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HomeMy WebLinkAboutCHECKER AUTO AT THE MARKET PLACE PUD - PRELIMINARY & FINAL - 21-89D - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTNo Text FINAL DRAINAGE REPORT FOR THE MARKET PLACE LOCATED AT SOUTH COLLEGE AVENUE AND TROUTMAN PARKWAY FORT COLLINS, COLORADO REVISED 1/2/90 TO BE DEVELOPED BY: ROSENBAUM/DEAN COLORADO SPRINGS, COLORADO PREPARED BY: PARSONS & ASSOCIATES 432 Link Lane Plaza Fort Collins, CO 80524 (303) 221-2400 PROJECT NO. 89.07 ROS PARSONS & ASSOCIATES 77 CONSULTING ENGINEERS 1 j anuary 2, 1990 Mr. Glen Schlueter Storm Water Utility City of Fort Collins P.O. Box 580 Fort Collins, Colorado 80522 RE: The Market Place P.U.D. Dear Glen: A Checker Auto Parts store is being proposed for Pad A (Lot 3) of the Market. Place P.U.D. As shown on the revised grading and drainage plan, the building area has increased by 780 square feet from the original building footprint shown on our previous submittal of 10/19/89. Because a run-off coefficient of 1.0 was used for Basin A-i, this change will have no effect on the drainage calculations. The site play: for the Checker Auto Parts store as prepared by the architects, Yergensen, Obering, & Wittaker, P.C., conforms to the Drainage Plan of this submittal. Included in Yergensen, Obering, & Wittaker's site plan is provision for all roof drainage to flow into Basin A-1. if you have any questions, or need additional information, please call our office at your earliest convenience. Sincerely yours,. Donald M. arsons, P.E. Colorado License #13131 DMP/cd • 432 Link Lane Plaza Ft. Collins, Colorado 80524 3 1- 4 TABLE OF CONTENTS COVER LETTER INTRODUCTION SITE DESCRIPTION HISTORIC DRAINAGE MASTER DRAINAGE DRAINAGE UNDER DEVELOPED CONDITIONS CONCLUSIONS AND RECOMMENDATIONS VICINITY MAP CALCULATIONS ENCLOSURE: GRADING AND DRAINAGE PLAN ,70 PARSONS In ASSOCIATES CONSULTING ENGINEERS October 19, 1989 Mr. Glen Schlueter Storm Water Utilities City of Fort Collins P. 0. Box 580 Fort Collins, CO 80522 RE: The Market Place P.U.D. Dear Glen: Due to the changes requested by the owner, we have revised the final drainage report for the Market Place that was approved by your office on 8/10/89. The anchor tenant's desire to expand into a portion of the adjacent building to the south has allowed a relocation of the loading dock, an area used for storm water detention on the original plan (Basin B-1). As the grading and drainage plan indicates, the dock has been replaced by a grass lined detention pond in a newly formed landscaped area between the building and JFK Parkway. The new pond exceeds the storage volume of that originally provided, and no adjustment was made to the conservative coefficient of runoff used for this basin in the approved report. Therefore, we believe this revision is a benefit to the storm drainage system for the project. Grades have been adjusted in the new vendor parking area and access drive south of the loading dock to improve driveability and delivery functions (Basin A-5). However, detention volumes have remained unchanged. Downspout piping has been -added to accommodate the additional space occupied by the anchor tenant and downspout piping as originally approved has been relocated to connect to the interior roof drain system. You will note that minor modifications have been made to the calculations on page 13 and 14. However, release rates from the two affected basins remain as previously approved. Sincerely yo/s , 14- z Donald M. Persons, P.E. DMP/nc n1.17;1 F'r �.,n,.. r„�.,.,,a„ vn:�n 11011 991-94 n FINAL DRAINAGE REPORT FOR THE MARKET PLACE FORT COLLINS, COLORADO INTRODUCTION This drainage investigation has been performed for the purpose of providing design information for the development of a proposed commercial shopping center to be located at the Northeast corner of the intersection of South College Avenue and Troutman Parkway, Fort Collins, Colorado. The City of Fort Collins "Storm Drainage Design Criteria and Construction Standards" was used as a basis for guidelines and criteria throughout this investigation. SITE DESCRIPTION The study area is situated in the Southwest Quarter of Section 36, Township 7 North, Range 69 West of the 6th Principal Meridian, City of Fort Collins, Larimer County, Colorado. The site is bounded by: South College Avenue on the West; the Fountainhead P.U.D. on the North; the JFK Parkway on the East; and Troutman Parkway on the South. A small parcel of land located at the Northwest corner of JFK Parkway and Troutman Parkway, known as Superblock Holding, is excluded from this development. This phase of development' contains approximately 8 acres. The area is presently undeveloped and used for three residential acreages with the major portion of the property being vacant. The topography of the site slopes from Northwest to Southeast at grades varying from 0.5% to 2%. The site is predominantly covered with grasses and native vegetation. HISTORIC DRAINAGE Prior to the construction of the streets bounding the site on the east and south, the Larimer No. 2 Canal formed the easterly boundary of these lands. The No. 2 Canal was reconstructed and relocated as a part of the Heart Special Improvement District. Prior to this construction the area drained into .the No. 2 Canal. The Heart Special Improvement District installed storm drainage pipes onto the properties at the intersection of Troutman Parkway and JFK Parkway. The construction was performed in accordance with an agreement between the City of Fort Collins and the Larimer County Canal No. 2 Irrigation Company whereby the Ditch Company allowed the City to discharge stormwater into the No. 2 Canal. MASTER DRAINAGE . The site has been considered in several previous drainage studies in this area. The "McClelland's Mail Creek" Basin is the City's designated master plan basin in which this site is located. The site has not been studied to any detail within this Basin Master Plan. An investigation for the area to the Northreporand East was prepared by Cornell Consulting Company. This"Master Storm Drainage Report For The Landings P.U.D.the 2. It was recommended in this report that the area above the No. 2 Canal be allowed to develop and detain stormwater on -site and to release run-off at the 2-year historic rate into the No. 2 canal. •A subsequent report prepared by Engineering Professionals, Inc. for the Heart Special Improvement District recommends that in conjunction with the reconstruction and relocation of the No. 2 Canal, as a part of the S.I.D., that the rate of discharge into the canal be limited to 0.87 cfs/acre. The storm drainage pipes that were, installed to serve the properties were sized on that basis. This site is a portion of Basin A (6.12 acres of 9.96) and a portion of Basin B (1.85 acres of 6.14) as defined by the Heart S.I.D. Flows from those portions of Basin A & B north of this site have been calculated using 0.87 cfs per acre and passed through the Market Place drainage system. (2.83 cfs for Basin A, 3.51 cfs for Basin B) Additionally, 7.6 cfs from the Fountainhead P.U.D. will be allowed through this site and discharged to the No. 2 canal. DRAINAGE UNDER DEVELOPED CONDITIONS This site is proposed to be a retail shopping center with perimeter pads for food service and other high traffic uses. The majority of the site will be directed westerly to Basin A and ultimately to the Troutman crossing, (7.405 ac.) and the remainder of the site will be directed to the JFK Parkway Crossing. Flows from Troutman Parkway and JFK Parkway will be released directly to Canal No. 2, but detention has been provided on -site for those adjacent portions of Troutman & JFK. The release rate used was 0.87 cfs per acre per the Heart S.I.D., and detention provided on - site based on the difference between 100-year storm and 0.87 cfs/acre release rate. 60,000 cubic feet of detention is required for this site. No detention has been provided for flows from College Avenue. However, these flows will overflow through the Market Place site and ultimately drain to the Troutman crossing.* Also, flows from the 0.83 acres (Superblock Holding) were not considered, although pipe stub -outs have been provided and capacity in the existing system has been provided per the Heart S.I.D., allowing future development of the site. All easements for off -site, drainage structures as shown on these plans are handled by separate document and not by the plat of Market Place P.U.D. CONCLUSIONS AND RECOMMENDATIONS 1.) The site is to be developed to retain the general drainage pattern existing prior to development. 2.) All final design.and construction shall conform with the City of Fort Collins "Storm Drainage Design; Criteria and Construction Standards". 3.) On -site detention is to be provided with controlled release rates that meet established criteria per Heart Special Improvement District Final Drainage Report. 4.) The site is not located within an established floodway or floodplain. 5.) The existing condition of the property to the north is such that natural ponding is already in existence. Overflow of that natural ponding occurs approximately at elevation 5031 per aerial topography of the site. Future development of that property will require filling this low area to elevation 5031. The development of Market Place does not substantially alter any drainage characteristics of the adjacent northerly property and does provide drainage facilities to accommodate future development of that property. Prepared under the direct supervision of: Donald M. Parsons, P. E. # 13131 *So some detention of flows from College Avenue will occur in all situations except the 100-year storm, and even in the 100-year event, the time of concentrations for College Avenue will be increased.