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HomeMy WebLinkAboutAIRPARK VILLAGE - ODP - 16-05A - CORRESPONDENCE - (8)el a. This cross section, and sections upstream of this station, will also be underestimating the potential for flooding under proposed conditions hydrology. Please provide an explanation for this output condition, and include a summary of errors, warnings, and notes as part of the HEC-RAS-generated report for review. 7. Please show the Poudre River 500-year floodplain on the Floodplain Information Map in the Reference Materials section of the ODP Drainage Report Appendix. 8. Repeat portion of comment No. 5 from 09-28-2007. At time of PDP submittal a floodplain report should be submitted. A copy of the floodplain report requirements are available upon request. 9. The following comments apply to Sheet 1 of 2 from the map pocket of the ODP Drainage Report: a. This sheet indicates portions of the project are located within the Cache la Poudre River 500-year floodplain. Since critical facilities are prohibited in the 500-year floodplain by City Code 10-81(a), those areas must be clearly identified on Sheet 1 of 2. b. The legend on Sheet 1 of 2 from the map pocket of the ODP Drainage Report indicates HEC-RAS cross sections are identified, but the sections do not appear on the work map. Please add these sections to Sheet 1 of 2. c. FEMA approval of the Dry Creek PMR is anticipated for June 2008. The City floodplain and floodway lines identified on Sheet 1 of 2 may be re -labeled as FEMA floodplain and floodway lines since this approval is imminent. Please remove the old FEMA floodplain and floodway boundaries from the map. 10. The following comments apply to Sheet 3 of 5 of the construction drawing set: a. Please note that critical facilities will not be permitted in the Poudre River 500-year floodplain, and that all proposed structures and development activities will require an approved flood use permit per City Code Chapter 10. Comments from Current Planning On sheet 3 of 5, please use larger and darker font for "Dry Creek Flood Channel." 2. On sheet 3 of 5, please add street names for the surrounding area to the east. 3. On sheets 3 and 4 of 5, please add the helicopter flight path easement. And, a note on sheet 1 describing the limitations on land use within this easement. 4. See redlines. Be sure and return all of your redlined plans when you re -submit. If you have any questions regarding these issues or any other issues related to this project, please feel free to call me at (970) 221-6750. Sincerely: Ted Ted Shepard Chief Planner Page 2 i STAFF PROJECT REVIEW City of Fart Collins TROY JONES Date: 4/15/2008 MTA 204 WALNUT STREET, SUITE D FORT COLLINS, CO 80524 Staff has reviewed your submittal for AIRPARK VILLAGE ODP - TYPE II, and we offer the following comments: ISSUES: Department: Engineering Issue Contact: Sheri Langenberger Topic: General Number: 51 Created: 3/24/2008 [3/24/08] There is some text in the document that doesn't meet the minimum text height requirements for plans. Text needs to be at least 2 mm in height. Currently some of the text is closer to only 1 mm high. Please correct before any final mylars are submitted for recording. Department: Stormwater-Water-Wastewater Issue Contact: Basil Harridan Topic: Floodplain Comments Number: 52 Created: 4/8/2008 [4/8/08] 1. The ODP Drainage Report must be signed, stamped, and dated by a registered Professional Engineer (P.E.) licensed to practice in the state of Colorado. 2. Repeat portion of comment No. 5 from 09-28-2007. The site is in the FEMA 500-year floodplain for the Poudre River. The Poudre River 500-year floodplain will not change as part of the Dry Creek Diversion Project. Therefore, no critical facilities will be allowed within the Poudre 500-year Floodplain. a. The response to comments provided by QED Associates indicates all proposed critical facilities have been removed from the proposed use list. This must be explicitly stated on Page 4, 4th Paragraph of the ODP Drainage Report, and may read as follows; "No critical facilities shall be constructed in the Poudre River 500-year floodplain per City Code 10- 81(a)." The same note shall be added to the General Notes of the construction drawings. 3. Please adjust the reference to DFIRM Panel 08069C981 F on Page 4, 4th Paragraph, 1 st Sentence of the ODP Drainage Report to represent the correct community number. The current report includes too many zeros in the community number. 4. Please identify the source of the 20 cfs of groundwater flow identified on Page 8, 4th Paragraph of the ODP Drainage Report for completeness of documentation. 5. Please add hydraulic output from Cross Section 2 to Table 2 on Page 9 of the ODP Drainage Report, and to Table 3 on Page 11 of the same. 6. The HEC-RAS model output for the DC3 Capacity Analysis, as modified by QED Associates, is included in the Appendix of the ODP Drainage Report. Page 24 of the HEC- RAS-generated report indicates River Station 2 is flowing at or near critical depth. The downstream boundary condition is defined with a normal depth condition, with a user - defined friction slope of 0.0033 ft/ft. Due to this user -defined downstream boundary condition, River Station 2 should not be reporting a critical depth solution. It is likely that the calculated water surface elevation at River Station 2 is too low due to the critical depth solution at that section. This problem is clearly illustrated on the 11 "xl 7" general profile included in the Appendix after the HEC-RAS cross sections plots. Page 1