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Home My WebLink AboutRIGDEN FARM, PARKSIDE WEST - FDP - 56-98G - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTrvQ a I" z 0 z M1 Abilene I C Ct a o a CD V o Custer D Pecos PI a n o � � N 6 E o � C O � v; .0 _ 7 Dr L Sonora St .n Conne ' ut Ma ccD�iusetts I t I Vermont Dr I Donfield er Ct . n C Elk Rd Coyote pL 3 Puma 1 o Bi horn Rd �+ Sunstone I — c� c � 1 Y J I Y d E. Drake Rd Coal Bank Dr st Red �` -. c-, - I t — N r t croon Littl 3 l i DPP ea o Ctlz 4 Jade st ne ��—• Ct o - q`o o 4Vhitw< agnDr.9_St _ Y o \ E Rd o t East Ga e is e e Ln Ln G Chariie n laesa ! w landscaping to cover the soil. Re -seeded areas shall be mulched with straw or hay to protect exposed soil until vegetation is established. EROSION CONTROL PLAN The proposed erosion control measures are presented on the Grading and Erosion Control Plan located in the Appendix of this report. In summary, the erosion control measures consist of. 1. Temporary seeding on all of the land to be developed 2. Inlet protection at every inlet 3. Silt fences installed on the Eastern side of the development 4. Vehicle tracking control by Drake Road curb and gutter conveying storm flows to new inlets on Rigden parkway, which in turn discharge into the North Tributary System. In effect, the swale and culverts are temporary or interim. The North Tributary System conveys all flows from Basins H, I, J & K. CONCLUSION The runoff that will be produced by Parkside West at Rigden Farm has been accounted for. More area will drain to the inlet at DP 6 than was previously calculated in the Drainage Report for Rigden Farm Filing One. However, the increase area is only 2% from this site and less than % of one percent of the entire area for sub -basin 111 (5.61 acres). EROSION AND SEDIMENT CONTROL This report describes methods, which are recommended to control wind erosion, water erosion and sediment during and after the construction of drainage structures and site grading. DISCUSSION The clearing and stripping of land for site grading, overlot grading, or for the construction of drainage structures, may cause localized erosion rates with subsequent deposition and damage to offsite properties. Uncontrolled, such erosion could destroy the aesthetic and practical values of individual sites, and cause damage to downstream property. In general, erosion and sediment control measures will consist of minimizing soil exposure, control runoff across exposed areas, and sediment control at drainage structures. Each of these measures is described below and shall be utilized by the developer and/or the contractor during any construction activity that occurs at this site. GENERAL EROSION AND SEDIMENT CONTROL MEASURES Minimizing Soil Exposure: The construction area and duration of soil exposure shall be kept to a minimum. All other areas shall have a good cover of vegetation or mulch. Grading shall be completed as soon as possible after commencement. A temporary cover crop, a permanent vegetative cover crop, or other landscaping shall be established in the disturbed areas. Re -vegetation shall consist of native grasses, lawn grasses, or various winter wheat. Decorative rock, flower gardens, or shrubs shall also be utilized in the final 4 OFFSITE RUNOFF There is no offsite runoff that enters this site. ONSITE RUNOFF The runoff produced from the 11 onsite basins drains into the Rigden Farm Filing One storm system. Sub -basins A and B- These sub -basins will drain onto Rockford Drive and then onto that portion of Limon Drive that drains west. The Drainage and Erosion Control Report for Rigden Farm Filing One assumed 0.28 acres from this site would drain onto Limon Drive and head west. Sub -basins A and B consists of 0.25 acres, with a composite C of 0.70. Sub -basins C, D, E, and F- These sub -basins will drain onto Rigden Parkway or that portion of Limon Drive that drains east to Rigden Parkway. The Drainage and Erosion Control Report for Rigden Farm Filing One assumed 1.34 acres from this site would drain onto Limon Drive and head east to Rigden Parkway. Sub -basins C, D, E, and F consist of 1.06 acres, with a composite C of 0.70. Sub -basin G- This sub -basin will drain westerly onto Rockford Drive. The storm system in Rockford Drive is designed to convey the runoff from this sub -basin to the existing storm system in Drake Road (North Tributary Storm Sewer). Sub -basin K- This sub -basin will drain easterly onto Rigden Parkway. The curb and - gutter in Rigden Parkway is designed to convey the runoff from this sub - basin to the existing storm system in Drake Road (North Tributary Storm itSewer). Sub -basins H, I, and J - These sub -basins will drain northerly to the roadside swale adjacent to Drake Road. This swale drains easterly into the North Tributary Storm Sewer before conveying all flows under Rigden Parkway. According to the Drainage and Erosion Control Report for Rigden Farm Filing One, the North Tributary Storm Sewer is sized to accommodate runoff flows from the developed area using a design capacity of 23.21 cfs. The combined runoff from these basins including sub=basin G and K is 12.2 cfs using a composite C of 0.70. The North Tributary System combines with the 24-inch culvert under Rigden Parkway almost immediately downstream of Rigden Parkway. JR Engineering's ultimate design for the Rigden Parkway — Drake Road intersection calls for the drainage Swale and culverts parallel to Drake to be removed and replaced 3 / Drainage Impact Proposed Site Conditions Parkside West at Rigden Farm consists of 8 buildings with 6 dwelling units each, for a total of 48 residential units. In addition to the 8 residential buildings, there are 6 garage buildings. The proposed development is accessed from Rigden Parkway and Rockford Drive. Major Drainage Basins Parkside West at Rigden Farm lies within Reach 2 of the Foothills Basin. Offsite Basins Due to the construction of the adjacent streets, there are no offsite drainage basins that enter this site. Onsite Basins Sub -basins A and B- These sub -basins makeup the southwest 0.28 acre portion of the site that drains onto Rockford Drive and then onto that portion of Limon Drive that drains west. The basin's proposed land use consists of %z of one multi- family building, a portion of one garage, and a portion of an asphalt parking lot with the remainder being landscaped. Sub -basins C, D, E, and F- These sub -basins makeup the southeast 1.37 acre portion of the site that drains onto that portion of Limon Drive that drains east onto Rigden Parkway. The basins proposed land use consists of several multi- family buildings and garages, asphalt driveways and parking, with the remainder being landscaped. Sub -basin G- These sub -basins makeup the northwestern 0.37 acre portion of the site that drains to a proposed inlet in Rockford Drive. The basin's proposed land use consists of a portion of several multi -family buildings with the remainder being landscaped. Sub -basins H, I, J and K - These sub -basins makeup the northeastern 1.20 acre portion of the site that drains to an existing 24" culvert under Rigden Parkway at Drake Road. The basins' proposed land use consists of multi -family buildings and garages with the remainder being landscaped. FINAL DRAINAGE STUDY FOR PARKSIDE WEST AT RIGDEN FARM Introduction Parkside West at Rigden Farm is a proposed multi -family residential subdivision in the City of Fort Collins, Colorado. The site is generally located on the South side of East Drake Road midway between Timberline Road and County Road 9. The entire Rigden Farm development consists of the majority of the North ''/z of Section 29, T7N, R68W, Sixth Principal Meridian, Larimer County, Colorado. Parkside West at Rigden Farm consists of approximately 3.22 acres located west of Rigden Parkway between Drake Road and Limon Drive. The purpose of this Final Drainage Study is to evaluate and present the drainage impacts from Parkside West at Rigden Farm. In the evaluation, a site description of the project and its relationship to the Rigden Farm development will be presented. This Final Drainage Study presents the changes to the developed flow condition and proposed improvements to resolve the impact of the developed flow condition. This Final Drainage Report demonstrates compliance with the approved final "Drainage and Erosion Control Report for Rigden Farm Filing One, P.D.P," dated September 30, 1999, by JR Engineering. Existing Condition Description Currently the ground is gently sloping and covered with native grass. The site is bound by Rigden Parkway on the East, Drake Road on the North, Limon Drive on the South and Rockford Drive on the West. In its' present state, the site slopes from the West to the East at approximately 1.5%. The current runoff drains East and South into Pond 216 (from JR's Filing One report). Pond 216 is being built by the developers of Rigden Farm. This pond provides the Detention and water quality for this site. The North Tributary System combines with the 24-inch culvert under Rigden Parkway almost immediately downstream of Rigden Parkway. JR Engineering's ultimate design for the Rigden Parkway — Drake Road intersection calls for the drainage swale and culverts parallel to Drake to be removed and replaced by Drake Road curb and gutter conveying storm flows to new inlets on Rigden parkway, which in turn discharge into the North Tributary System. In effect, the swale and culverts are temporary or interim. The North Tributary System conveys all flows from the north part of the site. The developed runoff from this site has been accounted for in the "Drainage and Erosion Control Report for Rigden Farm Filing One, P.D.P," dated September 30, 1999, by JR Engineering. Please refer to attached excerpts from their study that is located in Appendix A. Table of Contents Introduction................................................................................page 1 Existing Condition.........................................................................page 1 i Drainage Impact...........................................................................page 1 Proposed Site Conditions Major Drainage Basins Offsite Basins Onsite Basins OffsiteRunoff............................................................................page 2 OnsiteRunoff..............................................................................page 2 Conclusion.................................................................................page 3 Erosion and Sediment Control ..........................................................page 3 APPENDIX A Final Drainage Study w r r r ZOOO" & r¢¢joc. 90c, P 0. Fax 270852 576V 621h a, e0 80527 (970) 493-2908 ;W l970I 495- 9735 May 29, 2001 Mr. Glenn Schlueter City of Fort Collins Stormwater Utility Department 700 Wood Street Fort Collins, CO 80522 Dear Mr. Schlueter: On behalf of our client we are submitting the attached Final Drainage Study for Parkside West at Rigden Farm. The purpose of this report is to evaluate and present the drainage impacts from the proposed Construction of Parkside West at Rigden Farm. The drainage report assesses the changes to the developed flow conditions and proposed improvements to resolve the impacts of the drainage flow condition. The Final Drainage Study for Parkside West at Rigden Farm was prepared in accordance with the provisions of the City of Fort Collins Storm Drainage Criteria — revised January 1997. Loonan and Associates, Inc. James R. Loonan, P.E. Registered Professional Engineer Colorado P.E. 19195 No Text