HomeMy WebLinkAboutDrainage Reports - 09/21/2017 (2)NORTHERN
ENGINEERING
Drainage Memo
Date: September 21, 2017
Project: Stadium Apartments Project No. 1232-001
Fort Collins, Colorado
Attn: Mrs. Heather McDowell City of Fort Collins Approved Plans
Fort Collins Water Utilities Engineering Approved by: P�J��v1GW
700 Wood Street
Fort Collins, Colorado 80521 Date:--L-)--/- / 7
Purpose
This letter serves to document the design revision made to Stadium Apartments. The revisions
included a redesign of detention Pond B and the revised storm outfall and water quality of basin Al.
Below is a detailed description of the items revised from the original drainage report. Also, attached
to this memo are supporting calculations.
Design Modifications
Detention Pond B has been reconfigured to avoid being constructed above the revised sanitary
sewer main running through the site. The proposed chambers designed above the revised sanitary
sewer line have been relocated and dispersed into the chambers located south and west of the
building. Calculations showing the storage provided with both sets of chambers has been provided
and is attached to this memo.
Storm Line A2 was redesigned to daylight directly into the bio-media through a perforated pipe.
Flows above the water quality event will surcharge the grated inlet located in the bio-swale and flow
as previously designed.
Conclusion
In concluding, the revision to the design of Stadium Apartments will not deviate from the orginial
design. All previous requirements and standards are being upheld and the overall site will function
as originally intended.
If you should have any questions as you review this report, please feel free to contact us.
Northern Engineering Services Inc.
Cody Snowdon, PE
Project Manager
FORT COLLINS: 301 North Howes Street, Suite 100, 80521 J 970.221.4158
GREELEY: 820 8'' Street, 80631 1 970.395.9880 1 WEB: www.northernengineering.com
8/15/2017
ADS Design Tool Site
User Inputs
Chamber Model
SC-740
Outlet Control Structure
Yes (Outlet)
Project Name
Stadium Apartments
Engineer
C.Snowdon
Project Location
Pond B
Project Date
04/03/2017
Measurement Type
Imperial
Required Storage Volume
10,787 cubic ft.
Stone Porosity
40%
Stone Foundation Depth
6 in.
Stone Above Chambers
6 in.
Average Cover Over Chambers
18 in.
Design Constraint
Width
Design Constraint Dimension
34 ft.
stol A I leul t
fl.
Results
System Volume and Bed Size
Installed Storage Volume
10788 cubic ft.
Storage Volume Per Chamber
74.90 cubic ft.
Number Of Chambers Required
133 each
Number Of End Caps Required
12 each
Rows/Chambers
1 row(s) of 23
chamber(s)
Leftover Rows/Chambers
5 row(s) of 22
chamber(s)
Maximum Length
171.18 ft.
Maximum Width
30.60 ft.
Approx. Bed Size Required
5086 square ft.
System Components
Amount Of Stone Required
433 cubic yards
Volume Of Excavation (Not Including
659 cubic yards
Fill)
Non -woven Filter Fabric Required
1284 square yards
Length Of Isolator Row
165.29 ft.
Non -Woven Isolator Row Fabric
146 square yards
Woven Isolator Row Fabric
182 square yards
TPAVEMENT LAYER (DESIGNED
BY SITE DESIGN ENGINEER)
51"(1295MM,
(150mm)MIN
18" I1) (2.4 m)
(450 mm)MIN MAX
5D mm) MIN
30-
(760 mm)
ZDEPTH OF STONE TO BE DETERMINED
BY DESIGN ENGINEER 6' (150 mm) MIN
�. 12" (300 mm) TYP
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User Inputs
Results
Chamber Model
SC-310
Outlet Control Structure
Yes (Outlet)
System Volume and Bed Size
Project Name
Stadium Apartments
Installed Storage Volume
1162 cubic ft.
Engineer
C.Snowdon
Storage Volume Per Chamber
31.00 cubic ft.
Project Location
Pond B3-B4
Number IN Chambers Required
30 each
Project Date
04/0312017
Number IN End Caps Required
6 each
Measurement Type
Imperial
Rows/Chambers
2 row(s) Of 12
Required Storage Volume
1,159 cubicft.
chamber(s)
Stone Porosity
40%
Leftover Rows/Chambers
1 row(s) of 6 chamber(s)
Stone Foundation Depth
6 in.
Maximum Length
92.07 ft.
Stone Above Chambers
6 in.
Maximum Width
12.10 ft.
Average Cover Over Chambers
18 in.
Approx. Bed Size Required
960 square ft.
Design Constraint
Length
Design Constraint Dimension
95 ft.
System Components
Amount Of Stone Required
67 cubic yards
Volume Of Excavation (Not Including
83 cubic yards
Fill)
Non -woven Filter Fabric Required
266 square yards
Length Of Isolator Row
86.60 ft.
Non -Woven Isolator Row Fabric
47 square yards
Woven Isolator Row Fabric
38 square yards
(150 mm)MIN
34" (865 mm)
PAVEMENT LAYER (DESIGNED
BY SITE DESIGN ENGINEER)
6. (150 mm) 8'
MIN 1
M (24
(450 mm)MINhI MAX
fie^ i
(405 mm)
DEPTH OF STONE TO BE DETERMINED
BY DESIGN ENGINEER 6" (150 mm) MIN
12' (300 mm) TYP
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