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4 - Wetland Permit WP 02-04, Boulder Auto Park, Lots 2 and 4ACITY OF BOULDER / ~~`~~ WETLAND PERMIT ~ Final Approval Date: Mav 29, 2002 Any appeel or call up must be received in wdUng pdor to 5:00 p.m. on this date. PitoJEC'r: Boulder Auto Pazk, Lots 2 and 4A Location: 5995 Arapahoe Avenue APPLICANT: Wells Group Architects Contact Person: Ron Wells (303-443-4202) Wetland Permit No: WP 02-04 DESIGNATED WETLAND: Wetland #50, South Bouldei Creek Functional Value Ratings: South Boulder Creek north of Arapahoe Avenue is a historically channelized and heavily disturbed area. Wetland areas containing hydrophytic vegetation occur within the creek section averaging 10 feet in width with a jurisdictiona] riparian fringe of approximately 20 feet along either side. Steep side slopes four to six feet in height confine the riparian corridor with a distinct transition to upland vegetation in the 50-foot wide wetland buffer. Highest functional values of this wetland include flood storage, shoreline anchoring, sediment trapping, short-term nutrient retention and removal, downstream food chain support and wildlife habitat. Moderate functional values include ground water rechazge and in-basin food chain. support. PxoJECT/AcTiviTY DESCx[rT[ox: The project at 5995 Arapahoe Avenue includes the construction of an addition to the existing service center building on I.ot 2, Boulder Auto Park, for Flatirons Acura. It also includes the construction of a second 5,300-square foot service building and 41,580-square foot asphalt parking lot on I.ot 4A adjacent to Lot 2 on the northeast side of the Public Service Company Feeder Canal. Improvements that extend into the regulatory wetland area include a buried 18-inch diameter storm-water outfall pipe to South Boul@er Creek with a rock erosion apron. Wetland area to be disturbed by the improvements totals 222 square feet. This impact will be mitigated by the provision of 444 square feet (2:1 ratio) of wetland enhancement along South Boulder Creek to reduce erosion potential and enhance wetland vegetation. Improvements within the wetland buffer include construction of a water quality pond to treat runoff draining to the South Boulder Creek storm water outfall and a limited widening of the Lot WP 02-O1 Broadway Utilities wETL^noeeR"uT 2 service driveway around the west side of the existing building to accommodate the new building addition. Wetland buffer impacts total 1,965 squaze feet for the water quality pond and 430 square feet for the driveway. The water quality pond construction creates a temporary impact and will be revegetated. The driveway expansion will pave a small portion of the wetland buffer without draining towards the creek and will not alter the hydrology serving the wetland. BASIS OF APPROVAL: Underground utility drainage and storm water outfall systems may be permitted in a wetland area, and water quality ponds and paved driveways may be pernutted in a wetland buffer under Section 9-12-8, "Standards for Wetland Permits," Boulder Revised Code 1981 (B.R.C.), if the applicant has demonstrated: (a) That all adverse impacts on a wetland have been avoided through a reduction in size, scope or density of the project, or through a change in configuration or design, or that it is not feasible to do so; South Boulder Creek is the primary storm water system serving the Boulder Auto Park area and provides the final storm water outfall for the basin. Direct wetland impacts aze ]imited to the storm water outfall and erosion protection measures proposed affecting a tot~l wetland area of 222 square feet. Mitigation proposed to offset the impact will provide a 2:1 ratio enhancement (444 square feet) of the South Boulder Creek wetland corridor through the planting of new wetland vegetation and management of non-native and weedy species. In addition, a storm water quality pond will be provided in the wetland buffer to avoid any adverse affect of storm water runoff draining from the project site. (b) That any impact on a wetland has been minimized, will result in minimal impact or impairment to any wetland function, and will not jeopardize the continued existence of habitat for identified plant, animal or other wildlife species; The South Boulder Creek wetland has been historicaIly channelized and heavily impacted. Direct wetland impacts proposed are limited to the storm water outfall and erosion protection affecting 222 square feet. Mitigation proposed wil] enhance wetland functions with the addition of wetland vegetation and management of non-native and weedy species. The proposed improvements encroaching into the wetland and wetland buffer are not expected to adversely impact the existing habitat for critical plant or wildlife species. This reach of South Boulder Creek is not considered to provide habitat for threatened species Preble's meadow jumping mouse (Zapus hudsonius preblei) or Ute-Ladies Tresses Orchid (Spiranthes diluvialis), and known populations of species of concern Plains Topminnow and Orange-Spotted Sunfish are more than a mile from this location. The U.S. Army Corps of Engineers issued Nationwide Permit No. 43, Corps File No. 2 WP 02-O1 Broadway Utilities wE'n.,+no P~RnuT 20028127, March 18, 2002, approving the proposed improvements and providing cleazance for the U.S. Fish and Wildlife listed species. (c) That the project is in the public interest, considering the public need, the functional values of the wetland that may be affected, the extent and permanence of any adverse effects and the cumulative adverse effects of past activities on the wetland, and the uniqueness and scarcity of the wetland that may be affected. Development of the property has been anticipated under the Boulder Valley Comprehensive Plan, and the proposed project and use was approved under Site and Use Review, LUR 2001-00056, Direct impacts to the South Boulder Creek regulatory wetland aze the minimum necessary to provide a storm water outfall from the property to the creek, and the creation of the storm water quality pond serves to enhance the water quality of runoff entering the creek. The impacted regulatory wetland along the bank of South Boulder Creek is not unique and historically is channelized and heavily impacted. The wetland will not be adversely affected by the proposed improvements. Considering the standards outlined under Section 9-12-8, staff finds that the proposed project meets the intent of 9-12-1, B.R.C. j CONDITIONS OF APPROVAL: 1. All construction and work activities in the regulatory wetland and wetland bu~'fer shall conform to the "City of Boulder Wetland Permit Application, Boulder Auto P~ark Lots 2& 4, 5995 Arapahoe Road" prepared by Ecological Resource Consultants, Inc., dated July 2001. 2. All construction and work activities in the regulatory wetland and wetland buffer area shall comply with the "City of Boulder Wetlands Protection Program Best Management Practices (BMPs) and Revegetation Rules." 3. Mitigation monitoring and related maintenance of the storm water outfall mitigation area and buffer shall be performed for a period of five yeazs after project completion. Special attention should be placed on_weed control, maintaining plant species diversity and successful wetland perFormance. The applicant shall control weeds and other invasive species by approved methods. Annual monitoring reports shall be prepared by a qualified wetland consultant and submitted to the city. A financial guarantee in an amount sufficient to guarantee the performance of the mitigation plan shall be provided during the five-year mitigation-monitoring period. NOTE: This permit expires three years after the date of final approval, pursuant to Section 9-12-12, "Expiration of Wetland Permit," B.R.C. 1981 WP02-04 5995 ARAPAHOE ~ WE~n,ArvD PeRMIT PERMIT ISSUANCE: Staff Review: Alan Taylor Issued By: ~ Issue Date: May 14, 2002 NOTE: Permit Approval, if Not Appealed, is Final 14 Days After NotiCcation of Permit Issuance. WP02-04 5995 ARAPAHOE 4 WETLAND PERM17'