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SECTION 2 Study Area Characteristics 2.5.1.5 Highway 99 This drainage system mainly consists of a long roadside ditch along Highway 99. This ditch drains in a northwesterly direction and into the A -1 channel. The ditch is owned and maintained by the Oregon Department of Transportation. 2.5.2 Wetlands Most wetland features within the basin are associated with riparian areas adjacent to creeks and open waterways. There are also a few wetland sites located primarily near the relatively undeveloped northern and western portions of the basin outside the UGB. About 281 acres of wetlands are identified in the basin in the National Wetland Inventory (NWI) which provides basic data about the general characteristics and extent of wetlands in the nation. The NWI identifies the general boundaries of wetlands; however, in many instances actual wetland boundaries are more extensive than what is identified. About 54 percent of the NWI wetlands in the basin are located outside the UGB, and the area outside the UGB represents about 42 percent of the total basin area. A Local Wetland Inventory (LWI) was conducted in 2005, and the wetland sites evaluated for potential protection as part of the City and County's Goal 5 efforts. Several wetland sites in the River Road Santa Clara basin are identified in the adopted 2007 Goal 5 Water Resources Conservation Plan in the River Road Santa Clara basin and are protected in the form of the Water Resources Conservation Overlay Zone adopted by the City of Eugene and Lane, including setbacks ranging from 25 to 50 feet from the jurisdictional wetland boundary. The River Road Santa Clara basin also includes several open water ponds; all located in the general vicinity of the Northwest Expressway and /or Highway 99 North. These ponds are identified in the adopted 2007 Goal 5 Water Resources Conservation Plan as Site E62: Northwest Expressway Ponds. The Northwest Expressway ponds are located just south of Maxwell Road and on both the east and west sides of the Northwest Expressway. The eastern pond (Dianna's Pond) is within the River Road Santa Clara basin and is hydrologically connected with Upper (or South) Flat Creek. The pond is a former borrow pit that currently supports willow, black cottonwood, reed canary grass, rush and sedge as the predominant plant species. The southern and eastern arms of the pond have healthy riparian strips, while much of the rest of the banks are bare and eroding. 2.5.3 Public Piped Drainage System Most of the existing development in this basin occurred prior to the City of Eugene having jurisdiction over urban land use requirements and, as a consequence, this basin lacks a stormwater pipe system found in the other basins. Only 94.5 miles of stormwater pipes exist in this basin and 43 of these miles are located outside the UGB, mostly serving Mahlon Sweet Airport. The piped system located within the UGB was constructed to serve more recent development that was required to annex and develop to City of Eugene standards. See Map 5. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 2-16