Stormwater Drainage Report 1-28-09
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CITY OF CHANHASSEN
RECEIVED
JAN 3 0 2009
CHANHASSEN PLANNING DEPT
STORMWATER
DRAINAGE
REPORT
...'
Apple Tree Estates
(Plowe #08-1227)
Chanhassen, MN
ORIGINAL DATE: January 15, 2009
Rev: January 28, 2009
PlOWE
ENGINEERING, INC.
6776 Lake Drive, Suite 110
Lino Lakes, Minnesota 55014
Office (651) 361-.8210
Fax (651) 361-.8701
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SUMMARY OF RESULTS
GENERAL
This.7.l-acre parcel willbe subdivided into 8 single-family lots. Approximately two-thirds of the
existing site drains directly to Lake Susan; the remaining portion drains to a small wetland on the east
side bfthe.property. Proposed.drainage from the street and most of the roof and driveways will be
collected and routed to a pre-treatment vortex manhole and a bio-retention basin, which drains to an
existing pond and wetland complex to the west (Chanhassen Hills), and ultimately outlets to Lake Susan.
The remainder of the site will still drain directly to either Lake Susan or the existing wetland.
WATER QUALITY
Water quality is provided via the use of a pre-treatment vortex manhole and the construction of a bio-
retention basin, which collects most of the proposed hard surface (new street, roof and driveways). A
concrete skimmer structure is proposed that will provide skimming for floatables.
For drainage to the wetland, pre-treatment is provided via the grassed areas and buffer zone around the
wetland. Most of the hard surface to the wetland is roof run-off.
WATER QUANTITY
For the bio-retention basin, a multi-staged orifice is provided to minimize run-off rates for all storm
events. For drainage to the wetland, run-off volumes are less than or equal to existing volumes. A
comparison of existing versus proposed is provided.
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RATE AND VOLUME COMPARISON
TO LAKE SUSAN
Rate Control
STORM EVENT
(Rate Control)
2-yr 10-yr 100-yr
(cfs) (cfs) (cfs)
.
Exisitng (1) 2.00 7.84 18.88
Proposed (2 + Bio) 1.52 5.59 16.95
TO WETLAND
Volume Control
STORM EVENT
(Volume Control)
2-yr 10-yr 100-yr
(cf) (cf) (cf)
Existing (2) 4,811 13,109 28,306
Proposed (3) 3,464 8,339 16,754
- - - - - - - - - - - - - - - - - - -
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To Lake
~Jg~ I~~~~hl A ~
To Wetland
Drainage Diagram for 081227 Existing
Prepared by Plowe Engineering, Inc., Printed 1/8/2009
HydroCAD@ 8.50 sIn 001574 @ 2007 HydroCAD Software Solutions LLC
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081227 Existing
Prepared by Plowe Engineering, Inc.
HydroCAOO 8.50 sin 001574 @2007 HydroCAD Software Solutions LLC
Type /I 24-hr 2-year (2. 70'? Rainfal/=2.70"
Printed 1/8/2009
PaQe ?
Time span=0.00-150.00 hrs, dt=0.01 hrs, 15001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method
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Subcatchment 1: To Lake
Runoff Area=295,720 sf 9.24% Impervious Runoff Depth=0.38"
Flow Length=625' Tc=18.3 min CN=65 Runoff=2.00 cfs 9,264 cf
Subcatchment 2: To Wetland
Runoff Area=130,354 sf 10.09% Impervious Runoff Depth=O.44"
Flow Length=300' Slope=0.0520 'f Tc=17.5 min CN=67 Runoff=1.19 cfs 4,811 cf
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Total Runoff Area = 426,074 sf Runoff Volume = 14,075 cf Average Runoff Depth = 0.40"
90.50% Pervious = 385,590 sf 9.50% Impervious = 40,484 sf
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081227 Existing
Prepared by Plowe Engineering, Inc.
HvdroCAOO 8.50 sin 001574 @2007 HvdroCAD Software Solutions LLC
Type /I 24-hr 2-year (2.70'? Rainfal/=2.70"
Printed 1/8/2009
Page 3
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Runoff
Summary for Subcatchment 1: To Lake
2.00cfs @ 12.15 hrs, Volume=
9,264 cf, Depth= 0.38"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 2-year (2.70") Rainfall=2.70"
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Area (sf)
13,695
13,630
8,830
259.565
295,720
268,395
27,325
CN Description
98 Roof
98 Bituminous/Concrete Drive
85 Gravel Drive
61 >75% Grass cover, Good, HSG B
65 Weighted Average
Pervious Area
Impervious Area
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Tc Length Slope Velocity Capacity Description
(min) (feet) (ftlft) (ftlsec) (cfs)
16.9 300 0.0567 0.30 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
1.4 325 0.0635 3.78 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0fps
18.3 625 Total
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Runoff
Summary for Subcatchment 2: To Wetland
1.19 cfs @ 12.13 hrs, Volume=
4,811 cf, Depth= 0.44"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 2-year (2.70") Rainfall=2.70"
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Area (sf)
5,352
4,585
3,222
5,150
8,872
103,173
130,354
117,195
13,159
CN Description
98 Roof
98 Trail
98 Concrete
85 Gravel
85 Wetland
61 >75% Grass cover. Good. HSG B
67 Weighted Average
Pervious Area
Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ftlft) (ftlsec) (efs)
17.5 300 0.0520 0.29 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
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081227 Existing
Prepared by Plowe Engineering, Inc.
HvdroCAOO 8.50 sin 001574 @2007 HvdroCAD Software Solulions LLC
Type /I 24-hr 10-year (4.10'J Rainfa//=4.10"
Printed 1/8/2009
Page 4
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Time span=0.00-150.00 hrs, dt=0.01 hrs, 15001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method
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Subcatchment 1 : To Lake
Runoff Area=295,720 51 9.24% Impervious Runoff Deplh=1.09"
Flow Length=625' Tc=18.3 min CN=65 Runoff=7.84 cIs 26.787 cl
Subcatchment2: To Wetland
Runoff Area=130,354 51 10.09% Impervious Runoff Deplh=1.21"
Flow Lenglh=300' Slope=0.0520'r Tc=17.5 min CN=67 Runoff=4.05 cIs 13,109 cl
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Total Runoff Area = 426,074 sf Runoff Volume = 39,896 cf Average Runoff Depth = 1.12"
90.50% Pervious = 385,590 sf 9.50% Impervious = 40,484 sf
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081227 Existing
Prepared by Plowe Engineering, Inc.
HvdroCAD@8.50 sin 001574 @2007 HVdroCAD Software Solutions LLC
Type 1/24-hr 10-year (4.10'1 Rainfal/=4.10"
Printed 1/8/2009
PaQ8 5
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Runoff
Summary for Subcatchment 1: To Lake
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-150.00 hrs, dt= 0.01hrs
Type II 24-hr 10-year (4.10") Rainfall=4.10"
7.84 cfs @ 12: 13 hrs, Volume=
26,787 cf, Depth= 1.09"
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Area (sf)
13,695
13,630
8,830
259.565
295,720
268,395
27,325
CN Description
98 Roof
98 Bituminous/Concrete Drive
85 Gravel Drive
61 >75% Grass cover, Good, HSG B
65 Weighted Average
Pervious Area
Impervious Area
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Tc Length Slope Velocity Capacity Description
(min) (feet) (fUft) (fUsee) (cfs)
16.9 300 0.0567 0.30 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
1.4 325 0.0635 3.78 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
18.3 625 Total
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Runoff
Summary for Subcatchment 2: To Wetland
4.05 cfs @ 12.11 hrs, Volume=
13,109 cf, Depth= 1.21"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-year (4.10") Rainfall=4.10"
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Area (sf)
5,352
4,585
3,222
5,150
8,872
103,173
130,354
117,195
13,159
CN Description
98 Roof
98 Trail
98 Concrete
85 Gravel
85 Wetland
61 >75% Grass cover, Good, HSG B
67 Weighted Average
Pervious Area
Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (fUft) (fUsee) (cfs)
17.5 300 0.0520 0.29 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
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081227 Existing
Prepared by Plowe Engineering, Inc.
HvdroCA[)@8.50 sin 001574 @2007 HvdroCAD Software Solutions LLC
Type /I 24-hr tOO-year (6. to'? Rainfa//=6.tO"
Printed 1/8/2009
Page 6
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Time span=0.00-150.00 hrs, dt=0.01 hrs, 15001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method
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Subcatchment 1 : To Lake
Runoff Area=295,720 sf 9.24% Impervious Runoff Depth=2.42"
Flow Length=625' Tc=18.3 min CN=65 Runoff=18.88 cfs 59,743 cf
Subcatchment2: To Wetland
Runoff Area=130,354 sf 10.09% Impervious Runoff Depth=2.61"
Flow Length=300' Slope=0.0520 'f Tc=17.5 min CN=67 Runoff=9.25 cfs 28,306 cf
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Total Runoff Area = 426,074 sf Runoff Volume = 88,048 cf Average Runoff Depth = 2.48"
90.50% Pervious = 385,590 sf 9.50% Impervious = 40,484 sf
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081227 Existing
Prepared by Plowe Engineering, Inc.
HVdroCA[)@8.50 sin 001574 @2007 HvdroCAD Software Solutions LLC
Type II 24-hr 100-year (6.10'~ Rainfal/=6.10"
Printed 1/8/2009
Page 7
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Runoff
Summary for Subcatchment 1: To Lake
18.88 cts @ 12.12 hrs, Volume=
59,743 ct, Depth= 2.42"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 100-year (6.10") Raintall=6.10"
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Area (sf)
13,695
13,630
8,830
259,565
295,720
268,395
27,325
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CN Description
98 Root
98 Bituminous/Concrete Drive
85 Gravel Drive
61 >75% Grass cover, Good, HSG B
65 Weighted Average
Pervious Area
Impervious Area
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Tc Length Slope Velocity Capacity Description
(min) (feet) (ftlft) (ft/sec) (cfs)
16.9 300 0.0567 0.30 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
1.4 325 0.0635 3.78 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
18.3 625 Total
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Runoff
Summary for Subcatchment 2: To Wetland
9.25 cfs @ 12.11 hrs, Volume=
28,306 ct, Depth= 2.61"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 100-year (6.10") Rainfall=6.10"
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Area (sf)
5,352
4,585
3,222
5,150
8,872
103,173
130,354
117,195
13,159
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CN Description
98 Roof
98 Trail
98 Concrete
85 Gravel
85 Wetland
61 >75% Grass cover, Good, HSG B
67 Weighted Average
Pervious Area
Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
17.5 300 0.0520 0.29 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
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To Bi.oretention
Direct to Lake
To Wetland
~Ubca) IReachl g ~
~
Bioretention
Drainage Diagram for 081227 Proposed REV#1
Prepared by Plowe Engineering, Inc., Printed 1/29/2009
HydroCAD@8.50 sIn 001574 @2007 HydroCAD Software Solutions LLC
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081227 Proposed REV#1
Prepared by Plowe Engineering, Inc.
HvdroCAOO8.50 sin 001574 @2007HvdroCADSoftwareSolulionsLLC
Type /I 24-hr 2-year (2. 70'~ Rainfal/=2.70"
Printed 1/29/2009
PHilP. ?
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Time span=0.00-150.00 hrs, dt=0.01 hrs, 15001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method
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Subcatchment 1: To Bioretention
Runoff Area=234,986 sf 24.10% Impervious Runoff Depth=0.55"
Flow Length=205' Slope=0.1075 'f Tc=9.7 min CN=70 Runoff=4.14 cts 10,851 ct
Subcatchment 2: Direct to Lake
Runoff Area=125, 767 sf 12.07% Impervious Runoff Depth=0.38"
Flow Lenglh=195' Slope=0.1850 'f Tc=7.5 min CN=65 Runoff=1.42 cfs 3,940 cf
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Subcatchment 3: To Wetland
Runoff Area=65,379 sf. 20.86% Impervious Runoff Depth=0.64"
Flow Length=255' Tc=8.0 min CN=72 Runoff=1.48 cts 3,464 ct
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Pond Bio: Bioretention
PeakElev=907.08' Storage=6,977 ct Inflow=4.14 cts 10,851 ct
Primary=0.02 cts 379 ct Secondary=0.08 cts 10,473 cf Outflow=0.10 cfs 10,852 cf
Total Runoff Area = 426,132 sf Runoff Volume = 18,256 cf Average Runoff Depth = 0.51"
79.95% Pervious = 340,690 sf 20.05% Impervious = 85,442 sf
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081227 Proposed REV#1
Prepared by Plowe Engineering, Inc.
HvdroCAOO 8.50 sin 001574 @2007 HvdroCAD Software Solutions LLC
Type J/24-hr 2-year (2. 70'? Rainfal/=2.70"
Printed 1/29/2009
Page 3
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Runoff
Summary for Subcatchment 1: To Bioretention
4.14 cfs @ 12.03 hrs, Volume=
10,851 cf, Depth= 0.55"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 2-year (2.70") Rainfall=2.70"
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Area (sf)
17,614
19,465
17,950
1,600
178,357
234,986
178,357
56,629
CN Description
98 Roof
98 Bituminous/Concrete Drive
98 Road
98 Trail
61 >75% Grass cover, Good, HSG B
70 Weighted Average
Pervious Area
Impervious Area
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Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
9.7 205 0.1075 0.35 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
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Runoff
Summary for Subcatchment 2: Direct to Lake
1.42 cfs @ 12.01 hrs, Volume= 3,940 cf, Depth= 0.38"
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Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 2-year (2.70") Rainfall=2.70"
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Area (sf)
6,235
8,940
110,592
125,767
110,592
15,175
CN Description
98 Roof
98 Bituminous/Concrete Drive
61 >75% Grass cover. Good, HSG B
65 Weighted Average
Pervious Area
Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 195 0.1850 0.43 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
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Runoff
Summary for Subcatchment 3: To Wetland
1.48 cfs@ 12.01 hrs, Volume=
3,464 cf, Depth= 0.64"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 2-year (2.70") Rainfall=2.70"
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Area (sf)
7,538
1,650
4,450
8,872
42,869
65,379
51,741
13,638
CN Description
98 Roof
98 Drive
98 Bituminous
85 Wetland
61 >75% Grass cover, Good, HSG B
72 Weighted Average
Pervious Area
Impervious Area
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Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.3 125 0.0800 0.28 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
0.7 130 0.0384 2.94 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
8.0 255 Total
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Inflow Area =
Inflow
Outflow
Primary
Secondary =
Summary for Pond Bio: Bioretention
234,986 sf, 24.10% Impervious,
4.14 cfs @ 12.03 hrs, Volume=
0.10 cfs @ 19.76 hrs, Volume=
0.02 cfs @ 19.76 hrs, Volume=
0.08 cfs @ 19.76 hrs, Volume=
Inflow Depth = 0.55" for 2-year (2.70") event
1 0,851 cf
10,852 cf, Allen= 98%, Lag= 463.5 min
379 cf
10,473 cf
Routing by Dyn-Stor-Ind method, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Peak Elev= 907.08'@ 19.76 hrs Surf.Area= 7,186 sf Storage= 6,977 cf
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Plug-Flow detention time= 891.4 min calculated for 10,851 cf (100% of inflow)
Center-of-Mass del. time= 891.5 min ( 1,782.1 - 890.6)
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081227 Proposed REV#1
Prepared by Plowe Engineering, Inc.
HvdroCAOO 8.50 sIn 001574 @2007 HVdroCAD Software Solutions LLC
Type /I 24-hr 2-year (2. 70") Rainfal/=2.70"
Printed 1/29/2009
Page 4
Volume
#1
Invert
906.00'
Avail.Storage Storage Description
28,547 cf Custom Stage Data (Prismatic) Listed below (Recalc)
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Elevation
(feet)
906.00
908.00
909.00
909.50
Surf. Area
(SQ-ft)
5,692
8,450
9,979
10,781
Inc. Store
(cubic-feet)
o
14,142
9,215
5,190
Cum. Store
(cubic-feet)
o
14,142
23,357
28,547
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Device
#1
#2
#3
#4
Routing
Secondary
Device 4
Device 4
Primary
Invert
906.00'
907.00'
908.40'
907.00'
Outlet Devices
0.500 in/hr Exfiltration over Surface area
4.0" Vert. Orifice/Grate C= 0.600
4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
15.0" x 201.0'long Culvert Ke= 0.500 Outlet Invert= 906.20' S= 0.0040 'f' Cc= 0.900 n= 0.013
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Primary OutFlow Max=0.02 cfs@ 19.76 hrs HW=907.08' (Free Discharge)
Y=Culvert (Passes 0.02 cfs of 0.02 cfs potential flow)
t2=orifiCe/Grate (Orifice Controls 0.02 cfs @ 0.98 fps)
3=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
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~condary OutFlow Max=0.08 cfs@ 19.76 hrs HW=907.08' (Free Discharge)
1=Exfiltration (ExfiltrationControls 0.08 cfs)
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081227 Proposed REV#1
Prepared by Plowe Engineering, Inc.
HydroCAD@8.50 sin 001574 @2007HydroCADSoftwareSolutionsLLC
Type /I 24-hr 10-year (4.10'~ Rainfal/=4.10"
Printed 1/29/2009
P::lgp,5
I
Time span=0.00-150.00 hrs, dt=0.01 hrs, 15001 points
Runoff by SCS TR-zO method, UH=SCS
Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method
Subcatchment 1: To Bioretention
.Runoff Area=234,986 sl 24.10% Impervious RunoffDepth=1.40"
Flow Length=205' Slope=0.1075 'f Tc=9.7 min CN=70 Runoff=11.57 cIs 27,353 cl
Subcatchment2: Directto Lake
Runoff Area=125,767 sl 12.07% Impervious Runoff Deplh=1.09"
Flow Length=195' Slope=0.1850 'f Tc=7.5 min CN=65 Runoff=5.10 cIs 11,392 cl
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Subcatchment 3: To Wetland
Runoff Area=65,379 sl 20.86% Impervious Runoff Depth=1.53"
Flow Length=255' Tc=8.0 min CN=72 Runoff=3.80 cIs 8,339 cl
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Pond Bio: Bioretention
Peak Elev=908.03' Storage=14,418 cf Innow=11.57 cIs 27,353 cl
Priniary=0.39cls 14,986 cl Secondary=0.10 cIs 12,367 cl Outflow=0.49 cIs 27,353 cl
Total Runoff Area = 426,132 sf Runoff Volume = 47,084 cf Average Runoff Depth = 1.33"
79.95% Pervious = 340,690 sf 20.05% Impervious = 85,442 sf
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081227 Proposed REV#1
Prepared by Plowe Engineering, Inc.
HydroCA[)@8.50 sin 001574 @2007 HydroCAD Software Solutions LLC
Type1l24-hr10-year (4.10'? Rainfal/=4.10"
Printed 1/29/2009
Page 6
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Runoff
Summary for Subcatchment 1: To Bioretention
11.57 cfs @ 12.02 hrs, Volume=
27,353 cf, Depth= 1.40"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-year (4.10") Rainfall=4. 1 0"
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Area (sf)
17,614
19,465
17,950
1,600
178,357
234,986
178,357
56,629
CN Description
98 Roof
98 Bituminous/Concrete Drive
98 Road
98 Trail
61 >75% Grass cover, Good. HSG B
70 Weighted Average
Pervious Area
Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ftlft) (ftlsec) (cfs)
9.7 205 0.1075 0.35 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
Runoff
Summary for Subcatchment 2: Direct to Lake
5.10 cfs@ 12.00 hrs, Volume= 11,392 cf, Depth= 1.09"
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Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-year (4.10") Rainfall=4. 1 0" .
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Area (sf)
6,235
8,940
110,592
125,767
110,592
15,175
CN Description
98 Roof
98 Bituminous/Concrete Drive
61 >75% Grass cover. Good. HSG B
65 Weighted Average
Pervious Area
Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ftlft) (ftlsec) (cfs)
7.5 195 0.1850 0.43 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
Runoff
Summary for Subcatchment 3: To Wetland
3.80 cfs @ 12.00 hrs, Volume=
8,339 cf, Depth= 1.53"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-year (4.10") Rainfall=4.10"
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Area (sf)
7,538
1,650
4,450
8,872
42,869
65,379
51,741
13,638
eN Description
98 Roof
98 Drive
98 Bituminous
85 Wetland
61 >75% Grass cover. Good. HSG B
72 Weighted Average
Pervious Area
Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ftlft) (ftlsec) (efs)
7.3 125 0.0800 0.28 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
0.7 130 0.0384 2.94 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
8.0 255 Total
Inflow Area =
Inflow
Outflow
Primary
Secondary =
Summary for Pond Bio: Bioretention
234,986 sf, 24.10% fmpervious,
11.57 efs @ 12.02 hrs, Volume=
0.49 cfs @ 14.25 hrs, Volume=
0.39 cis @ 14.25 hrs, Volume=
0.10 cis @ 14.25 hrs, Volume=
Inflow Depth = 1.40" for 10-year (4.10") event
27,353 cl
27,353 cf, Allen= 96%, Lag= 133.8 min
14,986 cf
12,367 cl
Routing by Dyn-Stor-Ind method, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Peak Elev= 908.03' @ 14.25 hrs Surf.Area= 8,500 sl Storage= 14,418 cf
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Plug-Flow detention time= (not calculated: outflow precedes inflow)
Center-ol-Mass del. time= 574.9 min ( 1,434.0 - 859.1 )
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081227 Proposed REV#1
Prepared by Plowe Engineering, Inc.
HvdroCAOO 8.50 sin 001574 @ 2007 HvdroCAD Software Solutions LLC
Type 1l24-hr 10-year (4.10'1 Rainfal/=4.10"
,Printed 1/29/2009
PallA 7
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Volume
#1
Invert
906.00'
Avail.StoraQe StoraQe Description
28,547 cf Custom Stage Data (Prismatic) Listed below (Recalc)
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Elevation
(feet)
906.00
908.00
909.00
909.50
Surf.Area
(SQ-ft)
5,692
8,450
9,979
10,781
Inc. Store
(cubic-feet)
o
14,142
9,215
5,190
Cum. Store
(cubic-feet)
o
14,142
23,357
28,547
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Device
#1
#2
#3
#4
RoutinQ
Secondary
Device 4
Device 4
Primary
Invert
906.00'
907.00'
908.40'
907.00'
Outlet Devices
0.500 in/hr Exfiltration over Surface area
4.0" Vert. Orifice/Grate C= 0.600
4.0' longSharp-Crested Rectangular Weir 2 End Contraction(s)
15.0" x 201.0'long Culvert Ke= 0.500 Outlet Invert= 906.20' S= 0.0040 '/' Cc= 0.900 n= 0.013
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Primary OutFlow Max=0.39 cfs @ 14.25 hrs HW=908.03' (Free Discharge)
~Culvert (Passes 0.39 cfs of 2.81 cfs potential flow)
t2=orifice/Grate (Orifice Controls 0.39 cfs @ 4.48 fps)
3=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
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t:.condary OutFlow Max=0.10 cfs @ 14.25 hrs HW=908.03' (Free Discharge)
1=Exfiltration (Exfiltration Contro.ls 0,1 0 cfs)
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081227 Proposed REV#1
Prepared by Plowe Engineering, Inc.
HvdroCA[)@6.50 sin 001574 @2007 HvdroCAD Software Solutions LLC
Type 1/24-hr 100-year (6.10'? Rainfal/=6.10"
Printed 1/29/2009
Page 8
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subcatchment 1: To Bioretention
Sub catchment 2: Direct to Lake
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subcatchment 3: To Wetland
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Pond Bio: Bioretention
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Timespan=0.00-150.00 hrs, dt=0.01 hrs, 15001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method
Runoff.Area=234,966 sl 24.10% Impervious Runoff Deplh=2.88"
Flow Length=205' Slope=0.1075 'f Tc=9.7 min CN=70 Runoff=24.29 cIs 56,490 cl
Runoff Area=125,767 sl 12.07% Impervious Runoff Depth=2.42"
Flow Lenglh=195' Slope=0.1850 'f Tc=7.5 min CN=65 Runoff=11.83 cfs 25,406 cl
Runoff Area=65,379 sl 20.86% Impervious Runoff Depth=3.08"
Flow Lenglh=255' Tc=6.0 min CN=72 Runoff=7.66 cIs 16.754 cl
Peak Eiev=909.04' Storage=23,801 cl Inftow=24.29 cIs 56,490 cf
Primary=5.00 cIs 42,170 cl Secondary=0.12 cIs 14,320 cl Dutflow=5.12 cIs 56,490 cl
Total Runoff Area = 426,132 sf Runoff Volume = 98,652 cf Average Runoff Depth = 2.78"
79.95% Pervious = 340,690 sf 20.05% Impervious = 85,442 sf
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081227 Proposed REV#1
Prepared by Plowe Engineering, Inc.
HydroCA[)@8.50 sin 001574 @2007HydroCAD Software Solutions LLC
Type /I 24-hr 100-year (6.10'? Rainfal/=6.10"
Printed 1/29/2009
Page 9
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Runoff
Summary for Subcatchment 1: To Bioretention
24.29 cfs @ 12.02 hrs. Volume=
56,490 cf, Depth= 2.88"
Runoff by ses TR-20 method, UH=SeS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 1 DO-year (6.10") Rainfall=6.10"
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Area (sf)
17,614
19,465
17,950
1,600
178,357
234;986
178,357
56,629
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CN Description
98 Roof
98 Bituminous/Concrete Drive
98 Road
98 Trail
61 >75% Grass cover, Good, HSG B
70 Weighted Average
Pervious Area
Impervious Area
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Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
9.7 205 0.1075 0.35 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
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Runoff
Summary for Subcatchment 2: Direct to Lake
11.83 cfs @ 11.99 hrs, Volume= 25,408 cf, Depth= 2.42"
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Runoff by ses TR-20 method, UH=SCS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 1 DO-year (6.10") Rainfall=6.10"
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Area (sf)
6,235
8,940
110,592
125,767
110,592
15,175
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CN Description
98 Roof
98 Bituminous/Concrete Drive
61 >75% Grass cover. Good, HSG B
65 Weighted Average
Pervious Area
Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 195 0.1850 0.43 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
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Runoff
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Summary for Subcatchment 3: To Wetland
7.66 cfs @ 12.00 hrs, Volume=
16,754 cf, Depth= 3.08"
Runoff by ses TR-20 method, UH=SeS, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Type II 24-hr 1 DO-year (6.10") Rainfall=6.10"
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Area (sf)
7,538
1,650
4,450
8,872
42,869
65,379
51,741
13,638
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eN Description
98 Roof
98 Drive
98 Bituminous
85 Wetland
61 >75% Grass cover, Good, HSG B
72 Weighted Average
Pervious Area
Impervious Area
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Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.3 125 0.0800 0.28 Sheet Flow,
Grass: Short n= 0.150 P2= 2.70"
0.7 130 0.0384 2.94 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
8.0 255 Total
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Inflow Area =
Inflow
Outflow
Primary
Secondary =
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Summary for Pond Bio: Bioretention
234,986 sf, 24.10% Impervious,
24.29 cfs @ 12.02 hrs, Volume=
5.12 cfs @ 12.26 hrs, Volume=
5.00 cfs @ 12.26 hrs, Volume=
0.12 cfs @ 12.26 hrs, Volume=
Inflow Depth = 2.88" for 100-year (6.10") event
56,490 cf
56,490 cf, Allen= 79%, Lag= 14.4 min
42,170 cf
14,320 cf
Routing by Dyn-Stor-Ind method, Time Span= 0.00-150.00 hrs, dt= 0.01 hrs
Peak Elev= 909.04' @ 12.26 hrs Surf.Area= 10,050 sf Storage= 23,801 cf
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Plug-Flow detention time= (not calculated: outflow precedes inflow)
Center-of-Mass del. time= 386.1 min ( 1,223.7 - 837.6 )
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081227 Proposed REV#1
Prepared by Plowe Engineering, Inc.
HvdroCA[)@8.50 sin 001574 @2007 HvdroCAD Software Solutions LLC
Type /I 24-hr 100-year (6. 10'? Rainfal/=6. 10"
Printed 1/29/2009
Page 1 0
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Volume
#1
Invert
906.00'
Avail.StoraQe StoraQe Description
28,547 cf Custom Stage Data (Prismatic) Listed below (Recalc)
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Elevation
(feet)
906.00
908.00
909.00
909.50
Surf. Area
(sq-ft)
5,692
8,450
9,979
10,781
Inc. Store
(cubic-feet)
o
14,142
9,215
5,190
Cum. Store
(cubic-feet)
o
14,142
23,357
28,547
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Device RoutinQ
#1 Secondary
#2 Device 4
#3 Device 4
#4 Primary
Invert
906.00'
907.00'
908.40'
907.00'
Outlet Devices
0.500 in/hr Exfiltration over Surface area
4.0" Vert. Orifice/Grate C= 0.600
4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
15.0" x 201.0' long Culvert Ke= 0.500 Outlet Invert= 906.20' S= 0.0040 'I' Cc= 0.900 n= 0.013
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Primary OutFlow Max=5.00 cfs @ 12.26 hrs HW=909.04' (Free Discharge)
Y=Culvert (Barrel Controls 5.00 cfs @ 4.07 fps)
t2=orifice/Grate (Passes < 0.58 cfs potential flow)
3=Sharp-Crested Rectangular Weir (Passes < 6.55 cfs potential flow)
.t:.condary OutFlow Max=0.12 cfs @ 12.26 hrs HW=909.04' (Free Discharge)
1=Exfiltration (Exfiltration ControlsO.12 cfs)
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