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HomeMy WebLinkAboutHEARTHFIRE PUD, 2ND FILING - FINAL - 31-95E - CORRESPONDENCE - CITY STAFF (21)Y � Y PAGE 6 October 26, 1999 Project No: 1552-01-96 Re: Hearthfire P.U.D., Second Filing; Ft. Collins, Colorado This concludes our response to your review comments concerning the Final Drainage and Erosion Control Report and the final utility plans for Hearthfire P.U.D., Second Filing. We trust that this response has addressed a majority of your specific comments and concerns. If you have further comments or questions, please call us directly at 226-5334 so we can resolve any specific issue immediately. Sincerely, Mark Oberschmidt, Design Engineer Shear Engineering Corporation MEO / mo Shear Engineering Corporation cc: Tom Kennedy; Hearthfire, Inc. Steve Olt; City Planning Tom Dugan; PineCrest Planning and Design Sheri Wamhoff, City of Fort Collins Engineering PAGE 5 October 26, 1999 Project No: 1552-01-96 Re: Hearthiire P.U.D., Second Filing; Ft. Collins, Colorado • Basin 6 consists of the limits of Hearthfire Second Filing that sheet flows into Pond 2. No peak flows were determined for this basin. • Basin 8 consists of the rear area of the lots on the North side of Grosbeak Court. Limited runoff is expected from this basin. Easements will be provided as needed prior to final approval. • The statement regarding pans required for slopes that are less than 1.0% has been revised to indicated 2.0%. • The crosspan at Grosbeak and Pondview has been removed. • The plans now represent 20' inlets in profile C north of Buntwing Court on Town Center Drive. • A trickle pan was added to the swale in profile D • We have verified that the capacity of the existing inlets that were constructed with the First Filing are adequate for the flows from their respective contributing areas. • The design flow for swale section D-D is 50.16 cfs. This is reflected on the plans and in the report. • The drainage calculations now include peak flows and inlet capacity verification for all design points associated with Second Filing. • Drainage calculations have been reviewed and adjusted accordingly to reflect accurate time of concentrations to the inlets. Carryover flows from upstream inlets are added directly to the inlet flows to determine the overall flows. This results in a conservative estimate of the total flow as the upstream time of concentration is usually greater than or equal to the time of concentration at the downstream point. PAGE 4 October 26, 1999 Project No: 1552-01-96 Re: Hearthfire P.U.D., Second Filing; Ft. Collins, Colorado SHEETS 27-30; Final Drainage and Erosion Control Plan (4 sheets) • Basin delineation has been revised to match the final grading. In particular the sub -basin line at Pondview Court has been revised to reflect the removal of cross pan. Runoff coefficients and sub -basin areas shown on the plan correspond to those in the calculations located in Appendix I of the drainage report. • Ponds 1 & 2 have been labeled. • All streets are labeled. • A swale has been added to the southwestern corner of the site to convey flows from Tract B to Richards Lake. A culvert is also proposed under Town Center Way to convey the flows to Richards Lake. • The capacity of the existing inlets and pipes on Town Center Drive and Grosbeak Court were originally designed with the expectation that there would be flows from the Second Filing. This has been verified with the Final Drainage and Erosion Control report for Hearthfire P.U.D., Second Filing. SHEETS 31; Drainage and Erosion Control Plan Notes • We have provided a summary table for the design of all the swales. • The purpose of the cross section is to give the contractor a typical section for use in construction and staking. It creates unnecessary clutter to add slope labels (4:1) to the grading plan. We have added a note to the Grading and Drainage plans to see cross sections on this sheet. • Stormceptor details have been added to this sheet. • A riprap apron detail has been added to this sheet. The following represents our responses to the redlined comments in the drainage report. • It is typical to provide a professional engineer's signature and stamp once the review process is completed. The Stormwater Utility typically requests several copies of the Final Drainage and Erosion Control Report once it is determined that the report is complete and no more revisions are required. Therefore, no stamp is provided at this time. 0 Grading along North County Road 13 has been provided. PAGE 3 October 26, 1999 Project No: 1552-01-96 Re: Hearthfire P.U.D., Second Filing; Ft. Collins, Colorado SHEET 17; Town Center Dr. Street Plan and Profile • The 15' type R inlet is called out in the profile. SHEET 20; Grosbeak Ct. & Pondview Ct. Street Plan and Profile • The pan has been removed on all sheets. Basin delineation shown on the previous submittal was correct. SHEETS 23-26; Final Grading Plans (4 sheets) • Pond 1 and 2 are labeled. • All contours are tied in appropriately. • All proposed contours are labeled. • Existing contours are in 2' intervals. Proposed contours are in 1' increments. • Building pads are shown with recommended finished grade and finished floor elevations on all lots. • All lot corner elevations are labeled. • All streets are labeled. • A trickle channel has been added to the swale in profile D located in Tract D. • The riprap at the upstream end of the culvert at the Whiting Oil easement has been revised to match the proposed grading. • Graded slopes are maintained at 4:1 or flatter throughout the site. • Grading from First Filing is now shown on Town Center Drive and Grosbeak Court. • The grading between lots 55 and 54 on Pondview Court has been revised to reflect an overflow swale. The inlet at the low point on Pondview Court is adequate for intercepting the 100-year flow. The overflow swale is only needed if the inlet is completely clogged. The swale was sized to handle the 100-year flow only. PAGE 2 October 26, 1999 Project No: 1552-01-96 Re: Hearthfire P.U.D., Second Filing; Ft. Collins, Colorado The following represents our responses to the redlined comments on the plans. FINAL PLAT • All tracts have been clarified and coordinated between the final plat and the utility plans. • All Storm sewers are located in easements which are described on the final plat. All tracts have been clearly dedicated as drainage easements. Specific easements for stormwater purposes only has not been provided. The approach and concepts for Hearthfire P.U.D., Second Filing follows that of the Hearthfire P.U.D., First Filing. SHEET 2; Overall Master Utility Plan • All storm sewer infrastructure (existing and proposed) has been labeled. • Tracts in First and Second Filings have been labeled and clarified. SHEETS 3, 4 & 5; Master Utility Plan • All storm sewer infrastructure (existing and proposed) has been labeled. A note has been added to the plan to indicate where the storm sewer profiles are located. This is also indicated on the cover sheet in the index. • Stormceptors are now labeled. • A trickle channel has been added to the swale in profile D located in Tract D. • Tracts in First and Second Filings have been labeled and clarified SHEETS 12; Storm Sewer Profiles • Hydraulic grade lines have been added to the profiles. • A trickle channel has been added to the swale in profile D located in Tract D. • Storm sewer pipes crossing over water lines have been encased in concrete per Section 5.3.4. • Details of the Stormceptor and a construction installation schedule are included on the Drainage and Erosion Control Notes sheet. • Widths of the riprap aprons are called out at all storm sewer outfalls. The lengths of the riprap aprons are in feet. A detail is provided on the Drainage and Erosion Control Notes sheet. Project No: 1552-02-97 October 26, 1999 Glen Schlueter / Basil Harridan / Donnie Dustin City of Ft. Collins Stormwater Utility P.O. Box 580 Ft. Collins, Colorado 80524 Re: Hearthfire P.U.D., Second Filing; Ft. Collins, Colorado Dear Glen, Basil and Donnie, This letter serves as the response to your review comments concerning the final utility plans and the Final Drainage and Erosion Control Report for Hearthfire P.U.D., Second Filing. The following sheets have been added to the plan set to provide additional detail and improved clarity. • Intersection Details • Three (3) Drainage and Erosion Control Plans at 50 scale We have addressed the utility plan review comments, as well as written comments noted on a letter from Steve Olt dated June 30,1999. The stormwater comments came from Glen Schlueter. The following represents our responses to the written comments on the plans • A SWMM (Storm Water Management Model) model has not been provided at this time. Your request for this model requires certain clarification. All major storm drainage improvements for Hearthfire P.U.D. were designed and installed without the benefit of a SWMM model which was not required at that time. Hearthfire P.U.D., Second Filing drainage improvements are minor in comparison to those provided with the First Filing. Our client has been advised of the SWMM model request and the potential delay of approval of the project. We would anticipate an arranged meeting and lengthy discussion concerning this requirement. • Calculations for sizing inlets, pipes and swales are provided in appendix I of the Final Drainage and Erosions Control Report. • We are unsure as to the meaning of the comment concerning where the concentrated flow from Town Center Way goes. All flow down Town Center Way will flow overland to Richards Lake based on the existing topography. Required offsite easements will be provided in the near future. We understand that any offsite easement which is determined to be required, must be provided prior to final approval. • Offsite flows were considered and approved with the First Filing. 4836 S. College, Suite 12 Ft. Collins, CO 80525 (970) 226-5334 FAX.(970) 282-0311