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HomeMy WebLinkAboutPOUDRE R1 JUNIOR HIGH SCIENCE LAB ADDITIONS SITE PLAN ADVISORY REVIEW - 7 93 - CORRESPONDENCE - STORMWATER-RELATED DOCUMENTS (4)An engineering analysis of the existing storm drainage system in Stover Street showing that sufficient capacity exists to accept the additional runoff must be submitted to support your request for a variance from detention requirements. If the additional undetained runoff can enter the system without adverse impacts, a variance can be granted. Please let me know if you have any questions. Sincerely, Kate Malers Civil Engineer I cc: William O. Brenner T.ed-_Sh`epard Utility Sei .es Stormwater February 3, 1993 Mr. Ron Daggett Project Manager PR-1 School District 2407 LaPorte Ave. Fort Collins, Colorado 80521 Dear Mr. Dagget, This letter is in response to the January 27, 1993 letter from William Brenner of Robb, Brenner and Brelig, Inc. to Ted Shepard of the City Planning Department. That letter gave additional detail on the storm drainage impacts of the planned Science Room addition at Blevins, Boltz, and Lesher Junior High Schools. Blevins Jr. High: I understand that the additional will be built in an area that is presently paved. Therefore there will be no increase in imperviousness and no impact on storm runoff from the site. No additional analysis is necessary. Boltz Jr. High: The January 27 letter indicated that the addition at Boltz Jr. High will increase the impervious area at the site by 1,620 square feet. The letter also references a drywell capable of capturing drainage from roof areas, although I am not clear about whether this drywell is existing or is proposed in conjunction with the addition. It is requested that no detention requirements be imposed at the Boltz site. Regardless of the capacity of any existing or proposed drywell, the location of Boltz Junior High School immediately upstream of the Lemay Detention Pond makes it likely that a variance to detention requirements can be granted at this site. An engineering analysis should show that the peak runoff from the school site will not coincide with the peak inflow to the Lemay Detention Pond (runoff from the school site will be routed through the pond before runoff from upstream portions of the basin reaches the pond). Please submit documentation showing that there will be no adverse downstream impacts to support your request for a variance. Lesher Jr. High: It is my understanding that the entire 3,183 square foot addition at Lesher Junior High School will convert existing grassed area into impervious area. The January 27 letter indicates that runoff from the addition will tie into the existing storm drainage system in Stover Street, as the runoff from the existing roof area does. 235 Mathews Street • P.O. Box 580 • Fort Collins, CO 80522-0580 • (303) 221-6589 • FAX (303) 221-6239