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HomeMy WebLinkAboutTIMBERVINE, SECOND FILING - FDP - FDP150028 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTPage 1 of 2 3760 E. 15th Street, Suite 202 Loveland, CO 80538 Phone: (970) 800-3300 May 19, 2015 Galloway Project No. SPHLV0001.01 RE: Timbervine drainage letter of revision Timbervine has had lot revisions and additions and subtractions, this letter documents the impacts upon the previously approved drainage design. Basins A1, A3, A6, A7, B4, B5, B6, OS1 and OS2 were unaffected by the adjustments to the lot lines. The amount of residential area was unchanged. Basin A2 the residential area changed from 66,782 sqft to 67,170 sqft with an equal reduction in the landscape area. This results in C value adjustments of 0.34 to 0.35 in the minor storm event and no change in the major storm event. Basin A4 the residential area changed from 81,524 sqft to 82,938 sqft with an equal reduction in the landscape area. This results in no C value adjustments in the minor and major storm events. Basin A5 the residential area changed from 27,494 sqft to 29,672 sqft with an equal reduction in the landscape area. This results in C value adjustments of 0.21 to 0.22 in the minor storm event and no change in the major storm event. Basin A8 the Landscape area changed from 29601 sqft to 27,783 sqft with an equal reduction in the Basin area due to the shift in Dunkle. This results in no C value adjustments in the minor or major storm events. Basin A9 and Basin A10 had lots added. The foot prints were shrunk and they encapsulated the same areas having no effect on the C values. Basin B1 the residential area changed from 141,090 sqft to 142,908 sqft with an equal increase in the basin area. This results in no C value adjustments in the minor and major storm events. Basin B2 the residential area changed from 66,973 sqft to 67,169 sqft with an equal reduction in the landscape area. This results in no C value adjustments in the minor and major storm events. Basin B3 the residential area changed from 46,751 sqft to 47,152 sqft with an equal reduction in the landscape area. This results in no C value adjustments in the minor and major storm events. Page 2 of 2 The overall site experienced a change from 593,771 sqft to 600,107 sqft in residential area with an equal reduction in the landscape area. This results in no net change in the percent impervious and in no C value adjustments in the minor and major storm events. Overall the revisions had a negligible impact upon the storm system design and the detention pond sizing and outlets. If you have additional questions or require additional information, please call. Sincerely, Galloway James Prelog, PE Senior Civil Project Engineer