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RESIILTS <br />Historv of the Study Site <br />Aerial photographs four dates 1957, 1966, 1982, 1988 and <br />1993 were examined to determine changes that have occurred to the <br />site in the elapsed 36 years. The site conditions during each <br />year are briefly described. <br />1957. During 1957 the site was very different than it <br />appears today. The river meandered widely through the study area <br />and several large ox-bow systems occurred. This photograph was <br />copied from the USDA Soil Survey of the area, and little detail <br />can be seen. <br />1966. During June of 1966 large unvegetated point bars <br />occur on the inside of every meander bend. Today these bars are <br />completely or largely stabilized and support Fremont cottonwood <br />forests which must date from this time. The ox-bows at station <br />CE10 and CE2 appear connected to the river and actively supported <br />aquatic ecosystems. Several ox-bows and floodplain forest areas <br />seen on this photograph are today in agricultural production. <br />However, these sites were all inundated by floodwater during <br />1993. <br />1982. By 1982 dikes were constructed on the north side of <br />the river from its eastern property edge downstream through the <br />first big meander. Cottonwood forests were well developed by <br />this time on the bars seen in the 1966 photographs. In addition, <br />the only large stream channel flowed along the southern side of <br />the property where today two large channels occur. <br />1988. By 1988 the river was actively cutting a new channel <br />through the center of the property. This cutting may have <br />occurred during the large water years of 1983 through 1986. A <br />considerable area of cottonwood forest has been eroded and bare <br />bars are visible again, although not of the extent as was seen in <br />1966. <br />1993. The photograph from 1993 was taken during high water <br />and obscures some land features, but makes the flooding patterns <br />clear. Since 1988 the new channel has become the primary <br />channel, and the old channel is a late summer backwater. The <br />river has also claimed a considerable area of land on the <br />northern side of the river, and a new dike was built to contain <br />it. <br />4 <br />