HomeMy WebLinkAboutWPO202100013 Calculations 2021-04-23JARMANS GAP DEVELOPMENT PLAN
STORMWATER MANAGEMENT CALCULATIONS PACKET
Date of Calculations
MARCH 3, 2021
Revised On
APRIL 23, 2021
PREPARED BY:
APPROVED
by the Albemarle County
Community Development Department
Date 06/23/21
File WP0202100013
COLLINS ENGINMERING
200 GARRETT STREET, SUITE K
CHARLOTTESVILLE, VA 22902
434.293.3719 PH
434.293.2813 FX
www.collins-engineering.com
SCS TR-55 Calculations
Soils Mapping (Source: NRCS Web Soil Survey Online Database)
Soils Table (Source: NRCS Web Soil Survey Online Database)
Albemarle County, Virginia (VA003)
Map Unit
Map Unit Name
Percent of
Symbol
AOI
7B
Braddock loam,
42.6%
2 to 7 percent
slopes
36B
Hayesville
10.1%
loam, 2 to 7
percent slopes
36C
Hayesville
47.3%
loam, 7 to 15
percent slopes
Totals for Area of
100.00/0
Interest
The NRCS web soil survey defines this development's soils as predominantly having a hydrologic group type B.
Precipitation Data
(Source: NOAA's National Weather Service, Hydrometerorological Design Studies Center, Atlas 14
Point Precipitation Frequency Estimates)
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POINT PRECIPITATION FREQUENCY (PF) ESTIMATES
WITH 90%CONFIDENCE INTERVALS AND SUPPLEMENTARY INFORMATION
NOAA Atlas 14, Volume 2, Version 3
PDS4mmed precipitafion frequency estimates with 900/ confidence Intervals (in inchi
AveraOe recurrerce irdeml (years)
2M 3A8 3.735.61 6.86 793 9.11 10A 12.1 14.0
(1783.15) (3.36.4.17) (4.27.5.31) 11 (5.0141.25) 1 (6.02-7.63) 1 (6.11M.82) 1 Q9&10.1) (8.99.11.8) (10.5.138) 1 (11.7-15.6)
Photographs of Downstream, Receiving Channel
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U.S. Department of Agriculture
Natural Resources Conservation Service
TR 55 Worksheet 3: Time of Concentration (Tc) or Travel Time (Tt)
Project: Jarmans Gap Dev. Plan Designed By:
Location: Jarmans Gap Checked By:
Check One: Present X Developed X
Check One: T, X T,
Segment ID:
Sheet Flow: (Applicable to Tc only)
1 Surface description (Table 3-1)
2 Manning's roughness coeff., n (Table 3-1
3 Flow length, L (total L < 100) (ft)
4 Two-year 24-hour rainfall, PZ (in.)
5 Land slope, s (ft/ft)
6 Compute Tt = [0.007(n*L)0"sl / Pz s s04
Shallow Concentrated Flow-
7 Surface description (paved or unpaved)
8 Flow Length, L (ft)
9 Watercourse slope, s (ft/ft)
10 Average velocity, V (Figure 3-1) (ft/s)
11 Tt= L / 3600*V
Channel Flow:
12 Cross sectional flow area, a (ft)
13 Wetted perimeter, Pw (ft)
14 Hydraulic radius, r = a/Pw (ft)
15 Channel Slope, s (ft/ft)
16 Manning's Roughness Coeff, n
17 V= [ 1.49r2/3.0 s ) / n
18 Flow length, L (ft)
19 Tt= L / 3600*V
20 Watershed or subarea T, or Tt
(Add Tt in steps 6, 11 and 19)
Note: The shoretest SCS Tc is 0.10 hrs.
FGM, PE Date
SRC. PE Date
Through subarea
FL-ENG-21A
06/04
3/3/2021
DA A
DA A
DA B
(Pre-Dev.)
(Post-Dev.)
(Offsite)
Dense
Dense
Dense
Grass
Grass
Grass
0.24
0.24
0.24
100
100
100
3.73
3.73
3.73
0.02 0.02 0.03
0.22 0.22 0.19
Unpaved
Unpaved
Unpaved
560
415
535
0.10
0.06
0.06
5.2
3.9
3.9
0.03
0.03
0.04
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Channel and Flood Protection Computations
9 VAC 25-870-66 (Subarea A)
Section B: Channel Protection
"Concentrated stormwater flow shall be released into a stormwater conveyance system and shall
meet the criteria in subdivision 1, 2 or 3 of this subsection..."
Section B.1: Manmade stormwater conveyance systems
"When stormwater from a development is discharged to a manmade stormwater conveyance
system, following the land -disturbing activity, either..." a. or b. shall be met:
Section B.l.b.
"The peak discharge requirements for concentrated stormwater flow to natural stormwater
conveyance systems in subdivision 3 of this subsection shall be met."
Section B.3
"... the maximum peak flow rate from the one-year 24-hour storm following the land -disturbing
activity shall be calculated either.." a. or b."
Section B.3.a.
In accordance with the following methodology:
Q Allowed (Calcuated) < I. F. * (Q Pre -Developed * [RV Pre -Developed ) ) / (RV Developed)
Q Allowed (Calcuated) <
Where: QPre-Developed —
CN Pre -Developed —
5 Pre -Developed —
RV Pre -Developed =
CN Post -Developed —
S Post -Developed =
RV Post -Developed =
I.F. =
Q Developed
1.17 cfs
2.23 cfs
(From Worksheet 4 Watershed Summary)
63
(From Worksheet 4 Watershed Summary)
5.89
(From SCS TR-55 eq. 2-4)
0.46 in.
(From SCS TR-55 eq. 2-3)
69
(From Worksheet 4 Watershed Summary)
4.51
(From SCS TR-55 eq. 2-4)
0.71 in.
(From SCS TR-55 eq. 2-3)
0.80
(Factor of Safety)
= 1.17 cfs
Section B.4 Limits of Analysis
The analysis terminates at the SWM Facility's outfall since "...subsection 3 of this subsection is
utilized to show compliance with the channel protection criteria..."
9 VAC 25-870-66 (Subarea A)
Section C: Flood Protection
"Concentrated stormwater flow shall be released into a stormwater conveyance system and
shall meet one of the following criteria as demonstrated by use of acceptable hydrologic and
hydraulic methodologies:"
Section C.2.b.:
The point of discharge (the SWM Facility's outfall), "releases a postdevelopment peak flow
rate for the 10-year 24-hour storm event that is less than the predevelopment peak flow rate
from the 10-year 24-hour storm event. Downstream stormwater conveyance systems do not
require any additional analysis to show compliance with flood protection criteria if this
option is utilized."
10-Year, 24-Hour Pre -Development Subarea A Peak Flow Rate = 9.14 cfs
10-Year, 24-Hour Post -Development Subarea A Peak Flow Rate = 8.39 cfs
Section C.3 Limits of Analysis
The flood protection analysis terminates at the SWM Facility's outfall since subsection C.2.b
is met.
Pre -Development SCS TR-55 Hydrographs
Worksheet 5b (Modified for Clarity): Basic watershed Data
1-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc Listed Below
Subarea Tc (hrs.) Tt (hr.) la / P Am*Q (miz-in)
DA A (Pre-Dev.) 0.25 0.25 0.38 0.0032
Hydrograph Time 1-yr Discharges
(hrs.) (cfs)
0.0
0.00
11.0
0.00
11.3
0.00
11.6
0.00
11.9
0.12
12.0
0.58
12.1
1.74
12.2
2.23
12.3
1.59
12.4
0.88
12.5
0.63
12.6
0.51
12.7
0.42
12.8
0.35
13.0
0.30
13.2
0.26
13.4
0.23
13.6
0.21
13.8
0.19
14.0
0.18
14.3
0.16
14.6
0.15
15.0
0.14
15.5
0.12
16.0
0.11
16.5
0.10
17.0
0.10
17.5
0.09
18.0
0.09
19.0
0.08
20.0
0.07
22.0
0.06
26.0
0.00
2.50
2.00
1.50
1.00
0.50
0.00
0.0
-0.50
SCS TR-55 Pre -Development Unit
Hydrograph (Onsite DA A)
5.0 10.0 15.0 20.0 25.0 30.0
Worksheet 5b (Modified for Clarity): Basic watershed Data
2-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc Listed Below
Subarea Tc (hrs.) Tt (hr.) la / P Am*Q (mi2-in)
DA A (Pre-Dev.) 0.25 0.25 0.32 0.0053
Hydrograph Time 2-yr Discharges
(hrs.)
WS)
0.0
0.00
11.0
0.00
11.3
0.00
11.6
0.00
11.9
0.21
12.0
0.96
12.1
2.90
12.2
3.70
12.3
2.64
12.4
1.47
12.5
1.05
12.6
0.94
12.7
0.69
12.8
0.58
13.0
0.49
13.2
0.43
13.4
0.39
13.6
0.36
13.8
0.32
14.0
0.30
143
026
14.6
0.24
15.0
0.23
15.5
0.21
16.0
0.19
16.5
0.17
17.0
0.16
17.5
0.15
18.0
0.14
19.0
0.13
20.0
0.11
22.0
0.10
26.0
0.00
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
0.0
SCS TR-55 Pre -Development Unit
Hydrograph (Onsite DA A)
50 100 150 200 25.0 30.0
Worksheet Sb (Modified for Clarity): Basic watershed Data
10-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc Listed Belov
Subarea Tc (hrs.) Tt (hr.) la / P Am*Q (mi2-in)
DA A(Pre-Dev.) 0.25 0.25 0.21 0.0131
Hydrograph Time 10-yr Discharges
(hrs.)
(cfs)
0.0
0.00
11.0
0.00
11.3
0.00
11.6
0.00
11.9
0.51
12.0
2.36
12.1
7.14
12.2
9.14
12.3
6.51
12.4
3.62
12.5
2.60
12.6
2.07
12.7
1.70
12.8
1.44
13.0
1.22
13.2
1.06
13.4
0.96
13.6
0.88
13.8
0.80
14.0
0.73
14.3
0.64
14.6
0.60
15.0
0.56
15.5
0.51
16.0
0.46
16.5
0.42
17.0
0.39
17.5
0.38
18.0
0.35
19.0
0.31
20.0
0.28
22.0
0.25
26.0
0.00
10.00
9.00
8.00
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
SCS TR-55 Pre -Development Unit
Hydrograph (Onsite DA A)
0.0 5.0 10.0 150 zoo 250
300
SWM Facility Routing Calculations
7armans Gap Development- SWM Facility Routings
BasinFlow printout
1401911M
Basin: 7armans Gap Development- SWM Facility Routings
7 Contour Areas
Elevation(ft)
Area(sf)
Computed Vol.(cy)
732.00
385.00
0.0
733.00
686.00
19.6
734.00
1059.00
51.6
735.00
1504.00
98.9
736.00
2024.00
164.0
737.00
2619.00
249.7
738.00
3281.00
358.7
Start—Elevation(ft)
4 Outlet Structures
Outlet structure 0
Orifice
732.00 Vol.(cy) 0.00
name: Barrel
area (sf) 0.785
diameter or depth (in) 12.000
width for rect. (in) 0.000
coefficient 0.500
invert (ft) 729.000
multiple 1
discharge out of riser
Outlet structure 1
Orifice
name: Low -Flow Orifice
area (sf) 0.175
diameter or depth (in) 5.670
width for rect. (in) 0.000
coefficient 0.500
invert (ft) 732.000
multiple 1
discharge into riser
Page 1
7armans Gap Development- SWM Facility Routings
Outlet structure 2
Weir
name: Riser
diameter (in)
36.000
side angle
0.000
coefficient
3.300
invert (ft)
735.670
multiple
1
discharge
into riser
transition at (ft)
0.912
orifice coef.
0.500
orifice area (sf)
7.069
Outlet structure 3
Weir
name:
length (ft)
side angle
coefficient
invert (ft)
multiple
discharge
4 Inflow Hydrographs
Hydrograph 0
SCS
Emergency Spillway
25.000
75.960
3.300
736.670
1
through dam
name: 1-yr SCS
Area (acres)
CN
Type 2
rainfall, P (in)
time of conc. (hrs)
time increment (hrs)
time limit (hrs)
fudge factor
routed
peak flow (cfs)
peak time (hrs)
volume (cy)
24-hr Design Storm-
4.410
69.000
3.080
0.2500
0.0200
30.000
1.00
true
3.196
12.003
422.233
Page 2
Onsite DA A
3armans Gap Development- SWM Facility Routings
Hydrograph 1
SCS
name: 2-yr SCS 24-hr Design Storm- Onsite DA A
Area (acres) 4.410
CN 69.000
Type 2
rainfall,
P (in)
3.730
time of conc.
(hrs)
0.2500
time increment
(hrs)
0.0200
time limit
(hrs)
30.000
fudge
factor
1.00
routed
true
peak flow
(cfs)
4.907
peak time
(hrs)
12.003
volume
(cy)
648.215
Hydrograph 2
SCS
name:
Area (acres)
CN
Type
rainfall, P (in)
time of conc. (hrs)
time increment (hrs)
time limit (hrs)
fudge factor
routed
peak flow (cfs)
peak time (hrs)
volume (cy)
Hydrograph 3
SCS
10-yr SCS 24-hr Design
4.410
69.000
2
5.610
0.2500
0.0200
30.000
1.00
true
10.811
12.003
1428.175
Storm- Onsite DA A
name: 100-yr SCS 24-hr Design Storm- Onsite DA A
Area (acres)
4.410
CN
69.000
Type 2
rainfall, P (in)
9.110
time of conc. (hrs)
0.2500
time increment (hrs)
0.0200
time limit (hrs)
30.000
fudge factor
1.00
routed
true
peak flow (cfs)
23.793
peak time (hrs)
12.003
volume (cy)
3143.066
Page 3
3armans Gap Development- SWM Facility Routings
OUTPUT:
Routing Method: storage -indication
Hydrograph 0
Routing Summary of
inflow (cfs)
discharge (cfs)
water level (ft)
storage (cy)
Hydrograph 1
Routing Summary of
inflow (cfs)
discharge (cfs)
water level (ft)
storage (cy)
Hydrograph 2
Routing Summary of
inflow (cfs)
discharge (cfs)
water level (ft)
storage (cy)
Hydrograph 3
Routing Summary of
inflow (cfs)
discharge (cfs)
water level (ft)
storage (cy)
Peaks: 1-yr SCS 24-hr Design Storm- Onsite DA A
3.192 at
12.00 (hrs)
1.173 at
12.22 (hrs)
735.016 at
12.22 (hrs)
99.764
Peaks: 2-yr SCS 24-hr Design Storm- Onsite DA A
4.901 at
12.00 (hrs)
2.991 at
12.12 (hrs)
735.812 at
12.12 (hrs)
150.209
Peaks: 10-yr SCS 24-hr Design Storm- Onsite DA A
10.798 at
12.00 (hrs)
8.385 at
12.10 (hrs)
736.586 at
12.10 (hrs)
211.480
Peaks: 100-yr SCS
23.764 at
23.517 at
736.981 at
247.888
Fri Apr 23 10:32:23 EDT 2021
24-hr Design Storm- Onsite DA A
12.00 (hrs)
12.00 (hrs)
12.00 (hrs)
Page 4
Riprap Lined Ditch Calculations
Worksheet 5b (Modified for Clarity): Basic watershed Data
1-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P 8: Tc Listed Below
Subarea Tc (hrs.) Tt (hr.) la / P Am*Q (mi1-in)
DA B (Offsite) 0.23 0.23 0.23 0.0113
Hydrograph Time 1-yr Discharges
(hrs.)
(cfs)
0.0
0.00
11.0
0.27
11.3
0.38
11.6
0.60
11.9
3.77
12.0
7.30
12.1
11.39
12.2
7.03
12.3
2.45
12.4
1.66
12.5
1.39
12.6
1.17
12.7
0.97
12.8
0.86
13.0
0.74
13.2
0.64
13.4
0.58
13.6
0.52
13.8
0.47
14.0
0.43
143
038
14.6
0.36
15.0
0.33
15.5
0.29
16.0
0.26
16.5
0.24
17.0
0.23
17.5
0.21
18.0
0.20
19.0
0.17
20.0
0.15
22.0
0.14
26.0
0.00
1200.
10.00
8.00
6.00
4.00
2.00
0.00
0.0
SCS TR-55 Inflow Unit Hydrograph
(Offsite DA B)
5.0 10,0 150 200 250 300
Worksheet 5b (Modified for Clarity): Basic watershed Data
2-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc Listed Below
Subarea Tc (hrs.) Tt (hr.) la / P Am*Q (mil -in)
DA B (Offsite) 0.23 0.23 0.19 0.0165
Hydrograph Time 2-yr Discharges
(hrs.)
(cfs)
0.0
0.00
11.0
0.40
11.3
0.56
11.6
0.88
11.9
5.52
12.0
10.69
12.1
16.68
12.2
10.29
12.3
3.58
12.4
2.43
12.5
2.03
12.6
1.72
12.7
1.42
12.8
1.26
13.0
1.09
13.2
0.94
13.4
0.84
13.6
0.76
13.8
0.69
14.0
0.63
143
0.56
14.6
0.53
15.0
0.48
15.5
0.43
16.0
0.38
16.5
0.35
17.0
0.33
17.5
0.31
18.0
0.30
19.0
0.25
20.0
0.21
22.0
0.20
26.0
0.00
18.00
16.00
14.00
12.00
10.00
8.00
6.00
4.00
2.00
0.00
0.0
SCS TR-55 Inflow Unit Hydrograph
(Offsite DA B)
5.0 10.0 15.0 200 250
30 0
Worksheet 5b (Modified for Clarity): Basic watershed Data
30-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc Listed Below
Subarea Tc(hrs.) Tt(hr.) la/P Am*Q (ml2-in)
DA B (Offsite) 0.23 0.23 0.13 0.0338
Hydrograph Time 10-yr Discharges
(hrs.)
(cfs)
0.0
0.00
11.0
0.81
11.3
1.15
11.6
1.79
11.9
11.30
12.0
21.90
12.1
34.18
12.2
21.08
12.3
7.34
12.4
4.97
12.5
4.16
12.6
3.52
12.7
2.91
12.8
2.57
13.0
2.23
13.2
1.93
13.4
1.73
13.6
1.56
13.8
1.42
14.0
1.29
143
1.15
14.6
1.08
15.0
0.98
15.5
0.88
16.0
0.78
16.5
0.71
17.0
0.68
17.5
0.64
18.0
0.61
19.0
0.51
20.0
0."
22.0
0.41
26.0
0.00
40.00
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
0.0
SCS TR-55 Inflow Unit Hydrograph
(Offsite DA B)
5.0 30.0 15.0 20.0 25.0 30.0
Riprap Ditch- 2yr Calculation
Complex Channnel
Input:
Slope 0.051
Flow (given) 16.680
line x y
0 0.000 2.000
1 4.000 0.000
2 8.000 2.000
Output:
Depth 1.327
(Y) ( 1.327)
Channel bed segment output:
line Q V
1 8.34 4.74
2 8.34 4.74
kit -MaETiI OMC5M.WEM4..1WXOP44I
n
0.050 (first n value not used)
0.050
0.050
A P
1.76 2.97
1.76 2.97
Page 1
Riprap Ditch- 10yr Calculation
Complex Channnel
Input:
Slope 0.051
Flow (given) 34.181
line x y
0 0.000 2.000
1 4.000 0.000
2 8.000 2.000
Output:
Depth 1.736
(y) ( 1.736)
Channel bed segment output:
line Q V
1 17.09 5.67
2 17.09 5.67
� i� F.> • a FTit <.I�i �A� l ii� 7.� iZ.7�l� I
n
0.050 (first n value not used)
0.050
0.050
A P
3.01 3.88
3.01 3.88
Page 1
Riprap Lined Outlet Protection Calculations
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Runoff Volume and Curve Number Calculations
Enter design storm rainfall depths (in):
'. L ea� Z. eareantor�
3.OB 3.]3 5.61
the NOMAtlai IC (MpJ/M1Oss.nxx ma.Po Mtl+NYHN
'Notes (see below):
[11 the rune number, and runsuff.ntmme: computed in this spreadsheet for each drainage area are limited in their app6wbinty for determining and compression, compliance wdh—let qumuay
requirement. See VRRM users Ouide and Documentation for additmnal mf rrman an.
[21 Runoff Volume RV) for Weandpmtdemlopment drainage areas must be in voiumemr unit (e.g., acre-feet or cubic feet) when using the Ecem Ralarce Nuauon. Runoff measured in wareMed-
mrhe, and :howr m the spreadsheet as RVlwater:ned-imom can only be used in the energy rfa dance Equadon when the pre, and mm,1c,elopmen[ drainage areas are equal. Dmenaeo RV(wwwsW dInch)
must be mulnpbed by the drainage area.
131 Adjusted CNS are based on runoff reduction walmom as calculated in D.A.Uhs.AnaltemationCN adjustment ralruladon tar Vegetated Rands is included in RMP spoil non No. 5,
Drainage Area Curve Numbers and Runoff Depths•
Curve numbers (CN, Mail and runoff depths (RV pi are computed with and without reduction practices.
OrairoMe Area• AWas aSoils CSlid, 0$.a, Total Arealwreg: 401
lmc,D0cen Swse- uMbwrbed, woreted fourth ben I Are,aaes 0.00 0.00 am 0.00 Reem. RMutbn
spattonelorestedl,ed F CN 30 55 70 ]] ydume loci: O
Managed Dan- disturbed, graded for yardsw often turf 1 Arealacresl 0.00 347 0.00 am
to be mowed/mana et i (:F 39 61 ]< W
tmisernaus Corer Aregnes) 0.0] o,ce 000 000
CN 98 R. 9g 9a
CNIo.AN
1- earstarm 2-year storm 10-year storm
RVarMapd(wererchedtinch) with no Runoff Reduction' 0 1.IS 2.A3
RVenewp,dm (wen5edinrh) with Runoff Reduction'2A1
Adjusted CN' 69 6g 69
'See Notes above
Drainage Area ASoils ,Soils Csails DSeils 1.1 Area(oi 0.00
rarest/Open Spare- uMlStummir protected! fwgt/apen Area(acre5) am RAW Ran ADD Rumff RMandion
Spare or reforested land CN 3o 55 70 1 Volume h': 0
11I Turf- dehomed, gr,d,d far yards cur mover herf ~ ealaveel haper
he he d/mono ea hisofDs1 ]A m
Inew ,erne, Arnalacresl D.m DR.DOD D.m
CN 9R 9R 9B 9B
CNloaq
1-year storm 2-year storm 10-year Rorm
RYpwnaded (worerNedarrN) with no Runoff R..:-,on' 0 W o.00 OW
0.Yp�pp,d(wotershedtirsch)with Runoff RNEYRild 05 o,00 000
Adjugred CN'1 0 1 0 1 0
'See Notes above
Werinne AmaC
ASoils
BSolls
CSoils
DSoils
Tewl Neelanes):
0.00
Forest Ocenswce- undlnumed.protM"arcsopen Areaacres
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D,Do
000
000
a a
nvalame[1n':
spade ar efoested land CN
30
55
J0
n
0
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a.O]
0.00
0.a0
000
to be mowedmanaed CN
39
6l
J<
SO
Imper'dausCww Area acres
0.00
000
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am
9g
98
9g
N
CNIow CI
0
1-yearstorm
2-year storm
10-yearstorm
RVpe,wyyed (woreashed-Inch) with no Runoff Reduction:
ON
ON
0.On
RVpeeex�(lvmrsbed-lndJ with Runoff Reduction'
ON
o.Do
R.oR
Atljurtetl CN"
a
0
0
*See Notes above
Draina,a, Area
ASoils
Is Soils
CSoils
DSoils
ialal Area (anes):
0,00
rarest/Open Space- uMNturned, pmiMM(oreo/open Mealanes
...
xw
ON
6W
wn
Rwff Redun
spare ar reforested land CN
30
55
]0
1
Volume h'^
0
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OW
000
000
000
b ne mowed/managed CN
39
fit
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9O
Impe... Cwtt Area pere5)
O.Ip
oao
O00
an
CN
98
9g
9g
9g
CNloaol
0
RVDeaeyged (wate.snedaraM) wRh no Runoff Reduction:
1-yearstorm
a.BD
2-yearstorm
D,Db
10-yearstorm
DBn
_
RVanegoaJ (watersAedlnd) wkll Runoff PeEUCYIon'
a.00
0,00
O00
Atljusted CN-
0
0
0
'See Notes above
Drainage Area
ASoils
Bsolls
CSoils
DSoils
IDtal Nea (xres):
0.00
ForesunOwnSpace- urmnturbed.prorenedf—Vapen Area ac
ON
ONONONPunoff
Reduction
spaceor rel—nd land cxa
3o
55
70
JJ
Volumatt':
0
manage.turf- cauunxdgradedmrrems a,omer our Nefed a
0.00
ON
O
ON
O
to be w moed/managed cN
to
39
61
70
m
Imperrmru Cmn Area acres
0.00
0.00
am
cx
S
9R
99
9R
CNIow n
0
1-yearstorm
2-yearstorm
10-yearstorm
RVolvesseg (walershe6imh) with no Runoff Redug, ion"
O.00
ON
0W
RV�. _,(water.shed-stuff) with Runoff Redue:t1c,
0.m
R.w
OUD
AdjuetelCN"
a
B
o
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