HomeMy WebLinkAboutDrainage Reports - 10/05/2007City of Ft. Collins ppro ed Plans
Approved By�
Date 10 3-0-
September 27, 2007
J•R ENGINEERING
A Westrian Company
Wes Lamarque
City of Fort Collins Stormwater
700 Wood St.
Fort Collins, CO 80521
RE: Sidehill Filing 2 Blk 9, Lots 12-22 Drainage
Dear: Mr. Lamarque,
JR Engineering recently updated the grading on block 9, lots 12-22 at Sidehill Filing 2 to
accommodate a front load garage design instead of the previously approved alley load style. The
new front load garages off of Cocklebur required a new finished grading plan to be developed,
which is included with this letter.
The lots were originally graded as `B Lots" and had a high point on the property line in the
middle of each lot. The new front load lots required the high point to be moved further towards
the alley creating more of an "A Lot" configuration. Lots 20-22 did not change in lot grading
type and remained `B Lots" as they were originally. There are only a total of 8 lots that are
being changed to "A Lots". These changed lots create an area of approximately .46 acres to
drain into Cocklebur and not into the alley.
The changed flows will be decreasing the amount of water flowing onto the private drive alley
and slightly increasing the flow on Cocklebur Drive. In the 2-yr and 100-yr Cocklebur Drive has
extra capacity and the increased flows should not significantly impact the height of flow in the
street. The extra flow will now be going to a different inlet then originally. The original flow
into the alley went to inlet dp-32, which was a flow by inlet. Approximately 2 cfs flowed by the
inlet to the sump inlet located at dp-23 and dp-28 on Kerry Hill Drive. The extra flow in
Cocklebur Drive will now be flowing to these same sump inlets. The inlets had a design
capacity of 38.3 cfs in the 100-yr and only 31.2 cfs actual flow going to the inlet. The extra
capacity provided in these inlets should be able to handle the slightly higher flows created by the
lot changes.
Since the affected flows are not being significantly altered by this grading change and the sump
inlets have extra capacity, JR Engineering feels that this letter can be added to the drainage
report for Sidehill Filing 2 and that no additional calculations need to be performed.
2620 Fast Prospect Road; Suite 190, Fort Collins, CO 80525
970-491-9888 • Fax: 970-491-9984 • wJrengineering.com
We appreciate your time and consideration in reviewing this submittal. If yol
questions or need additional information please call (970) 491-9888.
Prepared by:
Adam Copper, E.I.
Design Engineer II
Reviewed by:
Mike Walker, P.I
Project Lead
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