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HomeMy WebLinkAboutTHE MARKET PLACE PUD - PRELIMINARY - 21-89 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTNo Text PRELIMINARY DRAINAGE REPORT FOR THE MARKET PLACE LOCATED AT SOUTH COLLEGE AVENUE & TROUTMAN PARKWAY FORT COLLINS, COLORADO TO BE DEVELOPED BY: ROSENBAUM/DEAN COLORADO SPRINGS, COLORADO JUNE 7, 1989 PREPARED BY: PARSONS & ASSOCIATES 432 Link Lane Plaza Fort Collins, CO 80524 (303) 221-2400 PROJECT NO. 89.07 ROS 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 PARSONS & hmi ASSOCIATES CONSUI_T1NG E_.._NGIN.__....__.._..-.._ _... EERS June 7, 1989 Mr. Steve Boyette Rosenbaum/Dean 101 North Cascade Suite 400 Colorado Springs, CO 80903 RE: "The Market Place" a shopping center to be located at the Northeast corner of South College Avenue & Troutman Parkway, Fort Collins, Colorado Dear Mr. Boyette: As you have requested, this firm has performed a preliminary drainage study for the subject project. Enclosed you will find the results of that study. The investigation was based upon: the proposed site plan, topographic surveys, previous investigations performed for the surrounding development and on -site observations. We sincerely appreciate the opportunity to be of service to you. If you should have any questions or desire additional information, please advise. /r Reviewed and Approved by: Donald M. P rsons, CO P.E. #13131 � ® W" P'�p����+ey�'�4 Rn�'YhOp. •fl� J 0 . 1131 e, M Q� 0 �i°p S e1 0 OF C0' 4#�taf4.rrrs a �a.y�� 432 Link Lane Plaza Ft. Collins, Colorado 80524 13031 22I-2400 PRELIMINARY DRAINAGE REPORT FOR THE MARKET PLACE FORT COLLINS, COLORADO INTRODUCTION This preliminary drainage investigation has been performed for the purpose of providing planning and preliminary 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. The total site contains approximately 16 acres. The first phase is to contain 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 North and East was prepared by Cornell Consulting Company. This report was the "Master Storm Drainage Report For The Landings P.U.D.". 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. Additional runoff that flows onto the site from the adjacent properties is directed through detention facilities in the Fountainhead P.U.D. onto the site. The investigation and plan preparation for facilities that were installed with the Fountainhead P.U.D. were performed by Parsons & Associates. The release rate for flows from the detention facilities onto this site is 10.0 cfs. DRAINAGE UNDER DEVELOPED CONDITIONS The site is proposed to be a retail shopping center with perimeter pads for food services and other high traffic uses. The site is proposed to be developed in phases so that the southerly 500'± of the site will be the initial development. The site has been considered to divide flow into two separate points of concentration based on the work performed under the Heart S.I.D. The most westerly area is Basin A and is considered to have 9.96 acres concentrating at the 18" diameter storm drain pipe located on the south side of Troutman Parkway approximately 200 feet west of JFK Parkway. Of the total 9.96 acres concentrating at this point 6.81 acres is within Phase 1. The easterly drainage area, Basin B, is adjacent to JFK Parkway and concentrates at an 18" storm drain pipe located on the east side of JFK Parkway at a point approximately 200 feet north of Troutman Parkway. An area of 6.14 acres concentrates at this point along with the controlled release from the Fountainhead P.U.D. of 7.6 cfs. Phase I will contain approximately 1.55 acres in Basin B. The Superblock Holding is.0.85 acres at the southeast corner of the site and runoff shall be directed at the existing pipes crossing Troutman and JFK Parkway with runoff not to exceed 0.738 cfs per the Heart S.I.D. Based upon the criteria established in the Report for the Heart S.I.D., the area should be allowed to release at a rate of 0.87 cfs/acre. Therefore the maximum flows released from this area at the concentration points for Basins A & B are 8.67 cfs and (5.34 + 7.6) 12.94 cfs, respectively. Due to existing topographic conditions, it is suggested that this release rate be reduced to allow for flattened slopes of storm drainage piping and thereby diminish fill requirements. The suggested release rate for Basin A is 6 cfs and 12 cfs for Basin B. The total detention volume required for Basin A is 68,750 cubic feet with 39,990 cubic feet to be provided with this initial phase of development. The total detention volume estimated for Basin B is 40,800 cubic feet with 12,060 cubic feet to be provided with Phase I. The total detention volume estimated for Superblock Holding is 5,544 cubic feet to be provided when development occurs. 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 or exceed established criteria. 4.) The site is not located within an established floodway or floodplain. HARMONY ROAD MAlt CREEK VI Cl NI TY MAP 1 APPENDIX 1 —, J� PARSONS & CLIENT 4�0��.�QLijU�]I��� ��LYItI JOB NO. !� ASSOCIATES PROJECT_ I�/ I LL 1C E✓T 1. C�I� C CALCULATIONS FOR �I 4L v QC11 �I QGr� CONSULTING ENGINEERS Q F1. Collin,, Colo -do 80524 MADE. 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