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HomeMy WebLinkAboutpitkin.eh.264305302001 (2008)_MEMODocument Layout (From Most Recent to Oldest Permit) Permit Application Log Sheet/Notes & Photos Communications. As -built Design Engineer Design Soil Information Water Permit & Information Second System on property Third System.etc. Floor Plans Please See Building and Land Use Approvals Files for additional information. 0 MEMORANDUM To: Suzanne Wolff, Community Development Department From: Warren Rider, Environmental Health & Natural Resources Department Date: April 10, 2008 Re: Aspen Valley Ranch Special Review, Designation to Historic Register, Minor Amendment to Development Permit, GMQS Exemption (PID 2643-053-02-001; Case P166-07) ------------------------------------------------- ------------------------------------------------- SUMMARY OF RELEVANT PARTS OF APPLICATION: The applicant is seeking approval for streambank restoration and enhancement, pond development, and encroachment into the established setbacks to river and stream corridors and wetlands. DISCUSSION: A site visit was conducted on June 26, 2007 by Warren Rider and Suzanne Wolff from the Community Development Department. The Pitkin County Environmental Health & Natural Resources Department ("EH/NR") has reviewed the details of the Aspen Valley Ranch application under the authority of the Pitkin County Land Use Code and has the following comments. 1-60-220 Erosion Applicant has stated that the owners of individual lots will submit erosion control plans as part of the construction management process. Applicant currently holds a State of Colorado Stormwater Discharge Permit for Construction. This permit should cover activities for the individual lots until permits are transferred to individual lot owners. Subdivisions are viewed as a "Common Plan of Development" under CDPHE stormwater rules: 'A common plan of development or sale' is a site where multiple separate and distinct construction activities may be taking place at different times on different schedules. Examples include: 1) phased projects and projects with multiple filings or lots, even if the separate phases or filings/lots will be constructed under separate contracts or by separate owners (e.g., a project where developed lots are sold to separate builders); 2) a development plan that may be phased over multiple years, but is still under a consistent plan for long-term development; and 3) projects in a contiguous area that may be unrelated but still under the same contract, such as construction of a building extension and a new parking lot at the same facility. If the project is part of a common plan of development or sale, the I o� 3 0 0 disturbed area of the entire plan must be used in determining permit requirements. CDPHE website, accessed January 4, 2008, Stormwater Fact Sheet - Construction, emphasis added. Applicant shall provide for all lots to be included within its Stormwater Management Plan until its permit(s) can be officially transferred to individual lot owners through CDPHE. 7-20-30 Water Courses and Drainage Applicant proposes streambank restoration and channel enhancements on Red Canyon Creek as well as diversions and potential pond and wetland creation. Sections 7-20-30(c)(1)(a) and (b) require "[m]aintenance of historical flow patterns and runoff amounts to reasonably preserve the natural character of an area" and the "unimpeded flow of natural water courses." Applicant has not provided details on the specific methods to be employed in those areas proposed for enhancement. Recommendations from a restoration hydrologist have been provided but again, design details have not been provided for review. Proposed actions have not adequately addressed how maintenance of historical flow patterns will be achieved, nor has the applicant addressed how the natural character of the area (stream corridor) will be preserved given the potential diversions of water out of the natural channel. Diversions, in and of themselves, could be viewed as impediments to the flow of natural water courses on the property by generating reductions in natural flows through Red Canyon Creek. Applicant shall show that the proposed actions do not adversely impact the natural character and function of Red Canyon Creek. Generation of man-made wetlands, ponds, and trout fisheries should not be approved at the expense of the natural systems of Red Canyon and Dry Woody Creeks and in the name of "habitat improvements." 7-20-40 Floodplain Hazards Applicant represents that no improvements will be located within the floodplain with the exception of one homestead driveway and stream enhancements. Applicant was not specific as to which homestead this driveway applies to. However, if no other alignment is possible for the driveway and the applicant applies for and receives a Floodplain Development Permit the proposed driveway could be allowed within the floodplain. Stream enhancements would also be allowed within the floodplain if a Floodplain Development Permit is applied for and issued. In reviewing the application, staff observed that the ISDS easement on Homestead 4 appears to encroach into the floodplain of Red Canyon Creek. Section 7-20-40(b)(2)(g) states that "no use, fill, construction, excavation, embankment, or alteration on or over any portion of the floodplain shall be permitted that would result in ... [t]he infiltration of floodwaters into on-site wastewater disposal systems that would impair their functioning or pollute the stream." Applicant was required to address this issue before approval of the application and remove the ISDS easement from the floodplain of Red Canyon Creek on Homestead 4. This requirement has not been completed by applicant. 7-20-80 River and Stream Corridors and Wetlands Applicant does not propose extensive encroachment into the setbacks as established in Section 7-20-80. However, applicant has vested rights allowing for encroachment into the current setbacks on Homesteads 4, 8, and 9. Additional proposed actions within the established setbacks include stream restoration and enhancement actions, as described in Attachment 6 to the application. Per Section 7-20-80(c)(2), "[b]ank stabilization and riparian restoration work may also be permitted in riparian wetland buffer areas upon a finding that any adverse impacts will be adequately mitigated as required by subsection (d)." As noted above, applicant has provided a narrative description of activities that are being contemplated. No details, design specifications, or channel restoration techniques have been provided to adequately determine whether or not the proposed (or contemplated) activities meet the requirements of Section 7-20-80. Applicant should provide more detailed description and details of the proposed actions prior to approval of those portions of the application. Summary of Conditions of Approval: Applicant must provide details on the specific methods to be employed in those areas proposed for stream enhancement. Applicant shall show that the proposed stream enhancement actions and water diversions do not adversely impact the natural character and function of Red Canyon Creek. Applicant must remove the ISDS easement from the floodplain of Red Canyon Creek on Homestead 4. V