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<br />6 | Page <br />CWCB Feasibility Study – County Road 52 Improvements & Grading <br /> <br />Purpose <br /> <br />The purpose of this Loan Application and Feasibility Study is to seek funding for a third loan for <br />Improvements under County Road 52 associated with the two original regional improvement projects. <br />The need for these improvements came from Larimer County’s (County) concerns about roadway <br />overtopping on County Road 52 immediately adjacent to the East Side Detention Facility (ESDF). ESDF <br />is one of the original regional improvement projects approved for a loan in May 2013. ESDF is a large <br />stormwater detention facility (1700 ac-ft.) to be constructed adjacent to the Gray Lakes Reservoirs <br />(existing irrigation storage reservoirs owned and operated by the Lake Canal Reservoir Company). ESDF <br />is located on the east side of Interstate 25 across from the Budweiser Brewery, between County Road 50 <br />and County Road 52 (see Exhibit C). <br /> <br />This third project as proposed will be completed in tandem with ESDF and will reduce the overtopping of <br />County Road 52 by installing four 4X20 box culverts under the roadway, removing trees along the north <br />side of the roadway and grading an area within the adjacent golf course north of County Road 52. <br />Clearing the trees from the proposed culvert openings and regrading a portion of the golf course fairway <br />will increase the hydraulic capacity of these culverts. This increased capacity will allow the overtopping <br />of County Road 52 in a 100-year event to be reduced to a level that addresses the concerns of the County. <br />By addressing these concerns the County has agreed to approve the IGA Amendment needed to approve <br />the original CWCB loans for ESDF and the other regional improvement project (Larimer Weld Canal <br />Crossing Structure (LWCCS). <br /> <br />These three projects will reduce the threat of flooding to homes and businesses downstream and remove <br />large areas from the FEMA mapped floodplain of Boxelder Creek. Kevin Houck, Chief of Watershed and <br />Flood Protection for the CWCB recently restated that, “The Boxelder watershed remains on the Top 10 <br />list of high risk watersheds for the State of Colorado, due primarily to its enormous size of 265 square <br />miles.” <br />Coordination with Other Projects <br /> <br />It should be noted that as this project, along with ESDF and LWCCS, moves forward into final design <br />and construction, the City of Fort Collins and the Town of Timnath have parallel plans to move forward <br />with two projects which will further reduce floodplain boundaries downstream. The construction of <br />ESDF reduces the downstream flows in Boxelder Creek drastically from over 7000cfs to less than <br />2400cfs. This flow reduction has allowed the City of Fort Collins and the Town of Timnath to consider <br />“unplugging” two large box culverts at the crossing of I-25 and Boxelder Creek. Two of the four box <br />culverts originally constructed at this location have been plugged since they were first built. When <br />FEMA revised the floodplain mapping in this area, the resulting overflow from this blockage extended the <br />floodplain south along the east side of I-25 flooding large sections of Timnath. Opening of the two box <br />culverts will eliminate this overflow path. Projected flows on the west side of I-25 will be less than the <br />current flood flow projections under existing conditions. This will allow the City of Fort Collins and <br />Timnath to move forward with constructing conveyance improvements on west Prospect Road where <br />Boxelder Creek flows under the roadway. The design of the Prospect Road improvements scheduled to <br />coincide with the design of ESDF and LWCCS. Exhibit D depicts the existing and post-project flood <br />flows in Boxelder Creek for comparison at critical locations. The Authority, the City of Fort Collins and <br />the Town of Timnath are planning on joint submittals of the Conditional Letter of Map Revision