HomeMy WebLinkAboutDrainage Reports - 01/21/2016City offt .,Collins rov Plans
P►PProved BY
Date
January 20, 2016
Wes Lemarque
City of Fort Collins — Stormwater Utility
700 Wood Street
Fort Collins, CO 80522
RE: FMC — Fort Collins - Drainage Letter
JVA Job No. 2456c
Dear Mr. Lemarque:
JVA, Incorporated
25 Old Town Square
Suite 200
Fort Collins, CO 80524
Ph: 970.225.9099
Fax: 970.225.6923
Toll Free: 877.444.1951
Web site:
www.jvajva.com
E-mail:
info@jvajva.com
This letter has been prepared to summarize the proposed drainage design, comparison to the
Timberline Center Master Plan and changes in impervious area associated with the site
improvements for the FMC — Fort Collins Dialysis Center project located at 2107 South Timberline
Road, Fort Collins, Colorado. This letter represents a second addendum to the Timberline Center
Final Drainage and Erosion Control Report, revision date April 12, 2006, prepared by North Star
Design.
Overview
The existing site (Lot 9) is a vacant lot approximately 0.8 acres which is part of the Timberline
Center Subdivision, see Figure 1 for a site location map. In general, all major storm sewer
infrastructure has been installed prior to the development of the subdivision. Site drainage will
connect to existing pipes to direct water to regional detention ponds offsite. Proposed site
improvement include construction of a medical facility (approximately 7,600 square feet), drive
access, and parking lot with a total of 31 stalls. The referenced Final Drainage Report for the project
accounted for the anticipated development of the site and the design of the regional detention ponds
included the required volume to handle runoff from the 10-year and 100-year storm events for the
site's full buildout condition. This letter will serve to supplement the original report and
demonstrate that the development of the FMC — Fort Collins Dialysis Center complies with the
approved stormwater drainage plan designed by North Star Design.
Existing Drainage Design
Based on the referenced Final Drainage Report, the predeveloped site historically drained overland
in three directions. Basin H1 includes the southwest portion of the site. This area flows to a sump
inlet and is conveyed to Regional Detention Pond A, north of the site along Joseph Allen Drive.
Basin H2 includes the center and southeast portion of the site. This basin drains to an existing inlet
and is piped to Regional Detention Pond B. Pond B is located east of Lot 10 along Timberline Road.
Basin H3 includes the northern portion of the site and flows overland into Bear Mountain Drive
which drains to a sump inlet and into Regional Detention Pond B. Figure 2 illustrates the historic
drainage.
Proposed Drainage Design
The drainage characteristics for the development of Lot 9 deviate slightly from the original
Timberline Center drainage report. The site was divided into five sub basins. Sub basin OS 1 directs
flow from the western portion of the site and flow from the southwest quarter of the building to the
existing inlet constructed on Lot 8. This inlet outfalls to Pond A located north along Joseph Allen
Drive. The 100 year flow for this sub basin is 1.07 cubic feet per second (cfs).
BOULDER I FORT COLLINS I WINTER PARK
FMC — Fort Collins
January20, 2016
2of3
Sub basin OS2 includes the existing parking area, half of the access road to the east of the site, and
half of the road along the southern property line. Flow from OS2 is directed to the existing inlet
along the eastern access road and outfall to Pond B. The 100 year flow rate for this sub basin is 1.22
cfs. Sub basin Al includes the other three quarters of the building roof. Flow from the roof will be
directed via gutters and downspouts from the building to an earthen swale along the north side of the
building to a proposed 12 inch area inlet which is piped to Pond B. Flow from the southeastern
quarter of the roof will be directed via downspouts to the proposed storm sewer pipe. The 100 year
flow for sub basin Al is 1.38 cfs. Sub basin B1 includes a portion of the access and drop-off area.
Flow from sub basin B 1 will be directed to a rain garden in the landscape area. The rain garden will
be constructed with an underdrain system that will direct captured flow directed into the proposed
storm sewer pipe. The 100 year flow for sub basin B 1 is 0.82 cfs. Sub basin CI includes the
parking area and permeable pavers. Flow from the asphalt paving will be directed to the permeable
pavers. An underdrain system will be constructed as part of the permeable paver system. Flow
entering the underdrain will enter the proposed storm sewer pipe. The 100 year flow for sub basin
C 1 is 0.99 cfs. Figure 3 in the attachment shows the developed drainage map. Once flow has entered
the storm sewer pipe from sub basins Al, B1, and C1 the storm sewer will connect to the existing
storm sewer pipe along at the existing inlet located on the eastern access road. Although the develop
drainage basins differ from the original report, the proposed flow is ultimately directed to the
designated ponds as specified in the Timberline Center drainage report. Rational calculations are
included in the attachments.
Sub basins Al, Bl, C1, and OS2 make up a portion of sub basin 12 from the original Timberline
Center report. The combined 100 year peak flow for these sub basins A1, B1, C1, and OS2 is 4.42
cfs which is only 17% of the proposed 25.9 cfs for sub basin 12 calculated the Timberline Center
drainage report. Based on the Timberline drainage report sub basin Al was supposed to be part of
the original sub basin 13. Flow from this area was to be directed off site and ultimately flow into
Pond B. Due to site grading restraints this flow is captured but continues to be directed to Pond B.
Sub basin OS 1 is part of sub basin 11 in the Timberline Center drainage report. The 100 year flow
for this basin is 1.07 csf, which is 5.4% of the overall flow for sub basin 11 in the original report.
LID Requirements and Design
Low impact development (LID) has been incorporated into the site design and will treat a portion of
the onsite runoff using a rain garden and pervious pavers. The rain garden was designed using
Urban Drainage Best Management Practice spreadsheet version 3.03. A print out of the spreadsheet
is included in this letter. The 406cf rain garden will treat runoff flow from 5,553 square feet of the
site. Of this area 4,369 square feet is impervious. Flow will be directed into the rain garden by a curb
cut with a rip rap blanket acting as a flow dissipater prior to entering the rain garden.
The required area of pervious pavers was calculated using 25% of the total new impervious
pavement area. This area included both asphalt and concrete pavement. The pervious pavers will
treat a total area of 8,430 square feet which includes the pervious paver area. Utilizing the rain
garden and pervious pavers a total of 51% of the impervious area on the site will be treated. The
LID Compliance Table and Urban Drainage spreadsheets for the rain garden and permeable pavers
are included in the attachment documents.
BOULDER I FORT COLLINS I WINTER PARK
FMC — Fort Collins
January20, 2016
3 of 3
Erosion and Sediment Control
During construction, temporary erosion and sediment control practices will be used to limit soil
erosion and sediment discharge off the site. An erosion and sediment control plan with stormwater
management plan and details will be provided in the utility plans for construction.
Please feel free to contact me to discuss any questions you may have.
Sincerely,
NA, INCORPORATED
By:
Erik T. Nakos, P.E.
Project Manager
ByCIIIIIII,��
Charles R. Hager, P.E.
Vice President
B•y�c9`�o
7146
?0/2016'C_:h*
•••••••••G���\
AaAI
Enclosed: Figure 1 Site Map
Figure 2 Historical Drainage Map
Figure 3 Developed Drainage Map
Rational Calculations
Urban Drainage Permeable Pave Calculations
Urban Drainage Rain Garden Calculations
LID Compliance Table
BOULDER I FORT COLLINS I WINTER PARK
!'` '
f' 7 �gJ
—atr'd aft
itAW
PROJECT
LOCATION �I
'ify
NOT TO SCALE
a
`a
s
a
9
w Z
J
U O
Q
Q �
z
50
O
w
� �
Q
� U
U
2i
O
w }
w _
L
LL
lL
SHUTNC
FIGURE 1
BEAR MOUNTAIN DRIVE
MEDICAL CENTER l
Tt:>
H 1
Q 0.31 0.11 t
H3
O.J1 0.1�
I
LEGEND
A
A
HISTORIC
RUNOFF TABLE
BASIN
DESIGN
AREA
10 YR
100 YR
POINT
(ACRES)
RUNOFF
PEAK
(CFS)
(CFS)
H1
1
0.11
0.09
0.23
H2
2
0.8
0.36
0.91
H3
3
0.19
0.16
0.40
TOTAL
0.80
0.61
1.55
HISTORIC DRAINAGE BASIN BOUNDARY (SUB BASIN)
DIRECTION OF FLOW (HISTORIC)
BASIN DESIGN POINT
DRAINAGE BASIN IDENTIFICATION BUBBLE
A = DEVELOPED BASIN DESIGNATION
.5 = 100-YR RUNOFF COEFFICIENT
1.0 = AREA ACRES
w?
a
J
U OJ
U
w
Q U F-
(� Q
o O
Z
Q
U0
U
Q
ZLLU
w}
Ff
U) �-
O
Lu
U
L
uY<
_
30 0 30 60
SCALE IN FEET
FT'. -
FIGURE 2
—So SD SD 1G,
— - — - — - — - — _ — BEABJM011UM DRIVE —
W W W W W W
— ri
vw W—� W—
w
SDI s
A------
a
-w—w
— s
r-----------
I
I
I
I
RUNOFF TABLE
BASIN
DESIGN
POINT
AREA
(ACRES)
10 YR
RUNOFF
(CFS)
100 YR
PEAK
(CFS)
Al
1
0.16
0.63
1.38
B1
2
0.13
0.38
0.82
C1
3
0.24
0.53
1.16
OS1
4
0.13
0.50
1.07
OS2
5
18
0.56
1.22
TOTAL
E83
2.52
5.49
LEGEND
■ ■ IN I HISTORIC DRAINAGE BASIN
BOUNDARY (SUB BASIN)
fl DIRECTION OF FLOW (HISTORIC)
Al BASIN DESIGN POINT
A DRAINAGE BASIN IDENTIFICATION BUBBL
5 1.0
A = DEVELOPED BASIN DESIGNATION
.5 = 100-YR RUNOFF COEFFICIENT
1.0 = AREA ACRES
-0
30 0 30 60
SCALE IN FEET
_zd _
?sa3
w z a
J Q
U 2
U W
Q
U 0O Z
w
LL
:E 0
U
�2 Lu
— LL W
w } o
U ~ w
W J
La w
LL
FIGURE 31
JVA Incorpanwd
25 Old Town Square
Fart Collins, CO 80524
Ph: 970.225,9099
Fax 970 225.6923
FMC - Fort Collins
Historic Runoff Coefficient & Time of Concentration Calculations
Location: Fort Collins
Minor Design Stonn: 10
Major Design Storm: 100
Soil Type. CID
Job Name: FMC - Fort Collins
Job Number'. 2456c
Date, 10/19115
By: DSF
1%
C2
C5
C70
C700
Streets Paved
100%
0.95
0.00
0,95
1,00
Concrete DrlveslWalks
90%
0.95
0.00
0.95
1,00
Roof
90%
0.95
0,00
0.95
1.00
Gravel
40%
0,50
0.00
0,50
0.63
Landscaping IS sell)
0%
0,15
0.00
0.15
0,19
Landscaping (CID sail)
0Y.
0.25
0.00
0.25
0.31
Playground
10%
0.11
0,00
0.11
0.14
ArdOcial Turn
25%
0.20
0,00
0.20
0.25
Basin Des l
n Data
I (%) =
100 %
90%
90%
40%
10 %
25%
U%
0%.
11%)
Runoff CoeRs
Initial Overland Time I%)
Travel Time IQ 4=Lenglh/(Veladly x
1, Comp
tc Urbanlznd Check
I,60)OFF
Final
Basin
Design
Am..v
A,mrc
A„a
Axvx
Ay19,a
Am. wr
Avroan
A,A.w.'W
ATulal
ATaa
Imp
Un'pvr
i osl
Sara
t
Length
Slops
Velocity
4
Time of
Tow
t�-(Ulllfj
Name
Point
•I"'I'
°"`
(sf)
(sf)
(so
(at)
.wl
.a1
(SO
(ac)
M)
C2
CS
C70
C100
L."If,
(%i
(min)
Mir
I%l
Type of Land Surface
C,
(cps)
(min)
04nc4
L
101min.)
Min
ls0
(af)
(so
(sf)
do
t
(��
Al
1
4,619
4.619
0.lt
0.0%
0.25
0.00
0.25
0,31
54
1.5%
12.9
Tillage/leld
5
too
08
129
54
NIA
12.9
H2
2
21.962
21,962
0.50
0.0%
0.25
0.00
0.25
0,31
1362
2.0%
18.7
Short Pasture and
7
0.0
0.0
18.7
136.2
NIA
187
awns
H3
3
8,321
8,321
0.19
0.0%
0.25
0:00
0.25
0.31
47 5
1.0%
13.9
Short Pasture and
7
0.0
0.0
139
47.5
N/A
13.9
awns
0
0.00
Paved areas 8 shallow
20
0
NIA
10
Paved swalea
0
0.00
Paved areas 8 shallow
20
0
1 N/A
aved swat
TOTAL SITE
0
0
0
0
0
34,901
34,901
080
0.0%
0.25
0.00
0.25
0.31
Coeffs
Rainfall Intensities
Inlhr
Area
Flow Rates
cfs)
Basin
Name
Design
Point
Time o
Conic
(tc)Hi
S
C10
5
10
100
ATwx
(so(ac)02OS010
ATaa
0100
1
12.900
JRunoff
0.25
0.00
340
6,94
4.619
0.11
0.06
0.00
0.09
0,23
H2
2
18.700
0,25
JT311.67
0.00
2.84
5.80
21,962
0.50
0.21
0.00
0.36
0.91
H3
3
13200
0.25
0.00
3.30
673
8,321
0.19
(L09
0.00
0.16
040
0
a
0
0.00
0
0
0
0.00
TOTAL SITE
34,901
Oil)
10.35
0.00
0.61
1.55
2456c - Rational Galas. xlsx Historic Page 1 of 5
JVA Incorporated
25 Old Town Square
Fort Collins, CO 80524
Ph: 970.225A099
Fax: 970.225.6923
FMC - Fort Collins
Composite Runoff Coefficient Calculations
Location: Fort Collins
Minor Design Storm: 10
Major Design Storm 1 100
Soil Type: I CID
Job Name:
FMC - Fort Collins
1%
C2
C5
C10
C100
Jab Number:
2456c
spears Paved
100%
0.95
a.0a
0.95
1.00
Dale:
10/19/15
Concrete OdvesMalks
90%
(.95
0.00
0.95
1,00
By:
DSF
Roof
90%
0.95
0.00
0.95
1,00
Gravel
40%
0.50
0.00
0.50
0.63
Landscaping a soil)
0%
0.15
0.00
0.15
0,19
Landscaping (CID soip
0%
0,25
0.00
025
0.31
Playground
10%
0,11
0.00
(.11
0.14
Artificial Turf
25%
0,20
0.00
0.20
0,25
Basin Desi n Data
I(%)=
1J0 ..
_..
990N
40%
11)%
25%
01„
0%
1(%)
Runoff CoefPs
Basin
Name
Design
Point
Apaved
sneers
(sf)
Adnvesic
ana (si)
^root
(sf)
e
Agravel
(sf)
p
• plygnd
(sO
Aan turl
(sf)
m
ApereaNe
Pavers
(SO
Ascape
(CIO soil)
(so
ATotal
(5f)
ATotal
(ac)
Imp
(%)
C2
C5
C10
C100
A l
1
5.577
1.186
7,062
0.16
71.1 %
0.80
0.00
0.80
0.86
61
2
2.678
1,692
1,183
5,553
0.13
75.6%
0.80
0.00
0.80
0.85
Cl
3
4,901
788
1.556
1,033
10,278
0.24
54.6%
0.60
0.00
0.60
0.65
OS1
4
1,705
1,264
1,913
822
5,704
0.13
80-0%
0.85
0.00
0.85
0.90
OS2
5
4.763
1.556
1.360
7,678
0.18
80.3%
0.83
0.00
0.83
0.88
0
0.00
0
0.00
0
0.00
TOTAL SITE
14.047
5,300
7,490
0
0
0
3,556
5.883
36,275
0,83
70.5%
0.76 1
0.00 1
0.76
0.81
2456c - Rational Calcs.xlsx Developed C Page 2 of 5
JVA Incorporated
25 Old Town Square
Fort Collins, CO 80524
Ph: 970.225.9099
Fax: 970.225.6923
FMC - Fort Collins
Time of Concentration Calculations
Location Fort Collins
Minor Design Storm:P110,1-1
Major Design Stonn:Soil Type-
Job Name: FMC - Fort Collins
Job Number. 2456c
Date: 10/19/15
By: DSF
Sub -basin Data
Initial Overland Time (t)
Travel Time (4)
tc Comp
tc Urbanized Check
I.
4=length/(Velocity x 60)
ON
Final
Upper
Time of
Total
Basin
Design
AT dy
most
Slope
4
Length
Velocity
y
4
k=(IJ180)*
Name
Point
(ac)
CB
Lencm"Ln
(min)
(rt)
Slope (%)
Type of Land Surface
C'
(fps)
(min)
Conic
Length
10 (min)
Min
Al
1
0.16
0.00
t u J%
2.5
90.t
2,0%
Paved areas & shallow
20
2.8
0.5
3.0
97.6
10.5
5.0
paved swales
B1
2
0.13
0.00
50.4
2.0%
11.4
44.6
2,0 %
Paved areas & shallow
20
2.8
0.3
11.6
95
10.5
10.5
paved swales
CI
3
0.24
0.00
54.5
2.5%
11.0
30.1
2.0%
Paved areas & shallow
20
2.8
0.2
11.1
94.6
10.5
10.5
paved swales
OSi
4
0.13
0.00
19
2.8%
6.2
173
1.0 %
Paved areas 8 shallow
20
2.0
0.1
6.4
36.3
10.2
6.4
aved swales
OS2
5
0.18
0.00
283
2 0%
8.5
161 5
2.0 %
Paved areas 8 shallow
20
2.8
1.0
9.5
189.8
11.1
9.5
avetl swales
0
D
O.IHI
Paved areas 8 shallow
20
D
10.0
pavedswales
0
0
0.00
Paved areas & shallow
20
0
10.0
paved swales
D
D
0.00
Paved areas & shallow
20
D
10.0
aved swales
2456c - Rational Calcs.xlsx Developed Tc Page 3 of 5
JVA Incorporated
25 Old Town Square
Job Name:
Job Number:
FMC - Fort Collins
2456c
•�.,"„`"' Fort Collins. CO B0524
Date:
10/19/15
Ph: 970,225,9099
By:
DSF
Fax: 970.225.6923
FMC - Fort Collins
Developed Storm Runoff Calculations
Design Storm : 100 Year
Point Hour Rainfall (P,)
2.81
-_-�®�m®_____
--______
--______
____-_-__----___
_-
_________-
2456c - Rational Calcs.xlsx Q100 Page 4 of 5
� � JVA Incorporated
25 Old Town Square
Job Name:
Job Number:
FMC - Fort Collins
2456c
`11111N`,
Fort Collins, CO 0524
Ph: 970.225.9 99
Date:
By:
9/15
DSF
Fax: 970.225.6923
FMC - Fort Collins
Developed Storm Runoff Calculations
Design Storm : 10 Year
Point Hour Rainfall (P,) :
1.75
2456c - Rational Calcs.xlsx O Minor
Page 5 of 5
Design Procedure Form: Permeable Pavement Systems (PPS)
Sheet 1 of 2
Designer: DSF
Company:
JVA, Inc.
Dale:
October 19, 2015
Project:
2456c FMC - Fort Collins
Location:
Bear Mountain Drive, Fort Collins
Choose One
1. Type of Permeable Pavement Section
Q No tnflltration
A) What type of section of permeable pavement is used?
® Partial Infiltration Section
(Based on the land use and activities, proximity to adjacent
O Full Infiltration Section
structures and soil characteristics.)
B) What type of wearing course?
Choose One
® PICP
O Concrete God Pavement
Q Pervious Concrete
O Porous Gravel
2. Required Storage Volume
A) Effective Imperviousness of Area Tributary to Permeable Pavement, I,
I, = 65.1 %
B) Tributary Area's Imperviousness Ratio (I = I,) 100)
1 = 0.661
C) Tributary Watershed Area
Aral = 8,892 sq ft
(including area of permeable pavement system)
D) Area of Permeable Pavement System
Avvs = 5,602 sq ft
(Minimum recommended permeable pavement area = 2184 sq ft)
E) Impervious Tributary Ratio
Rr= 0.4
(Contributing Imperviuos Area / Permeable Pavement Ratio)
F) Water Quality Capture Volume (WQCV) Based on 12-hour Drain Time
WQCV = 151 cu R
(WQCV=(0.8'(0.91'ia-1.19'io 0,78' i)/12)' Area)
Choose One
G) Is good control volume being added?
Q YES
NO
3. Depth of Reservoir
A) Minimum Depth of Reservoir
D.,, = a.0 inches
(Minimum recommended deplh is 6 inches)
Qioose One
B) is the slope of the reservoir/subgmde interface equal to 0%?
® YFS Fla[ or Stepped instillation
Q N6 Sloped Instillation
C) Porosity (Porous Gravel Pavement < 0.3, Others < 0 40)
P = 0.30
F) Volume Provided Based on Depth of Base Course
V = no cu R
Flat or Stepped: V = P • ((D„m,)/12)' Area
Sloped: V = P - i(Q,,,,- (O,a„- 6-SL-1)) / 121 Area
4 Lateral Flow Barriers
Otoase One
A) Type of Lateral Flow Banners
Q Concrete Walls
O PVC geomembrane installed normal to Flow
® N/A- Flat inatallation
O Other(Descobe):
B) Number of Permeable Pavement Calls
Celle e
5. Perimeter Banner
Chaise One -
A) Is a perimeter barren provided on all sides of the
O YES
pavement system?
106NO
(Recommeded for PICP, concrete grid pavement, or for any
no -infiltration section )
do-BMP v3.03.xism, PPS 10119/2015, 4:17 PM
Design Procedure Form: Permeable Pavement Systems (PPS)
Sheaf 2 of 2
Designer: DSF
Company: JVA, Inc.
Data: October 19. 2015
Protect: 2456c FMC - Fort Collins
Location. Bear Mountain Drive, Fort Collins
Fdler Material and Underdmin System
A) Is the underdrain placed below a Cinch thick layer o!
COOT Class C fitter material?
oseOne
1) ES Y
YES
ONO
��
O N/A
B) Diameter of Slatted Pipe (slat dimensions per Table PPs-2)
Choose One -
0 4-Inch
O 6-inch
C) Distance from the Lowest Elevation of the Storage Volume
y = 1.3 ft
(i.e. the bottom of the base course to me center of the odfice)
r Choc a One -
I Q YES
® NO
Choose One
O Raced above me liner
O Raced above and below the liner
8 Outlet
(Assumes each cell has similar area, subgrade slope, and length
between lateral barriers (unless subgrade is flat) Calculate cells
individually where this vanes.I
A) Depth of WOCV in the Reservoir
Dwucv = 1.08 inches
(Elevation of the Flood Control Outlet)
B) Diameter of Orifice for 12-hour Drain Time
De,lsr, = inches
(Use a minimum chl diameter of 3/8-Inches)
Notes
UD-BMP v3.03.xlsm, PPS 10/19/2015, 4:17 PM
Design Procedure Form: Rain Garden (RG)
Sheet 1 of 2
Designer: OSF
Company:
JVA, Inc.
Date:
October 19, 2015
Project:
2456c FMC - Fort Collins
Location:
Bear Mountain Drive, Fort Collins
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area. I,
I, =
71.0
%
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = 1.1100)
i =
0.710
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time
WQCV =
0.22
watershed inches
(WQCV= 0.8' (0.91• i3- 1.19' it+ 0.78, i)
D) Contributing Watershed Area (including rain garden area)
Area =
5,553
sq ft
E) Water Quality Capture Volume (WQCV) Design Volume
VwoU =
cu It
Vol = (WQCV / 12)' Area
F) For Watersheds Outside of the Denver Region, Depth of
ds =
0.43
in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region,
VW0V0n1rR =
103.5
cu it
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume
VwacvuseR =
cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)
Dwocv =
12
in
B) Rain Garden Side Slopes (Z = 4 min., honz. dist per unit vertical)
Z =
0.00
1t / ft
(Use "0" N rain garden has vertical walls)
C) Mimimum Flat Surface Area
AM,., =
69
sq it
D) Actual Flat Surface Area
A,,,x„ y =
259
sq it
E) Area at Design Depth (Top Surface Area)
AT,,,, =
552
sq it
F) Rain Garden Total Volume
VT=
406
cu it
(Vr ((Arm+ Ate) 12) * Depth)
3. Growing Media
r Choose One
Q 18" Rain Garden Growing Media
Q Other (Explain):
4. Underdrain System
Choose One
I* YES
A) Are underdrains provided?
Q NO
B) Underdrain system once diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage
y=
1.8
it
Volume to the Center of the Once
ii) Volume to Drain in 12 Hours
Vol,z=
104
cu ft
III) Orifice Diameter. 3/8" Minimum
Do =
0.24
in MINIMUM DIAMETER = 3!8"
UD-BMP_v3.03.xlsm, RG 1011912015, 4:11 PM
Design Procedure Form: Rain Garden (RG)
Sheet 2 of 2
Designer: DSF
Company: JVA, Inc.
Date: October 19, 2015
Project: 2456c FMC - Fort Collins
Location: Bear Mountain Drive, Fort Collins
5, Impermeable Geomembrane Liner and Geotextile Separator Fabric
Choose One -
p YES
A) Is an impermeable liner provided due to proximity
ONO
of structures or groundwater contamination?
6. Inlet / Outlet Control
r Choose One
Q Sheet Flow- No Energy Dissipation Required
A) Inlet Control
Concentrated Flow- Energy Dissipation Provided
Choose One
7. Vegetation
p Seed (Plan for frequent weed control)
QQ Plantings
Q Sand Grown or Other High Inftuatlon Sod
6. Irrigation
r Choose One -
Q YES NO SPRINKLER HEADS ON FLAT SURFACE
A) Will the rain garden be irrigated?
Q NO
Notes:
UD-BMP v3.03.xlsm, RG 10119/2015, 4:11 PM
LID COMPLIANCE TABLE
50% On -Site Treatment by LID Requirement
New Impervious Area 0.574 acre
Paver Area 0.082 acre
Traditional Asphalt Pavement Area 0.195 acre
Other Impervious Surface Area (Roofs, Concrete Walks, etc.) 0.298 acre
Required Minimum Impervious Area to be Treated 0.287 acre
Paver LID Treatment (Flow Area to LID)
Paver Area 0.194 acre
Rain Garden Treatment
Rain Garden Area 260 ft2
Roof Area 0.000
Run-on area for Rain Garden 0.127 acre
Impervious Area Treated by Rain Gardens 0.100 acre
Total Impervious Area Treated 0.295 acre
Percent of Impervious Area Treated 51%
25% Permeable Pavement Requirement
New Pavement Area (Paver Area Not Included)* 14,004 ft2
Required Minimum Area of Permeable Pavement 3,501 ft2
Total Permeable Pavement Area 3,556 ft2
Actual Percent of Permeable Pavement Provided 25%
*The pavement area includes concrete and asphalt.