Laserfiche WebLink
Another objective was to conduct preliminary hydrology screening at a <br />few (up to 20 sites) bottomland sites that ranked highest from the <br />prioritization. We believed that predicting flows necessary for overbank <br />flooding to inundate a bottomland site was necessary for determining sites <br />that could be practically restored or enhanced. <br />STUDY AREA <br />The study area included the mainstem river channels and adjacent <br />bottomland habitats in the Upper Colorado River Basin (Figure 1). River miles <br />[(rm); river kilometers (rkm)] inventoried were 398 rm (640.5 rkm) in the <br />Green River, 50 rm (80.5 rkm) in the Yampa River, 104.5 rm (168.2 rkm) in the <br />White River, 241 rm (387.9 rkm) in the Colorado River, and 75 rm (120.7 rkm) <br />in the Gunnison River. <br />METHODS <br />Inventory <br />A two-step approach was used to accomplish the bottomland inventory. <br />First, potential bottomland habitats adjacent to mainstem rivers were <br />identified and inventoried in 1993. Inventorying sites included cataloging <br />various information from different photographic imagery. Second, each <br />bottomland habitat site was classified using a numerical score from four <br />selection criteria, and prioritized in 1994. <br />Identification of Bottomlands <br />All existing information necessary,to conduct this aspect of the study <br />was identified and assembled. This included topographical maps (7-1/2 minute <br />quadrangle maps), land status maps, and various aerial photographic imagery <br />that included videography, color infrared photographs, and 35-mm colored <br />slides. Information sources included the U. S. Army Corps of Engineers, U. S. <br />Bureau of Reclamation (BR), U. S. Bureau of Land Management, U. S. Natural <br />Resources Conservation Service (NRCS), Argonne National Laboratories, and FWS. <br />A Cessna 206 fixed-winged aircraft was used to conduct low-level <br />reconnaissance photography flights over bottomland habitats along the Green <br />and Colorado rivers in 1993. The NRCS provided equipment and assistance <br />during each photography session. A 35-mm camera loaded with color slide film <br />was attached to the underside of the plane to facilitate direct overhead <br />photography of bottomland sites. The plane was flown at an altitude of 5,000 <br />to 6,000 feet (above ground level) directly overhead to allow for photo-image <br />coverage of the main river channel and adjacent floodplain areas. <br />Aerial photographs were taken along the Green, Yampa, and White rivers <br />in the Green River drainage and the Colorado and Gunnison rivers in the <br />Colorado River drainage during 1993. The beginning and ending locations for <br />flights in these river drainages were as follows: <br />3