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Home My WebLink AboutBOSTON CHICKEN PUD MAJOR AMENDMENT - 79 93B - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT1 DETENTION POND HIGH WATER LINE VOL. = 1/3 (AREA ABOVE) (DIFFERENCE IN COUNTOUR ELEV.) 2. FOR THE REMAIMDER OF THE VOLUMES BETWEEN CONTOURS (SECTION 9.2) VOL. = DEPTH/3 (A +(AB) ^ .5 + B)' FOR: Uniform Sides sec.(9.2) 3. HWL= (VOL.REO. —VOL.LOW CUML)*3/(AREA LOW+AREA HIGH +(low area*high area) ^ .5) 58 17 HWL POND' I I I I Boston Chicken Site Page 2 Existing runoff on Lemay Avenue will not be routed through this site. This runoff now flows north to a curb inlet at Riverside Avenue. To compensate for this undetained runoff, this project will detain onsite runoff from 0.7 acres of the existing offsite runoff from the south. This runoff now flows onsite into a low area and remains there as a retention pond. Runoff from this site and the offsite will be restricted to the two—year historic rate based on the site area of 2.7 acres. .Emergency overflow from the pond will be to Lemay Avenue. The capacity than 133% of the required capacity. EROSION CONTROL: will be.at elevation 58.50 feet. Overflow of the pond to elevation 58.50 is more The construction sequence for both phases will be to first do the rough grading of the site, including the construction of the detention pond. The foundations for the proposed buildings will then be constructed. The drainage pipes and water and sewer services will then be constructed. The curbs and paving will then be constructed, and the last phase will be landscaping. Erosion control will be A silt fence will be placed prevailing northwest wind. provided at the time the rough grading is started. along the east property line to mitigate the The outlet pipe from the detention pond will have a straw bale filter placed as soon as will also have straw bale filters as inlets in place. Gravel filters will paving is in place. The _filters will is completed. `,'Franklin ,'Franklin D. Blake, P.E. & L. S. enclosures m 7339 C� �v,¢9T•s a!'�M�ER &i 1L+F OF COO it is constructed. The two area inlets soon as the storm pipes are laid and the be placed at the area inlets after the remain in place until the landscaping PRELIMINARY DRAINAGE AND EROSION CONTROL REPORT FOR BOSTON CHICKEN LEMAY AND PENNOCK P.U.D. EXISTING SITE: This proposed site is located in the Northwest '—, of Section 18, Township 7 North, Range 68 West of the Sixth P.M., Fort Collins, Larimer County, Colorado. The site is bounded on the west by South Lemay Avenue, on the north by the Lemay Animal Clinic and the Robinson Press building, on the east by medical office buildings, and on the south by a medical office building and by a restaurant (Godfathers Pizza). The net site area is 2.0 acres. The gross site area which includes the East z of South Lemay Avenue is 2.4 acres. The proposed site was the location of the old Fort Collins sales barn, a railroad spur, two houses, a garage and a barn. The architectural survey of this site completed in 1971 is included as Exhibit "A" with this report. All structures were removed from this site before 1984. See Exhibit "B" which is part of the City aerial photograph taken in 1984. The proposed site slopes northeast at a slope of 1.6 percent. The site is covered with grass and weeds. Runoff from Lemay Avenue flows to the north. - There is no offsite runoff from the west, north or east. Undetained runoff from the existing restaurant and a small portion of the medical office building south of this site crosses over the proposed site. The area of this offsite flow is 0.7 acres. See the crosshatched area on Exhibit "B". DRAINAGE CRITERIA: Due to the small basin size, the Rational Method has been used to determine peak runoff rates and required detention pond volumes. Design factors used are in accordance with the recommendations and criteria of the City of Fort Collins Storm Drainage Design Criteria and Construction Standards Manual. This site is in the Poudre River Drainage Basin. This basin, by City of Fort Collins classification, is in the "Old Town" basin. DEVELOPED SITE: The site will be developed into two commercial building sites with parking, access roads and landscaping areas. A detention pond/wetland and also a picnic area will be developed on the north end of the site. The design concept is to detain the 100—year developed runoff onsite in a pond on the north side of the site and release at the historic release rate into the existing storm drain system on the west side of Lemay Avenue constructed with the Riverside Shopping Center. All runoff is to the Poudre River. Additional detention will be constructed on the east side of the parking areas of both lots. Both detention ponds will function as one with the release control at the headwall to the proposed 15" RCP that crosses Lemay Avenue. VICINITY MAP il i DRAINAGE AND EROSION CONTROL REPORT FOR BOSTON CHICKEN AT LEMAY AND PENNOCK P.U.D. PREPARED FOR ZTI GROUP II MARCH 14, 1994 I STEWART & ASSOCIATES, INC. 103 SOUTH MELDRUM STREET FORT COLLINS, COLORADO 80521 303/482-9331 11, UM STE VART&ALSSOCIATES PH 482-933D1RFAX 482-938C 20LLINS, CO 80521 / Consulting Engineers and Surveyors Rv- �Iae- Date: Client: /'!/% GrJ45 Sheet No. 7 of Project: Subject: 4:;:y9G f = /// 5 eG Yt456T 3 FOP. VOLvMES STEWART&ASSOCIATES 110i3 �S. ME9331 LDRUM,FAX FORT COLLINS, CO 80521 Consulting Engineers and Surveyors �^ / By: -✓0V1 Date: Client:�iD�i i9��G �ST /y�C='S Sheet No. _ of _ Project;,.-Z� ,u/2314 ztOw �f�ir! Subject: STEWART&ASSOCIATES Consulting Engineers and Surveyors October 7, 1997 Mr. Basil Hamdan Storm Water Utility City of Fort Collins P.O. Box 580 Fort Collins, CO 80522 Dear Basil, This is regarding the stormwater runoff for Lot 1, Boston Chicken At Lemay And Pennock, P.U.D. The existing restaurant building at 900 South Lemay Avenue is being remodeled as a bank building for Safeway Credit Union. A future expansion of the building to the East is planned and four drive -up lanes are also planned. The new site plan will have 1,056 square feet of pervious area changed to impervious area and 850 square feet of impervious area changed to pervious area, resulting in a total increase of impervious area of 224 square feet. Part of the detention area in the parking lot will be regraded for the four drive -up lanes which will reduce the volume of the existing detention pond by 1,690 cubic feet. The required detention volume is 17,445 cubic feet and the revised volume provided is 23,359 cubic feet. The existing detention pond in the open space North of the building will not be revised. The existing storm drain pipes will not be altered by this change in use. There will be disturbance of the existing surfacing where the future addition will be constructed and where the drive -up lanes will be constructed. A gravel filter will be constructed around the North inlet of the parking lot detention area during construction and a straw bale dike will be constructed at the outlet of the open space detention pond to control erosion. A copy of the approved drainage plan and report are enclosed with the revised report, and revised grading and drainage plan. A part of the existing drainage easement over the East 80.00 feet of Lot 1 is being requested to be vacated in order to allow the construction of the drive -up facility. This drainage report and the re -design of the drainage system are in compliance with City of Fort Collins Storm Drainage specifications and criteria. If you have questions regarding this revised report, please call. % X%I N ��a�, Sincerely, .�i°� , .ots,reb• 5028 Richard A. Rutherford, P.E. & L.S. °t�D rrc James H. Stewart and Associates, Inc. 103 S. Meldrum Street P.O. Box 429 Ft. Collins, CO 80522 970/482-9331 Fax 970/482-9382 FINAL DRAINAGE REPORT FOR SAFEWAY ROCKY MOUNTAIN FEDERAL CREDIT UNION OLD TOWN BASIN PREPARED FOR FINANCIAL CONSTRUCTION SERVICES OCTOBER 7.1997 PREPARED BY STEWART & ASSOCIATES, INC. 103 SOUTH MELDRUM STREET FORT COLLINS, COLORADO 80521 970/482-9331