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HomeMy WebLinkAboutTHE TOY SHED LOTS 1 AND 2 OF BLOCK 4 OF REPLAT NO 1 OF EVERGREEN PARK PDP - 50 91D - SUBMITTAL DOCUMENTS - ROUND 2 - DRAINAGE REPORTFINAL DRAINAGE AND EROSION CONTROL REPORT FOR LOTS 1 & 2, BLOCK 49 EVERGREEN PARK PREPARED FOR JERRY RUSSELL MARCH 31,1999 PREPARED BY STEWART & ASSOCIATES, INC. 103 SOUTH MELDRUM STREET P.O. BOX 429 'FORT COLLINS, COLORADO 80522 TEL. 970-482-9331 FAX. 970-482-9382 Hickory St 4 ne Dtive _ i STEWART&ASSOCIATES IiConsulting Engineers and Surveyors March 31, 1999 Mr. Basil Hamdan Storm Water Utility City of Fort Collins P.O. Box 580 Fort Collins, CO 80522-0580 Dear Basil, Lots 1 and 2, Block 4, Evergreen Park are for proposed outside storage parking. The lot area I} is 1.3838. There will be no buildings constructed on these lots. The proposed site will be covered l� with recycled asphalt. This development is in the Citys Greenbriar/Evergreen Basin. This project is an addition to the "Toy Shed" which is now located on Lots 3, 4 and 5. A small portion of the West and North side of this site is in the 100-year flood plain. . All design and calculations within this report are in compliance with the City of Fort Collins Storm Drainage Design Criteria and Construction Standards. If you have any questions or comments regarding this report, please let me know. cere v r ' D. Blake, P.E. & L.S. _— FDB/meh G� 1 James H. Stewart and Associates, Inc. .Y 103 S. Meldrum Street P.O. Box 429 Ft. Collins, CO 80522 970/482-9331 Fax 970/482-9382 1 FINAL DRAINAGE AND EROSION CONTROL REPORT FOR LOTS 1 AND 29 BLOCK 49 EVERGREEN PARK INTRODUCTION: Lots 1 and 2, Block 4, Evergreen Park, Fort Collins, Colorado area is 1.3838 acres. The site is bordered on the North by Red Cedar Circle which is constructed; on the East by undeveloped lots 15 and 16, Block 4; on the South by the "Toy Shed" which is a Vehicular/Recreational Storage area; and on the West by Red Cedar Circle which is developed. This development is located in the City's Greenbriar/Evergreen Basin. All runoff from this Basin is to Dry Creek. A portion of the West and also North side of this site is within the 100-year flood plain. Because there are no buildings proposed for this site the flood plain does not create any problems. The site slopes both to the West and East from a ridge line that is about 125' East of the West BoundaryLine. Existing slopes vary but average about 0.75%. Runoff to the West is to Red Cedar Circle and runoff to the East is to Lots 15 and 16, then to Blue Spruce Drive. This site is covered in weeds and alfalfa. There is no offsite runoff onto this site. �, Red Cedar Circle is constructed on the North and West side of this site. Runoff from Red Cedar 9, Circle is both to the South and or to the East with the high point being at the Northwest comer of this site at the curb return. Runoff from Red Cedar Circle adjacent to our site should be routed through this site but because the streets are constructed and we are also at the high point of the street there is no way to have these flows routed through this site. Therefor, we are asking for a variance to the City's Standard Requirement of routing the street/flows through our site. DRAINAGE CRITERIA: The Rational Method has been utilized to determine peak runoff rates and required detention pond volumes._ Design factors used are in accordance with the recommendations of the City of Fort Drain Collins age Criteria and Construction Standards Manual. In accordance with the City of Fort__ Collins drainage policy, the 100 year runoff from the developed site will be detained in the two proposed detention ponds and released at the 2 year undeveloped rate. DEVELOPED SITE: This site is proposed to be additional outside storage for the existing "Toy Shed" which is inside and outside recreational vehicular storage now on Lots 3, 4, and 5 of said Block 4. The site will be covered with recycled asphalt. There are no buildings proposed for this site. This site will be graded to have the runoff flow both to the West, to "West" Red Cedar Circle, and then also to the East, then North to "North" Red Cedar Circle. The ridge line runs North -South and is about 125 feet East of the sites West boundary line. All runoff will be to Dry Creek. The site will be graded with two detention ponds. One in the Southwest comer and one in the Northeast comer of the site. These ponds are sized to detain the 100-year storm and release at the two year historic rate. Outlets from the ponds will be to the street through a 4" P. V.C. pipe, then to JL a 2 foot wide sidewalk culvert; then to a 2 foot pan to Red Cedar Circle. The 4"pipe ends will be capped and then drilled to the allowable radius size calculated for each outlet from the ponds. The inverts of the outlet pipes will be set at an elevation above the bottom of the ponds, to retain the required volume of water for water quality control. This retention area will be required to be constructed in grass. Sod will be used in this area. Also using recycled asphalt over the site in place of asphalt will allow infiltration and help water quality control. The dikes created along the street sides of both ponds will be used as the spillway from the ponds. The spillways are 100 feet :long. EROSION CONTROL: This site is located in the moderate zone for both wind and rainfall erodibility. The construction on this site should only be about one week. A silt fence shall be installed along the East property line and remain in place until the construction is complete. The erosion control escrow for this site is $1000.00.