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<br />" <br /> <br />. <br /> <br />w <br />o <br />CD <br />o <br /> <br />~ .~\h..<{.. <br />'J t/z.fJ? 1'0'- <br /> <br />PROPOSAL <br /> <br />SEDIMENT :ANDSALINITY REDUCTION IN THE COLORADO RIVER BASIN <br />THROUGH <br />IDENTIFECATION AND TREATMENT OF EXCESSIVELY ERODING LANDS <br /> <br />SUMMARY: . <br />This proposal if implemented will identify eroding lands which <br />are contributing excessive amounts of salinity/sediment. toth~ <br />colorado River system that have a high probability of being <br />feasible to treat. Other benefits will also be derived from study <br />data. Time. frame for the study is one year. Personnel required <br />include a Sedimentation Geologist, a Range. Conservationist, a <br />Hydrologist. and a part time.. Soil scientist Total cost is frol\l <br />$150.000 to :$200,000. <br /> <br />SEDIMENTATlqN: EROSION VS. SALINITY: <br />salinitly enters the Colorado River system in two ways: <br />1) thrqugh groundwater and; <br />2) as S!;ldiment in transport through streams. Not all sediment <br />is of concern in regards to salinity control. <br /> <br />The Gol~rado River Basin does contain many saline bearing rock <br />units. The MancoS Shale, Carmel Formation, Tropic Shale, and Green MO<wlC.~i <br />River Formatlions are Just some of the h~gher sa1t content geolcigic''T.. <br />rock u"lL...' '.linese salt-laden rock units weather into soil which <br />can then become sediment through the processes of wind and water <br />erosion. A~ the sediment undergo mechanical erosion, the.size of <br />the indi vid1.tal particles decreases and the total surface area <br />subject to Elrosion increases. After a sediment mass is mobilized <br />by erosion into active stream drainages, it is constantly being <br />acted upon: by physical and Cl1emical processes. All of its <br />components (iincluding salt) are released directly into the surface <br />water and groundwater regimes. <br /> <br />The abciVe sedimentation scenario means that 100%.of. the salt. <br />content in amass of sediment or soil delivered t-n " . stream is <br />~vailable fqr dissolution into the stream and groundwater. Field <br />testing of carbonate- rich sOil/sediment of the Uinta Formation in <br />Duchesne County, utah, results in a positive test in the eroding <br />alluvial fan's and a negative test in the sediments at the outlet of <br />the channel a few miles downstream. This illustrates the efficient <br />removal of salts from sediment within alluvial channels. <br /> <br />In the Colorado River Basin there are rock units with varying <br />salt conten~s. Consider that for every ton of moderately saline <br />(3%) sediment/soil mass in a stream there are 60 pounds of salt <br />delivered or for every 33.3 tons of sediment delivered to the <br />stream there is 1 ton of salt delivered to the system. <br /> <br />;J <br />Yi <br />'-'\i <br />'-:j <br /> <br />- '-._'..-"'<.' <br /> <br />-" <br />