Loading...
HomeMy WebLinkAboutWPO201800048 Calculations 2018-06-21Copy of HydrologyMethodsPOST.xls Project:Ivy Creek Location:Albemarle Co., VA Date:07-Jun-18 Notation:Culvert design Project Data: Section: Holkham Drive Name of Channel: Little Ivy Creek Drainage Area: 515 ac.or 0.804945 sq. mi. Hydraulic Length: 8215 ft. Upper Elevation: 656 Lower Elevation: 490 "c" Factor:Developed Woods Field Subarea1 Subarea2 Subarea3 Subarea4 Subarea5 % Area 30% 65% 5% Ac. 154.5 334.75 25.75 0.00 0.00 "C" 0.6 0.25 0.3 92.7 83.6875 7.725 0 0 Weighted "c" factor= 0.3575 Curve No.Subarea1 Subarea2 Subarea3 Subarea4 Subarea5 % Area 30% 65% 5% 0% 0% Ac. 154.5 334.75 25.75 0.00 0.00 CN 71 60 74 10969.5 20085 1905.5 0 0 Weighted CN= 64 Estimated Impervious percentage 5% Tc TR-55 0.71 hrs. Stream "n" factor 0.035 ************************************************************************************************* Summary Findings Q2 Q10 Q25 Q50 Q100 (cfs)(cfs)(cfs)(cfs)(cfs) SCS Method (TR-55) 231 630 938 1218 1604 Bureau of Reclamation 17 136 273 372 444 Snyder Method 127 249 450 541 637 Anderson Method 343 754 1130 1507 1850 USGS Regression (Blue Ridge) 81 255 387 503 634 USGS Regression (S.Piedmont- DA Only)) 106 294 444 584 752 USGS Regression (S.Piedmont- multiple)) 106 296 448 590 749 Average 144 374 582 759 953 Design Storm Events:Q2 Q10 Q25 Q50 Q100 (use Average) 130 345 533 687 875 Ignored Bureau of Rec and Anderson Prepared by Jim Taggart 06/15/2018 Page 1 BurofRec Bureau of Reclamation Method Ivy Creek Albemarle Co., VA June 7, 2018 100 Yr. - 6 hr. 2.6 inches (NOAA) Drainage Area= 515 ac. or 0.804945 sq. mi. Assume Hourly Distruibution of Rainfall: Time % Accum. Incremt'l 1 49% 1.27 1.27 2 64% 1.66 0.39 3 75% 1.95 0.29 4 84% 2.18 0.23 5 92% 2.39 0.21 6 100% 2.60 0.21 2.60 (total rainfall in In.) Design Storm: (hour dist.) (6,4,3,1,2,5) Curve No.= 64 Direct Runoff= 0.31 S= 5.63 Rainfall Rainfall Accum. Incrmt'l Time incrmt'l Accum. Runoff Runoff hr. 0-1 0.21 0.21 0.02 0.02 hr. 1-2 0.23 0.44 0.05 0.03 hr. 2-3 0.29 0.73 0.09 0.03 hr. 3-4 1.27 2.00 0.24 0.15 hr. 4-5 0.39 2.39 0.28 0.05 hr. 5-6 0.21 2.60 0.31 0.02 hr. 6-7 0.21 2.81 0.33 0.02 hr. 7-8 0.21 3.02 0.36 0.02 Compute Triangular Hydrograph (D=1) Tp= D/2 + 0.6*Tc Tc= 0.7133939 min. Tp= 0.507134 Tb= 2.67*Tp= 1.4 hr. Qp= 484AQ/Tp= 768.2 cfs Tc= 0.01 hrs. Plotting Table incr. q-peak for q-peak for graph graph graph time runoff 1 inch incr. runoff begin peak end hr. 0-1 0.02 768.2 19 0 0.507134 1.4 hr. 1-2 0.03 768.2 21 1 1.507134 2.4 hr. 2-3 0.03 768.2 26 2 2.507134 3.4 hr. 3-4 0.15 768.2 115 3 3.507134 4.4 hr. 4-5 0.05 768.2 35 4 4.507134 5.4 hr. 5-6 0.02 768.2 19 5 5.507134 6.4 hr. 6-7 0.02 768.2 19 6 6.507134 7.4 hr. 7-8 0.02 768.2 19 7 7.507134 8.4 Page 1 BurofRec 19 21 26 115 35 19 19 19 0 20 40 60 80 100 120 140 1 2 3 4 5 6 7 8CFS Hours Bureau of Rec. Hydrograph Page 2 Snyder Snyder Method Ivy Creek Albemarle Co., VA June 7, 2018 Drainage Area= 0.804945 sq. Mi. Length= 1.555871212 Mi. Ct= 1.7 hrs/mile (see below) Impervious Area= 5% Base Formula:Hrs/mile Ct= 1.7 Natural Basin 0.85 Overland Flow 0.42 Sewered Areas L'= 10 x L x n = 0.074557179 Sqrt(S) Tc= Ct x L' ^0.6 = 1.454783241 Frequency (Yrs)2 10 25 50 100 Rainfall (in.) 1.7 3 3.7 4.25 4.7 % runoff Natural 23 28 40 43 47 % runoff adj. 27 30 44 46 49 Runoff 0.459 0.9 1.628 1.955 2.303 Ir 0.315510921 0.618648864 1.119067057 1.343842811 1.583053705 Qp 127 249 450 541 637 Page 1 Anderson Anderson Method Ivy Creek Albemarle Co., VA June 7, 2018 Drainage Area= 0.804945 sq. mi. Length= 1.555871 mi. Impervious Cover= 5% Slope= 2.02% or 106.7 ft. per mile Flood Frequency ratio: 2 yr. 1 (VDOT fig. 1) 10 yr. 2.2 25 yr. 3.3 50 yr. 4.4 100 yr. 5.4 K (Impervious factor)= 1.075 T (time lag) 2.10 hrs. for Natural Basins 0.35 hrs. for developed basins partly channeled 0.21 hrs. for completely developed and sewered basins Selected T 0.35 Adjusted for large rural, channeled basin Peak Flows:Q10 Q10 Q25 Q50 Q100 342.5405 753.5891 1130.384 1507.178 1849.719 Page 1 Print Mini Summary............. O-C-M Protected Rainfall Type II...... O-C-y Print Full Summary................... O-C-S Rainfall Type III.... O-C-z Print Schedule Summary...............O-C-s Worksheet Index Clear Drain Area only.....................O-C-c Curve Num.-CN ...... Rows 14-38 Clear all job info...................... O-C-C Enter Rainfall.......... Rows 40-50 Insert Urban District................. O-C-U Time of Concentrat.. Rows 53-138 Rainfall Type I............................O-C-w Peak Q's....................... Rows 152-169 Q Schedule................. Rows 158-171 ENTER Date Below:ENTER Your Name or Initials Below: 15-Jun-18 Rainfall Type II JLT ENTER Job name/number below:ENTER Drain Area Name/Number below: Ivy Creek Holkham Drive RUNOFF CURVE NUMBER CN,Tc and Peak Q (1) NON IMPERVIOUS AREAS (TR-55, Chapter 2, Pg2-5,6,7,8) ENTER data to Columns D&E; ENTER data to Columns A,B&C for Full Summary. A B C D E F GROUP CN from AREA CN x AREA COVER DESCRIPTION SOIL NAME A,B,C,D?TABLE 2-2 (In acres) Sub #1 unk C 71 154.50 Ac. 10969.5 Sub #2 unk C 60 334.75 Ac. 20085 Sub #3 unk C 74 25.75 Ac. 1905.5 Sub #4 unk C 0 0.00 Ac. 0 Sub #5 unk C 0 0.00 Ac. 0 0 0 0 0 0 AREA SUBTOTALS:515.00 Ac.32960 (2) IMPERVIOUS AREAS OR URBAN DISTRICT Enter Data only if impervious area(s) Option-Command-Shift-U flow into a drainage system, (pipes) for Urban Worksheet! WEIGHTED CN equals sum of all CN x area: 32960 divided by total area:515.00 TOTAL AREA WEIGHTED CN =64 (Min CN = 40) ENTER Rainfall Distribution Type: Type I....Opt.-Com.-w Type IA...Opt.-Com.-x Ivy Creek Drainage Area Summary Type II...Opt.-Com.-y STORM RAINFALL RUNOFF (TR-55,Chapter 3) Type III...Opt.-Com.-z P(24 Hr)Q (in.) ENTER Rainfall (P) for 1 YEAR 3.50 In.0.71 In.S= Selected _Yr. Storms.2 YEAR 3.70 In.0.81 In.5.63 Always include 5 YEAR 4.80 In.1.45 In.INITAL 2-Year Storm 10 YEAR 5.60 In.1.98 In.ABSTRACTION= S.C.S.25 YEAR 6.80 In.2.85 In.1.13 Rainfall Distribution 50 YEAR 7.80 In.3.62 In.Weighted CN = TYPE II 100 YEAR 9.10 In.4.68 In.64 TIME OF CONCENTRATION: Sheet Flow+Shallow Concentrated Flow+Channel Flow (A) SHEET FLOW Depths up to 0.1 ft. and distances of up to 300 ft. 1. CHOOSE an appropriate roughness coefficient from this table. SURFACE DESCRIPTION MANNING'S N Concrete, asphalt, gravel, bare soil 0.011 Fallow 0.05 CULTIVATED SOILS Notes: Residue Cover less than 20%0.06 * Includes weeping love- Residue Cover over 20 %0.17 grass, bluegrass, buffalo GRASS grass, blue grama grass Short grass prairie 0.15 and native grass mixtures. Dense grasses*0.24 Burmudagrass 0.41 **Consider only cover to Natural Range 0.13 a height of ± 0.1 ft. WOODS** Light underbrush 0.4 Dense underbrush 0.8 2. ENTER THE FOLLOWING: For varying cover Manning's N.....................................0.4 and/or slope, Flow Length in ft............................200 Ft.use weighted avg. Hydraulic grade line slope in ft./ft. 7.00% for 'N' and/or grade line slope. 2-Yr.24 Hr. rainfall in inches.......3.7 In. Sheet flow Tt equals.....0.35 HRS (B) SHALLOW CONCENTRATED FLOW After 300 ft. of sheet flow 1. ENTER THE FOLLOWING: Section #1 #2 #3 Surface: PAVED or UNPAVED UNPAVED UNPAVED UNPAVED Flow Length (L)1541 Ft. Watercourse slope in ft./ft.3.80% Averge velocity (FPS)=3.15 0.00 0.00 Tt(Hours)= 0.14 Hrs. #DIV/0! #DIV/0! Total Shallow flow Tt equals...0.14 Hrs. (C) OPEN CHANNEL FLOW 1. CHOOSE an appropriate roughness factor from this table: CHANNEL Manning's N Bare earth 0.022 Grass 0.03 Weeds 0.04 Weeds and brush 0.05 Concrete or street gutters 0.013 Gravel and rip rap 0.03 Gravel and earth sides 0.03 2. ENTER the following...SECTION #1 SECTION #2 X-Section Area (enter if known or estimated)*50 Wetted perimeter (enter if known or estimated)*25 Hydraulic radius equals 2.00 2.50 Manning's n from table.......................................0.035 Flow length (L in feet).......................................6274 Ft. Channel slope in ft./ft. .....................................1.30% Velocity equals 7.70 F.P.S. #DIV/0! Channel flow Tt equals 0.23 Hrs. #DIV/0! TOTAL CHANNEL FLOW Tt equals 0.23 Hrs. * If channel X-section area and wetted perimeter are not known or cannot be estimated, the worksheet automatically assigns a Hydraulic Radius based on the chart below. The Hy. R. for each area category may be changed to account for varying topographic conditions. Acres Hydraulic Radius 0-25 0.75 26-65 1.00 65-125 1.25 125-250 1.50 250-500 2.20 500+2.50 (D) TIME OF CONCENTRATION Sheet flow Tt 0.35 Hours +Shallow concentrated flow 0.14 Hours +Channel flow 0.23 Hours Tc =0.71 Hours (Min Tc = 0.1 Hr.) % of POND and SWAMPY AREAS (TR-55,Chapter4,Page4-2) %Fp 0.0 1.00 0.2 0.97 Select POND FACTOR, 1.0 0.87 Fp 3.0 0.75 and ENTER BELOW: 5.0 0.72 Fp=1 Print Schedule Summary..........Opt-Command-s Print Mini Summary....Opt.-Command-Shift-M Clear Drain Area Only........Opt.-Command-c Print Full Summary.....Opt.-Command-Shift-S Clear All Job info......Opt.-Command-Shift-C Do Not Clear All Job until you have printed a Summary or Schedule. PEAK DISCHARGE SUMMARY JOB:Ivy Creek DRAINAGE AREA NAME: Holkham Drive 06/15/2018 Total Area in Acres=515.00 Ac.Sheet Shallow Channel Weighted CN =64 Flow=Flow=Flow = Time Of Concentration=0.71 Hrs.0.35 Hrs.0.14 Hrs.0.23 Hrs. Pond Factor =1 RAINFALL TYPE II PEAK Precipitation Runoff DISCHARGE STORM (P) inches (Q)Qp= 1 Year 3.5 In.0.7 In.194 CFS 1 2 Year 3.7 In.0.8 In.231 CFS 5 Year 4.8 In.1.5 In.447 CFS Calculation by 10 Year 5.6 In.2.0 In.630 CFS S.C.S. T.R. 55 25 Year 6.8 In.2.9 In.938 CFS June, 1986 Ed. 50 Year 7.8 In.3.6 In.1218 CFS Graphical Peak 100 Year 9.1 In.4.7 In.1604 CFS Discharge Method 0.80 SqMi P Runoff InitialAbstrac STORM (inches) (Q)Ia Ia/P 1 Year 3.5 In.0.7 In.1.13 0.32 2 YEAR 3.7 In.0.8 In.1.13 0.30 5 YEAR 4.8 In.1.5 In.1.13 0.23 10 YEAR 5.6 In.2.0 In.1.13 0.20 25 YEAR 6.8 In.2.9 In.1.13 0.17 50 YEAR 7.8 In.3.6 In.1.13 0.14 100 YEAR 9.1 In.4.7 In.1.13 0.12 RAINFALL Ia/P Co C1 C2 Diff 0.01 "space holders" 0.02 TYPE 0.10 2.55323 -0.61512 -0.16403 0.20 II 0.30 2.46532 -0.62257 -0.11657 0.05 0.35 2.41896 -0.61594 -0.0882 0.05 0.40 2.36409 -0.59857 -0.05621 0.05 0.45 2.29238 -0.57005 -0.02281 0.05 0.50 2.20282 -0.51599 -0.01259 0.00 Vlookup-1 Vlookup-1a Intrp-Co.Interp.-C1 Interp.-C2 0.30 0.35 2.44545 -0.61973 -0.10441 0.30 0.35 2.46156 -0.62203 -0.11427 0.10 0.30 2.49417 -0.62013 -0.13214 0.10 0.30 2.50888 -0.61888 -0.14009 0.10 0.30 2.52447 -0.61756 -0.14850 0.10 0.30 2.53379 -0.61677 -0.15353 0.10 0.30 2.54285 -0.61600 -0.15842 Unit Peak Discharge(CFS per sqaure mile per inch of runoff),Qu log Qu=Co+C1log(Tc)+C2[log(Tc)]^2 Peak Discharge(CFS),Qp=QuAmQFp Area in acres =515.00 Ac.fr. worksheet Qp, PEAK Pond STORM Qu=SQ.Miles Runoff (Q)=DISCHARGE=Fact. 1 YEAR 342.06 0.80 0.7 In.194 CFS 1 2 YEAR 355.09 0.80 0.8 In.231 CFS 1 5 YEAR 382.19 0.80 1.5 In.447 CFS 1 10 YEAR 395.04 0.80 2.0 In.630 CFS 1 25 YEAR 409.12 0.80 2.9 In.938 CFS 1 50 YEAR 417.78 0.80 3.6 In.1218 CFS 1 100 YEAR 426.37 0.80 4.7 In.1604 CFS 1 Project Name Drainage Area 0.80 sq.mi. Recurrence Interval Peak Discharge (cfs) Standard Error of Prediction, % Standard Error of Prediction, ±cfs 2 81 33.4 27 5 172 34.1 59 10 255 35.5 91 25 387 38.8 150 50 503 42.2 212 100 634 46.2 293 USGS regression equations for estimating peak discharges of rural, unregulated streams in the Blue Ridge region Input Data Ivy Creek Drainage-area-only regional regression equations for estimating peak discharges (USGS Fact Sheet 023-01, 2001) Project Name Drainage Area 0.80 sq.mi. Average Basin Elevation 573 feet optional Main Channel Length 1.6 miles optional Recurrence Interval Peak Discharge (cfs) Standard Error of Prediction, % Standard Error of Prediction, ±cfs 2 106 40.2 43 5 204 38.7 79 10 294 38.5 113 25 444 40.8 181 50 584 43.8 256 100 752 47.7 359 Recurrence Interval Peak Discharge (cfs) Standard Error of Prediction, % Standard Error of Prediction, ±cfs 2 106 40.2 43 5 205 35.7 73 10 296 35.5 105 25 448 38.0 170 50 590 41.4 244 100 749 45.7 342 Drainage-area-only regional regression equations for estimating peak discharges (USGS Fact Sheet 023-01, 2001) Multiple-parameter regional regression equations for estimating peak discharges (USGS Fact Sheet 023-.01, 2001) USGS regression equations for estimating peak discharges of rural, unregulated streams in the Southern Piedmont region Input Data Ivy Creek