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HomeMy WebLinkAboutDRAKE CROSSING, WALGREENS - MAJOR AMENDMENT/FINAL PLAN - 35-96A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTVICINITY MAP NOT TO SCALE APPENDIX A References: 1. Urban Storm Drainage Criteria Manual, Urban Drainage and Flood Control District, March 1986 (with current revisions). 2. Flood Insurance Rate Map, City of Ft. Collins. Larimer County, Colorado, Community Panel No. 080102 0011 C 3. Storm Water Drainage Report, for the Drake Crossing Shopping Center in the City of Ft. Collins, Colorado, March 1982. 4. Storm Drainage Design Criteria and Construction Standards, City of Ft. Collins May 1984. 4 proposed additions to the building, there is 0 landscaping, 0 paved area, and 56,700 S.F. of roof area. This is an increase in impervious area of 6,600 S.F. The increase in impervious area for the Walgreens redevelopment is similar to the increase in the Safeway redevelopment in that portion of the center. (See appendix C for calcs.) IV. CONCLUSION This drainage report describes the drainage as related to the redevelopment of a portion of the Drake Crossing Shopping Center. This redevelopment will remove two strip retail buildings and replace them with one Walgreens building. This redevelopment will surface flow runoff to existing facilities located on the east side of the center, to match the existing site. This redevelopment is similar in nature to the addition that Safeway is doing to the east side of their building. Previous drainage reports have described and defined facilities for the original development of the site. Temporary erosion control measures will include silt fences, hay bail barriers, and a Itemporary gravel construction entrance and will be installed prior to the construction of the redevelopment of this site. Temporary erosion control will be removed with Ithe placement of permanent erosion control measures, which include final landscaping, paving and permanent building. 3 II. EROSION CONTROL MEASURES Throughout construction, many erosion control measures will be taken. A gravel construction entrance will be installed on the North part of the site. A silt fence will encompass the downward sides of the site to filter water draining off the site. Hay bail barriers will be placed in appropriate spots where a silt fence will not work. I11. DRAINAGE FACILITY DESIGN A. Proposed Design All drainage from this site will be sheet flow from the site to the northeast into the drainage tract to match previous drainage paths from the existing development. There are no existing underground storm sewer systems on this portion of the site and n-one are proposed with this redevelopment. Previous reports have addressed runoff and detention for the development of this center. (see references) B. Impervious percentage calculations The redevelopment of this area of the shopping center will increase the impervious area slightly from 60% to 68%. The existing portion of the site included 18,831 S.F. of landscaping, 21,136 S.F. of paved area, and 12,534 S.F. of roof area. The proposed portion of this site includes 14,506 S.F. of landscaping, 23,505 S.F. of paved area, and 14,490 S.F. of roof area. This is an increase in impervious area of 4,325 S.F. of the 52,501 S.F. site. In comparison, the recently approved redevelopment of the main Safeway building had an increase in impervious area for that portion of the site from 80% to 90%. The existing Safeway site had 6,600 S.F. of landscaping, 1,900 S.F. of paved area, and 48,200 S.F. of roof area. After the N I. GENERAL LOCATION AND DESCRIPTION A. Intent and Location Intent: The intent of this report is to provide results of the onsite drainage design that will be constructed on a portion of land in the Drake Crossing Shopping Center to be re -developed as a Walgreens retail building. Location: The project is located in the SE 1/4 of Section 21, Township 7 North, Range 69 West of the 6th P.M. The current project location is in the southern portion of the Drake Crossing Shopping Center directly east of the Bank One drive-thru building. Drake Crossing Shopping Center is located on the NW corner of Drake Road and Taft Hill Road. B. Property Description The existing property consists of two commercial retail buildings with an asphalt pavement parking lot and landscaping. The site currently slopes to the NE at approximately 1.5% towards the center of the shopping center. The redevelopment of the 52501 S.F. site will consist of a Walgreens Drug Store. The site will consist of a building, parking lot and landscaping. Some of the existing trees will remain and be part of the new landscaping plan. Access to the project will be provided from Drake Road and Hampshire Road. C. Floodplain The Canal Importation Master Drainageway Plan has mapped the floodplain in this area (see appendix B). This plan had not been adopted by the City Council as of June 4, 2001. According to the CIMDP the proposed floodplain skirts along the northern edge of the site. As shown on the Flood Insurance Rate Map (FIRM), community panel No. 080102 0011 C bearing a revision date of March .. �1 18, 1996. (see appendix B) 1 Table of Contents I. General Location and Description 1 II. Erosion Control Measures 1 III. Drainage Facility Design 2 IV. Conclusion 3 References 4 Appendices: A. Vicinity Map B. F000dplain information and floodplain vicinity map C. Runoff coefficient and percent impervious tables "I hereby certify that this report for the preliminary drainage design of the proposed Walgreen's at Ft. Collins was prepared under my direct supervision in accordance with the provisions of the City of Ft. Collins "Storm Drainage Design Criteria and Construction Standards". I understand that the City of Ft. Collins does not and will not assume liability for drainage facilities designed by others." (I a� lb -- Dave A. Guetig, P.E. Registered Professional Engineer State of Colorado No. 30020 Galloway, Romero & Associates Design Engineering Planning Final Drainage, Erosion and Sediment Control Report for Walgreens A Portion of the Drake Crossing Shopping Center September 19, 2001 p. GUF., cl" m Utr' O p ;t�O 'nl 30020 ;¢ Prepared for: Edgemark Development Services 410 17th Street, Suite 1705 Denver, CO 8202 (303) 571-0700 Attn: Richard Sapkin Prepared by: Galloway, Romero & Associates 5350 DTC Parkway Englewood, CO 80111 (303)770-8884 (Fax) 770-3636 Attn: Dave A. Guetig, P.E.