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Pacific Water Resources, Inc. <br /> Lower Amazon Floodplain Analysis <br /> City of Eugene Public Works Department <br /> Project #3890 <br /> PACIFIC SCOPE OF WORK <br /> WAFER RESOURCES, INC. <br /> December 31, 2003 <br /> <br /> Project Understanding <br /> The City of Eugene desires a floodplain study of Lower Amazon Creek from Greenhill <br /> <br /> Road to the downstream limit of the existing detailed FEMA flood study at the Southern <br /> <br /> Pacific Rail Road (SPRR). The Corps, in partnership with the City of Eugene, recently <br /> constructed a wetland restoration project in this area, which may provide some flood <br /> <br /> reduction and/or storage benefits. The area in question is designated an "approximate A <br /> zone" by FEMA for which each new development must perform an analysis to determine <br /> BFE's. The results of this floodplain study will determine: 1) to what extent the Corps <br /> project provides additional flood protection and/or storage and 2) will result in more <br /> updated and more detailed base flood elevation data. It is the intent of the City to work in <br /> partnership with FEMA under their "Cooperating Technical Partners" agreement to <br /> conduct this study and then submit a letter of map revision (LOMR). <br /> This reach of the Lower Amazon is extremely complex both hydrologically and <br /> hydraulically. Significant work has been performed by others over many decades to <br /> understand and alter area hydrology and hydraulics. The complexities of this reach <br /> include: a diversion of the main flow of the Amazon Creek (Diversion Channel), the <br /> original creek alignment (A Channel), a siphon structure of the Greenhill Road ditch <br /> under the Diversion Channel, a structure on the A Channel which produces the flow split <br /> to the Diversion Channel, a structure at the confluence of the Greenhill tributary and the <br /> A Channel, existing uncertified levees below Royal Avenue, an existing wetland <br /> restoration/setback levee project upstream from Royal Avenue (pending certification), <br /> backwater effects from Fernridge Reservoir and tributary areas associated with the <br /> PACIFIC <br /> r WATER RESOURCES, INC. <br /> <br />