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HomeMy WebLinkAboutCONIFER INDUSTRIAL PARK LOT 4 IL SITE PLAN REVIEW - 61 91A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTDRAINAGE INVESTIGATION FOR THE GLOVE WAGON 1219 BLUE SPRUCE DRIVE FORT COLLINS, COLORADO 80524 Prepared for ARCHITECTURE ONE 150 East 29th Street Suits 200 Loveland, Colorado 80537 August 27,1996 Project No. GRD - 215 - 96 MIRDOMM Emineeft Associates 150 E. 29th Street, #238 Loveland, Colorado 80538 lhlephone: (970) 663 - 2221 EX�HI :ITS VICINTY MAP (Not -to -Scale) 3 V 1CH*4W MAP Tim GLOVE WAGON Address: 1219 Blue Spruce Drive, Fort Collins, CO 80524 Property Description Lot 4 of A Minor Subdivision Plat of Conifer Industrial Park being a Replat of Lots 10,11 and 12, Block 4 of the Replat No.1 of Evergreen Park," Fort Collins, Colorado i I[,,, August 27, 1996 Project No. GRD - 215 - 96 Mr. Basil Y. Hamdan Stormwater Utility 235 Mathews P. O. Box 580 Fort Collins, Colorado 80522-0580 Dear Mr. Hamdan, The enclosed report represents the results of the drainage investigation for the proposed "The Glove Wagon" to be located on Lot 4 of the Minor Subdivision of Conifer Industrial Park in the City of Fort Collins, Larimer County, Colorado. This investigation was based upon the proposed site development plan; proposed site grading plan; on -site observations; and available topographic information. The investigation was performed in accordance with the criteria established in the City of Fort Collins "Storm Drainage Design Criteria and Construction Specification Standards" manual. If you should have any questions, please feel free to contact this office. Respectfully Submitted, MESSNER Engineering Associates Dennis R. Messner, P.E. DRM/mkm Enclosures cc: Architecture One 1 Civil and Environmental Engineering Consultants 150 E. 29th Street, Suite 238 Loveland, Colorado 80538 Telephone: (970) 663-2221 TABLE OF CONTENTS Letter of Transmittal Table of Contents Scope Site Description "Historic" Conditions Proposed Development Erosion Control Measures Conclusions and Recommendations Drainage Summary Erosion Control Cost Estimate letter EXHIBITS Vicinity Map "Historic" Conditions Exhibit Proposed Conditions Exhibit Calculations ii aQQPE The following report represents the results of a drainage investigation for a proposed office and warehouse facility to be located in the Northwest Quarter of Section 1, Township 7 North, Range 69 West of the 6th P.M.in the City of Fort Collins, Larimer County, Colorado. The investigation was PC The purpose of rmed for the project architect, Architecture One, Architects and Planners, this investigation is to determine the effects of the proposed development on the area's existing drainage conditions and to determine the improvements, if any, and the appropriate sizing for the proposed improvements so that it may be incorporated with the construction of the project. The conclusions and recommendations presented in this report are based upon the proposed site development plan; proposed building construction plans; on -site observations; and the available topographic information. The analysis was performed in accordance with the City of Fort Collins "Storm Drainage Design Criteria and Construction Standards" manual. SITE DESCRIPTION The site is rectangular and contains approximately 0.61 acres, exclusive of the adjacent Blue Spruce Drive street right-of-way which contains approximately 0.09 acres. The site's East-West dimension is 265 feet and its North -South dimension is 100 feet. The site abuts the westerly right-of-way of Blue Spruce Drive. The site is located in the GREENBRIAR/EVERGREEN DRAINAGE BASIN. "HISTORIC" CONDITIONS The site is vacant and has been unused for several years. The surface adjacent to Blue Spruce Drive rises gradually toward the West for a distance of approximately 75 feet from the existing curb. The ground then forms a short embankment rising approximately 3 feet in a distance of 20 feet. The balance of the site's ground surface is relatively uniform rising gradually toward the West. The ground surface has been graded and a moderate ground cover of grasses is found on the parcel. The slope of the ground surfaces is considered to be flat with slopes ranging from 0.5 % to 1.5 %. The major portion of the site currently drains onto the adjacent vacant lot to the South. The run-off generated on the adjacent lots to the West and North flows onto the site and then flows southerly across the site to Blue Spruce Drive. The run-off in the street flows to the South along Blue spruce Drive to the intersection with Conifer Street. The flow travels South across Conifer Street where it is discharged into an open channel. The run-off is directed along this open drainage channel to the Southeast where it ultimately discharges into the Cache la Poudre River. The site lies adjacent to the westerly limits of the 100 Year Flood Plain for Dry Creek as indicated on the Dry Creek Flood Study performed by Gingery Assoc., Inc. and dated April 1980. 1 PROPOSED DEVELOPMENT The proposed development of the site is to consist of constructing 4,200 square feet of office and warehouse structure together with approximately 11,800 square feet of access drives and parking area. The structure and associated parking is to be located on the eastern half of the site. The proposed development plan indicates that the western 0.25 acres of the site is to remain vacant with a potential for future development. Since the type or extent of future development is not known at this time, this investigation has not considered any future development as a part of the construction that is currently proposed. As previously stated the run-off from the site flows onto Blue Spruce Drive. There are no other drainage facilities available to accept run-off from the site. The current City policies require that the difference between the historic rate of run-off and the developed rate of run-off be detained onsite. Through previous studies performed for the area, the release rate has been established at 0.47 cubic feet per second. The City's policies normally require that the adjacent street flows be incorporated with the onsite detention requirements. This policy applies most efficiently when the street construction and onsite detention are performed concurrently. In this instance, it is not physically feasible to combine the two flows since the flow generated on the streets can not be intercepted and directed into an on -site detention facility and then routed back into the curb and gutter. The area within the westerly half of the Blue Spruce Drive right-of-way has been considered as tributary to the detention facility for sizing purposes. EROSION CONTROL MEASURES Erosion control considerations are based upon the short term activities that occur during construction and the long term measures that are to be placed for the life of the facility. The long term erosion control measures are the proposed methods and materials to be used to provide surface treatments for the driveways, parking areas, walkways and the landscaped open areas. Landscape materials and plantings in the open areas will provide a combination of. ground covers to deter erosion. The anticipated construction schedule should have the site grading completed, within one (1) month after commencing construction. The schedule for construction activities is anticipated to be: October 1 - October 5, perform site grading; October 5 - October 10, install water and sewer service lines; October 7 - October 15 construct curb, gutter and sidewalks and drainage related facilities; October 21 - October 24 place pavement; November 1 - November 5 install landscaping. 2 EROSION CONTROL MEASURES (continued) The recommended short term erosion control methods to be incorporated with the construction activities consist of the following: upon completion of grading operations and at the time that the drainage outlet is installed a "Straw Bale Filter is to be placed at the inlet; and a "Silt Fence" is to be placed along the southern boundary of the site in order to control and contain mud and debris onsite. Due to the size of the lot, the nature of the surface soils, and the the fact that the site will be open and subject to the wind, wind erosion measures have not been considered for the site. 3 CONCLUSIONS AND RECOMMENDATIONS_ 1. The proposed development will retain the "historic" drainage patterns. 2. The site is located in the GREENBRIAR/EVERGREEN DRAINAGE BASIN. The site is not located within a designated floodway or flood plain. The westerly limit of the DRY CREEK FLOOD PLAIN is the westerly right- of-way of Blue Spruce Drive per the Dry Creek study performed by Gingery Assoc., Inc. and dated April 1980. 3. All development is to be performed in accordance with City of Fort Collins criteria. A variance to the City's policies is requested from detention of adjacent street flows due to physical impracticality. 4. Onsite detention of storm water is required by the City of Fort Collins. The volume of run-off to be detained is estimated to be 4,500 cu. ft. The detention volume has been determined based upon the calculated volume of run-off generated by a 100 Year Storm. The entire site and one-half of the adjacent Blue Spruce Drive have been considered as the tributary area to determine the volume of the detention facility. The calculated volume generated from the tributary area is to be released at a controlled rate that has been previously determined as the `historic' rate of run-off from the site for a 2 Year Storm. The designated release rate is 0.47 c.f.s. 5. The City of Fort Collins Standards for temporary erosion control measures are to be incorporated with the construction activities. Specifically, the following are to be incorporated in the site construction activities: a. A "Silt Fence" is to be placed along the southern border of the site. b. A "Straw Bale Filter" is to be placed at the the inlet end of the outfall control structure until paving and landscaping are in place. 4 STORM WATER DETENTION SLJMIVIARY SITE DRAINS TO "GREENBRIAR / EVERGREEN' DRAINAGE BASIN GROSS SITE AREA (includes 1/2 of Blue Spruce Drive) = 30,500 sq. ft. = 0.700 ac ± NET SITE AREA = 26,500 sq.ft. = 0.608 ac ± HISTORIC "C" = 0.30 DEVELOPED "C" = 0.64 DESIGNATED RELEASE RATE = HISTORIC "Q2" = 0.47 c.f.s. CRITERIA BASED DETENTION VOLUME = 3,636 cu.ft. ± PLAN DETENTION VOLUME = 3,829 cu.ft. MAXIMUM DEPTH OF DETAINED WATER = 1.10 Ft. ® Elevation 4967.10 PEAK DISCHARGE FROM DETENTION, Q = 0.47 c.f.s. Engineering August 27, 1996 Project No. GRD-215-96 Mr. Basil Hamdan Stormwater Utility City of Fort Collins 235 Mathews R O. Box 580 Fort Collins, Colorado 80522 - 0580 Re: The Glove Wagon, 1219 Blue Spruce Drive, Fort Collins, Colorado Dear Mr. Hamdan, The estimated cost for erosion control devices for the subject site has been estimated to be: 1. Silt Fence 2751.f. @ $2.50/ft. = $687.50 2. Straw Bale Filter 2 Each @ $75.00/Ea. $150.00 Total $837.50 Cost @ 150% = 1.5 x $837.50 = $1,256.25 The cost to re -seed the 26,500 square foot site at $0.0298/sq.ft. = $789.70 150% of the re -seeding cost = 1.5 x $789.70 = $1,184.55 Therefore, the subject project's estimated erosion control security amount is determined to be $1,256.25. This amount is to be included as surety for the erosion control guarantee along with any other surety requirements that may be a part of the City's "Developer's Agreement" requirements. If you should have any questions or desire additional information, please feel free to contact this office. Submitted, iaineerina Associates Dennis R. Messner, P.E. cc: Architecture One Civil and Environmental Engineering Consultants 150 E. 29th Street, Suite 238 Loveland, Colorado 80538 Telephone: (970) 663-2221