HomeMy WebLinkAboutWESTFIELD PARK POOL - PDP - 27-94B - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE RELATED DOCUMENT7
1 � SEAR• BROWN
1
1
Mr. Matt Fater
ARCHITECTURE 2095outh Meldrum
ENGINEERING Fort Colllns�CO 80521
PLANNING 970.482.5922 phone
CONSTRUCTION 970A82.6368 fax
www.searbrown.com
July 31, 2001
City of Fort Collins Utilities
700 Wood Street
tFort Collins, Colorado 80522
RE: Pool of Dreams SWMM analysis
Dear Matt:
We are pleased to submit to you, for your review this SWMM analysis for the proposed "Pool of Dreams"
site. The base SWMM model which was used for this analysis was prepared by Sear -Brown for Regional
Detention Pond 278, McClellands & Mail Creek Basin, Fort Collins, Colorado in October 2000. Included
in the Appendix herein is the changes which were made to basin 180, where the "Pool of Dreams" site is
located. The "Pool of Dreams" site encompasses 1 acre, and has a percent impervious value of 62% (this
includes the pool surface as being impervious). In the current SWMM model the "Pool of Dreams" site is
assumed to be open space. With the "Pool of Dreams" site the % impervious value for basin 180 would
increase from 38% to 39%.
An updated SWMM model with the revised impervious value has been included in the Appendix. None of
the other parameters for basin 180 would change with the development of the pool of dreams site. The
result of adding the pool of dreams site is negligible to the downstream flow values. Any of the flow
values that changed have been highlighted in the summary section of the SWMM model. Most
significantly the "Pool of Dreams" site does not increase the discharge from the downstream pond 278.
Based on the results of this analysis we would like to receive a variance from detention for the "Pool of
Dreams" site. In addition, because the total impervious area for the site is only 0.62 acres the requirements
for water quality volume would be 0.02 ac-ft based on Figure 5-1 from Urban Drainage (included herein).
Because this volume is so small we request a variance from providing water quality also.
Prepared
by:
_Z/l4gA,
Andrea H. Faucett, PE
Senior Water Resource Engineer
I
Preliminary Detention Study for
Westfield Park Pool
(Pool of Dreams)
Fort Collins, Colorado
July 31, 2001
Prepared by:
S
INSEAR•BROWN
Sear -Brown
209 South Meldrum
Fort Collins, CO 80521
(970) 482-5922