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Home My WebLink AboutWAKE-040_Final Report DAM HYDRAULIC CAPACITY ASSESSMENT REPORT Milburnie Fish Club Lake Dam WAKE-040 WAKE COUNTY, NC PREPARED BY: Ted L. Bartelt, PE 2019 EXECUTIVE SUMMARY A hydraulic capacity analysis was completed for the Milburnie Fishing Club Dam in Wake 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 the 25-year and 50-year storm event while overtopping occurred at all other rainfall events. The height of over- topping ranged from 0.07 ft. to 0.38 ft. above the dam. 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. The elevation-storage calculation does not include the storage below the normal pool elevation for this study. All elevations in this report are based on North American Vertical Datum of 1988 (NAVD88). MILBURNIE FISHING CLUB DAM WAKE-040 February 3, 2020 Drainage Area (Sq. Mi.)= Curve Number = Lag Time (min.)= Rainfall Distribution Methods = 201.27 67.85 77.00 203.00 20.19 Stone Masonry Weir 200.82 200.00 200.50 STORAGE (ACRE-FT)ELEVATION ELEVATION 205.50 206.00 0.00 13.56 STORAGE (ACRE-FT) 96.47 106.85 Auxiliary Stone Masonry Weir SUMMARY SHEET OF HYDRAULIC CAPACITY RESULTS MILBURNIE FISHING CLUB DAM, WAKE-040 42.48 50.59 34.72 117.66206.50 27.30 SPILLWAY ANALYSIS PERFORMED BY: TED L. BARTELT, PE, ALPHA & OMEGA GROUP 24 HOUR - 1000 YEAR EVENT, 10.6 INCHES, ELEVATION 202.54 (0.38 FT OVERTOPPED) 24 HOUR - 500 YEAR EVENT, 9.68 INCHES, ELEVATION 202.45 (0.29 FT OVERTOPPED) 24 HOUR - 200 YEAR EVENT, 8.52 INCHES, ELEVATION 202.34 (0.18 FT OVERTOPPED) TOP OF DAM ELEVATION = 202.16 Principal NOT TO SCALE 128.86207.00 201.00 201.50 202.00 202.50 205.00 86.53 203.50 204.00 204.50 59.06 24 HOUR - 100 YEAR EVENT, 7.69 INCHES, ELEVATION 202.23 (0.07 FT OVERTOPPED) ELEVATIONTYPE 24 HOUR - 50 YEAR EVENT, 6.88 INCHES, ELEVATION 202.12 (0.04 FT FREEBOARD) 24 HOUR - 25 YEAR EVENT, 6.10 INCHES, ELEVATION 202.00 (0.16 FT FREEBOARD) SUMMARY OF INPUT PARAMETERS NRCS-NOAA 1.18 73.32 65 APPENDIX A Watershed Boundary Sources: Esri, HERE, Garmin, Intermap, increment P Corp., GEBCO, USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance Survey, Esri Japan, METI, Esri China (Hong Kong), (c) OpenStreetMap contributors, and the GIS User Community Milburnie Fish Club Dam - WAKE-040 - Watershed Boundary Legend Longest Flowpath Watershed Boundary . 0 0.2 0.40.1 Miles Drainage Area: 1.182 Square Miles Flowpath Length: 10,927.86 Feet 12/10/2019 APPENDIX B Time of Concentration Calculation Dam No:Wake 040 Date:1/31/2020 Dam Name:Milburnie Fish Club Dam Engineer:TL Bartelt Input By:TLB Checked By:RLB 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 =73.32 from StreamStats S =3.63884 in. Mean Basin Slope Y =5.77 %from StreamStats Longest Flowpath:2.048 mi.from StreamStats Flow Length l =10813.4 ft. Time of Concentration Tc =1.80 Hours Tc =108 mins Lag Time TL =1.08 Hours TL =65 mins APPENDIX C NRCS Curve Number Summary Sheet Change CN according to TR-55 (see tables below) HSG Type A CN B CN C CN D CN Open Water 57750.2078 100 5775020.778 46047.0374 100 4604703.736 0.0000 100 0 1103621.8791 100 1.1E+08 Developed, Open Space 616971.4739 68 41954060.23 2352307.1708 79 185832266.5 1183918.3399 86 101816977.2 348818.2007 89 31044820 Developed, Low Intensity 495466.8871 57 28241612.57 1545861.0975 72 111301999 1063661.2754 81 86156563.31 134953.8383 86 11606030 Developed, Medium Intensity 306820.2640 77 23625160.33 1202545.5466 85 102216371.5 1368564.6297 90 123170816.7 151960.0514 92 13980325 Developed, High Intensity 46629.4740 89 4150023.186 438823.2842 92 40371742.15 1530979.4680 94 143912070 223462.5045 95 21228938 Barren Land 0.0000 77 0 45573.9551 86 3919360.139 774869.9522 91 70513165.65 141956.8299 94 13343942 Deciduous Forest 1771344.971 36 63768418.97 1000507.607 60 60030456.43 2126845.186 73 155259698.5 1820640.44 79 1.44E+08 Evergreen Forest 988907.2531 36 35600661.11 1685674.8209 60 101140489.3 1130063.4378 73 82494630.96 804939.3745 79 63590211 Mixed Forest 426608.5208 36 15357906.75 420344.2689 60 25220656.13 312432.6732 73 22807585.15 468239.7275 79 36990938 Shrub/Scrub 55741.0495 35 1950936.733 70457.7636 56 3945634.762 116361.4924 70 8145304.467 80671.3759 77 6211696 Herbaceuous 510432.1675 50 25521608.37 1535111.0191 71 108992882.4 214878.9714 81 17405196.68 93014.6181 89 8278301 Hay/Pasture 161810.3523 49 7928707.264 1523065.015 69 105091486.1 177681.1527 79 14036811.06 283341.8612 84 23800716 Cultivated Crops 0.0000 71 0 0.0000 80 0 0.0000 87 0 0.0000 90 0 designed by dan.k Woody Wetlands 0.0000 80 0 0.0000 85 0 0.0000 90 0 12714.7582 95 1207902 Emergent Herbaceuous Wetlands 0.0000 80 0 0.0000 85 0 0.0000 90 0 0.0000 95 0 Weighted CN=73.32 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. Hydrologic Condition assumed as "Fair" 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 0.02.04.06.08.010.012.00 2 4 6 8 10 12 14 16 18 20 22 24Cumulative Inches of RainHoursHyetographs for 24‐Hour Rainfall Distributions25YR50YR100YR200YR500YR1000YR 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: Neuse River Basin Location name (ESRI Maps): Raleigh North Carolina USA Station Name: - Latitude: 35.8020° Longitude: -78.5310° Elevation (USGS): 184.44 ft PRECIPITATION FREQUENCY ESTIMATES by duration for ARI (years):1 2 5 10 25 50 100 200 500 1000 5-min: 0.406 0.473 0.541 0.605 0.67 0.721 0.766 0.806 0.85 0.888 10-min: 0.649 0.757 0.866 0.968 1.07 1.15 1.22 1.28 1.34 1.4 15-min: 0.811 0.951 1.1 1.22 1.35 1.45 1.54 1.61 1.69 1.76 30-min: 1.11 1.31 1.56 1.77 2.01 2.19 2.36 2.51 2.69 2.84 60-min: 1.39 1.65 2 2.31 2.67 2.97 3.25 3.52 3.86 4.15 2-hr: 1.63 1.94 2.37 2.77 3.25 3.67 4.06 4.47 4.99 5.45 3-hr: 1.72 2.06 2.53 2.97 3.53 4.01 4.49 4.99 5.65 6.25 6-hr: 2.06 2.47 3.03 3.57 4.26 4.86 5.46 6.09 6.95 7.72 12-hr: 2.43 2.9 3.59 4.25 5.1 5.86 6.63 7.45 8.59 9.62 24-hr: 2.89 3.49 4.4 5.12 6.1 6.88 7.69 8.52 9.68 10.6 2-day: 3.35 4.03 5.04 5.83 6.91 7.77 8.65 9.57 10.8 11.8 3-day: 3.55 4.26 5.3 6.12 7.24 8.13 9.05 9.99 11.3 12.3 4-day: 3.75 4.5 5.57 6.41 7.57 8.49 9.44 10.4 11.8 12.8 7-day: 4.35 5.19 6.34 7.26 8.51 9.51 10.5 11.6 13 14.2 10-day: 4.96 5.9 7.11 8.06 9.34 10.4 11.4 12.4 13.8 14.9 20-day:6.64 7.84 9.3 10.4 12 13.2 14.4 15.7 17.4 18.7 30-day: 8.25 9.71 11.3 12.6 14.2 15.5 16.7 18 19.7 20.9 45-day: 10.5 12.3 14.1 15.5 17.3 18.7 20 21.4 23.1 24.4 60-day: 12.6 14.7 16.7 18.2 20.2 21.6 23 24.4 26.2 27.6 Date/time (GMT): Tue Dec 10 18:18:50 2019 pyRunTime: 0.0101280212402 APPENDIX F Outlet Works Rating Curves Primary Spillway: Auxiliary Spillway 1: RWS Elevation (ft) Primary Spillway Discharge (cfs) Auxiliary Spillway 1 Discharge (cfs) Total Structure Discharge (cfs) 200.8 0.0 0.0 0 201.3 55.2 0.0 55 201.8 156.0 122.0 278 202.3 286.6 345.0 632 202.8 441.2 633.8 1,075 203.3 616.6 975.8 1,592 203.8 810.6 1363.7 2,174 204.3 1021.5 1792.7 2,814 204.8 1248.0 2259.0 3,507 205.3 1489.2 2760.0 4,249 205.8 1744.1 3293.3 5,037 206.3 2012.2 3857.2 5,869 206.8 2292.7 4450.0 6,743 207.3 2585.2 5070.4 7,656 207.8 2889.2 5717.3 8,606 208.3 3204.2 6389.5 9,594 208.8 3529.9 7086.2 10,616 209.3 3865.9 7806.5 11,672 209.8 4212.0 8549.6 12,762 210.3 4567.8 9315.0 13,883 210.8 4933.2 10101.9 15,035 211.3 5307.7 10909.9 16,218 115' Stone Masonry Weir SPILLWAY ASSESSMENT MILBURNIE FISH CLUB DAM WAKE-040 52' Stone Masonry Weir 200.0 202.0 204.0 206.0 208.0 210.0 212.0 0.0 2000.0 4000.0 6000.0 8000.0 10000.0 12000.0 14000.0 16000.0 18000.0RWS Elevation (ft) Discharge Flow Rate (cfs) RWS Elevation vs. Discharge Flow Primary Spillway Auxiliary Spillway 1 Total Structure