HomeMy WebLinkAboutPARAGON POINT PUD PRELIMINARY - 48 91A - CORRESPONDENCE - STORMWATER-RELATED DOCUMENTS (2)Utility Ser ' -es
Stormwater
City of Fort Collins
MEMORANDUM
DATE: May 24, 1991
TO: Steve Burkett, City Manager
Diane Jones, Deputy City Manager
Steve Roy,. City Attorney
John Duval, Assistant City Attorney
Mike Powers, Director Cultural, Library, Recreation
Services
Tom Peterson, Planning Director
THRU: Rich Shannon, Utilities Director/
FROM: Bob Smith, Stormwater Utility Manager
RE: Trilby and Lemay Property
Along with the recent discussion concerning the role of Southridge
Golf Course, discussions also centered on the developability of the
parcel to the south. This parcel is impacted by the Fossil Creek
floodplain. The attached summary is offered to help clarify this
impact and the possible measures to mitigate that impact.
if you have any questions on the above please don't hesitate to
contact me.
Thank you.
233 )4athews • P.O. Box 580 Fort Collins, CO 80322-0380 • (303) 221-6389
TRILBY ROAD AND LEMAY AVENUE FLOODPLAIN SUMMARY
The large parcel located on the northeast corner of Trilby Road and
Lemay Avenue has been considered for development. This parcel is
adjacent to and south of the Southridge Golf Course and is bounded
on the east by Lemay Avenue and the south by Trilby Road. The
floodplain of Fossil Creek has a substantial impact on .this parcel.
The following is presented as a summary of the floodplain impacts
on the site and the improvements recommended in the Fossil Creek
Master Plan to mitigate this impact. This .is meant to only provide
an overview of the floodplain implications, other areas may impact
the site as well and should be investigated to determine their
magnitude. The attached map is provided to help clarify this
summary.
Existincr conditions
Fossil Creek traverses the parcel in a north to south direction.
The 100 year floodplain of Fossil Creek is confined to the east
bank by rock out croppings immediately adjacent to the creek. The
floodplain is quite extensive west ofthe creek because of the
elevation of the overbank area. At the northern property boundary
the floodplain is necessary for the conveyance of flood flows.
However, the remaining portion of the sites floodplain is required
because of ponding conditions. The Union Pacific Railroad
embankment dc-�n,stream of the parcel restricts flows on Fossil Creek
and creates an impoundment of water upstream of the embankment.
Trilby Road is also inundated because of undersized culverts and
the backwater from the railroad embankment.
Recommended Master Plan Improvements
The Fossil Creek Drainage Basin Master Drainageway Planning Study
analyzed and recommended cost effective measures for the basin to
mitigate the flood flows on Fossil Creek. The basin master plan
recommended a combination of structural improvements and floodplain
failure improvements were recommended. Trilby Road is one of these
road crossings which needs an enlarged culvert crossing and the
embankment raised above the ponding limits. The property will be
expected to participate toward the local portion of the Trilby Road
improvements. Along Fossil Creek drop structures were recommended
to stabilize the gradient of Fossil Creek. Also recommended was
the administration of floodplain regulations where structures were
not threatened. The master plan identified both the existing
floodplain and the future floodplain if the basin were fully
developed. For those properties impacted by the fully developed
floodplain reimbursement would be made for the increased floodplain
limits. This reimbursement would be for right of way needed for
the fully developed floodplain less the existing or historic
floodplain. Actual reimbursement values would be based on actual
land values and the area impacted by the floodplain above historic
conditions.
Property Owner Options
The floodplain limits or boundaries on the attached map show these
floodplains given existing site conditions. These limits can be
altered as long as upstream and downstream properties are not
negatively impacted by any floodplain alteration activity. in this
case, the floodplain can be reduced by balancing the cutting and
filling of areas, although impacts to natural resources should be
addressed before any work is started. This grading work may
reclaim critical areas desired for development and sacrifice those
areas not as critical. In other areas of the City, prime areas in
the floodplain have been removed by filling building sites and
allowing open space or parking areas to remain in the floodplain.
A second option would be for the Developer, wishing to reduce the
ponding floodplain impact, to increase carrying capacity of
downstream obstructions and allow the passage of flows above
historic conditions. Because these improvements would be above
those recommended in the master plan, costs of these improvements
would be the responsibility of the Developer. Because flows are
discharged above historic conditions, specific impacts would need
to be mitigated for the Union Pacific Railroad embankment, lands
between the railroad and County Road 11, the crossing of County
Road 11 and the area adjacent to and including Fossil Creek
Reservoir.
if there are any questions on the above, please feel free to
contact Bob Smith at 221-6589.
a
-,Ctr4444C64