Vantage to Pomona FEIS Index 34 - Laserfiche WebLink

Home Browse Search

Vantage to Pomona Heights Chapter 3 230 kV Transmission Line Project FEIS Affected Environment PAGE 3-281 Dam (Wanapum Dam Reservoir). In Kittitas County, shoreline jurisdiction includes: all shorelines of the state; upland areas (shorelands) within 200 feet of the ordinary high water mark of those waters; associated wetlands and river deltas; and floodways and contiguous floodplain areas landward 200 feet from such floodways. All proposed uses and development occurring within shoreline jurisdiction must conform to the intent and requirements of RCW Chapter 90.58, the SMA, and the Kittitas County SMP whether or not a permit or other form of authorization is required. No substantial development shall be undertaken on shorelines of the state without first obtaining a permit. If any of the support structures will be located within 200 feet of the OHWM of the Columbia River or Manapum Dam Reservoir or if there will be any ground disturbing activities within this same area, the appropriate permit (substantial development, variance, or conditional use) will be acquired through Kittitas County. Floodplains A floodplain is the area on the sides of a stream, river, or watercourse that is subject to periodic flooding. The extent of the floodplain is dependent on soil type, topography, and water flow characteristics. A 100- year flood is a flood stage that statistically has a one percent probability of occurring in any given year. Flood flows are typically experienced in the Columbia River Basin during May and June as a result of the melting of the winter snowpack. Maximum flood peaks result from heavy snow accumulation and a prolonged period of intense snowmelt, occasionally augmented by heavy rain. Natural streamflow recedes during July and August and remains at relatively low levels throughout the winter (U.S. Army Corps of Engineers [USACE] 2003). Floodplain categories in the Project study area included 100-year floodplain zones (Zone A) and no flood zones (Zone X), which are outside the 100 and 500-year floodplains. Flood Insurance Risk Zone A areas are subject to inundation by the one-percent-annual-chance flood event. Hundred-year floodplains located within the Project study area (two-mile wide corridor) are associated with the Yakima River, Lower Crab Creek, Dry Creek, and Selah Creek. No 500-year floodplains are located within the Project study area. The 100-year floodplain associated with the Columbia River is located within the Project study area. Appendix A - Water Resources and Wetlands map shows floodplains in the Project study area. Wetlands The regulatory definition of Section 404 CWA jurisdictional wetlands according to the U.S. Environmental Agency (USEPA) and USACE are “those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions.” Wetlands can be vegetated or non-vegetated and are classified on the basis of their hydrology, vegetation, and substrate. Wetlands are classified according to the system proposed by Cowardin and others (Cowardin et al. 1979), which is used by the NWI to map and inventory the nation’s wetlands. Given the semi-arid nature of the Project study area, wetlands are scarce. The three wetland types found within the Project study area are palustrine, lacustrine, and Riverine System. Palustrine wetlands are a grouping of the vegetated wetlands traditionally called by such names as marsh, swamp, bog, fen, and prairie, which are found throughout the U.S. It also includes the small, shallow, permanent, or intermittent water bodies often called ponds. Palustrine wetlands may be situated shoreward of lakes, river channels, or estuaries; on river floodplains; in isolated catchments; or on slopes. They may also occur as islands in lakes or rivers. Within the Project study area, palustrine wetlands are