RANDO-029 Final Report

DAM HYDRAULIC CAPACITY
ASSESSMENT REPORT
(DRAFT)
ASHEBORO COUNTRY CLUB LAKE DAM
RANDO-029
RANDOLPH COUNTY, NC
PREPARED BY:
HDR Engineering Inc. of the
Carolinas under contract with
WOOD E&I Solutions
2020

EXECUTIVE SUMMARY
A hydraulic capacity analysis was completed for the Asheboro Country Club Lake Dam in
Randolph County, North Carolina. The purpose of the study was to analyze the existing potential
of the dam for overtopping during predetermined specified rainfall events using the North
Carolina Dam Safety defined process and templates. 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 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 =
962.1
782.5
811.1
840.2
869.9
900.1
930.8
524.4
524.9
525.4
525.9
526.4
ELEVATION
521.9
522.4
522.9
523.4
523.9
70.2
81.4
93.0
STORAGE (ACRE-FT)
0.0
9.4
18.9
28.7
38.6
48.9
59.4
505.9
502.9
503.4
503.9
504.4
504.9
505.4
501.4
502.3
ELEVATION
501.4
501.9
502.4
STORAGE (ACRE-FT)
699.6
726.7
754.4
78.79
32
SCS Type 2
SPILLWAY
Primary
Auxiliary
TYPE
Inverted Riser
Grass Lined Trapezoidal Channel
ELEVATION
24 HOUR - 100 YEAR EVENT, 7.41 INCHES, ELEVATION 504.4 (0.5 FT OVER-TOPPED)
24 HOUR - 50 YEAR EVENT, 6.67 INCHES, ELEVATION 504.1 (0.2 FT OVER-TOPPED)
TOP OF DAM ELEVATION = 503.9
24 HOUR - 25 YEAR EVENT, 5.95 INCHES, ELEVATION 503.8 (0.1 FT FREE-BOARD)
SUMMARY OF INPUT PARAMETERS
0.51
SUMMARY SHEET OF HYDRAULIC CAPACITY RESULTS
ASHEBORO COUNTRY CLUB LAKE DAM, RANDO-029
ANALYSIS PERFORMED BY: S. MURPHY, HDR
24 HOUR - 1000 YEAR EVENT, 10 INCHES, ELEVATION 505.3 (1.4 FT OVER-TOPPED)
24 HOUR - 500 YEAR EVENT, 9.21 INCHES, ELEVATION 505.1 (1.2 FT OVER-TOPPED)
24 HOUR - 200 YEAR EVENT, 8.17 INCHES, ELEVATION 504.7 (0.8 FT OVER-TOPPED)
RANDO-029ASHEBORO COUNTRY CLUB LAKE DAM OCTOBER 27, 2020
2232.3
NOT TO SCALE
1919.5
1969.3
2020.0
2071.7
2124.3
2177.8
1638.5
1683.2
1728.7
1775.1
1822.4
1870.5
1387.3
1427.2
1467.9
1509.3
1551.6
1594.6
1162.1
1197.9
1234.5
1271.7
1309.5
1348.0
993.9
1026.2
1059.1
1092.6
1126.9
539.4
539.9
540.4
540.9
541.4
536.4
536.9
537.4
537.9
538.4
538.9
533.4
533.9
534.4
534.9
535.4
535.9
530.4
530.9
531.4
531.9
532.4
532.9
527.4
527.9
528.4
528.9
529.4
529.9
526.9
596.3
621.3
646.9
673.0
456.3
478.4
501.0
524.1
547.7
571.8
335.4
354.3
373.7
393.6
414.0
434.9
232.3
248.3
264.8
281.7
299.1
317.0
144.1
157.9
172.1
186.6
201.5
216.7
105.2
117.7
130.7
520.9
521.4
517.9
518.4
518.9
519.4
519.9
520.4
514.9
515.4
515.9
516.4
516.9
517.4
511.9
512.4
512.9
513.4
513.9
514.4
508.9
509.4
509.9
510.4
510.9
511.4
506.4
506.9
507.4
507.9
508.4
RANDO-029ASHEBORO COUNTRY CLUB LAKE DAM OCTOBER 27, 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 theGIS User Community
Asheboro Country Club Lake Dam - RANDO-029 - Watershed Boundary
Legend
Longest FlowPath
Watershed Bound ary
0 0.2 0.40.1 Miles
Date: 10 /2/2020
/Drainage Area: 0.51 Square MilesFlowpath Length: 1.3 miles

APPENDIX B

Lag Time Calculation
Dam No:RANDO-029 Date:10/26/2020
Dam Name:Asheboro Country Club Lake Dam Engineer:K. Trefzger
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 =78.7865 from NRCS CN Calculation
S =2.69252 in.
Mean Basin Slope Y =8.57561 %from Watershed Mean slope
Longest Flowpath:1.34 mi.from Watershed Longest flowpath
Flow Length l =7075.2 ft.
Time of Concentration Tc =0.90 Hours Tc =54 mins
Lag Time TL =0.54 Hours TL =32 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 0 100 0 52206 100 5220612 596719 100 59671883
Developed, Open Space Open space - Fair condition (grass cover 50% to 75%)0 49 0 2112265 69 145746303 834756 79 65945700 3054516 84 256579378
Developed, Low Intensity Residential districts by average lot size: 1/3 acre 0 57 0 133664 72 9623788 34883 81 2825490 171767 86 14771927
Developed, Medium Intensity Residential districts by average lot size: 1/8 acre 0 77 0 49520 85 4209228 10702 90 963152 19324 92 1777792
Developed, High Intensity Urban districts - Commercial and business 0 89 0 18355 92 1688616 961 94 90351 0 95 0
Barren Land Newly graded areas 0 77 0 0 86 0 0 91 0 0 94 0
Deciduous Forest Woods - Fair 0 36 0 591419 60 35485144 150340 73 10974814 2342493 79 185056923
Evergreen Forest Woods - Fair 0 36 0 44589 60 2675347 24505 73 1788857 240105 79 18968271
Mixed Forest Woods - Fair 0 36 0 188078 60 11284695 15092 73 1101739 907564 79 71697522
Shrub/Scrub Brush - Fair 0 35 0 67441 56 3776706 2551 70 178600 17179 77 1322749
Herbaceuous Herbaceuous - Fair 0 60 0 75779 71 5380283 46978 81 3805191 752030 89 66930703
Hay/Pasture Pasture - Fair 0 49 0 483654 69 33372159 264754 79 20915584 836584 84 70273026
Cultivated Crops Row crops (SR + CR) - Poor 0 71 0 0 80 0 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=78.79
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 Analysis

0.0
2.0
4.0
6.0
8.0
10.0
12.0
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): Asheboro, North Carolina USA
Station Name: -
Latitude: 35.727863°
Longitude: -79.915669°
Elevation (USGS): 540.87 ft
PRECIPITATION FREQUENCY ESTIMATES
by
duration
for ARI
(years):1 2 5 10 25 50 100 200 500 1000
5-min:0.398 0.471 0.548 0.6 0.656 0.693 0.724 0.75 0.775 0.791
10-min:0.635 0.753 0.878 0.959 1.05 1.1 1.15 1.19 1.23 1.25
15-min:0.794 0.947 1.11 1.21 1.33 1.4 1.46 1.5 1.54 1.56
30-min:1.09 1.31 1.58 1.76 1.96 2.1 2.23 2.33 2.46 2.53
60-min:1.36 1.64 2.02 2.29 2.62 2.85 3.07 3.27 3.52 3.7
2-hr:1.6 1.94 2.4 2.74 3.18 3.5 3.81 4.11 4.49 4.78
3-hr:1.71 2.07 2.58 2.95 3.44 3.81 4.17 4.53 5 5.35
6-hr:2.07 2.5 3.11 3.58 4.2 4.69 5.17 5.66 6.33 6.84
12-hr:2.46 2.98 3.72 4.31 5.11 5.75 6.41 7.09 8.04 8.79
24-hr:2.88 3.48 4.35 5.03 5.95 6.67 7.41 8.17 9.21 10
2-day:3.37 4.05 5.02 5.77 6.77 7.56 8.36 9.17 10.3 11.2
3-day:3.58 4.29 5.3 6.08 7.13 7.96 8.81 9.67 10.9 11.8
4-day:3.78 4.54 5.58 6.39 7.5 8.37 9.26 10.2 11.4 12.4
7-day:4.33 5.16 6.27 7.15 8.34 9.28 10.2 11.2 12.6 13.6
10-day:4.93 5.86 7.03 7.95 9.19 10.2 11.1 12.2 13.5 14.6
20-day:6.63 7.82 9.23 10.4 11.9 13.1 14.3 15.5 17.2 18.5
30-day:8.19 9.63 11.2 12.4 14 15.2 16.4 17.6 19.3 20.5
45-day:10.3 12.1 13.8 15.2 17 18.3 19.6 20.9 22.7 24
60-day:12.4 14.4 16.3 17.7 19.5 20.9 22.2 23.5 25.2 26.5
Date/time (GMT): Mon Oct 26 20:52:51 2020
pyRunTime: 0.0310769081116

APPENDIX F
Outlet Works Rating Curves

Total outlet discharge from the spillway system
Client:NCEM Date:10/26/2020
Project:Overtopping Study Engineer:T.Carter
Dam:Asheboro Country Club Lake Dam Dam No.RANDO-029
Reservior Water
Level (RWS)
Elevation (ft)
Total discharge from the
spillway system (cfs)
(from Hydrocad)
501.4 0.0
502.2 0.8
503.0 58.4
503.8 199.3
504.6 412.0
505.4 698.1
506.2 1060.9
507.0 1374.3
507.8 1605.9
508.6 1804.3
509.4 1981.3
510.2 2143.0
511.0 2292.9
511.8 2433.3
512.6 2565.9
513.4 2691.8
514.2 2812.0
515.0 2927.2
515.8 3038.0
516.6 3144.9
517.4 3248.2
518.2 3348.3
519.0 3445.5
519.8 3540.0
520.6 3632.0
521.4 3721.8
522.2 3809.4
523.0 3895.0
523.8 3978.8
524.6 4060.9
525.4 4141.3
526.2 4220.2
527.0 4297.6
527.8 4373.7
528.6 4448.5
529.4 4522.0
530.2 4594.3
531.0 4665.5
531.8 4735.7
532.6 4804.8
533.4 4873.0
534.2 4940.2
535.0 5006.5
535.8 5071.9
536.6 5136.5
537.4 5200.3
538.2 5263.3
-1000.0
0.0
1000.0
2000.0
3000.0
4000.0
5000.0
6000.0
495.0 500.0 505.0 510.0 515.0 520.0 525.0 530.0 535.0 540.0 545.0Total discharge from the spillway system (cfs)Reservior Water Level (RWS) Elevation (ft)
The whole spillway system rating curve (cfs)
RANDO-029 Asheboro Country Club Lake Dam
Rainfall not specifiedRANDO-029
Printed 10/26/2020Prepared by HDR, Inc
Page 1HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC
Summary for Pond 1P: RANDO-029 Asheboro Country Club Lake Dam
Volume Invert Avail.Storage Storage Description
#1 501.40' 97,036,941 cf Custom Stage Data (Prismatic) Listed below (Recalc)
RANDO-029 Asheboro Country Club Lake Dam
Rainfall not specifiedRANDO-029
Printed 10/26/2020Prepared by HDR, Inc
Page 2HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
501.40 10,801 0 0
501.90 824,893 208,924 208,924
502.40 830,801 413,924 622,847
502.90 860,752 422,888 1,045,735
503.40 878,662 434,854 1,480,589
503.90 901,250 444,978 1,925,567
504.40 928,975 457,556 2,383,123
504.90 960,078 472,263 2,855,386
505.40 993,779 488,464 3,343,851
505.90 1,033,037 506,704 3,850,555
506.40 1,078,145 527,796 4,378,350
506.90 1,113,975 548,030 4,926,380
507.40 1,149,561 565,884 5,492,264
507.90 1,185,859 583,855 6,076,119
508.40 1,219,414 601,318 6,677,437
508.90 1,249,209 617,156 7,294,593
509.40 1,279,893 632,276 7,926,869
509.90 1,310,996 647,722 8,574,591
510.40 1,343,848 663,711 9,238,302
510.90 1,377,627 680,369 9,918,671
511.40 1,412,461 697,522 10,616,193
511.90 1,452,686 716,287 11,332,479
512.40 1,493,213 736,475 12,068,954
512.90 1,535,293 757,127 12,826,081
513.40 1,579,697 778,748 13,604,828
513.90 1,624,902 801,150 14,405,978
514.40 1,669,707 823,652 15,229,630
514.90 1,714,639 846,087 16,075,717
515.40 1,755,156 867,449 16,943,165
515.90 1,796,650 887,952 17,831,117
516.40 1,842,227 909,719 18,740,836
516.90 1,901,699 935,982 19,676,818
517.40 1,948,359 962,515 20,639,332
517.90 1,991,563 984,981 21,624,313
518.40 2,033,291 1,006,214 22,630,526
518.90 2,073,535 1,026,707 23,657,233
519.40 2,115,264 1,047,200 24,704,432
519.90 2,159,248 1,068,628 25,773,060
520.40 2,204,307 1,090,889 26,863,949
520.90 2,250,205 1,113,628 27,977,577
521.40 2,294,883 1,136,272 29,113,849
521.90 2,338,887 1,158,443 30,272,292
522.40 2,387,197 1,181,521 31,453,813
522.90 2,429,658 1,204,214 32,658,026
523.40 2,471,807 1,225,366 33,883,393
523.90 2,514,385 1,246,548 35,129,941
524.40 2,560,439 1,268,706 36,398,647
524.90 2,607,285 1,291,931 37,690,578
525.40 2,654,639 1,315,481 39,006,059
RANDO-029 Asheboro Country Club Lake Dam
Rainfall not specifiedRANDO-029
Printed 10/26/2020Prepared by HDR, Inc
Page 3HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC
525.90 2,701,152 1,338,948 40,345,006
526.40 2,746,680 1,361,958 41,706,964
526.90 2,793,262 1,384,986 43,091,950
527.40 2,841,094 1,408,589 44,500,539
527.90 2,892,090 1,433,296 45,933,835
528.40 2,947,100 1,459,798 47,393,632
528.90 3,029,863 1,494,241 48,887,873
529.40 3,094,004 1,530,967 50,418,840
529.90 3,153,750 1,561,939 51,980,778
530.40 3,211,904 1,591,414 53,572,192
530.90 3,268,770 1,620,169 55,192,360
531.40 3,325,986 1,648,689 56,841,049
531.90 3,385,537 1,677,881 58,518,930
532.40 3,446,309 1,707,962 60,226,892
532.90 3,509,971 1,739,070 61,965,962
533.40 3,578,096 1,772,017 63,737,978
533.90 3,646,758 1,806,214 65,544,192
534.40 3,716,260 1,840,755 67,384,946
534.90 3,786,396 1,875,664 69,260,610
535.40 3,857,930 1,911,082 71,171,692
535.90 3,930,020 1,946,988 73,118,679
536.40 4,004,814 1,983,709 75,102,388
536.90 4,078,994 2,020,952 77,123,340
537.40 4,155,703 2,058,674 79,182,014
537.90 4,228,945 2,096,162 81,278,176
538.40 4,303,428 2,133,093 83,411,269
538.90 4,377,783 2,170,303 85,581,572
539.40 4,459,297 2,209,270 87,790,842
539.90 4,542,178 2,250,369 90,041,211
540.40 4,625,752 2,291,983 92,333,193
540.90 4,703,525 2,332,319 94,665,513
541.40 4,782,188 2,371,428 97,036,941
Device Routing Invert Outlet Devices
#1 Primary 501.40'8" DIP 8.000" Diameter, C= 0.600
250.0' Long Tube, Hazen-Williams C= 140
Inlet / Outlet Elev. = 476.20' / 501.40'
#2 Secondary 502.30'Emergency Spillway, Cv= 3.10 (C= 3.88)
Head (feet) 0.00 1.00 2.00 3.00 4.00
Width (feet) 23.00 31.00 39.00 47.00 55.00
Primary OutFlow Max=0.00 cfs @ 5.00 hrs HW=0.00' (Free Discharge)
1=8" DIP ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 5.00 hrs HW=0.00' (Free Discharge)
2=Emergency Spillway ( Controls 0.00 cfs)
RANDO-029 Asheboro Country Club Lake Dam
Rainfall not specifiedRANDO-029
Printed 10/26/2020Prepared by HDR, Inc
Page 4HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC
Stage-Discharge for Pond 1P: RANDO-029 Asheboro Country Club Lake Dam
Elevation
(feet)
Discharge
(cfs)
Primary
(cfs)
Secondary
(cfs)
501.40 0.00 0.00 0.00
501.80 0.55 0.55 0.00
502.20 0.79 0.79 0.00
502.60 16.23 0.98 15.26
503.00 58.42 1.14 57.28
503.40 119.84 1.28 118.56
503.80 199.31 1.41 197.90
504.20 296.64 1.53 295.12
504.60 412.00 1.64 410.36
505.00 545.69 1.74 543.94
505.40 698.11 1.84 696.26
505.80 869.70 1.94 867.76
506.20 1,060.92 2.03 1,058.89
506.60 1,236.62 2.11 1,234.50
507.00 1,374.26 2.20 1,372.06
507.40 1,495.52 2.28 1,493.24
507.80 1,605.93 2.36 1,603.57
508.20 1,708.28 2.44 1,705.84
508.60 1,804.25 2.51 1,801.74
509.00 1,894.98 2.58 1,892.39
509.40 1,981.29 2.65 1,978.63
509.80 2,063.80 2.72 2,061.07
510.20 2,142.99 2.79 2,140.20
510.60 2,219.25 2.86 2,216.39
511.00 2,292.89 2.92 2,289.96
511.40 2,364.16 2.99 2,361.18
511.80 2,433.30 3.05 2,430.25
512.20 2,500.48 3.11 2,497.37
512.60 2,565.87 3.17 2,562.70
513.00 2,629.60 3.23 2,626.37
513.40 2,691.79 3.29 2,688.51
513.80 2,752.56 3.34 2,749.22
514.20 2,812.00 3.40 2,808.60
514.60 2,870.19 3.46 2,866.74
515.00 2,927.21 3.51 2,923.70
515.40 2,983.13 3.56 2,979.57
515.80 3,038.01 3.62 3,034.39
516.20 3,091.90 3.67 3,088.24
516.60 3,144.87 3.72 3,141.15
517.00 3,196.95 3.77 3,193.18
517.40 3,248.19 3.82 3,244.36
517.80 3,298.62 3.87 3,294.75
518.20 3,348.29 3.92 3,344.37
518.60 3,397.23 3.97 3,393.26
519.00 3,445.47 4.02 3,441.45
519.40 3,493.05 4.07 3,488.98
519.80 3,539.97 4.12 3,535.86
520.20 3,586.28 4.16 3,582.12
520.60 3,632.00 4.21 3,627.79
521.00 3,677.15 4.25 3,672.89
521.40 3,721.75 4.30 3,717.45
Elevation
(feet)
Discharge
(cfs)
Primary
(cfs)
Secondary
(cfs)
521.80 3,765.81 4.34 3,761.47
522.20 3,809.37 4.39 3,804.98
522.60 3,852.43 4.43 3,847.99
523.00 3,895.01 4.48 3,890.53
523.40 3,937.13 4.52 3,932.61
523.80 3,978.80 4.56 3,974.24
524.20 4,020.04 4.61 4,015.44
524.60 4,060.86 4.65 4,056.21
525.00 4,101.27 4.69 4,096.58
525.40 4,141.29 4.73 4,136.56
525.80 4,180.92 4.77 4,176.15
526.20 4,220.18 4.81 4,215.37
526.60 4,259.08 4.86 4,254.22
527.00 4,297.62 4.90 4,292.73
527.40 4,335.82 4.94 4,330.89
527.80 4,373.69 4.98 4,368.71
528.20 4,411.23 5.02 4,406.21
528.60 4,448.45 5.05 4,443.40
529.00 4,485.36 5.09 4,480.27
529.40 4,521.98 5.13 4,516.84
529.80 4,558.29 5.17 4,553.12
530.20 4,594.32 5.21 4,589.11
530.60 4,630.07 5.25 4,624.82
531.00 4,665.54 5.28 4,660.26
531.40 4,700.75 5.32 4,695.43
531.80 4,735.69 5.36 4,730.33
532.20 4,770.38 5.40 4,764.98
532.60 4,804.82 5.43 4,799.38
533.00 4,839.01 5.47 4,833.54
533.40 4,872.96 5.51 4,867.45
533.80 4,906.67 5.54 4,901.13
534.20 4,940.16 5.58 4,934.58
534.60 4,973.42 5.61 4,967.80
535.00 5,006.46 5.65 5,000.81
535.40 5,039.28 5.68 5,033.59
535.80 5,071.89 5.72 5,066.17
536.20 5,104.29 5.75 5,098.53
536.60 5,136.48 5.79 5,130.69
537.00 5,168.48 5.82 5,162.65
537.40 5,200.27 5.86 5,194.42
537.80 5,231.88 5.89 5,225.99
538.20 5,263.29 5.93 5,257.37
538.60 5,294.52 5.96 5,288.56
539.00 5,325.56 5.99 5,319.57
539.40 5,356.43 6.03 5,350.40
539.80 5,387.11 6.06 5,381.06
540.20 5,417.63 6.09 5,411.54
540.60 5,447.97 6.13 5,441.84
541.00 5,478.14 6.16 5,471.99
541.40 5,508.15 6.19 5,501.96