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HomeMy WebLinkAboutFOX GROVE ODP - ODP130003 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT1 Overall Drainage Report Date: August 7, 2013 Project: Fox Grove Overall Development Plan Fort Collins, Colorado Attn: Mr. Wes Lamarque Fort Collins Utilities 700 Wood Street Fort Collins, Colorado 80524 Mr. Lamarque: This letter report accompanies the submittal for the Fox Grove Overall Development Plan (ODP). Specifically, this letter report serves to document the overall drainage impacts associated with the proposed Fox Grove Development. The proposed development site is located southeast of the I-25/Mulberry (State Highway 14) interchange in Fort Collins, Colorado. The site is situated along the existing I-25 east frontage road, just south of the existing Interchange Business Park development. The overall Fox Grove site is roughly 36 acres in size. A portion of the site is encroached by the FEMA regulatory Boxelder Creek 100-year Floodplain per FEMA Map Number 08069C1003G, dated May 2, 2012. Accordingly, the site design must satisfy the standards of Chapter 10 of City Code. The proposed development site is in the City of Fort Collins Boxelder Creek Basin. Detention requirements for this basin are to detain the difference between the 100-year developed inflow rate and the historic 2-year release rate. However, if it can be shown by basin modeling that undetained flows from the developed site would result in no increase in peak discharge within Boxelder Creek, the detention requirement would be waived. No modeling has been done at the present, but may be considered as this project progresses. The current submittal does show proposed on-site detention. 2 Previous submittals for the Fox Grove site are briefly described below:  CLOMR Request for Lee MLD, Northern Engineering, September 2007. This CLOMR was submitted to FEMA in 2007 and approved in November 2008. The proposed work shown with the CLOMR included both Lot 1 (west of Boxelder Creek) and Lot 2 (east of Boxelder Creek) of Lee MLD. The CLOMR included proposed grading along the east bank of Boxelder Creek, and proposed revisions to the regulatory floodplain and floodway. Due to land development market conditions at the time of the CLOMR, the project was placed on hold. The project did not move to construction, and no LOMR was submitted for the project. The proposed Fox Grove site will drain into on-site detention ponds which will release into the Boxelder Creek, located just west of the site. We do not currently propose any release to the east. All water quality treatment requirements and LID requirements will be satisfied with the proposed development. Means of providing for these requirements will be worked through at the Preliminary and Final stages of the design process. In summary, this Overall Drainage Report letter adequately addresses any potential stormwater changes associated with the proposed development. In general, there are no significant changes proposed at a major drainage level. The ODP complies with the governing City of Fort Collins Master Drainage Plans, and the previously approved drainage plans specific for the subject property. Please feel free to contact me with any questions you may have. Sincerely NORTHERN ENGINEERING Aaron Cvar, PE Project Engineer