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Ecological Role and Site Context Portland Metro' provides the following definition of a Riparian Area: "Land and vegetation adjacent to waterbodies such as streams, rivers, wetlands and lakes that are influenced by perennial or intermittent water and hydric soils (soils formed under periodic saturation or flooding). These areas are dynamic biological and physical systems that act as the interface between terrestrial (land) and aquatic (water) ecosystems. " One of the most important zones of a riparian area is the floodplain, which Metro defines as "the area immediately adjacent to the stream or river channel that becomes inundated with overbank flows during large storm events." The floodplain by its very definition is a dynamic and changing environment. As described below, maintaining floodplain dynamism while simultaneously creating sufficient bank stabilization and flood protection to meet the needs of intensive human use and economic development is one of the key challenges of urban riparian restoration. Recovery of riparian ecological function typically emphasizes restoration, defined by the Society for Ecological Restoration as "the process of assisting the recovery of an ecosystem that has been degraded, damaged or destroyed ". Ecological science emphasizes that maintaining biodiversity and other important ecological functions depends primarily on the maintenance of dynamic ecological processes that create and maintain diversity, rather than the simple recreation of habitat structure itself. In this section we will analyze the historical and current ecological role of the EWEB site in relation to existing riparian vegetation and structure in public ownership on both the north and south sides of the Willamette River within the Eugene - Springfield metro area. Historical and Desired Conditions The historical plant communities of the EWEB Riverfront Property are described by the 1850s General Land Office Survey, conducted roughly at the time of Euro- American settlement. Figure 2 shows the landscape mosaic of riparian forest (bright green), wetland and upland prairie (pale green and tan), and oak savanna (brown) that comprised the majority of the valley floor and lower foothills. The red arrow indicates the approximate location of the EWEB site. Today, riparian forest occupies less than 20% of its historical area along this reach of the Willamette River. The survey shows that circa 1850 a majority of the 27 -acre EWEB site was covered by riparian bottomland forest with a small sliver of upland prairie in the southwest corner (Figure 3). Riparian forest occupied the north bank of the river as well, with areas of oak savanna and upland prairie bracketing the riparian forest on both sides of the river. During this time, the riparian bottomland forests of the Willamette Valley included a diverse mosaic of bushy thickets, marshes, and tree stands averaging 1 -2 miles in width 1 Portland Metro. January 2002. Technical Report for Goal 5, Revised Draft. 2 Society for Ecological Restoration International Science & Policy Working Group. 2004. The SER International Primer on Ecological Restoration. www.ser.org & Tucson_ Society for Ecological Restoration International. 3 Hulse, D_ W_, S_ V. Gregory, and J. P. Baker. 2002. Willamette River Basin: Trajectories of environmental and ecological change. Oregon State University Press, Corvallis, OR. 0