HomeMy WebLinkAboutpitkin.eh.246527402007 (2008)_NEW ADD EMAIL,,
MEMORANDUM
To: Suzanne Wolff, Planning Department
From: Warren Rider, Environmental Health & Natural Resources Department
Date: March 27, 2008
Re: Middle Ranch LLC Activity Envelope, Site Plan Review, Special
Review and GMQS Exemption for TDR Receiver Site and a Caretaker
Dwelling Unit (PID 2465-274-02-007; Case P022-08)
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SUMMARY OF RELEVANT PARTS OF APPLICATION: The applicant is requesting activity
envelope and site plan approval to construct a single family home, caretaker dwelling unit and
three creek crossings to access the property.
DISCUSSION: The Pitkin County Environmental Health & Natural Resources (EH/NR)
Department has reviewed the details of the Middle Ranch LLC application under the authority of
the Pitkin County Land Use Code and has the following comments.
Warren Rider conducted a site visit on November 15, 2007; Catherine Berg and Suzanne Wolff
were also present. Mitch Haas was present as the applicant's representative.
Water Courses and Drainage: Section 7-20-30:
Applicant proposes to cross three watercourses on the subject property: West Sopris Creek, an
unnamed tributary to West Sopris Creek, and a small intermittent stream. Applicant proposes
that the crossings of both West Sopris Creek and the unnamed tributary will be designed to
pass the 100-year event and the intermittent stream crossing will be designed to pass the 25-
yearevent. Applicant asserts that runoff will be managed in a manner that will minimize erosion
and sediment transport and commits to a more detailed plan at time of building permit
application. Applicant shall submit a drainage and erosion control plan and/or CDPS General
Permit for Stormwater Discharges Associated with Construction Activity (including stormwater
management plan) to staff for review and approval at time of Building/Earthmoving Permit
application.
Floodplain Hazards: Section 7-20-40:
Applicant has noted that the only mapped floodplain on the subject property is along West
Sopris Creek. This area is mapped as Zone A and therefore does not have determined base
flood elevations (BFEs). Even though West Sopris Creek does not have determined BFEs, and
applicant has designed the crossings to pass the 100-year event on West Sopris Creek,
applicant will be required to submit a Floodplain Development Permit Application to Pitkin
County EH/NR for all development within the mapped Zone A areas.
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River and Stream Corridors and Wetlands: Section 7-20-80:
Applicant commits to maintaining all required setbacks to water courses, wetlands, and riparian
areas, with three exceptions. The three exceptions exist to allow for roadway stream crossings
on the subject property. Applicant states that all three crossings have been designed to
minimize impacts to the stream, riparian, and wetland resources on the parcel and that
adequate mitigation will take place when impacts occur.
The crossing of West Sopris Creek will be achieved by installing a 130-foot free span bridge
that will originate and terminate outside all riparian and wetland communities. However, the
bridge abutments will encroach within the 100-foot setback to streams and watercourses. Per
Sec. 7-20-80 (c)(1), "(b]ridges, roads, paved and gravel trails ...maybe permitted in riparian
and wetland buffer areas upon a finding that there is no feasible altemative location and that
any adverse impacts will be adequately mitigated as required by subsection (d) below."
The crossing of the intermittent channel proposes to impact 480 square feet of the channel and
its associated wetlands. As the applicant understands it, this small fringe wetland is the result
of irrigation return flows and may not occur or exist under natural conditions. This crossing will
utilize two 24-inch culverts.
The crossing of the unnamed tributary to West Sopris Creek will be achieved through the
installation of a 45-foot free span bridge that avoids direct impacts to the stream and its
associated riparian and wetland resources. As is the case with the West Sopris Creek crossing,
this bridge will encroach into the setback but is exempted per Sec. 7-20-80(c)(1) (see above).
To take advantage of the exceptions to the setback requirements of Sec. 7-20-80, an applicant
must demonstrate that there is "no feasible alternative location" for its proposed development.
Applicant has explored the possibility of utilizing the existing ranch road and determined that it is
not feasible. Applicant has indicated that to bring the existing ranch road into compliance,
blasting would need to occur. Sec. 7-100-20 states that "No activity or development shall cause
inherent and recurring generated vibration perceptible without instruments at any point along
the property line." This may preclude the applicant from blasting to create the alternative
roadway. Applicant has also demonstrated that the existing ranch road crosses slopes greater
than 45% for more than 100 feet, which is not permitted under the Land Use Code. Applicant
also states that utilizing the old ranch road would create greater harm to the aquatic resources
than the proposed alignment.
Applicant has committed to mitigate any adverse impacts to riparian and wetland resources.
Applicant proposes the creation of 1000 square feet of wetland adjacent to the unnamed
tributary to mitigate for the 480 square feet of impact associated with the crossing of the
intermittent stream. All reclamation/mitigation of disturbed areas within the buffer areas must
be carried out in accordance with the Pitkin County Revegetation Guide, U.S. Army Corps of
Engineers standards or conditions, Colorado Division of Wildlife standards or conditions, and
USEPA standards or conditions, as applicable to this project. Applicant shall submit detailed
mitigation plans with its future Building/Earthmoving Permit(s) to be reviewed and approved by
staff and such plans shall be accompanied by, and demonstrate compliance with standards and
conditions set by other permitting or referral agencies.
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EH/NR staff recommends approval of this application for activity envelope and site plan review.
Applicant has committed to site design characteristics that protect and enhance water courses
and the natural resources related to them. Where impacts do occur, applicant has provided
commitments to address and mitigate those impacts.
Summary of Conditions of Approval:
Applicant shall submit a drainage and erosion control plan and/or CDPS General Permit
for Stormwater Discharges Associated with Construction Activity (including stormwater
management plan) to staff for review and approval at time of Building/Earthmoving
Permit application.
Applicant will be required to submit a Floodplain Development Permit Application to Pitkin
County EH/NR for all development within the mapped Zone A areas.
All reclamation/mitigation of disturbed areas within the buffer areas must be carried out in
accordance with the Pitkin County Revegetation Guide, U.S. Army Corps of Engineers
standards or conditions, Colorado Division of Wildlife standards or conditions, and
USEPA standards or conditions, as applicable to this project. Applicant shall submit
detailed mitigation plans with its future Building/Earthmoving Permit(s) to be reviewed
and approved by staff and should be accompanied by, and demonstrate compliance with
standards and conditions set by other permitting or referral agencies.
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