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Home My WebLink AboutHORSETOOTH EAST BUSINESS PARK PUD, 3RD FILING (RITE AID) - FINAL - 43-94G - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTFINAL DRAINAGE ANALYSIS FOR RITE AID - HORSETOQTH AND TIMBERLINE. FORT COLLINS, COLORADO VII. REFERENCES 1. Storm Drainage Design and Technical Criteria, City of Fort Collins, Colorado, latest revision. 2. Urban Storm Drainage Criteria Manual, Denver Regional Council of Governments, Denver, Colorado, March 1969, with current revision. 3. Final Drainage and Erosion control Study for the Carriage Wash P.U.D. Fort Collins. Colorado, by RBD Inc., Engineering Consultants, October 2, 1995. Page 3 I FINAL DRAINAGE ANALYSIS FOR RITE AID - HORSETOOTH AND TIMBERLINE 1 FORT COLLINS, COLORADO An outlet structure in the detention pond is designed as a water quality enhancing feature. Gravel filtering and a riser pipe are included to promote sediment removal. The design also includes controls for the release of the 10-year and 100-year rainfall events. The release from the outlet structure is designed to comply with values taken from the RBD report. Refer to the comparison in the Appendix. V. EROSION CONTROL AND BEST MANAGEMENT PRACTICES Construction Activities Storm Water Quality Control Silt fences will be used along the edges of the site abutting public right-of-way. The fence will be placed behind the back of curb or, in the case of an attached sidewalk, behind the back of walk. Inlet protection, consisting of gravel filters and straw bale barriers will be used for all of the inlets until disturbed areas are paved or landscaping is established. The contractor is required to used vehicle tracking control where vehicles enter and exit the site from public right-of-way. The detention pond and outlet structure will serve as sediment basins during construction. Permanent Stabilization and Storm Water Quality Enhancement Permanent measures used to achieve final stabilization and to control pollutants in storm water discharge after construction operations have been completed include site paving, landscaping, and a "Dry Extended Detention Basin." When complete, all of the site will be either paved or landscaped. Landscaping will be gravel or bark mulch and turf grass. Where possible, runoff will be allowed to pass through the detention pond and other landscaped areas providing "turf filtering" and the opportunity for biological digestion of nutrients. All areas not paved, mulched or sodded will be seeded with an approved seed mix. VI. CONCLUSIONS The drainage improvements for this site are designed in accordance with the Criteria and are in general agreement with the Final Drainage and Erosion Contorl Study for the Carriage Wash PUD by RBD Engineering. I Page 2 I I I I I I I I I I I I I FINAL DRAINAGE ANALYSIS FOR RITE AID - HORSETOOTH AND TIMBERLINE FORT COLLINS, COLORADO I. GENERAL LOCATION AND DESCRIPTION The site is located in the southwest quadrant of the intersection of East Horsetooth and Timberline Roads. It lies in Section 31, Township 7 North, Range 68 West of the 6`h Principal Meridian, City of Fort Collins, Larimer County, Colorado. Refer to the vicinity map on the drainage plan in the back pocket of this report. II. DRAINAGE BASINS AND SUB -BASINS The total drainage basins made up of sub -basins A, B, C, D, and U1 correspond the total area comprised of basins 1, 2, 3, and 13 from the report titled Final Drainage and Erosion control Study for the Carriage Wash P.U.D., by RBD, Inc., Consulting Engineers. The proposed basins drain to a detention pond and pass through a water quality control structure before entering the storm sewer. The outlet structure in the pond is designed to enhance storm water quality and limit the release to levels for the 10-year and 100-year event as calculated in the RBD report. III. DRAINAGE DESIGN CRITERIA This report is done in accordance with the City of Fort Collins Storm Drainage Design and Technical Criteria Manual ("The CRITERIA"), and shall follow the provisions of the Urban Drainage and Flood Control District (The "MANUAL"). Peak runoff for the 10-year and 100-year rainfall events were calculated by the Rational Method using rainfall intensities provided in the CRITERIA. The calculations appear in the Appendix. Refer to the drainage plan in the back pocket. IV. DRAINAGE FACILITY DESIGN 1 Stormwater is conveyed across paved surfaces and along curb and gutter to low points where it is collected in storm inlets and conveyed in storm sewer to the detention pond. Low points in the curb and gutter along the west side of the project release directly into the detention pond. I Page 1 I I FINAL DRAINAGE ANALYSIS FOR RITE AID - HORSETOOTH AND TIMBERLINE FORT COLLINS, COLORADO TABLE OF CONTENTS General Location and Description .................................... 1 Drainage Basins and Sub -Basins .................................... 1 Drainage Design Criteria ........................................... 1 Drainage Facility Design ............................................ 1 Erosion Control and Best Management Practices ........................ 2 Conclusions..................................................... 2 References..................................................... 3 Appendix A - Hydrologic Calculations Appendix B - Hydraulic Calculations Appendix C - Detention Pond Design Appendix D - Detention Pond Outlet Design Appendix G - Reference Materials Back Pocket - Drainage Plan FINAL DRAINAGE ANALYSIS FOR RITE AID - HORSETOOTH AND TIMBERLINE FORT COLLINS, COLORADO May 22, 1998 Prepared for: Grace Enterprises, Inc. 1950 N. Park Place #150 Atlanta, GA 30339 (770) 955-1500 Joel Langsfeld Prepared by: Jeffrey Holley, PE CLC Associates, Inc. 8480 E. Orchard Rd, #2000 Englewood, CO 80111 0 (CLC Job No. 98.012)