HomeMy WebLinkAboutWPO201800027 Calculations 2019-03-12MARTHA JEFFERSON HOSPITAL APARTMENTS
STORMWATER MANAGEMENT CALCULATIONS PACKET
(WPO 201800027)
Date of Calculations
J U LY 26, 2018
Revised on
MARCH 12, 2019
PREPARED BY:
COLLINS
200 GARRETT STREET, SUITE K
CHARLOTTESVILLE, VA 22902
434.293.3719 PH
434.293.2813 FX
www.collins-engineering.com
OIL
SCL7T7-
R. COLLINS
Lip. A10. 03576-7 �
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SCS TR-55 Calculations
(The following summaries of the Stormwater Quantity Calculations/Compliances are
provided for each subarea to assist the reviewer.)
Subarea A Summary:
Subarea A ( ) drains to a Level II wet pond that provides stormwater quality and quantity treatment.
The 1-, 2-, 10- and 100-year design storm routings can be viewed in the ✓1JH Apartments- Level 11 Wet Pond
rsourirn documents.
Channel protection for subarea A is met through 9VAC25-870-66, subsection B.3.a. The limits of the channel
protection analysis end at the wet pond since subdivision 3 of the aforementioned subsection is utilized.
Flood protection is met through 9VAC25-870-66, subsection C.2.b. The limits of the flood protection analysis
ends at the dry detention cell's outfall since section C.2.b is met.
Subarea B Summary:
Subarea B (DA B-UG►.) drains to an underground detention system for stormwater quantity treatment. The
underground detention system then outfalls into a dry detention cell( -► rs-►ora,) for secondary stormwater
quantity treatment. Because there are two separate subareas, four different design storms and multiple
hydrographs, the applicant will attempt to assist the reviewer by providing a summary of the extensive
work performed and its methodology. Subarea B was analyzed for stormwater quantity as follows:
A. was analyzed in the TR-55 SCS Method worksheets 2, 3 and 4. This subarea was then
routed in the 'MJH Apartments- UGD System' calculations. The routings were then used to generate
the 1-, 2-, 10- and 100-year'Outflow Hydrgoraphs from UGD System'. Please note, the raw data
with time increments of 0.02 hours for a duration of 24.5 hours for each storm event were used in
the calculations throughout for optimal accuracy. However to avoid providing dozens of pages of
raw data for each design storm, condensed summaries of the hydrographs have been provided
within this packet.
B. Following step A described above, 1-, 2-, 10- and 100-year'Inflow Hydrographs From DA B Outside
the Limits of the UGD System's Subarea' were created. These inflow hydrographs represent the area
draining to the dry detention cell that were not routed in the underground detention system and
previously accounted for in step A. These inflow hydrographs were created using the same 0.02
hour increments over a period of 24.5 hours. Similar to above, condensed summaries of the
hydrographs have been provided to avoid dozens of pages of raw data for each design storm.
C. The'Outflow Hydrgoraphs from UGD System' were then summed with the 'Inflow Hydrographs
From DAB Outside the Limits of the UGD System's Subaru '.The combined 1-, 2-, 10- and 100-year
hydrograph data represent the flows feeding the dry detention cell. These combined hydrographs
are named 1-, 2-, 10- and 100-Year "Combined Inflow Hydrographs to Detention Cel►'. These
hydrographs were then routed in the 'MJH Apartments- Detention Cell Routings' and represent the
inflow hydrographs to the facility.
Channel protection for subarea B was analyzed in 9VAC25-870-66, subsection B.3.a. Please note, in order to
meet 9VAC25-870-66 energy balance calculations with the small Q Allowed calculated, a low -flow orifice
less than 3" is required. However a low -flow orifice this small, even with a trashrack, increases the risk of
clogging. To resolve this concern the design provides an underground detention system with a 4" low -flow
orifice followed by a dry detention cell with a 3" low -flow orifice. Having a minimum low -flow orifice
diameter of 3" is in accordance with prior Albemarle County Engineering direction and with the Virginia
Stormwater BMP Clearinghouse, which states "Orifices less than 3 inches in diameter may require extra
attention during design to minimize the potential for clogging."
Flood protection was also analyzed for subarea B and is compliant with minimum requirements. Flood
protection is met via subsection C.2.b of 9VAC25-870-66. The limits of the flood protection analysis ends at
the dry detention cell's outfall since subsection C.2.b is met.
Subarea C Summary:
Subarea C ( ) drains to a proposed adequate channel that contains the 1-, 2- and 10-year design storms
within its banks. The proposed manmade riprap-lined channel is not erosive during these design storms and
was designed in accordance with the VESCH standard and specification 3.19. These flows, along with
subareas A and B, were analyzed in the TR-55 SCS Method worksheets 2, 3 and 4. Please see the
accompanying Riprap Lined Outfall Channel Calculations for subarea C for additional details.
Channel protection for subarea C is met through 9VAC25-870-66, subsection B.1.a. The limits of the channel
protection analysis ends at the riprap channel's outfall since its subarea is less than or equal to 1% of the
existing downstream channel's overall watershed. This compliance is shown in 9VAC25-870-66, subsection
B.4.a and the attached ` ,jbarea C- One Percent Exhibit'. Flood protection is met through 9VAC25-870-66,
subsection C.2.a. The limits of the flood protection analysis also ends at the riprap channel's outfall since
subarea C is less than or equal to 1% of the existing downstream channel's overall watershed. This
compliance is shown in 9VAC25-870-66, subsection C.3.a.
Soils Table (Source: NRCS Web Soil Survey Online Database)
Albemarle County. Virginia (VA0031
Albemarle County, Virginia
(VA003)
Map
Unit
Map Unit Name
Percent of
AOI
symbol
23C
Davidson clay
1.811/0
loam, 7 to 15
percent slopes
59❑
Myersville very
8.811/0
stony silt loam,
15to25
percent slopes
71❑
Rabun clay
0.6%
loam, 15 to 25
percent slopes
72C3
Rabun clay, 7
24.1%
to 15 percent
slopes, severely
eroded
72D3
Rabun clay, 15
18.60/a
to 25 percent
slopes, severely
eroded
73❑
Rabun very
18.60/0
stony clay
loam, 15 to 25
percent slopes
73E
Rabun very
26.70/6
stony clay
loam, 25 to 45
percent slopes
89B
Unison silt
0.40/6
loam, 2 to 7
percent slopes
W
Water
0.30/6
Totals for Area of
100.00/0
Interest
Note: The NRCS web soil survey has catorgized this parcel's soil types as predominantley having hydrologic
group types of B.
Precipitation Data
(Source: NOAA's National Weather Service, Hydrometerorological Design Studies Center, Atlas 14
Point Precipitation Frequency Estimates)
slap
❑� Terrain
f� ryp f4l�5'
T �31�r
4�i r cc
$r'! Sy �i�nl•'t•'rJ
r i f
sr f
ro� ti
,y �7
M O�f6S
GTctiK 1-9
,,pr ES
0,4km
2mi
POINT PRECIPITATION FREQUENCY (PF) ESTIMATES
WITH WX3 CONFIDENCE INTERVALS AND SUPPLEMENTARY INFORMATION
NOAA Atlas 14, Volume 2, Version 3
e
d
PDS-based precipitation frequency estimates with 90% confidence intervals (in inches)'
Average recurrence interval (years)
Duration 500
��
7 2 5 7D 25 50 100 2D0 10D0
24-hr 3.02 3.65 d.66 5.52 6.78 7.87 9.07 70.4 12.4 94.7
(2 71-3 39) [3 28-4.10] (4.18-5 24) (4 92-6 18) [6 N-7 57] (6 93A 76) (7 92-10 1 } [8 98-713] [10 5-73 7] (71 8-15 6}
U.S. Department of Agriculture
Natural Resources Conservation Service
FL-ENG-21A
06/04
TR 55 Worksheet 2: Runoff Curve Number and Runoff
Project: Martha Jefferson Hospital Apartments Designed By: FGM, PE Date: 3/12/2019
Location: Peter Jefferson Parkway Checked By: SRC, PE Date: 3/12/2019
Check One: Present X Developed
1. Runoff curve Number (CN)
Cover description
CN (weighted) _Calculated
Drainage Area
Soil name and hydrologic
(Cover type, treatment, and hydrologic condition; percent
CN
Area
Product of CN
total product/
'S'
Description
group (Appendix A)
impervious; unconnected/ connected impervious area ratio)
(Acres)
xArea
total area
Value
Impervious Areas
98
0.05
5.1
DA A
Woods in Good Condition
55
2.66
146.3
(Present)
B
Bare, Exposed Pervious Areas
86
1.55
133.3
64.2
5.57
Lawns in Good Condition (75%+Groundcover)
61
3.36
204.9
Impervious Areas
98
0.00
0.0
DA B
Woods in Good Condition
55
1.10
60.5
(Present)
B
Bare, Exposed Pervious Areas
86
0.20
17.2
60.6
6.50
Lawns in Good Condition (75%+Groundcover)
61
2.79
170.2
Impervious Areas
98
3.80
372.6
DAA
B
Woods in Good Condition
55
0.00
0.0
84.4
1.85
(Developed)
Lawns in Good Condition (75%+Groundcover)
61
2.22
135.3
Impervious Areas
98
2.85
279.3
DAB - Total
(Developed)
B
Woods in Good Condition
55
0.00
0.0
81.2
2.31
Lawns in Good Condition (75%+Groundcover)
61
2.36
144.0
Impervious Areas
98
0.21
20.5
DA C
B
Woods in Good Condition
55
0.00
0.0
77.1
2.97
(Developed)
Lawns in Good Condition (75%+Groundcover)
61
0.27
16.5
Impervious Areas
98
2.71
265.4
DA B- UGD
B
Woods in Good Condition
55
0.00
0.0
83.0
2.05
(Developed)
Lawns in Good Condition (75%+Groundcover)
61
1.85
113.0
2. Runoff
1-Year Storm
2-Year Storm
10-Year Storm
Drainage Area Description
Frequency -years
1
2
10
n/a
Rainfall, P (24 hour)- inches
3.02
3.65
5.52
n/a
Runoff, Q- inches
0.49
0.79
1.95
DA A (Present)
Runoff, Q- inches
0.36
0.62
1.66
DA B (Present)
Runoff, Q- inches
1.56
2.10
3.79
DA A (Developed)
Runoff, Q- inches
1.34
1.85
3.47
DA B-Total (Developed)
Runoff, Q- inches
1.09
1.55
3.07
DA C(Developed)
Runoff, Q-inches
1.46
1.98
3.65
DA B-UGD (Developed)
U.S. Department of Agriculture
Natural Resources Conservation Service
TR 55 Worksheet 3: Time of Concentration (T) or Travel Time (T)
Project: Martha Jefferson Hospital Apartments
Location: Peter Jefferson Parkway
Check One: Present X Developed X
Check One: T, X Tt
Sheet Flow: (Applicable to T, only)
Designed By: FGM, PE
Checked By: SRC, PE
Through subarea n/a
FL-ENG-21A
06/04
Date: 3/12/2019
Date: 3/12/2019
DA A DA B DA A DA B - Total DA C DA B- UGD
Segment ID: (Present) (Present) (Developed) (Developed) (Developed) (Developed)
1 Surface description (Table 3-1)
Dense Grass
Dense Grass
2 Manning's roughness coeff., n (Table 3-1
0.24
0.24
3 Flow length, L (total L < 100) (ft)
100
100
4 Two-year 24-hour rainfall, PZ (in.)
3.7
3.7
5 Land slope, s (ft/ft)
0.19
0.16
6 Compute Tt = [0.007(n*L)08] / PZ .s s °
0.09
0.10
Shallow Concentrated Flow:
7 Surface description (paved or unpaved)
Unpaved
Unpaved
8 Flow Length, L (ft)
775
635
9 Watercourse slope, s (ft/ft)
0.108
0.110
10 Average velocity, V (Figure 3-1) (ft/s)
5.2
5.3
11 Tt = L / 3600*V
0.04
0.03
Channel Flow:
12 Cross sectional flow area, a (ft)
13 Wetted perimeter, P. (ft)
14 Hydraulic radius, r = a/Pw (ft)
15 Channel Slope, s (ft/ft)
16 Manning's Roughness Coeff, n
17 V= [ 1.49r2/35 .5 ] / n
18 Flow length, L (ft)
19 Tt= L / 3600*V
20 Watershed or subarea TcorTt
(Add Tt in steps 6, 11 and 19) 0.13 0.13 0.10 0.10 0.10 0.30
Note: The most conservative post -development SCS Tc is 0.10 hrs.
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Watershed Summary
CN Area 1-Year Flow 2-Year Flow 10-Year Flow
DA A (Present) 64.2 7.62 4.49 8.04 20.87
DA A (Developed) 84.4 6.02 0.92 2.85 13.23
CN Area 1-Year Flow 2-Year Flow 10-Year Flow
DA B (Present) 60.6 4.09 1.55 3.09 9.29
DA B -Total (Developed) 81.2 5.21 0.45 0.64 8.98
CN Area 1-Year Flow 2-Year Flow 10-Year Flow
DA C (Developed) 77.1 0.48 0.80 1.13 2.31
Area Summary
Ip
re-Development DA A & B 11.71 ac.
ost-Development DA A, B & C 11.71 ac.
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 13.1.1b.
"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
"When stormwater from a development is discharged to a natural stormwater conveyance
system, 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 Developed _< I•F• (Q Pre -Developed RV Pre -Developed) RV Developed
Q Allowed _< 1.12 cfs
Q Developed < 0.92 cfs
(From Routings)
Section B.4 Limits of Analysis
Where: Q Pre -Developed -
4.49 cfs
CN Pre -Developed—
64.2
S Pre -Developed -
5.57
RV Pre -Developed -
0.49 In.
CN Post -Developed-
84.4
S Post -Developed -
1.85
RV Post -Developed -
1.56 in.
The analysis terminates at the SWM facility since "...subdivision 3 of this subsection is utiilzed
to shown 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 "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."
Section C.3 Limits of Analysis
The analysis terminates at the proposed SWM facility since subsection C.2.b is met.
9 VAC 25-870-66 Subarea B- Total
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 113.1.1b.
"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
"When stormwater from a development is discharged to a natural stormwater conveyance
system, 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 Developed _ I.F. (Q Pre -Developed RV Pre -Developed) RV Developed
Q Allowed < 0.33 cfs Where: Q Pre -Developed - 1.55 cfs
CN Pre -Developed— 60.6
S Pre -Developed - 6.50
RV Pre -Developed - 0.36 in.
CN Post -Developed— 81.2
S Post -Developed - 2.31
RV Past -Developed- 1.34 In.
Energy Balance Notes:
In order to meet 9VAC25-870-66 energy balance calculations with the small Q Allowed flow
shown above, a low -flow orifice less than 3" is required. However a low -flow orifice, even with
a trashrack, increases the risk of clogging. To resolve this concern the design provides an
underground detention system with a 4" low -flow orifice followed by a dry detention cell with
a 3" low -flow orifice. Having a minimum low -flow orifice diameter of 3" is in accordance with
prior Albemarle County Engineering direction and with the Virginia Stormwater BMP
Clearinghouse, which states "Orifices less than 3 inches in diameter may require extra
attention during design to minimize the potential for clogging."
Q Developed 0.45 cfs
(From Routings)
9 VAC 25-870-66 Subarea B- Total
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 "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."
Section C.3 Limits of Analysis
The analysis terminates at the proposed SWM facility since subsection C.2.b is met.
9 VAC 25-870-66 Subarea C
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 13.1: 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 13.1.a.
"The manmade stormwater conveyance system shall convey the postdevelopment peak flow
rate from the two-year 24-hour storm event without causing erosion of the system."
NOTE:
The proposed storm sewer & riprap lined outfall channel convey the post -development peak
flow rate from the two-year 24-hour storm event without causing erosion. Please see the
following'Riprap Lined Outfall Channel Calculations' section.
Section B Limits of Analysis
"stormwater conveyance systems shall be analyzed for compliance with channel protection
criteria to a point where either.." a. or b. are met
Section B.4.a.
"Based on land area, the site's contributing drainage area is less than or equal to 1.0% of the
total watershed area;"
NOTE:
Subarea C is less than or equal to 1% of the existing channel's overall watershed at the end of
the riprap / point of discharage.
9 VAC 25-870-66 Subarea C
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.a.:
The point of discharge "Confines the postdevelopment peak flow rate from the 10-year 24-
hour storm event within the stormwater conveyance system to avoid the localized flooding."
Section C.3.a Limits of Analysis
The analysis terminates at the proposed outfall since "The site's contributing drainage area is
less than or equal to 1.0% of the total watershed area draining to a point of analysis in the
downstream stormwater conveyance system."
Level II Wet Pond Routing Calculations
(DA A)
MJH Apartments- Level II Wet Pond Routings
BasinFlow printout
INPUT:
Basin: MJH Apartments- Level II Wet Pond Routings
6 Contour Areas
Elevation(ft)
Area(sf)
Computed Vol.(cy)
376.00
682.00
0.0
378.00
2623.00
114.6
379.00
4712.00
248.6
380.00
8311.00
486.6
382.00
14412.00
1317.9
384.00
20500.00
2604.3
Start_Elevation(ft) 380.00 Vol.(cy)
Page 1
486.62
MJH Apartments- Level II Wet Pond Routings
4 Outlet Structures
Outlet structure 0
Orifice
name: Barrel
area (sf) 4.909
diameter or depth (in) 30.000
width for rect. (in) 0.000
coefficient 0.500
invert (ft) 372.500
multiple 1
discharge out of riser
Outlet structure 1
Orifice
name: Low -Flow Orifice
area (sf) 0.196
diameter or depth (in) 6.000
width for rect. (in) 0.000
coefficient 0.500
invert (ft) 380.000
multiple 1
discharge into riser
Outlet structure 2
Weir
name: Riser
diameter (in)
24.000
side angle
0.000
coefficient
3.300
invert (ft)
381.750
multiple
1
discharge
into riser
transition at (ft)
0.608
orifice coef.
0.500
orifice area (sf)
3.142
Outlet structure 3
Weir
name: Emergency Spillway
length (ft)
100.000
side angle
75.960
coefficient
3.300
invert (ft)
382.750
multiple
1
discharge
through dam
Page 2
MJH Apartments- Level II Wet Pond Routings
4 Inflow Hydrographs
Hydrograph 0
SCS
name: 1-yr 24-hr SCS Method Design Storm
Area (acres)
6.020
CN
84.400
Type 2
rainfall, P (in)
3.020
time of conc. (hrs)
0.1000
time increment (hrs)
0.0200
time limit (hrs)
30.000
fudge factor
1.00
routed
true
peak flow (cfs)
11.927
peak time (hrs)
11.917
volume (cy)
1262.762
Hydrograph 1
SCS
name: 2-yr 24-hr SCS Method Design Storm
Area (acres)
6.020
CN
84.400
Type 2
rainfall, P (in)
3.650
time of conc. (hrs)
0.1000
time increment (hrs)
0.0200
time limit (hrs)
30.000
fudge factor
1.00
routed
true
peak flow (cfs)
16.027
peak time (hrs)
11.917
volume (cy)
1696.813
Hydrograph 2
SCS
name: 10-yr 24-hr SCS Method Design Storm
Area (acres)
6.020
CN
84.400
Type 2
rainfall, P (in)
5.520
time of conc. (hrs)
0.1000
time increment (hrs)
0.0200
time limit (hrs)
30.000
fudge factor
1.00
routed
true
peak flow (cfs)
28.952
peak time (hrs)
11.917
volume (cy)
3065.166
Page 3
Hydrograph 3
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)
MJH Apartments- Level II Wet Pond Routings
100-yr 24-hr SCS Method Design Storm
6.020
84.400
2
OUTPUT:
Routing Method: storage -indication
Hydrograph 0
Routing Summary of Peaks: 1-yr 24-hr SCS Method Design Storm
inflow (cfs) 11.871 at 11.92 (hrs)
discharge (cfs) 0.922 at 12.50 (hrs)
water level (ft) 381.620 at 12.52 (hrs)
storage (cy) 1124.076
Hydrograph 1
Routing Summary of Peaks: 2-yr 24-hr SCS Method Design Storm
inflow (cfs) 15.952 at 11.92 (hrs)
discharge (cfs) 2.854 at 12.14 (hrs)
water level (ft) 381.948 at 12.14 (hrs)
storage (cy) 1290.384
Hydrograph 2
Routing Summary of Peaks: 10-yr 24-hr SCS Method Design Storm
inflow
(cfs)
28.817
at
11.92
(hrs)
discharge
(cfs)
13.232
at
12.06
(hrs)
water level
(ft)
382.659
at
12.06
(hrs)
storage
(cy)
1692.170
Hydrograph 3
Routing Summary
of
Peaks: 100-yr
24-hr
SCS
Method Design Storm
inflow
(cfs)
54.558
at
11.92
(hrs)
discharge
(cfs)
51.778
at
11.94
(hrs)
water level
(ft)
382.979
at
11.94
(hrs)
storage
(cy)
1891.521
Wed Mar 06 10:35:57 EST 2019
Page 4
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31 Ott
Underground Detention System
Routing Calculations and Hydrographs
(DA B-UGD)
MJH Apartments- UGD System
BasinFlow printout
INPUT:
Basin: MJH Apartments- UGD System Facility
0 Contour Areas
Elevation(ft) Area(sf) Computed Vol.(cy)
1 Storage Pipes
Storage pipe 0
name:
Detention Pipe
diameter (in)
120.000
length (ft)
162.000
invert (ft)
378.000
angle
0.287
volume (cy)
471.239
Start—Elevation(ft)
378.00 Vol.(cy) 0.00
6 Outlet Structures
Outlet structure 0
Orifice
name: Outlet Pipe
area (sf) 1.227
diameter or depth (in) 15.000
width for rect. (in) 0.000
coefficient 0.500
invert (ft) 377.970
multiple 1
discharge out of riser
Outlet structure 1
Orifice
name: Low -Flow Orifice in Weir Plate
area (sf) 0.087
diameter or depth (in) 4.000
width for rect. (in) 0.000
coefficient 0.500
invert (ft) 378.000
multiple 1
discharge into riser
Page 1
Outlet structure 2
Orifice
MJH Apartments- UGD System
name: Mid -Flow Orifice in Weir Plate
area (sf)
0.136
diameter or depth (in)
5.000
width for rect. (in)
0.000
coefficient
0.500
invert (ft)
385.150
multiple
6
discharge into
riser
Outlet structure 3
Orifice
name: Emergeny Spillway Overflow- Weir Plate
area (sf)
9.236
diameter or depth (in)
41.150
width for rect. (in)
0.000
coefficient
0.500
invert (ft)
386.250
multiple
1
discharge into
riser
Outlet structure 4
Weir
name:
Access MH with Weir Plate
diameter (in)
48.000
side angle
0.000
coefficient
3.300
invert (ft)
390.850
multiple
1
discharge
into riser
transition at (ft)
1.215
orifice coef.
0.500
orifice area (sf)
12.566
Outlet structure 5
Weir
name: Emergency Bypass Pipe
diameter (in)
15.000
side angle
0.000
coefficient
3.000
invert (ft)
386.250
multiple
1
discharge
out of riser
Page 2
MJH Apartments- UGD System
4 Inflow Hydrographs
Hydrograph 0
SCS
name: 1-yr.
24-yr Peak SCS Method Design Storm
Area (acres)
4.560
CN
83.000
Type 2
rainfall, P (in)
3.020
time of conc. (hrs)
0.1000
time increment (hrs)
0.0200
time limit (hrs)
36.000
fudge factor
1.00
routed
true
peak flow (cfs)
8.463
peak time (hrs)
11.917
volume (cy)
896.021
Hydrograph 1
SCS
name: 2-yr.
24-yr Peak SCS Method Design Storm
Area (acres)
4.560
CN
83.000
Type 2
rainfall, P (in)
3.650
time of conc. (hrs)
0.1000
time increment (hrs)
0.0200
time limit (hrs)
36.000
fudge factor
1.00
routed
true
peak flow (cfs)
11.488
peak time (hrs)
11.917
volume (cy)
1216.218
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)
10-yr. 24-yr Peak SCS Method Design Storm
4.560
83.000
2
5.520
0.1000
0.0200
36.000
1.00
true
21.109
11.917
2234.854
Page 3
Hydrograph 3
SCS
name: 100-yr.
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)
MJH Apartments- UGD System
24-yr Peak SCS Method Design Storm
4.560
83.000
9.070
0.1000
0.0200
36.000
1.00
true
40.526
11.917
4290.539
OUTPUT:
Routing Method: storage -indication
Hydrograph 0
Routing Summary of Peaks:
inflow (cfs)
discharge (cfs)
water level (ft)
storage (cy)
Hydrograph 1
Routing Summary of Peaks:
inflow (cfs)
discharge (cfs)
water level (ft)
storage (cy)
Hydrograph 2
Routing Summary of Peaks
inflow (cfs)
discharge (cfs)
water level (ft)
storage (cy)
Hydrograph 3
Routing Summary of Peaks:
inflow (cfs)
discharge (cfs)
water level (ft)
storage (cy)
1-yr. 24-yr Peak SCS Method Design Storm
8.424 at 11.92 (hrs)
0.925 at 12.22 (hrs)
385.147 at 12.24 (hrs)
337.766
2-yr. 24-yr Peak SCS Method Design Storm
11.434 at 11.92 (hrs)
5.340 at 12.06 (hrs)
386.522 at 12.06 (hrs)
409.373
10-yr. 24-yr Peak SCS Method Design Storm
21.010 at 11.92 (hrs)
20.194 at 11.92 (hrs)
387.524 at 11.92 (hrs)
450.343
100-yr. 24-yr Peak SCS Method Design Storm
40.336 at 11.92 (hrs)
38.161 at 11.92 (hrs)
388.397 at 11.92 (hrs)
469.816
Mon Mar 11 13:04:01 EDT 2019
Page 4
1-Year Outflow Hydrograph 1-Year Outflow Hydrograph
From UGD System From UGD System
Time (hrs)
Outflow (cfs)
0.0
0.00
0.5
0.13
1.0
0.14
1.5
0.14
2.0
0.15
2.5
0.15
3.0
0.16
3.5
0.16
4.0
0.17
4.5
0.17
5.0
0.18
5.5
0.19
6.0
0.20
6.5
0.21
7.0
0.21
7.5
0.22
8.0
0.23
8.5
0.24
9.0
0.27
9.5
0.28
10.0
0.30
10.5
0.33
11.0
0.36
11.1
0.37
11.2
0.38
11.3
0.40
11.4
0.41
11.5
0.43
11.6
0.46
11.7
0.52
11.8
0.61
11.9
0.74
12.0
0.86
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
Time (hrs)
Outflow (cfs)
12.1
0.92
12.2
0.92
12.3
0.92
12.4
0.92
12.5
0.92
12.6
0.91
12.7
0.91
12.8
0.90
12.9
0.90
13.0
0.89
13.5
0.85
14.0
0.81
14.5
0.76
15.0
0.71
15.5
0.66
16.0
0.60
16.5
0.55
17.0
0.48
17.5
0.41
18.0
0.34
18.5
0.28
19.0
0.23
20.0
0.17
20.5
0.16
21.0
0.15
21.5
0.15
22.0
0.15
22.5
0.15
23.0
0.14
23.5
0.14
24.0
0.14
24.5
0.00
UGD Outflow Hydrograph (1-yr Design Storm)
0.0 5.0 10.0 15.0 20.0 25.0 30.0
2-Year Outflow Hydrograph 2-Year Outflow Hydrograph
From UGD System From UGD System
Time (hrs)
Outflow (cfs)
0.0
0.00
0.5
0.16
1.0
0.17
1.5
0.18
2.0
0.19
2.5
0.19
3.0
0.20
3.5
0.20
4.0
0.21
4.5
0.22
5.0
0.23
5.5
0.23
6.0
0.24
6.5
0.25
7.0
0.26
7.5
0.27
8.0
0.27
8.5
0.29
9.0
0.31
9.5
0.33
10.0
0.34
10.5
0.37
11.0
0.42
11.1
0.43
11.2
0.44
11.3
0.46
11.4
0.48
11.5
0.50
11.6
0.53
11.7
0.60
11.8
0.70
11.9
0.85
12.0
3.84
6.00
5.00
4.00
3.00
2.00
1.00
0.00
Time (hrs)
Outflow (cfs)
12.06
5.34
12.1
4.56
12.2
3.42
12.3
2.42
12.4
1.66
12.5
1.12
12.6
0.93
12.7
0.92
12.8
0.92
12.9
0.91
13.0
0.91
13.5
0.88
14.0
0.84
14.5
0.80
15.0
0.76
15.5
0.71
16.0
0.67
16.5
0.62
17.0
0.56
17.5
0.51
18.0
0.45
18.5
0.38
19.0
0.32
20.0
0.24
20.5
0.21
21.0
0.20
21.5
0.20
22.0
0.19
22.5
0.19
23.0
0.19
23.5
0.18
24.0
0.18
24.5
0.00
UGD Outflow Hydrograph (2-yr Design Storm)
0.0 5.0 10.0 15.0 20.0 25.0
30.0
30-Year Outflow Hydrograph 30-Year Outflow Hydrograph
From UGD System From UGD System
Time (hrs)
Outflow (cfs)
0.0
0.00
0.5
0.23
1.0
0.25
1.5
0.27
2.0
0.27
2.5
0.28
3.0
0.29
3.5
0.29
4.0
0.30
4.5
0.31
5.0
0.31
5.5
0.32
6.0
0.33
6.5
0.34
7.0
0.35
7.5
0.36
8.0
0.37
8.5
0.38
9.0
0.41
9.5
0.44
10.0
0.47
10.5
0.51
11.0
0.58
11.1
0.60
11.2
0.62
11.3
0.64
11.4
0.66
11.5
0.69
11.6
0.73
11.7
0.81
11.85
5.47
11.9
19.48
11.96
19.31
25.00
20.00
15.00
10.00
5.00
0.00
Time (hrs)
Outflow (cfs)
12.00
17.37
12.05
14.06
12.10
7.65
12.15
5.40
12.25
3.95
12.5
2.39
12.6
1.92
12.7
1.48
12.8
1.24
12.9
1.09
13.0
1.00
13.5
0.92
14.0
0.90
14.5
0.88
15.0
0.85
15.5
0.83
16.0
0.79
16.5
0.76
17.0
0.72
17.5
0.69
18.0
0.65
18.5
0.61
19.0
0.57
20.0
0.47
20.5
0.42
21.0
0.37
21.5
0.33
22.0
0.31
22.5
0.29
23.0
0.28
23.5
0.28
24.0
0.27
24.5
0.20
UGD Outflow Hydrograph (10-yr Design Storm)
0.00 5.00 10.00 15.00 20.00 25.00
30.00
300-Year Outflow Hydrograph 300-Year Outflow Hydrograph
From UGD System From UGD System
Time (hrs)
Outflow (cfs)
0.0
0.00
0.5
0.30
1.0
0.34
1.5
0.36
2.0
0.37
2.5
0.38
3.0
0.39
3.5
0.40
4.0
0.41
4.5
0.42
5.0
0.44
5.5
0.46
6.0
0.48
6.5
0.50
7.0
0.52
7.5
0.54
8.0
0.56
8.5
0.59
9.0
0.63
9.5
0.67
10.0
0.71
10.5
0.78
11.0
0.87
11.1
0.89
11.2
0.92
11.3
1.89
11.4
2.67
11.5
3.12
11.6
4.11
11.7
12.21
11.85
25.43
11.90
37.94
11.92
38.16
45.00
40.00
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
0.00
Time (hrs)
Outflow (cfs)
12.00
30.06
12.05
24.52
12.10
12.97
12.15
9.10
12.25
5.65
12.5
4.01
12.6
3.60
12.7
3.19
12.8
2.86
12.9
2.58
13.0
2.32
13.5
1.58
14.0
1.11
14.5
0.94
15.0
0.92
15.5
0.92
16.0
0.91
16.5
0.90
17.0
0.88
17.5
0.86
18.0
0.84
18.5
0.82
19.0
0.80
20.0
0.74
20.5
0.71
21.0
0.68
21.5
0.65
22.0
0.63
22.5
0.60
23.0
0.57
23.5
0.54
24.0
0.51
24.5
0.47
UGD Outflow Hydrograph (100-yr Design Storm)
5.00 10.00 15.00 20.00 25.00 30.00
Inflow Hydrographs for the Area Outside of the
Underground Detention System that also Drains to the
Dry Detention Cell
1-Year Inflow Hydrograph
(From DA B Outside the Limits of the
UGD System's Subarea)
Time (hrs)
Inflow (cfs)
0.0
0.00
0.5
0.01
1.0
0.01
1.5
0.01
2.0
0.01
2.5
0.01
3.0
0.01
3.5
0.01
4.0
0.01
4.5
0.01
5.0
0.01
5.5
0.01
6.0
0.01
6.5
0.01
7.0
0.01
7.5
0.01
8.0
0.01
8.5
0.01
9.0
0.01
9.5
0.01
10.0
0.02
10.5
0.02
11.0
0.03
11.1
0.03
11.2
0.04
11.3
0.04
11.4
0.05
11.5
0.05
11.6
0.10
11.7
0.20
11.8
0.32
11.9
0.56
12.0
0.45
0.60
0.50
0.40
0.30
0.20
0.10
0.00
1-Year Inflow Hydrograph
(From DA B Outside the Limits of the
UGD System's Subarea)
Time (hrs)
Inflow (cfs)
12.1
0.15
12.2
0.08
12.3
0.07
12.4
0.06
12.5
0.05
12.6
0.04
12.7
0.04
12.8
0.03
12.9
0.03
13.0
0.03
13.5
0.02
14.0
0.02
14.5
0.02
15.0
0.01
15.5
0.01
16.0
0.01
16.5
0.01
17.0
0.01
17.5
0.01
18.0
0.01
18.5
0.01
19.0
0.01
20.0
0.01
20.5
0.01
21.0
0.01
21.5
0.01
22.0
0.01
22.5
0.01
23.0
0.01
23.5
0.01
24.0
0.01
24.5
0.00
Inflow Hydrograph (1-yr Design Storm)
0.0 5.0 10.0 15.0 20.0 25.0
30.0
2-Year Inflow Hydrograph
(From DA B Outside the Limits of the
UGD System's Subarea)
Time (hrs)
Inflow (cfs)
0.0
0.00
0.5
0.01
1.0
0.01
1.5
0.01
2.0
0.01
2.5
0.01
3.0
0.01
3.5
0.01
4.0
0.01
4.5
0.01
5.0
0.01
5.5
0.01
6.0
0.01
6.5
0.01
7.0
0.01
7.5
0.01
8.0
0.02
8.5
0.02
9.0
0.02
9.5
0.02
10.0
0.03
10.5
0.04
11.0
0.05
11.1
0.05
11.2
0.06
11.3
0.07
11.4
0.07
11.5
0.08
11.6
0.15
11.7
0.30
11.8
0.49
11.9
0.86
12.0
0.69
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
2-Year Inflow Hydrograph
(From DA B Outside the Limits of the
UGD System's Subarea)
Time (hrs)
Inflow (cfs)
12.1
0.23
12.2
0.12
12.3
0.10
12.4
0.09
12.5
0.07
12.6
0.06
12.7
0.06
12.8
0.05
12.9
0.05
13.0
0.04
13.5
0.03
14.0
0.03
14.5
0.02
15.0
0.02
15.5
0.02
16.0
0.02
16.5
0.02
17.0
0.01
17.5
0.01
18.0
0.01
18.5
0.01
19.0
0.01
20.0
0.01
20.5
0.01
21.0
0.01
21.5
0.01
22.0
0.01
22.5
0.01
23.0
0.01
23.5
0.01
24.0
0.01
24.5
0.00
Inflow Hydrograph (2-yr Design Storm)
0.0 5.0 10.0 15.0 20.0 25.0
30.0
30-Yearinflow Hydrograph 30-Yearinflow Hydrograph
(From DA B Outside the Limits of the (From DA B Outside the Limits of the
UGD System's Subarea) UGD System's Subarea)
Time (hrs)
Inflow (cfs)
0.0
0.00
0.5
0.02
1.0
0.02
1.5
0.02
2.0
0.02
2.5
0.02
3.0
0.02
3.5
0.02
4.0
0.02
4.5
0.02
5.0
0.03
5.5
0.03
6.0
0.03
6.5
0.03
7.0
0.03
7.5
0.03
8.0
0.03
8.5
0.04
9.0
0.05
9.5
0.05
10.0
0.06
10.5
0.08
11.0
0.11
11.1
0.12
11.2
0.13
11.3
0.15
11.4
0.16
11.5
0.18
11.6
0.34
11.7
0.67
11.8
1.11
11.9
1.92
12.0
1.54
2.50
2.00
1.50
1.00
0.50
0.00
Time (hrs)
Inflow (cfs)
12.1
0.51
12.2
0.28
12.3
0.23
12.4
0.19
12.5
0.16
12.6
0.13
12.7
0.12
12.8
0.12
12.9
0.11
13.0
0.10
13.5
0.08
14.0
0.06
14.5
0.05
15.0
0.05
15.5
0.04
16.0
0.04
16.5
0.03
17.0
0.03
17.5
0.03
18.0
0.03
18.5
0.03
19.0
0.02
20.0
0.02
20.5
0.02
21.0
0.02
21.5
0.02
22.0
0.02
22.5
0.02
23.0
0.02
23.5
0.02
24.0
0.02
24.5
0.00
Inflow Hydrograph (10-yr Design Storm)
0.0 5.0 10.0 15.0 20.0 25.0 30.0
100-Year Inflow Hydrograph
(From DA B Outside the Limits of the
UGD System's Subarea)
Time (hrs)
Inflow (cfs)
0.0
0.00
0.5
0.04
1.0
0.04
1.5
0.04
2.0
0.04
2.5
0.04
3.0
0.05
3.5
0.05
4.0
0.05
4.5
0.05
5.0
0.06
5.5
0.06
6.0
0.06
6.5
0.06
7.0
0.07
7.5
0.07
8.0
0.08
8.5
0.09
9.0
0.11
9.5
0.11
10.0
0.13
10.5
0.17
11.0
0.24
11.1
0.26
11.2
0.29
11.3
0.33
11.4
0.36
11.5
0.40
11.6
0.76
11.7
1.51
11.8
2.49
11.9
4.33
12.0
3.46
5.00
4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
100-Year Inflow Hydrograph
(From DA B Outside the Limits of the
UGD System's Subarea)
Time (hrs)
Inflow (cfs)
12.1
1.16
12.2
0.63
12.3
0.51
12.4
0.44
12.5
0.35
12.6
0.30
12.7
0.28
12.8
0.26
12.9
0.24
13.0
0.22
13.5
0.17
14.0
0.13
14.5
0.12
15.0
0.10
15.5
0.09
16.0
0.08
16.5
0.08
17.0
0.07
17.5
0.07
18.0
0.06
18.5
0.06
19.0
0.05
20.0
0.05
20.5
0.04
21.0
0.04
21.5
0.04
22.0
0.04
22.5
0.04
23.0
0.04
23.5
0.04
24.0
0.04
24.5
0.00
Inflow Hydrograph (100-yr Design Storm)
0.0 5.0 10.0 15.0 20.0 25.0 30.0
Combined Hydrographs
(The following hydrograph data is a combination of the Underground Detention
System's Outflow Hydrograph + the Inflow Hydrograph for the remaining DA B outside
the UGD system's subarea.)
* 1-Year Combined Inflow * 1-Year Combined Inflow
Hydrograph To Detention Cell Hydrograph To Detention Cell
Time (hrs)
Inflow (cfs)
0.0
0.00
0.5
0.13
1.0
0.14
1.5
0.15
2.0
0.15
2.5
0.16
3.0
0.16
3.5
0.17
4.0
0.17
4.5
0.18
5.0
0.19
5.5
0.20
6.0
0.21
6.5
0.22
7.0
0.22
7.5
0.23
8.0
0.24
8.5
0.26
9.0
0.28
9.5
0.30
10.0
0.32
10.5
0.35
11.0
0.39
11.1
0.41
11.2
0.42
11.3
0.44
11.4
0.46
11.5
0.48
11.6
0.56
11.7
0.72
11.8
0.94
11.9
1.30
12.0
1.31
Time (hrs)
Inflow (cfs)
12.05
1.23
12.1
1.07
12.2
1.01
12.3
0.99
12.4
0.98
12.5
0.96
12.6
0.95
12.7
0.94
12.8
0.94
12.9
0.93
13.0
0.92
13.5
0.87
14.0
0.82
14.5
0.77
15.0
0.72
15.5
0.67
16.0
0.61
16.5
0.56
17.0
0.49
17.5
0.42
18.0
0.35
18.5
0.29
19.0
0.24
20.0
0.17
20.5
0.16
21.0
0.16
21.5
0.16
22.0
0.15
22.5
0.15
23.0
0.15
23.5
0.15
24.0
0.14
24.5
0.00
* The hydrograph data shown above is a combination of the Underground Detention System's Outflow
Hydrograph + the Inflow Hydrograph for the remaining DA B outside the UGD system's subarea.
Combined Inflow Hydrograph (1-yr Design Storm)
1.40
1.20
1.00
0.80
0.60
0.40
0.20
0.00
0.0 5.0 10.0 15.0 20.0 25.0 30.0
* 2-Year Combined Inflow * 2-Year Combined Inflow
Hvdrograph To Detention Cell Hvdrograph To Detention Cell
Time (hrs)
Inflow (cfs)
0.0
0.00
0.5
0.17
1.0
0.18
1.5
0.19
2.0
0.19
2.5
0.20
3.0
0.21
3.5
0.21
4.0
0.22
4.5
0.23
5.0
0.24
5.5
0.25
6.0
0.26
6.5
0.26
7.0
0.27
7.5
0.28
8.0
0.29
8.5
0.31
9.0
0.33
9.5
0.35
10.0
0.37
10.5
0.41
11.0
0.46
11.1
0.48
11.2
0.50
11.3
0.52
11.4
0.55
11.5
0.57
11.6
0.68
11.7
0.90
11.8
1.20
11.9
1.70
12.0
4.52
Time (hrs)
Inflow (cfs)
12.05
5.66
12.1
4.79
12.2
3.54
12.3
2.52
12.4
1.75
12.5
1.19
12.6
0.99
12.7
0.98
12.8
0.97
12.9
0.96
13.0
0.95
13.5
0.91
14.0
0.87
14.5
0.82
15.0
0.78
15.5
0.73
16.0
0.68
16.5
0.63
17.0
0.58
17.5
0.52
18.0
0.46
18.5
0.40
19.0
0.33
20.0
0.25
20.5
0.22
21.0
0.21
21.5
0.20
22.0
0.20
22.5
0.20
23.0
0.19
23.5
0.19
24.0
0.19
24.5
0.00
* The hydrograph data shown above is a combination of the Underground Detention System's Outflow
Hydrograph + the Inflow Hydrograph for the remaining DA B outside the UGD system's subarea.
Combined Inflow Hydrograph (2-yr Design Storm)
6.00
5.00
4.00
3.00
2.00
1.00
0.00
0.0 5.0 10.0 15.0 20.0 25.0
30.0
* 10-Year Combined Inflow * 10-Year Combined Inflow
Hydrograph To Detention Cell Hydrograph To Detention Cell
Time (hrs)
Inflow (cfs)
0.0
0.00
0.5
0.25
1.0
0.27
1.5
0.28
2.0
0.29
2.5
0.30
3.0
0.31
3.5
0.31
4.0
0.32
4.5
0.33
5.0
0.34
5.5
0.35
6.0
0.36
6.5
0.37
7.0
0.38
7.5
0.39
8.0
0.40
8.5
0.42
9.0
0.46
9.5
0.48
10.0
0.53
10.5
0.59
11.0
0.69
11.1
0.71
11.2
0.75
11.3
0.78
11.4
0.82
11.5
0.86
11.6
1.06
11.7
1.48
11.8
3.39
11.9
21.39
12.0
18.91
Time (hrs)
Inflow (cfs)
12.05
15.20
12.1
8.16
12.2
4.49
12.3
3.81
12.4
3.18
12.5
2.54
12.6
2.05
12.7
1.60
12.8
1.36
12.9
1.20
13.0
1.10
13.5
0.99
14.0
0.96
14.5
0.93
15.0
0.90
15.5
0.87
16.0
0.83
16.5
0.79
17.0
0.75
17.5
0.72
18.0
0.68
18.5
0.63
19.0
0.59
20.0
0.49
20.5
0.44
21.0
0.39
21.5
0.35
22.0
0.33
22.5
0.31
23.0
0.30
23.5
0.30
24.0
0.29
24.5
0.19
* The hydrograph data shown above is a combination of the Underground Detention System's Outflow
Hydrograph + the Inflow Hydrograph for the remaining DA B outside the UGD system's subarea.
25.00
20.00
15.00
10.00
5.00
0.00
Combined Inflow Hydrograph (10-yr Design Storm)
0.0 5.0 10.0 15.0 20.0 25.0 30.0
* 100-Year Combined Inflow * 100-Year Combined Inflow
Hydrograph To Detention Cell Hydrograph To Detention Cell
Time (hrs)
Inflow (cfs)
0.0
0.00
0.5
0.33
1.0
0.38
1.5
0.40
2.0
0.41
2.5
0.42
3.0
0.43
3.5
0.44
4.0
0.46
4.5
0.47
5.0
0.49
5.5
0.51
6.0
0.54
6.5
0.56
7.0
0.59
7.5
0.61
8.0
0.63
8.5
0.68
9.0
0.74
9.5
0.78
10.0
0.85
10.5
0.95
11.0
1.11
11.1
1.15
11.2
1.21
11.3
2.22
11.4
3.03
11.5
3.52
11.6
4.87
11.7
13.72
11.8
23.69
11.9
42.25
12.0
33.52
Time (hrs)
Inflow (cfs)
12.05
27.10
12.1
14.13
12.2
7.08
12.3
5.48
12.4
4.83
12.5
4.36
12.6
3.90
12.7
3.47
12.8
3.12
12.9
2.81
13.0
2.55
13.5
1.75
14.0
1.24
14.5
1.05
15.0
1.03
15.5
1.01
16.0
0.99
16.5
0.97
17.0
0.95
17.5
0.93
18.0
0.90
18.5
0.88
19.0
0.85
20.0
0.79
20.5
0.75
21.0
0.72
21.5
0.70
22.0
0.67
22.5
0.64
23.0
0.61
23.5
0.58
24.0
0.55
24.5
0.47
* The hydrograph data shown above is a combination of the Underground Detention System's Outflow
Hydrograph + the Inflow Hydrograph for the remaining DA B outside the UGD system's subarea.
45.00
40.00
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
Combined Inflow Hydrograph (100-yr Design Storm)
0.0 5.0 10.0 15.0 20.0 25.0 30.0
Dry Detention Cell Routing Calculations
(DA B-Tots I )
MJH Apartments- Detention Cell Routings
BasinFlow printout
INPUT:
Basin: MJH Apartments- Detention Cell Routings.txt
5 Contour Areas
Elevation(ft)
Area(sf)
Computed Vol.(cy)
352.00
78.00
0.0
354.00
908.00
30.9
356.00
2834.00
162.9
358.00
5217.00
456.7
360.00
8001.00
942.5
Start_Elevation(ft) 352.00 Vol.(cy)
Page 1
MJH Apartments- Detention Cell Routings
4 Outlet Structures
Outlet structure 0
Orifice
name: Barrel
area (sf) 0.785
diameter or depth (in) 12.000
width for rect. (in) 0.000
coefficient 0.500
invert (ft) 350.000
multiple 1
discharge out of riser
Outlet structure 1
Orifice
name: Low -Flow Orifice
area (sf) 0.049
diameter or depth (in) 3.000
width for rect. (in) 0.000
coefficient 0.500
invert (ft) 352.000
multiple 1
discharge into riser
Outlet structure 2
Weir
name: Riser
diameter (in)
24.000
side angle
0.000
coefficient
3.300
invert (ft)
357.330
multiple
1
discharge
into riser
transition at (ft)
0.608
orifice coef.
0.500
orifice area (sf)
3.142
Outlet structure 3
Weir
name: Emergency Spillway
length (ft)
50.000
side angle
75.960
coefficient
3.300
invert (ft)
358.660
multiple
1
discharge
through dam
Page 2
MJH Apartments- Detention Cell Routings
4 Inflow Hydrographs
Hydrograph 0
Curve
name: 1-yr TR-55 SCS 24-hr Design Storm
time incr (minlhrs) 0.02
time limit (minlhrs) 30.00
file: lyr Inflow Hydrograph Data.txt
volume (cy) 1115.44
routed true
time in hours true
Hydrograph 1
Curve
name: 2-yr TR-55 SCS 24-hr Design Storm
time incr (minlhrs) 0.02
time limit (minlhrs) 30.00
file: 2yr Inflow Hydrograph Data.txt
volume (cy) 1463.20
routed true
time in hours true
Hydrograph 2
Curve
name: 10-yr TR-55 SCS 24-hr Design Storm
time incr (minlhrs) 0.02
time limit (minlhrs) 30.00
file: 10yr Inflow Hydrograph Data.txt
volume (cy) 2508.72
routed true
time in hours true
Hydrograph 3
Curve
name: 100-yr TR-55 SCS 24-hr Design Storm
time incr (minlhrs) 0.02
time limit (minlhrs) 30.00
file: 100yr Inflow Hydrograph Data.txt
volume (cy) 4573.29
routed true
time in hours true
Page 3
MJH Apartments- Detention Cell Routings
OUTPUT:
Routing Method: storage -indication
Hydrograph 0
Routing Summary
of
Peaks: 1-yr TR-55
SCS 24-hr
Design Storm
inflow
(cfs)
1.331
at
11.94
(hrs)
discharge
(cfs)
0.447
at
17.00
(hrs)
water level
(ft)
357.275
at
17.30
(hrs)
storage
(cy)
329.482
Hydrograph 1
Routing Summary
of
Peaks: 2-yr TR-55
SCS 24-hr
Design Storm
inflow
(cfs)
5.732
at
12.06
(hrs)
discharge
(cfs)
0.641
at
13.24
(hrs)
water level
(ft)
357.374
at
13.24
(hrs)
storage
(cy)
345.351
Hydrograph 2
Routing Summary
of
Peaks: 10-yr TR-55
SCS 24-hr
Design Storm
inflow
(cfs)
22.118
at
11.92
(hrs)
discharge
(cfs)
8.982
at
12.08
(hrs)
water level
(ft)
358.630
at
12.08
(hrs)
storage
(cy)
587.671
Hydrograph 3
Routing Summary
of
Peaks: 100-yr
TR-55
SCS
24-hr Design Storm
inflow
(cfs)
42.489
at
11.92
(hrs)
discharge
(cfs)
41.713
at
11.92
(hrs)
water level
(ft)
358.994
at
11.92
(hrs)
storage
(cy)
672.374
Mon Mar 11 14:04:35 EDT 2019
Page 4
Riprap Lined Outfall Channel Calculations
(DA C)
� r),, � A Q IDA ':
+ t CPS
Cl�' SNrCty
CIFS
'PEP, NOKNOlk 3.�`-A I paAo? 1,,j CHAW.4-L
�,o
ASO
Y,3
,FOR CLt"C-o
-p,ke,
A AL
F-I pjAL. N OW\ P, L\ad -oa m 6ro.mz
MJH Apartments Outfall
Complex Channnel- Subarea C Outfall Channel
Input:
Slope
Flow (given)
Output:
c•.
line
x
y
n
0
0.000
1.000
0.050 (first n value not used)
1
3.000
0.000
0.050
2
4.000
0.000
0.050
3
7.000
1.000
0.050
Depth 0.707
(y) ( 0.707)
Channel bed segment output:
line Q V
1 4.81 6.42
2 7.46 10.55
3 4.81 6.42
Thu Mar 07 14:46:10 EST 2019
A
P
0.75
2.24
0.71
1.00
0.75
2.24
Page 1
DEQ Virginia Runoff Reduction Method
Water Quality Calculations
(COMPLIANCE IS MET THROUGH THE BEST MANAGEMENT PRACTICES OF A LEVEL II WET POND & THE
PURCHASING OF NUTRIENT CREDITS)
DEQ Virginia Runoff Reduction Method New Development Compliance Spreadsheet - Version 3.0
M 2011 BMP Standards and Specifications 02013 Draft BMP Standards and Specifications
Project Name: Martha Jefferson Hospital Apartments
Date: 3/22/2029
BMP Design Specifications List: 2011 Stds & Specs
Site Information
Post-Develooment Proiect (Treatment Volume and Loads)
Land Cover (acres)
A Soils
BSolis
CSoils
DSoils
Totals
Forest/Open Space (acres) — undisturbed,
0.00
protected forest/open space or reforested land
0.00
Managed Tort (acres) — disturbed, graded for
20.01
ards or other turf to be mowed/managed
20.01
Impervious Cover (acres)
6.97
6.97
26.98
Constants
Annual Raln" (inches) 43
Target Rainfall Event linches) 1.00
Total Phosphorus (TP EMC(mg/L) 0.26
Total Nitrogen (TN) EMC(mg/L) 1.86
Target TP Load (lb/acre/yr) 0.41
PJ(unitless correction factor) 0.90
Land Cover Summary
Forest/Open Space Cover (acres)
0.00
Weighted RV (forest)
0.00
%Forest
0%
Managed Turf Cover (acres)
20.01
Weighted Rv(turf)
0.20
%Managed Turf
74%
Impervious Cover (acres)
6.97
RV (impervious)
0.95
%Impervious
26%
Site Area (acres)
26.98
Site RV
0.39
Runoff Coefficients (Rv)
Treatment Volume and Nutrient Loads
Treatment Volume
0.8853
(acre-ft)
Treatment Volume (cubic feet)
38,563
TP Load (lb/yr)
24.23
TN Load (Ib/yr)
final results
Drainage Area A
.- .... ... .... � 1— 1.-1
T.11 lh-ph.r- - —.1 i. — A (lb/r)
P- I—I.p.— net—t -.— m R.A. Air')
St-,ra—ter R— M--m—t Practices (RR = R,n,ff R,d,,ti,nl
an lArl
as )rrl
cs Ino RRI
EDIA, DIRQp aw EEADHEDK.DK.
TOTAL RUNOFF REDUCTION IN D.A. A (h')
TOTAL PHOSPHORUS AVAI .A.Allb/yN 9.25
A.AIIb/yG 0.00
TOTAL PHOSPHORUS a[mAININGSAFTER API ING RUNOFF REDULTOx PRA .SIx D.A. A (lb/yr)
SEE WATER QUALITY COMPLIANCE TAB FOR SITE COMPLIANCE CALCULATIONS
TOTALIMPFRVIOUS EOVER TREATED(") B.00
TOTAL MANAGEDTURIAREATREMEDI-) EA
TOTAL PHOSPHORUS REMOVAL REQUIRED ON SITE(lb/y,) 13O.1T
m.—IN D.A. A(lb/yl) 9.25
TD.A. A Ub/y,I
TOTAL PHOSPHO .A. A 11b/yrI
TOTAL PH Gp.ORUSLOA.0. AQb/yr)
TOTAL PHOSPHORUS REMAINING AFTER APPLYING BMP LOAD RED—ONS IN D.A. A IIb/yN
SEE WATER QUALITY COMPLIANCE TAB FOR SITE COMPLIANCE CALCULATIONS
0. A Qb/yN
NDROGEN REMOVED WITHOUT .A.AQb/yN
TOTAL nlmoGEx REmoveD m D.A. A (ln/yr)
W
Q
O
o
O
0
O
0
O
0
O
0
0
0
0
0
0
0
0
Q
0
0
0
0
0
0
0
0
0
0
0
00000
0
lJ
Q
0
O
0
O
0
O
0
O
0
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