YADKI-034 Final Report

DAM HYDRAULIC CAPACITY
ASSESSMENT REPORT
(DRAFT)
DEEP CREEK WS #22A (PL-566)
YADKI-034
YADKIN 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 Deep Creek WS #22a (Pl-566) in Yadkin
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, 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 =
737.6
576.3
601.9
628.0
654.6
681.7
709.4
835.2
835.7
836.2
836.7
837.2
ELEVATION
832.7
833.2
833.7
834.2
834.7
32.3
38.1
44.3
STORAGE (ACRE-FT)
0.0
3.8
7.8
12.1
16.8
21.7
26.8
816.7
813.7
814.2
814.7
815.2
815.7
816.2
824.2
828.2
ELEVATION
812.2
812.7
813.2
STORAGE (ACRE-FT)
503.2
526.9
551.3
68.92
62
SCS Type 2
SPILLWAY
Primary
Auxiliary
TYPE
Riser / Barrel
Grass Lined Trapezoidal Channel
ELEVATION
24 HOUR - 200 YEAR EVENT, 8.71 INCHES, ELEVATION 829.4 (1.9 FT FREE-BOARD)
24 HOUR - 100 YEAR EVENT, 7.83 INCHES, ELEVATION 828.7 (2.6 FT FREE-BOARD)
24 HOUR - 50 YEAR EVENT, 6.99 INCHES, ELEVATION 827.7 (3.6 FT FREE-BOARD)
24 HOUR - 25 YEAR EVENT, 6.17 INCHES, ELEVATION 826 (5.3 FT FREE-BOARD)
SUMMARY OF INPUT PARAMETERS
2.32
SUMMARY SHEET OF HYDRAULIC CAPACITY RESULTS
DEEP CREEK WS #22A (PL-566), YADKI-034
ANALYSIS PERFORMED BY: S. MURPHY, HDR
TOP OF DAM ELEVATION = 831.3
24 HOUR - 1000 YEAR EVENT, 10.9 INCHES, ELEVATION 830.7 (0.6 FT FREE-BOARD)
24 HOUR - 500 YEAR EVENT, 9.91 INCHES, ELEVATION 830.1 (1.2 FT FREE-BOARD)
YADKI-034DEEP CREEK WS #22A (PL-566)OCTOBER 28, 2020
1900.9
NOT TO SCALE
1610.1
1656.2
1703.3
1751.3
1800.2
1850.1
1352.1
1393.0
1434.7
1477.3
1520.7
1564.9
1122.4
1158.8
1196.0
1233.9
1272.6
1311.9
918.5
950.7
983.7
1017.3
1051.6
1086.6
766.3
795.5
825.4
855.8
886.8
850.2
850.7
851.2
851.7
852.2
847.2
847.7
848.2
848.7
849.2
849.7
844.2
844.7
845.2
845.7
846.2
846.7
841.2
841.7
842.2
842.7
843.2
843.7
838.2
838.7
839.2
839.7
840.2
840.7
837.7
414.0
435.5
457.5
480.1
296.5
314.6
333.3
352.6
372.5
393.0
204.7
218.7
233.1
248.1
263.7
279.7
129.2
140.9
153.0
165.4
178.2
191.3
73.7
82.0
90.7
99.7
109.1
118.7
51.1
58.3
65.8
831.7
832.2
828.7
829.2
829.7
830.2
830.7
831.2
825.7
826.2
826.7
827.2
827.7
828.2
822.7
823.2
823.7
824.2
824.7
825.2
819.7
820.2
820.7
821.2
821.7
822.2
817.2
817.7
818.2
818.7
819.2
YADKI-034DEEP CREEK WS #22A (PL-566)OCTOBER 28, 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
Deep Creek WS #22a (PI-566) - YADKI-034 - Watershed Boundary
Legend
Longest FlowPath
Watershed Bound ary
0 0.6 1.20.3 Miles
Date: 10 /5/2020
/Drainage Area: 2.32 Square MilesFlowpath Length: 2.5 miles

APPENDIX B

Lag Time Calculation
Dam No:YADKI-034 Date:10/23/2020
Dam Name:Deep Creek WS #22a (Pl-566)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 =68.9227 from NRCS CN Calculation
S =4.50901 in.
Mean Basin Slope Y =11.5315 %from Watershed Mean slope
Longest Flowpath:2.54 mi.from Watershed Longest flowpath
Flow Length l =13411.2 ft.
Time of Concentration Tc =1.71 Hours Tc =103 mins
Lag Time TL =1.03 Hours TL =62 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 9019 100 901864 458 100 45830 387693 100 38769288
Developed, Open Space Open space - Fair condition (grass cover 50% to 75%)0 49 0 1436157 69 99094852 2563367 79 202506011 109118 84 9165886
Developed, Low Intensity Residential districts by average lot size: 1/3 acre 0 57 0 163071 72 11741135 301395 81 24413002 0 86 0
Developed, Medium Intensity Residential districts by average lot size: 1/8 acre 0 77 0 9841 85 836489 23568 90 2121157 0 92 0
Developed, High Intensity Urban districts - Commercial and business 0 89 0 0 92 0 5397 94 507314 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 20762828 60 1245769689 5163198 73 376913449 2254737 79 178124190
Evergreen Forest Woods - Fair 0 36 0 905843 60 54350605 501765 73 36628832 171379 79 13538925
Mixed Forest Woods - Fair 0 36 0 6111066 60 366663966 1376706 73 100499517 638392 79 50432981
Shrub/Scrub Brush - Fair 0 35 0 274980 56 15398904 165765 70 11603540 0 77 0
Herbaceuous Herbaceuous - Fair 0 60 0 2104842 71 149443761 598608 81 48487237 94661 89 8424795
Hay/Pasture Pasture - Fair 0 49 0 7710330 69 532012756 5916374 79 467393510 584043 84 49059593
Cultivated Crops Row crops (SR + CR) - Poor 0 71 0 1809687 80 144774988 2350962 87 204533735 58793 90 5291379
Woody Wetlands Not Available 0 80 0 0 85 0 0 90 0 0 95 0
Emergent Herbaceuous Wetlands Not Available 0 80 0 2545 85 216313 0 90 0 16829 95 1598782 Weighted CN=68.92
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): Hamptonville, North Carolina USA
Station Name: -
Latitude: 36.08189°
Longitude: -80.742044°
Elevation (USGS): 904.58 ft
PRECIPITATION FREQUENCY ESTIMATES
by
duration
for ARI
(years):1 2 5 10 25 50 100 200 500 1000
5-min:0.358 0.424 0.5 0.556 0.622 0.669 0.714 0.756 0.806 0.843
10-min:0.571 0.678 0.801 0.889 0.992 1.07 1.14 1.2 1.28 1.33
15-min:0.714 0.852 1.01 1.13 1.26 1.35 1.44 1.51 1.61 1.67
30-min:0.979 1.18 1.44 1.63 1.86 2.03 2.2 2.35 2.56 2.7
60-min:1.22 1.48 1.85 2.12 2.48 2.76 3.03 3.3 3.67 3.94
2-hr:1.44 1.75 2.2 2.55 3.02 3.39 3.76 4.14 4.67 5.07
3-hr:1.56 1.89 2.38 2.76 3.29 3.7 4.13 4.57 5.19 5.68
6-hr:1.93 2.33 2.93 3.41 4.06 4.58 5.11 5.67 6.44 7.06
12-hr:2.36 2.86 3.59 4.17 4.97 5.61 6.27 6.96 7.91 8.67
24-hr:2.87 3.48 4.42 5.16 6.17 6.99 7.83 8.71 9.91 10.9
2-day:3.4 4.11 5.16 5.98 7.09 7.97 8.86 9.78 11 12
3-day:3.62 4.37 5.45 6.3 7.44 8.34 9.27 10.2 11.5 12.5
4-day:3.84 4.62 5.74 6.61 7.79 8.72 9.67 10.6 12 13
7-day:4.4 5.26 6.42 7.3 8.49 9.42 10.4 11.3 12.6 13.6
10-day:5.04 6.01 7.23 8.16 9.38 10.3 11.3 12.2 13.5 14.4
20-day:6.75 7.99 9.45 10.6 12.1 13.2 14.4 15.5 17.1 18.2
30-day:8.39 9.87 11.4 12.5 13.9 15 16 17 18.3 19.3
45-day:10.6 12.4 14 15.2 16.8 17.9 19 20 21.3 22.3
60-day:12.6 14.7 16.5 17.8 19.5 20.8 22 23.2 24.6 25.7
Date/time (GMT): Fri Oct 23 17:56:38 2020
pyRunTime: 0.019898891449

APPENDIX F
Outlet Works Rating Curves

Total outlet discharge from the spillway system
Client:NCEM Date:10/21/2020
Project:Overtopping Study Engineer:T.Carter
Dam:Deep Creek WS #22a (PI-566)Dam No.YADKI-034
Reservior Water
Level (RWS)
Elevation (ft)
Total discharge from the
spillway system (cfs)
(from Hydrocad)
812.2 0.0
813.0 5.2
813.8 14.4
814.6 20.7
815.4 25.3
816.2 29.2
817.0 32.7
817.8 35.8
818.6 38.6
819.4 41.3
820.2 43.7
821.0 46.1
821.8 48.3
822.6 50.5
823.4 52.5
824.2 54.5
825.0 90.9
825.8 145.7
826.6 157.7
827.4 160.5
828.2 163.3
829.0 434.8
829.8 943.8
830.6 1623.0
831.4 2451.6
832.2 3419.1
833.0 4519.8
833.8 5522.4
834.6 6284.0
835.4 6944.7
836.2 7540.1
837.0 8087.6
837.8 8597.9
838.6 9077.8
839.4 9532.5
840.2 9965.7
841.0 10380.1
841.8 10778.2
842.6 11161.7
843.4 11532.1
844.2 11890.8
845.0 12238.7
845.8 12576.9
846.6 12906.1
847.4 13227.0
848.2 13540.1
849.0 13846.1
0.0
2000.0
4000.0
6000.0
8000.0
10000.0
12000.0
14000.0
16000.0
810.0 815.0 820.0 825.0 830.0 835.0 840.0 845.0 850.0 855.0Total discharge from the spillway system (cfs)Reservior Water Level (RWS) Elevation (ft)
The whole spillway system rating curve (cfs)
YADKI-034 Deep Creek WS #22a (PI-566)
Rainfall not specifiedYADKI-034
Printed 10/21/2020Prepared by HDR, Inc
Page 1HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC
Summary for Pond 1P: YADKI-034 Deep Creek WS #22a (PI-566)
Volume Invert Avail.Storage Storage Description
#1 812.20' 82,813,986 cf Custom Stage Data (Prismatic) Listed below (Recalc)
YADKI-034 Deep Creek WS #22a (PI-566)
Rainfall not specifiedYADKI-034
Printed 10/21/2020Prepared 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)
812.20 322,402 0 0
812.70 340,127 165,632 165,632
813.20 361,729 175,464 341,096
813.70 388,877 187,652 528,748
814.20 415,410 201,072 729,820
814.70 437,393 213,201 943,020
815.20 462,207 224,900 1,167,920
815.70 488,359 237,642 1,405,562
816.20 523,926 253,071 1,658,633
816.70 567,441 272,842 1,931,475
817.20 606,426 293,467 2,224,942
817.70 640,420 311,712 2,536,653
818.20 672,920 328,335 2,864,988
818.70 707,012 344,983 3,209,971
819.20 740,625 361,909 3,571,880
819.70 771,904 378,132 3,950,013
820.20 800,879 393,196 4,343,208
820.70 827,920 407,200 4,750,408
821.20 855,645 420,891 5,171,299
821.70 1,009,707 466,338 5,637,637
822.20 1,037,051 511,690 6,149,327
822.70 1,068,848 526,475 6,675,802
823.20 1,097,578 541,607 7,217,408
823.70 1,124,072 555,413 7,772,821
824.20 1,154,346 569,605 8,342,425
824.70 1,192,051 586,599 8,929,024
825.20 1,236,572 607,156 9,536,180
825.70 1,282,236 629,702 10,165,882
826.20 1,330,869 653,276 10,819,158
826.70 1,376,943 676,953 11,496,111
827.20 1,426,904 700,962 12,197,073
827.70 1,524,531 737,859 12,934,932
828.20 1,602,793 781,831 13,716,763
828.70 1,658,936 815,432 14,532,195
829.20 1,709,443 842,095 15,374,290
829.70 1,759,141 867,146 16,241,436
830.20 1,807,939 891,770 17,133,206
830.70 1,852,959 915,225 18,048,430
831.20 1,895,547 937,127 18,985,557
831.70 1,938,691 958,560 19,944,116
832.20 1,985,977 981,167 20,925,283
832.70 2,040,420 1,006,599 21,931,883
833.20 2,098,174 1,034,649 22,966,531
833.70 2,152,373 1,062,637 24,029,168
834.20 2,202,412 1,088,696 25,117,864
834.70 2,249,180 1,112,898 26,230,762
835.20 2,296,035 1,136,304 27,367,066
835.70 2,341,211 1,159,312 28,526,377
836.20 2,387,197 1,182,102 29,708,479
YADKI-034 Deep Creek WS #22a (PI-566)
Rainfall not specifiedYADKI-034
Printed 10/21/2020Prepared by HDR, Inc
Page 3HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC
836.70 2,432,422 1,204,905 30,913,384
837.20 2,477,852 1,227,569 32,140,953
837.70 2,526,807 1,251,165 33,392,117
838.20 2,575,205 1,275,503 34,667,620
838.70 2,625,518 1,300,181 35,967,801
839.20 2,676,455 1,325,493 37,293,294
839.70 2,727,930 1,351,096 38,644,391
840.20 2,781,680 1,377,403 40,021,793
840.70 2,839,053 1,405,183 41,426,976
841.20 2,898,848 1,434,475 42,861,452
841.70 2,959,180 1,464,507 44,325,959
842.20 3,020,459 1,494,910 45,820,868
842.70 3,082,637 1,525,774 47,346,642
843.20 3,144,893 1,556,883 48,903,525
843.70 3,208,555 1,588,362 50,491,887
844.20 3,270,381 1,619,734 52,111,621
844.70 3,333,154 1,650,884 53,762,505
845.20 3,397,910 1,682,766 55,445,271
845.70 3,462,510 1,715,105 57,160,376
846.20 3,531,045 1,748,389 58,908,764
846.70 3,600,957 1,783,001 60,691,765
847.20 3,671,230 1,818,047 62,509,812
847.70 3,741,855 1,853,271 64,363,083
848.20 3,817,080 1,889,734 66,252,817
848.70 3,894,336 1,927,854 68,180,671
849.20 3,978,799 1,968,284 70,148,954
849.70 4,061,445 2,010,061 72,159,015
850.20 4,141,309 2,050,689 74,209,704
850.70 4,221,221 2,090,633 76,300,336
851.20 4,301,914 2,130,784 78,431,120
851.70 4,383,037 2,171,238 80,602,358
852.20 4,463,477 2,211,629 82,813,986
Device Routing Invert Outlet Devices
#1 Primary 803.30'36.0" Round 36" RCP
L= 189.0' RCP, sq.cut end projecting, Ke= 0.500
Inlet / Outlet Invert= 803.30' / 801.40' S= 0.0101 '/' Cc= 0.900
n= 0.013, Flow Area= 7.07 sf
#2 Device 1 812.20'27.0" W x 18.0" H Vert. Riser Orifice C= 0.600
#3 Device 1 824.20'90.0" W x 15.0" H Vert. Riser Weirs X 2.00 C= 0.600
#4 Secondary 828.20'Emergency Spillway, Cv= 3.10 (C= 3.88)
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00
Width (feet) 95.00 101.00 107.00 113.00 119.00 125.00
Primary OutFlow Max=0.00 cfs @ 5.00 hrs HW=0.00' TW=795.60' (Fixed TW Elev= 795.60')
1=36" RCP ( Controls 0.00 cfs)
2=Riser Orifice ( Controls 0.00 cfs)
3=Riser Weirs ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 5.00 hrs HW=0.00' (Free Discharge)
4=Emergency Spillway ( Controls 0.00 cfs)
YADKI-034 Deep Creek WS #22a (PI-566)
Rainfall not specifiedYADKI-034
Printed 10/21/2020Prepared by HDR, Inc
Page 4HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC
Stage-Discharge for Pond 1P: YADKI-034 Deep Creek WS #22a (PI-566)
Elevation
(feet)
Discharge
(cfs)
Primary
(cfs)
Secondary
(cfs)
812.20 0.00 0.00 0.00
812.60 1.83 1.83 0.00
813.00 5.17 5.17 0.00
813.40 9.49 9.49 0.00
813.80 14.39 14.39 0.00
814.20 17.87 17.87 0.00
814.60 20.69 20.69 0.00
815.00 23.13 23.13 0.00
815.40 25.34 25.34 0.00
815.80 27.35 27.35 0.00
816.20 29.23 29.23 0.00
816.60 30.99 30.99 0.00
817.00 32.66 32.66 0.00
817.40 34.24 34.24 0.00
817.80 35.75 35.75 0.00
818.20 37.20 37.20 0.00
818.60 38.60 38.60 0.00
819.00 39.95 39.95 0.00
819.40 41.25 41.25 0.00
819.80 42.51 42.51 0.00
820.20 43.74 43.74 0.00
820.60 44.93 44.93 0.00
821.00 46.09 46.09 0.00
821.40 47.22 47.22 0.00
821.80 48.33 48.33 0.00
822.20 49.41 49.41 0.00
822.60 50.47 50.47 0.00
823.00 51.51 51.51 0.00
823.40 52.52 52.52 0.00
823.80 53.52 53.52 0.00
824.20 54.50 54.50 0.00
824.60 67.64 67.64 0.00
825.00 90.85 90.85 0.00
825.40 120.63 120.63 0.00
825.80 145.72 145.72 0.00
826.20 156.28 156.28 0.00
826.60 157.71 157.71 0.00
827.00 159.12 159.12 0.00
827.40 160.53 160.53 0.00
827.80 161.92 161.92 0.00
828.20 163.29 163.29 0.00
828.60 258.73 164.66 94.07
829.00 434.75 166.02 268.73
829.40 665.94 167.36 498.58
829.80 943.84 168.69 775.15
830.20 1,263.84 170.02 1,093.82
830.60 1,623.03 171.33 1,451.70
831.00 2,019.41 172.63 1,846.78
831.40 2,451.55 173.93 2,277.63
831.80 2,918.38 175.21 2,743.17
832.20 3,419.08 176.48 3,242.60
Elevation
(feet)
Discharge
(cfs)
Primary
(cfs)
Secondary
(cfs)
832.60 3,953.04 177.75 3,775.29
833.00 4,519.75 179.01 4,340.75
833.40 5,075.37 180.25 4,895.12
833.80 5,522.35 181.49 5,340.85
834.20 5,919.45 182.72 5,736.72
834.60 6,283.95 183.94 6,100.01
835.00 6,624.05 185.16 6,438.89
835.40 6,944.70 186.36 6,758.34
835.80 7,249.24 187.56 7,061.68
836.20 7,540.09 188.75 7,351.34
836.60 7,819.08 189.94 7,629.14
837.00 8,087.64 191.11 7,896.52
837.40 8,346.92 192.28 8,154.64
837.80 8,597.87 193.44 8,404.43
838.20 8,841.29 194.60 8,646.69
838.60 9,077.83 195.75 8,882.09
839.00 9,308.08 196.89 9,111.19
839.40 9,532.52 198.02 9,334.49
839.80 9,751.58 199.15 9,552.43
840.20 9,965.65 200.27 9,765.37
840.60 10,175.06 201.39 9,973.67
841.00 10,380.10 202.50 10,177.61
841.40 10,581.06 203.60 10,377.46
841.80 10,778.16 204.70 10,573.46
842.20 10,971.63 205.79 10,765.83
842.60 11,161.66 206.88 10,954.78
843.00 11,348.43 207.96 11,140.47
843.40 11,532.11 209.03 11,323.07
843.80 11,712.84 210.10 11,502.74
844.20 11,890.78 211.17 11,679.61
844.60 12,066.04 212.22 11,853.81
845.00 12,238.74 213.28 12,025.46
845.40 12,409.00 214.33 12,194.67
845.80 12,576.91 215.37 12,361.54
846.20 12,742.58 216.41 12,526.17
846.60 12,906.09 217.44 12,688.65
847.00 13,067.52 218.47 12,849.05
847.40 13,226.95 219.49 13,007.46
847.80 13,384.46 220.51 13,163.95
848.20 13,540.11 221.52 13,318.58
848.60 13,693.97 222.53 13,471.43
849.00 13,846.10 223.54 13,622.56
849.40 13,996.55 224.54 13,772.01
849.80 14,145.39 225.53 13,919.86
850.20 14,292.66 226.52 14,066.14
850.60 14,438.41 227.51 14,210.90
851.00 14,582.69 228.49 14,354.20
851.40 14,725.54 229.47 14,496.07
851.80 14,867.01 230.45 14,636.56
852.20 15,007.13 231.42 14,775.71