HomeMy WebLinkAboutSDP200700065 Calculations 2007-08-28PRELIMINARY DRAINAGE CALCULATIONS FOR
LEWIS AND CLARK EXPLORATORY CENTER
August 28, 2007
LOCATION:
Tax Map 62, Parcel 23
Rivanna District, Albemarle County, Virginia
OWNER:
County of Albemarle and The City of Charlottesville
401 McIntyre Road
Charlottesville, Virginia 22902
APPLICANT:
Lewis and Clark Exploratory Center
PREPARED BY:
Dominion Development Resources
172 South Pantops Road
Charlottesville, VA 22911
434.979.8121
F) 434.979.1681
LD -268 Roadside Ditch Calculation
Lewis and Clark Exploratory Center I G-hti I o. + +;,,- I i-;-,
SCC 2
0.
9 0.
5 0.
3 CA Tc 12 Q2 Slope Allow n selec n =.03 n =.05
V
n =.015 110 Q10 DEP Remarks
STA STA WS CA WS CA WS CA Inc Acc ft/
ft Vel
20
Vel Qn VEL IDEP JQn IDEP
0.
051
SCC 2 I
211 20 10 0.
0211 44 0.
051 137 0.
095
0.
166
0.
166
5.
0 5.
5
0.
91
0.
100
4.
0
0.
05
0.
05
2.
83
0.
36
7.
07
1.
17
0.
39 EC -2
201 19 10 0.
021 48 272 0.
188
0.
264
0.
429
5.
6
5.
3
2.
27
0.
100
4.
0
0.
05 0.
11
3.
56
0.
50
6.
87
2.
95
0.
56 EC -2
191 18 10 0.
0211 36 0.
041 110 0.
076
0.
138 0.
567
6.
1
5.
1
2.
92
0.
100
4.
0
0.
05 0.
15
3.
79
0.
55
6.
71
3.
81
0.
61 EC -2
18 17 40 0.
083 82 0.
094 178 0.
123 0.
3
0.
867
6.
5
5.
0
4.
36
0.
100
4.
0 0.
05
0.
22
4.
19
0.
64
6.
58
5.
70
0.
71 EC -3 " ",
17 16 10 0.
021 161 0.
0181 75 0.
0521
0.
091
0.
958
6.
9
4.
9
4.
71 0.
100
4.
0
0.
05
0.
24
4.
27
0.
66
6.
46
6.
19
0.
74
16 15 10 0.
021 16 0.
018 4319 2.
98
3.
019
3.
977
7.
3
4.
8 19.
14
0.
100
4.
0
0.
05
0.
96
6.
07
1.
12 6.
34
25.
23
1.
25 E0
15 14 10 0.
021 16 0.
018 127 0 .088 0.
127
4.
104
7.
6
4.
7
19.
47
0.
100
4.
0
0.
05 n a7l A nal 1 .13 6.
26
25.
71
1.
25
EC-
3,"..:
PROJECT: wi
n irk RI4 2r C
nr_Date: 8 27107
Tc= 21.
6 min
CA= 0.
30 x 12.
8 =
3.
84
x 3.
85 (110)Road:Rood A
010 =14.
78 cfs Station 14 +26 Culvert A
CL Elev: 325.
34
Shoulder Elev: 325.
14
i
L
lnv Elev: 3 1.
0 So: =00- Inv Elev: 32
0148-
L: _.52' _
I
HEADWATER COMPUTATIONS CONT OUTLET j
CULVERT TYPE
SIZE Q Inlet Con Outlet Control HW VELOCITY
ELEVHW /D HW Ke do dc +D) /2 ho H LSo HW CM Smooth
24" RCP 14.
78
1.
11
2.
22
0.
5
1.
40
1.
70
1.
70
0.
57
0.
5
1.
75
323.
22
7.
7
I
i
I
PROJECT: LQw6s- -and- -C1Qr-
k - xPkrotQry —Gen tp—
r—
Tc = 5.
0 min
CA= 0.
65 x 0.
20 = 0.
13
x 7.
1 (110)
010 = 0.
92 cfs
Shoulder Elev: -349U5
Date: 8127107
Road: Road A
Station 17 +97 Culvert B
CL Elev: 349.
55
Inv Elev: 3 So: Q,
Q4-76 Inv Elev: -343 GQ-
L: --6 --
CULVERT TYPE
SIZE
HEADWATER COMPUTATIONS CONT
HW
ELEV
OUTLET
VELOCITYQInletConOutletControl
HW /D HW Ke do I (dc +D) /2 ho H LSo HW CM Smooth
15" RCP 0.
92
0.
40
0.
50
0.
5
0,
381
0.
82
0.
82
0.
401
3.
0
346.
50
6.
5
NOTE: USGS TOPO (10' CONTOURS) HAS br-
EN
ADDED TO THE SITE TOPO (2' CONTOURS)
ORDER 10 SHOW THE DRAINAGE AREA MAP
i' =:.•.a,;
c.: -3r. "
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r ` x
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et I
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t ! ` t \ \ rI \
CULVERT A, Tc = 2 I mug i' ; ,
IF jt ' tF I I / d r\ a \ - _ _ - - - . \
t
t `
min T `` \., <.\ ,
t \ - - - - -- - . _ `y4rr* 'x`
r • \'•
ctOverlandFlow = 7 0
Shallow Concentrated Flow
Concentrated flow —, 3.
3
r
O, - - -- - -. -- . 'trams.,•,, .. a,
r
a
OL > N \• \ - - - - - _ ` - - Y \ ' - \\, , ' \ \ <'r\ , '`,'_ ,.
C'
UL'VERT A` - -- - -_r _
T - 2 1 \ \ `1'
11n,
0
t x r .
s LEWIS AND CLARK
EXPLORATORY CENTER
DRAINAGE AREA MAP
for CULVERTS
r
r f 28 20 0
AN GUS
i ` . .
100 0 100, 200 \ sop
AN
I
NOTE USGS Too coN )HAS _ \
THETO (ADDED
AREA MAPS -- _THE DRAINAGE - - -ORDER TO SHOW _3 ' ". . ?,'y :.aro-.
a w ~»`.'`.'; .- .,°.4•'v ' ^
ri-.
i
t "
e
t
aJ _ _ 'f•
yi`i y ^ ,.f °yy ,,.. -: _^ = = '^+.:' - ,;;vv. , \rte t -= .-' .__ -° P_'`,•.
i,,.:.. ^y4` ='; ;'..,.a - §, ,
X•%
a-- '.."`x A"
o
F t '_ • \ \. \ *.rt 4i :'i"` -Y Y i'
f -=- SS
I "/
L
4
l' .--.°^.^«+ .: '" « ^_'r'•- 'i= .^..-- '.v?"
a .-"- Q, 3 ' ____ tt
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i4
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it. \ ` ,
L / .x. *mo /` *a, - - - `-. ,.. _.- ...._ -"'• - `' - - \'•. - _ 3 !^
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M sip LEWIS AND CLARK
EXPLORATORY CENTER t,\
r
A MAP forREDRAINAGEA
CONVEYANCE CHANNELSrSTORM
r
SCALE. 1" = 100
r
rrw GUS 28, 2AUI 100 200 31000
r, *•`1N
Short Version BMP Computations For Worksheets 2 - 6
Albemarle County Water Protection Ordinance: Modified Simple Method
Plan: LAMBERT CABLE COMPANY Water Resources Area:
Prep, NDN Date 26- Jul -07
Project Drainage Area Designatio 1310- FILTER 1
L storm pollutant export in pounds, L = [P(Pj)Rv /12 ] [ C(A)2.72 ]
Rv mean runoff coefficient, Rv = 0.05 + 0.009(1)
Pj small storm correction factor, 0.9
1 percent imperviousness
P annual precipitation, 43" in Albemarle
A project area in acres in subject drainage al A = I 0.71
C pollutant concentration, mg /I or ppm target phosphorus
f factor applied to RR
V required treatment volume in cy, 0.5" over imperv. area = A(1)43560(0.5/12)/27
RR required removal , L(post) - f x L(pre)
RR removal efficiency, RR100 /L(post)
Impervious Cover Computation (values in feet & square feet)
Item
pre - development Area post - development Area
Roads Length
0
0
Width subtotal
0
Length
0
0
0
Width
0
0
0
subtotal
0
0
0
0 0
01 0
0 0
0
0
Driveways Length Width
and walks 0 0
01 0
no.
1
0
subtotal
0
0
0 0
Length Width no.subtotal
0
0 0 01 0
0 0 0 010
Parking Lots 1 2
0
3 4
0
1 2 3 4
676067600
Gravel areas Area
x0.70=0
Area
x0.70=0
Structures Area
0
E10
no.
0
0
0
subtotal
0
0
0 0
Area
0
no.
11
0
1
subtotal
0
0
0 0
Actively - grazed pasture Area
yards and cultivated to 6856.3 x 0.08 =549 1
Area
21293.51x 0.08 =1703.48
Active crop land Area
x0.25=0
Area
x0.25=0
Other Impervious Areas
0
1 0
Impervious Cover 2%
I(pre) I(post)
V(posj V
0.30 1 13:1'
New Development For Development Areas, existini 1 impervious cover <= 20%
C f I (pre) *Rv(pre)L(pre)L(post)RR RR Area Type
0.70 1.00 20%0.23 1.00 1.29 0.29 22% Development Area
0.35 1.00 0%0.07 0.14 0.65 0.50 78% Drinking Water Watersheds
0.40 1.00 11 %0.07 0.16 0.74 0.57 78% Other Rural Land
min. values
Redevelopment (For Development Areas, existing impervious cover > 20 %)
C f I pre *Rv pre L pre L post RR RR Area Type
0.70 0.90 20%0.23 1.00 1.29 0.39 30%Development Area
0.35 0.85 0%0.07 0.14 0.65 0.52 81%Drinking Water Watersheds
0.40 0.85 1 0.07 0.16 0.74 0.60 81%Other Rural Land
Interim Manual, Page 70 rev. 16 Feb 1998 GEB
Project Drainage Area Designatio BIO- FILTER 2
L storm pollutant export in pounds, L = [P(Pj)Rv /12 ] [ C(A)2.72 ]
Rv mean runoff coefficient, Rv = 0.05 + 0.009(1)
Pj small storm correction factor, 0.9
1 percent imperviousness
P annual precipitation, 43" in Albemarle
A project area in acres in subject drainage a A = 1 2.15
C pollutant concentration, mg /I or ppm target phosphorus
f factor applied to RR
V required treatment volume in cy, 0.5" over imperv. area = A(1)43560(0.5/12)/27
RR required removal , L(post) - f x L(pre)
RR removal efficiency, RR100 /L(post)
Impervious Cover Computation (values in feet & square feet)
Item
f I (pre) *Rv(pre)L(pre)L(post)RR RR Area Type
pre - development
1.00 20%
Area post - development
1.29 0.29
Area
Roads Length Width subtotal
0
0.14
Length
0
0
0
Width
0
0
0
subtotal
0
0
0
0 0
0 01 0
0 0 0
0.57 780 /0
0
0
Driveways Length Width
and walks 0 0
0 0
no.
1
0
subtotal
0
0
0 0
Length Width no.subtotal
0
0 0 1 0
0 0 0 0
0
Parking Lots 1 2
0
3 4
0
1 2 3 4
4526.4324526.43221 1 0
Gravel areas Area
x0.70=0
Area
Ix 0.70=01
Structures Area
0
0
0
no.
0
0
0
subtotal
0
0
0 0
Area
0
no.
0
0
subtotal
0
0
0 0
Actively - grazed pasturE Area
yards and cultivated to 28232 x 0.08 =2259
Area
71014.5 x 0.08 =5681.16
Active crop land Area
x0.25=0
Area
Ix 0.25=0
Other Impervious Areas
0 0
Impervious Cover 7%
l(pre) ((post)
v pos V
0.30 1 13.1
New Development For Development Areas, existing impervious cover <= 20%
C f I (pre) *Rv(pre)L(pre)L(post)RR RR Area Type
0.70 1.00 20%0.23 1.00 1.29 0.29 22%Development Area
0.35 1.00 00 %0.07 0.14 0.65 0.50 78%Drinking Water Watersheds
0.40 1.00 1 %0.07 0.16 0.74 0.57 780 /0 Other Rural Land
min. values
Redevelopment (For Development Areas. existina impervious cover > 20 %1
C f I pre *Rv pre L pre L post RR % RR Area Type
0.70 0.90 20%0.23 1.00 1.29 0.39 30%Development Area
0.35 0.85 0%0.07 0.14 0.65 0.52 81%Drinking Water Watersheds
0.40 0.85 1%0.07 016 0.74 0.60 81%Other Rural Land
Interim Manual, Page 70 rev. 16 Feb 1998 GEB
Project Drainage Area DesignatiC 1310- FILTER 3
L storm pollutant export in pounds, L = [P(Pj)Rv /12 j [ C(A)2.72 )
Rv mean runoff coefficient, Rv = 0.05 + 0.009(1)
Pj small storm correction factor, 0.9
1 percent imperviousness
P annual precipitation, 43" in Albemarle
A project area in acres in subject drainage al A = I 0.94
C pollutant concentration, mg /I or ppm target phosphorus
f factor applied to RR
V required treatment volume in cy, 0.5" over imperv. area = A(1)43560(0.5/12)/27
RR required removal , L(post) - f x L(pre)
RR removal efficiency, RR100 /L(post)
Impervious Cover Computation (values in feet & square feet)
Item
f I (pre) *Rv(pre)L(pre)L(post)RR RR Area Type
pre - development
1.00 20%
Area post - development
1.29 0.29
Area
Roads Length Width subtotal
0%0.07
Length Width subtotal
78%
0 01 0
1 %0.07
0 0 0
78%
0 0 0 0 0 0
0 0 0 0
0 0 0 0
Driveways Length Width no.subtotal Length Width no.subtotal
and walks 0 0 11 0 0 0 1 0
0 0 01 0 0 0 0 0
0 0 0 0
Parking Lots 1 2 3 4 1 2 3 4
0 0 14977.414977.4 1 0
Gravel areas Area Area
x0.70=0 x0.70=0
Structures Area no.subtotal Area no.subtotal
0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
Actively - grazed pasturE Area Area
yards and cultivated to 5654.5 x 0.08 =452 1 15570.81x 0.08 =1245.664
Active crop land Area Area
x0.25=0 x0.25=0
Other Impervious Areas
0 0
Impervious Cover 1% 1 52%
I(pre) I(post)
V(posl V
0.30 1 13.1
New Development For Development Areas, existin impervious cover <= 20%
C f I (pre) *Rv(pre)L(pre)L(post)RR RR Area Type
0.70 1.00 20%0.23 1.00 1.29 0.29 22 %Development Area
0.35 1.00 0%0.07 0.14 0.65 0.50 78%Drinking Water Watersheds
0.40 1.00 1 %0.07 0.16 0.74 0.57 78%Other Rural Land
min. values
Redevelopment (For Development Areas. existing impervious cover > 20 %)
C f I (pre)*Rv pre L pre L post RR % RR Area Type
0.70 0.90 20%0.23 1.00 1.29 0.39 30%Development Area
0.35 0.85 0%0.07 0.14 0.65 0.52 81%Drinking Water Watersheds
0.40 0.85 1%0.07 0.16 0.74 0.60 81%Other Rural Land
Interim Manual, Page 70 rev. 16 Feb 1998 GEB