YADKI-036 Final Report

DAM HYDRAULIC CAPACITY
ASSESSMENT REPORT
(DRAFT)
DEEP CREEK WS #23 (PL-566)
YADKI-036
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 #23 (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, and 500 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 =
487.5
375.6
393.1
411.1
429.5
448.4
467.7
875.3
875.8
876.3
876.8
877.3
ELEVATION
872.8
873.3
873.8
874.3
874.8
15.7
18.9
22.3
STORAGE (ACRE-FT)
0.0
1.6
3.4
5.4
7.6
10.1
12.8
856.8
853.8
854.3
854.8
855.3
855.8
856.3
864.7
867.2
ELEVATION
852.3
852.8
853.3
STORAGE (ACRE-FT)
325.7
341.9
358.5
70.47
61
SCS Type 2
SPILLWAY
Primary
Auxiliary
TYPE
Riser / Barrel
Grass Lined Trapezoidal Channel
ELEVATION
24 HOUR - 200 YEAR EVENT, 8.63 INCHES, ELEVATION 868.8 (0.7 FT FREE-BOARD)
24 HOUR - 100 YEAR EVENT, 7.77 INCHES, ELEVATION 868.2 (1.3 FT FREE-BOARD)
24 HOUR - 50 YEAR EVENT, 6.94 INCHES, ELEVATION 867.6 (1.9 FT FREE-BOARD)
24 HOUR - 25 YEAR EVENT, 6.13 INCHES, ELEVATION 866.5 (3 FT FREE-BOARD)
SUMMARY OF INPUT PARAMETERS
1.5
SUMMARY SHEET OF HYDRAULIC CAPACITY RESULTS
DEEP CREEK WS #23 (PL-566), YADKI-036
ANALYSIS PERFORMED BY: S. MURPHY, HDR
24 HOUR - 1000 YEAR EVENT, 10.8 INCHES, ELEVATION 869.9 (0.4 FT OVER-TOPPED)
TOP OF DAM ELEVATION = 869.5
24 HOUR - 500 YEAR EVENT, 9.83 INCHES, ELEVATION 869.5 (0 FT FREE-BOARD)
YADKI-036DEEP CREEK WS #23 (PL-566)OCTOBER 28, 2020
1319.2
NOT TO SCALE
1110.0
1143.2
1177.0
1211.5
1246.7
1282.6
924.8
954.0
983.9
1014.5
1045.7
1077.5
760.7
786.7
813.3
840.3
867.9
896.1
615.2
638.2
661.7
685.7
710.2
735.2
507.6
528.2
549.3
570.8
592.7
890.3
890.8
891.3
891.8
892.3
887.3
887.8
888.3
888.8
889.3
889.8
884.3
884.8
885.3
885.8
886.3
886.8
881.3
881.8
882.3
882.8
883.3
883.8
878.3
878.8
879.3
879.8
880.3
880.8
877.8
264.9
279.5
294.5
309.9
186.0
198.1
210.6
223.5
236.8
250.6
122.0
131.6
141.7
152.1
163.0
174.3
74.0
81.0
88.4
96.1
104.3
112.9
38.9
43.9
49.2
54.9
60.9
67.3
26.0
30.0
34.3
871.8
872.3
868.8
869.3
869.8
870.3
870.8
871.3
865.8
866.3
866.8
867.3
867.8
868.3
862.8
863.3
863.8
864.3
864.8
865.3
859.8
860.3
860.8
861.3
861.8
862.3
857.3
857.8
858.3
858.8
859.3
YADKI-036DEEP CREEK WS #23 (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 #23 (PI-566) - YADKI-036 - Watershed Boundary
Legend
Longest FlowPath
Watershed Bound ary
0 0.45 0.90.225 Miles
Date: 10 /5/2020
/Drainage Ar ea: 1.5 Square MilesFlowpath Length: 2.4 miles

APPENDIX B

Lag Time Calculation
Dam No:YADKI-036 Date:10/26/2020
Dam Name:Deep Creek WS #23 (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 =70.4736 from NRCS CN Calculation
S =4.18971 in.
Mean Basin Slope Y =9.96403 %from Watershed Mean slope
Longest Flowpath:2.41 mi.from Watershed Longest flowpath
Flow Length l =12724.8 ft.
Time of Concentration Tc =1.69 Hours Tc =101 mins
Lag Time TL =1.01 Hours TL =61 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 35565 100 3556482 4929 100 492911 162934 100 16293386
Developed, Open Space Open space - Fair condition (grass cover 50% to 75%)0 49 0 838851 69 57880704 1303205 79 102953159 297 84 24941
Developed, Low Intensity Residential districts by average lot size: 1/3 acre 0 57 0 203506 72 14652412 167569 81 13573054 0 86 0
Developed, Medium Intensity Residential districts by average lot size: 1/8 acre 0 77 0 9157 85 778310 365 90 32810 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 0 86 0 0 91 0 0 94 0
Deciduous Forest Woods - Fair 0 36 0 12143572 60 728614295 2417371 73 176468084 1856946 79 146698766
Evergreen Forest Woods - Fair 0 36 0 1546106 60 92766372 401448 73 29305692 96397 79 7615354
Mixed Forest Woods - Fair 0 36 0 2772459 60 166347570 474467 73 34636065 487873 79 38541969
Shrub/Scrub Brush - Fair 0 35 0 54571 56 3055987 32612 70 2282836 0 77 0
Herbaceuous Herbaceuous - Fair 0 60 0 84307 71 5985773 23437 81 1898360 0 89 0
Hay/Pasture Pasture - Fair 0 49 0 5437366 69 375178284 2140980 79 169137444 275861 84 23172334
Cultivated Crops Row crops (SR + CR) - Poor 0 71 0 5021421 80 401713696 3609427 87 314020164 182340 90 16410642
Woody Wetlands Not Available 0 80 0 207 85 17585 0 90 0 9480 95 900614
Emergent Herbaceuous Wetlands Not Available 0 80 0 3476 85 295431 0 90 0 15898 95 1510346 Weighted CN=70.47
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): Yadkinville, North Carolina USA
Station Name: -
Latitude: 36.068681°
Longitude: -80.708162°
Elevation (USGS): 929.84 ft
PRECIPITATION FREQUENCY ESTIMATES
by
duration
for ARI
(years):1 2 5 10 25 50 100 200 500 1000
5-min:0.359 0.425 0.501 0.556 0.622 0.668 0.712 0.752 0.801 0.836
10-min:0.573 0.68 0.802 0.89 0.992 1.07 1.13 1.19 1.27 1.32
15-min:0.717 0.855 1.02 1.13 1.26 1.35 1.43 1.51 1.59 1.65
30-min:0.982 1.18 1.44 1.63 1.86 2.03 2.19 2.34 2.54 2.68
60-min:1.23 1.48 1.85 2.12 2.48 2.75 3.02 3.29 3.64 3.91
2-hr:1.44 1.75 2.2 2.55 3.01 3.38 3.74 4.11 4.62 5.01
3-hr:1.56 1.89 2.38 2.76 3.28 3.69 4.11 4.54 5.14 5.62
6-hr:1.92 2.33 2.93 3.4 4.04 4.56 5.09 5.63 6.39 6.99
12-hr:2.35 2.84 3.57 4.15 4.94 5.58 6.24 6.92 7.87 8.62
24-hr:2.85 3.46 4.39 5.12 6.13 6.94 7.77 8.63 9.83 10.8
2-day:3.38 4.08 5.12 5.92 7.02 7.89 8.77 9.68 10.9 11.9
3-day:3.6 4.33 5.41 6.24 7.37 8.26 9.18 10.1 11.4 12.4
4-day:3.81 4.59 5.69 6.55 7.72 8.64 9.58 10.5 11.9 12.9
7-day:4.36 5.22 6.36 7.24 8.42 9.35 10.3 11.2 12.5 13.5
10-day:5 5.96 7.17 8.09 9.31 10.2 11.2 12.1 13.4 14.4
20-day:6.7 7.93 9.37 10.5 12 13.1 14.3 15.4 17 18.1
30-day:8.32 9.78 11.3 12.4 13.8 14.9 15.9 16.9 18.3 19.2
45-day:10.5 12.3 13.9 15.1 16.7 17.8 18.9 20 21.3 22.3
60-day:12.5 14.6 16.4 17.7 19.4 20.7 21.9 23 24.5 25.6
Date/time (GMT): Mon Oct 26 20:33:51 2020
pyRunTime: 0.0416469573975

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:Deep Creek WS #23 (PI-566)Dam No.YADKI-036
Reservior Water
Level (RWS)
Elevation (ft)
Total discharge from the
spillway system (cfs)
(from Hydrocad)
852.3 0.0
853.1 4.3
853.9 12.0
854.7 17.2
855.5 21.1
856.3 24.4
857.1 27.2
857.9 29.8
858.7 32.2
859.5 34.4
860.3 36.5
861.1 38.4
861.9 40.3
862.7 42.1
863.5 43.8
864.3 45.4
865.1 59.2
865.9 105.0
866.7 106.9
867.5 151.8
868.3 420.7
869.1 835.8
869.9 1372.5
870.7 2021.7
871.5 2721.0
872.3 3225.5
873.1 3645.1
873.9 4015.4
874.7 4351.7
875.5 4662.1
876.3 4952.2
877.1 5225.5
877.9 5484.7
878.7 5731.8
879.5 5968.4
880.3 6195.8
881.1 6415.0
881.9 6626.8
882.7 6831.9
883.5 7030.9
884.3 7224.4
885.1 7412.8
885.9 7596.4
886.7 7775.7
887.5 7950.8
888.3 8122.2
889.1 8289.9
0.0
1000.0
2000.0
3000.0
4000.0
5000.0
6000.0
7000.0
8000.0
9000.0
850.0 855.0 860.0 865.0 870.0 875.0 880.0 885.0 890.0 895.0Total discharge from the spillway system (cfs)Reservior Water Level (RWS) Elevation (ft)
The whole spillway system rating curve (cfs)
YADKI-036 Deep Creek WS #23 (PI-566)
Rainfall not specifiedYADKI-036
Printed 10/26/2020Prepared by HDR, Inc
Page 1HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC
Summary for Pond 1P: YADKI-036 Deep Creek WS #23 (PI-566)
Volume Invert Avail.Storage Storage Description
#1 852.30' 57,464,602 cf Custom Stage Data (Prismatic) Listed below (Recalc)
YADKI-036 Deep Creek WS #23 (PI-566)
Rainfall not specifiedYADKI-036
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)
852.30 145,479 0 0
852.80 145,479 72,740 72,740
853.30 161,543 76,756 149,495
853.80 185,137 86,670 236,165
854.30 204,971 97,527 333,692
854.80 228,779 108,438 442,130
855.30 245,430 118,552 560,682
855.80 264,053 127,371 688,053
856.30 284,238 137,073 825,125
856.80 307,148 147,847 972,972
857.30 333,555 160,176 1,133,148
857.80 365,166 174,680 1,307,828
858.30 390,303 188,867 1,496,695
858.80 418,467 202,193 1,698,888
859.30 448,193 216,665 1,915,553
859.80 477,988 231,545 2,147,098
860.30 507,285 246,318 2,393,416
860.80 539,082 261,592 2,655,008
861.30 568,955 277,009 2,932,017
861.80 598,701 291,914 3,223,931
862.30 627,451 306,538 3,530,469
862.80 658,203 321,414 3,851,883
863.30 692,246 337,612 4,189,495
863.80 729,307 355,388 4,544,883
864.30 773,350 375,664 4,920,547
864.80 816,318 397,417 5,317,964
865.30 855,967 418,071 5,736,036
865.80 893,232 437,300 6,173,335
866.30 929,473 455,676 6,629,012
866.80 967,734 474,302 7,103,313
867.30 1,002,412 492,537 7,595,850
867.80 1,037,578 509,998 8,105,847
868.30 1,071,250 527,207 8,633,054
868.80 1,104,668 543,980 9,177,034
869.30 1,142,520 561,797 9,738,831
869.80 1,179,736 580,564 10,319,395
870.30 1,222,148 600,471 10,919,866
870.80 1,258,828 620,244 11,540,110
871.30 1,290,459 637,322 12,177,432
871.80 1,322,744 653,301 12,830,732
872.30 1,356,055 669,700 13,500,432
872.80 1,394,023 687,520 14,187,952
873.30 1,432,168 706,548 14,894,499
873.80 1,468,799 725,242 15,619,741
874.30 1,508,154 744,238 16,363,979
874.80 1,546,826 763,745 17,127,724
875.30 1,584,316 782,786 17,910,510
875.80 1,624,492 802,202 18,712,712
876.30 1,663,564 822,014 19,534,726
YADKI-036 Deep Creek WS #23 (PI-566)
Rainfall not specifiedYADKI-036
Printed 10/26/2020Prepared by HDR, Inc
Page 3HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC
876.80 1,702,451 841,504 20,376,230
877.30 1,738,154 860,151 21,236,381
877.80 1,774,961 878,279 22,114,660
878.30 1,812,715 896,919 23,011,579
878.80 1,852,617 916,333 23,927,912
879.30 1,892,900 936,379 24,864,291
879.80 1,936,445 957,336 25,821,627
880.30 1,982,012 979,614 26,801,241
880.80 2,024,883 1,001,724 27,802,965
881.30 2,067,461 1,023,086 28,826,051
881.80 2,110,342 1,044,451 29,870,502
882.30 2,155,127 1,066,367 30,936,869
882.80 2,200,391 1,088,880 32,025,749
883.30 2,244,541 1,111,233 33,136,982
883.80 2,289,297 1,133,460 34,270,441
884.30 2,336,553 1,156,463 35,426,904
884.80 2,382,529 1,179,771 36,606,674
885.30 2,427,324 1,202,463 37,809,137
885.80 2,475,391 1,225,679 39,034,816
886.30 2,524,951 1,250,086 40,284,902
886.80 2,576,680 1,275,408 41,560,309
887.30 2,631,846 1,302,132 42,862,441
887.80 2,688,301 1,330,037 44,192,478
888.30 2,745,059 1,358,340 45,550,818
888.80 2,802,949 1,387,002 46,937,820
889.30 2,861,406 1,416,089 48,353,908
889.80 2,918,877 1,445,071 49,798,979
890.30 2,975,566 1,473,611 51,272,590
890.80 3,035,313 1,502,720 52,775,310
891.30 3,095,781 1,532,774 54,308,083
891.80 3,157,080 1,563,215 55,871,298
892.30 3,216,133 1,593,303 57,464,602
Device Routing Invert Outlet Devices
#1 Primary 843.70'30.0" Round 30" RCP
L= 162.0' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 843.70' / 842.10' S= 0.0099 '/' Cc= 0.900
n= 0.013, Flow Area= 4.91 sf
#2 Device 1 852.30'22.5" W x 18.0" H Vert. Riser Orifice C= 0.600
#3 Device 1 864.70'90.0" W x 15.0" H Vert. Riser Weirs X 2.00 C= 0.600
#4 Secondary 867.20'Emergency Spillway, Cv= 3.10 (C= 3.88)
Head (feet) 0.00 1.00 2.00 3.00 4.00
Width (feet) 66.70 72.70 78.70 84.70 90.70
Primary OutFlow Max=0.00 cfs @ 5.00 hrs HW=0.00' (Free Discharge)
1=30" 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-036 Deep Creek WS #23 (PI-566)
Rainfall not specifiedYADKI-036
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: YADKI-036 Deep Creek WS #23 (PI-566)
Elevation
(feet)
Discharge
(cfs)
Primary
(cfs)
Secondary
(cfs)
852.30 0.00 0.00 0.00
852.70 1.52 1.52 0.00
853.10 4.31 4.31 0.00
853.50 7.91 7.91 0.00
853.90 11.99 11.99 0.00
854.30 14.90 14.90 0.00
854.70 17.24 17.24 0.00
855.10 19.28 19.28 0.00
855.50 21.11 21.11 0.00
855.90 22.79 22.79 0.00
856.30 24.36 24.36 0.00
856.70 25.83 25.83 0.00
857.10 27.21 27.21 0.00
857.50 28.53 28.53 0.00
857.90 29.79 29.79 0.00
858.30 31.00 31.00 0.00
858.70 32.17 32.17 0.00
859.10 33.29 33.29 0.00
859.50 34.37 34.37 0.00
859.90 35.43 35.43 0.00
860.30 36.45 36.45 0.00
860.70 37.44 37.44 0.00
861.10 38.41 38.41 0.00
861.50 39.35 39.35 0.00
861.90 40.27 40.27 0.00
862.30 41.18 41.18 0.00
862.70 42.06 42.06 0.00
863.10 42.92 42.92 0.00
863.50 43.77 43.77 0.00
863.90 44.60 44.60 0.00
864.30 45.41 45.41 0.00
864.70 46.21 46.21 0.00
865.10 59.18 59.18 0.00
865.50 82.23 82.23 0.00
865.90 104.97 104.97 0.00
866.30 105.95 105.95 0.00
866.70 106.93 106.93 0.00
867.10 107.89 107.89 0.00
867.50 151.77 108.84 42.93
867.90 264.97 109.79 155.18
868.30 420.72 110.73 309.99
868.70 612.11 111.66 500.45
869.10 835.76 112.58 723.18
869.50 1,089.66 113.50 976.16
869.90 1,372.49 114.41 1,258.08
870.30 1,683.38 115.31 1,568.07
870.70 2,021.72 116.20 1,905.52
871.10 2,387.08 117.09 2,270.00
871.50 2,720.96 117.97 2,602.99
871.90 2,988.13 118.84 2,869.29
872.30 3,225.52 119.71 3,105.81
Elevation
(feet)
Discharge
(cfs)
Primary
(cfs)
Secondary
(cfs)
872.70 3,442.85 120.57 3,322.28
873.10 3,645.06 121.43 3,523.64
873.50 3,835.23 122.27 3,712.96
873.90 4,015.44 123.12 3,892.32
874.30 4,187.20 123.95 4,063.24
874.70 4,351.66 124.79 4,226.88
875.10 4,509.73 125.61 4,384.12
875.50 4,662.13 126.43 4,535.69
875.90 4,809.44 127.25 4,682.19
876.30 4,952.16 128.06 4,824.10
876.70 5,090.72 128.87 4,961.85
877.10 5,225.45 129.67 5,095.78
877.50 5,356.67 130.46 5,226.21
877.90 5,484.65 131.25 5,353.40
878.30 5,609.62 132.04 5,477.58
878.70 5,731.79 132.82 5,598.97
879.10 5,851.33 133.60 5,717.74
879.50 5,968.43 134.37 5,834.06
879.90 6,083.21 135.14 5,948.07
880.30 6,195.82 135.90 6,059.92
880.70 6,306.38 136.66 6,169.72
881.10 6,414.99 137.41 6,277.58
881.50 6,521.76 138.17 6,383.59
881.90 6,626.78 138.91 6,487.86
882.30 6,730.13 139.65 6,590.47
882.70 6,831.89 140.39 6,691.50
883.10 6,932.13 141.13 6,791.00
883.50 7,030.93 141.86 6,889.07
883.90 7,128.33 142.59 6,985.74
884.30 7,224.40 143.31 7,081.09
884.70 7,319.20 144.03 7,175.17
885.10 7,412.76 144.75 7,268.02
885.50 7,505.15 145.46 7,359.69
885.90 7,596.40 146.17 7,450.23
886.30 7,686.55 146.88 7,539.68
886.70 7,775.65 147.58 7,628.07
887.10 7,863.72 148.28 7,715.45
887.50 7,950.81 148.98 7,801.84
887.90 8,036.95 149.67 7,887.28
888.30 8,122.17 150.36 7,971.81
888.70 8,206.49 151.04 8,055.44
889.10 8,289.94 151.73 8,138.21
889.50 8,372.56 152.41 8,220.15
889.90 8,454.36 153.09 8,301.27
890.30 8,535.37 153.76 8,381.61
890.70 8,615.62 154.43 8,461.18
891.10 8,695.11 155.10 8,540.01
891.50 8,773.88 155.77 8,618.12
891.90 8,851.95 156.43 8,695.52
892.30 8,929.33 157.09 8,772.24