGOON SURRY-099 SURRY COUNTY, NC PREPARED BY: WOOD E&I Solutions 2020 EXECUTIVE SUMMARY A hydraulic capacity analysis was completed for the Johnson Swine Waste Lagoon in Surry County, North Carolina. The purpose of the study was to analyze the existing potential of the dam for overtopping during predetermined specified rainfall events. The analyses were completed using the United States Army Corps of Engineers developed software Hydrologic Engineering Center – Hydrologic Modeling System (HEC-HMS) in combination with Arc-GIS to develop required input parameters. The rainfall events included in the analyses consist of 24-hour durations with return periods of 25 years, 50 years, 100 years, 200 years, 500 years, and 1000 years. Results of the analyses indicate that this structure is hydraulically adequate for 25 years, 50 years, 100 years, 200 years, 500 years, and 1000 years rainfall events. Data, input parameters, and final results can be found on the attached summary sheets and in the appendices of this report as well as in the associated electronic file in which all program files are stored. Drainage Area (Sq. Mi.) = Curve Number = Lag Time (min.) = Rainfall Distribution Methods = 86.1 90.9 94.7 NOT TO SCALE 984.6 985.0 28.7 33.5 978.1 978.6 980.6 76.5 982.6 983.1 983.6 52.6 57.4 62.2 67.0 71.8 81.3977.1 977.6 976.6 981.1 981.6 982.1 8.6 10.5 6.8 984.1 5.0 12.7 15.5 19.4 24.0 974.1 974.6 975.1 975.6 976.1 N/A ELEVATION 972.6 973.1 Auxiliary None STORAGE (ACRE‐FT) 0.0 1.6 ELEVATION 979.1 979.6 973.6 STORAGE (ACRE‐FT) 38.3 43.1 47.83.3 980.1 76.52 13 SCS Type 2 SPILLWAY Principal TYPE Grass‐Lined Trapezoidal channel ELEVATION 973.6 0.01496 SUMMARY SHEET OF HYDRAULIC CAPACITY RESULTS JOHNSON SWINE WASTE LAGOON, SURRY‐099 ANALYSIS PERFORMED BY: E.OKORIE, WOOD TOP OF DAM ELEVATION = 974.6 24 HOUR ‐ 1000 YEAR EVENT, 11.6 INCHES, ELEVATION 973.9 (0.7 FT FREE‐BOARD) 24 HOUR ‐ 500 YEAR EVENT, 10.5 INCHES, ELEVATION 973.8 (0.8 FT FREE‐BOARD) 24 HOUR ‐ 200 YEAR EVENT, 9.05 INCHES, ELEVATION 973.7 (0.9 FT FREE‐BOARD) 24 HOUR ‐ 100 YEAR EVENT, 8.06 INCHES, ELEVATION 973.6 (1 FT FREE‐BOARD) 24 HOUR ‐ 50 YEAR EVENT, 7.13 INCHES, ELEVATION 973.6 (1 FT FREE‐BOARD) 24 HOUR ‐ 25 YEAR EVENT, 6.25 INCHES, ELEVATION 973.5 (1.1 FT FREE‐BOARD) SUMMARY OF INPUT PARAMETERS JOHNSON SWINE WASTE LAGOON SURRY‐099 SEPTEMBER 18, 2020 APPENDIX A Watershed Boundary Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community Johnson Swine Waste Lagoon - Watershed Boundary Legend Longest FlowPath Watershed Boundary 0 0.05 0.10.025 Miles Date: 9/11/2020 /Drainage Area: 0.01496 Square Miles Flowpath Length: 1019.7 feet APPENDIX B Lag Time Calculation Dam No: SURRY-099 Date: 9/9/2020 Dam Name: Johnson Swine Waste Lagoon Engineer: E.Okorie Maximum Potential Retention (inches):S = (1000/cn')-10 Time of Concentration (hours):Tc =l0.8*(S+1)0.7 1140*Y0.5 Basin Data:Input Values in yellow Curve Number CN = 76.52 S =3.06848 in. Mean Basin Slope Y = 2.85 % Longest Flowpath: 0.193 mi. Flow Length l =1019.04 ft. Time of Concentration Tc =0.35 Hours Tc =21 mins Lag Time TL =0.21 Hours TL =13 mins APPENDIX C NRCS Curve Number Summary Sheet Change CN according to TR-55 (see tables below) NLCD (2016) Landuse TR-55 Landuse HSG A (sq. ft.)CN HSG B (sq. ft.)CN HSG C (sq. ft.)CN HSG D (sq. ft.)CN Open Water Not Available 0 100 0 38480 100 3848010 9961 100 996092 0 100 0 Developed, Open Space Open space - Fair condition (grass cover 50% to 75%)0 49 0 2355 69 162475 1529 79 120806 0 84 0 Developed, Low Intensity Residential districts by average lot size: 1/3 acre 0 57 0 14781 72 1064234 942 81 76302 0 86 0 Developed, Medium Intensity Residential districts by average lot size: 1/8 acre 0 77 0 70580 85 5999305 5649 90 508443 0 92 0 Developed, High Intensity Urban districts - Commercial and business 0 89 0 0 92 0 0 94 0 0 95 0 Barren Land Newly graded areas 0 77 0 9688 86 833187 0 91 0 0 94 0 Deciduous Forest Woods - Fair 0 36 0 9181 60 550863 0 73 0 0 79 0 Evergreen Forest Woods - Fair 0 36 0 0 60 0 0 73 0 0 79 0 Mixed Forest Woods - Fair 0 36 0 0 60 0 0 73 0 0 79 0 Shrub/Scrub Brush - Fair 0 35 0 0 56 0 0 70 0 0 77 0 Herbaceuous Herbaceuous - Fair 0 60 0 9688 71 687864 0 81 0 0 89 0 Hay/Pasture Pasture - Fair 0 49 0 223662 69 15432689 10470 79 827166 0 84 0 Cultivated Crops Row crops (SR + CR) - Poor 0 71 0 9688 80 775058 0 87 0 0 90 0 Woody Wetlands Not Available 0 80 0 0 85 0 0 90 0 0 95 0 Emergent Herbaceuous Wetlands Not Available 0 80 0 0 85 0 0 90 0 0 95 0 Weighted CN=76.52 NOTE: Curve Numbers are from SCS TR-55 with the exception of assumed HSG A (CN=60) for Herbaceous, Open Water, Woody Wetlands, and Emergent Herbaceous Wetlands. NOTE: double-check all the land types are being calculated and texts are accurate NOTE: double-check the exported attribute table has the same table format as the "Export_Output" table APPENDIX D Hyetograph Results Used for Analyses 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24Cumulative Depth (in)Time (hrs) Hyetographs for 24-Hour SCS Type II Rainfall Distributions 25YR 50YR 100YR 200YR 500YR 1000YR APPENDIX E NOAA Atlas 14 Rainfall Table Point precipitation frequency estimates (inches) NOAA Atlas 14 Volume 2 Version 3 Data type: Precipitation depth Time series type: Partial duration Project area: Ohio River Basin Location name (ESRI Maps): Siloam, North Carolina USA Station Name: - Latitude: 36.2930° Longitude: -80.5865° Elevation (USGS): 975.35 ft PRECIPITATION FREQUENCY ESTIMATES by duration for ARI (years):1 2 5 10 25 50 100 200 500 1000 5-min:0.355 0.422 0.499 0.554 0.62 0.666 0.709 0.749 0.795 0.829 10-min:0.567 0.674 0.799 0.886 0.989 1.06 1.13 1.19 1.26 1.31 15-min:0.708 0.848 1.01 1.12 1.25 1.34 1.42 1.5 1.58 1.64 30-min:0.971 1.17 1.44 1.62 1.86 2.02 2.18 2.33 2.52 2.65 60-min:1.21 1.47 1.84 2.12 2.47 2.74 3.01 3.27 3.62 3.87 2-hr:1.44 1.75 2.21 2.56 3.04 3.4 3.78 4.15 4.66 5.06 3-hr:1.56 1.9 2.4 2.78 3.3 3.71 4.12 4.54 5.12 5.57 6-hr:1.93 2.34 2.96 3.44 4.09 4.62 5.16 5.73 6.51 7.13 12-hr:2.37 2.87 3.62 4.22 5.05 5.72 6.43 7.17 8.22 9.06 24-hr:2.87 3.48 4.42 5.18 6.25 7.13 8.06 9.05 10.5 11.6 2-day:3.4 4.11 5.17 6.02 7.19 8.14 9.13 10.2 11.6 12.8 3-day:3.61 4.36 5.47 6.35 7.57 8.55 9.58 10.7 12.2 13.4 4-day:3.82 4.61 5.77 6.68 7.94 8.97 10 11.1 12.7 14 7-day:4.38 5.25 6.44 7.39 8.68 9.71 10.8 11.9 13.4 14.6 10-day:5 5.97 7.24 8.23 9.56 10.6 11.7 12.8 14.3 15.5 20-day:6.72 7.97 9.49 10.7 12.2 13.5 14.7 15.9 17.6 18.9 30-day:8.33 9.82 11.4 12.6 14.2 15.3 16.4 17.5 19 20 45-day:10.5 12.3 14.1 15.4 17.1 18.4 19.6 20.7 22.2 23.3 60-day:12.5 14.6 16.6 18 19.9 21.2 22.5 23.8 25.4 26.5 Date/time (GMT): Fri Sep 11 07:14:20 2020 pyRunTime: 0.016932964325 APPENDIX F Outlet Works Rating Curves Total outlet discharge from the spillway system Client: NCEM Date: 9/11/2020 Project: Overtopping Study Engineer: E.Okorie Dam: Johnson Swine Waste Lagoon Dam No. SURRY-099 Reservior Water Level (RWS) Elevation (ft) Primary spillway discharge (cfs) Total discharge from the spillway system (cfs) 973.6 0.0 0.0 974.1 21.1 21.1 974.6 63.5 63.5 975.1 123.5 123.5 975.6 200.8 200.8 976.1 295.5 295.5 976.6 407.9 407.9 977.1 538.6 538.6 977.6 688.0 688.0 978.1 856.7 856.7 978.6 1045.4 1045.4 979.1 1254.4 1254.4 979.6 1484.4 1484.4 980.1 1735.9 1735.9 980.6 2009.4 2009.4 981.1 2305.6 2305.6 981.6 2624.8 2624.8 982.1 2967.6 2967.6 982.6 3334.5 3334.5 983.1 3726.0 3726.0 983.6 4142.6 4142.6 984.1 4584.7 4584.7 984.6 5052.9 5052.9 985.1 5547.5 5547.5 0.0 1000.0 2000.0 3000.0 4000.0 5000.0 6000.0 972.0 974.0 976.0 978.0 980.0 982.0 984.0 986.0Total discharge from the spillway system (cfs)Reservior Water Level (RWS) Elevation (ft) The whole spillway system rating curve (cfs)