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USEPA REGION 10 REGIONAL ENVIRONMENTAL MONITORING AND ASSESSMENT PROGRAM: CHARACTERIZATION OF STREAM RIPARIAN AREA
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The USEPA designed and implemented the Environmental Assessment Program (EMAP) to determine the current status, extent, changes, and trends in indicators of the condition of the Nations ecological resources on regional and national scales with known confidence. USEPA Region 10s Regional Environmental Monitoring and Assessment Program (REMAP) adapted EMAP procedures for inland surface waters for use at the regional level. The REMAP is a cooperative program between USEPA Region 10, the Washington Department of Ecology, and the Oregon Department of Environmental Quality. Sample sites were selected with a randomized, systematic design using Region 10s Reach File 3 as the basis of the stream population. The sample population was restricted to wadeable streams represented by the blue- line stream network on USGS 1:100,00 maps. In 1994, 60 sites were sampled in the Coast Range Ecoregion (30 sites per state) and 15 sites were sampled in the Yakima River Basin. The study was repeated in 1995. In 1996, only Oregon conducted sampling; 30 sites in the Coast Range Ecoregion. Included as a component of the physical habitat assessment, estimates of riparian vegetation cover and structure were made to evaluate the health and level of disturbance of the stream corridor. Observations were made for each bank at odd-numbered locations of 11 equally- spaced transects in each stream reach. Three layers of riparian vegetation were measured: canopy, understory, and ground cover. Anthropogenic influence was evaluated by measuring the presence and proximity of various types of human land use activities in the stream riparian area. Riparian canopy cover over the stream was measured at every transect using a convex spherical densiometer. Data sets for other components of the physical habitat assessment are available, as well as other related data sets (e.g., fish, water chemistry) for this study, and can be linked with this data set.