Arkansas River; Bad Water Under Scrutiny: AG Journal

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Alm ansas river: Pact . water and By Michael Stoton ROCKY FORD, Colo. The Arkansas River is the most saline river, according to the U.S. Geological Survey (USGS), for its size in the United States. USGS records show that close to one million tons of salt was carried down the Arkansas and it's various canals in, 1999. As as example of salinity levels the Colorado River, as it enters Mexico, has about 800 to 1,000 parts per million (ppm) total dissolved solids (TDS). The Arkansas as it enters the State of Kansas ranges up to 5,100 ppm TDS. These levels have created concern among communities along the Arkansas River Basin and the real- ization that corrective measures have to be taken. Jim Valliant, regional irrigation specialist with Colorado State University,, says that there are sever- al efforts being made to help improve the quality of downstream waters in the Arkansas River. "Colorado State University is look- ing at more effective ways to apply our irrigation water that will reduce runoff and excessive leaching, two major sources of salting," he, said. "Some of the practices we are demon- strating and researching are surge irrigation, where we have substan- tially reduced the amount of water applied to the crop by more uniform irrigation and reducing runoff, up to 74 percent by combining the use of polyacrylamide (PAM) with surge." The Colorado River Salinity Control Program, a joint venture of the U.S. Bureau of Reclamation, USDA Natural Resources Conservation Service; and Cooperative Extension, measured on -farm and system -level irrigation performance in the Grand/Gunnison valley during the 1980s and early 1990s. During this period testers found that there is considerable potential for reducing selenium loading to the Gunnison and other rivers by improving irrigation system perform- ance. Karla Brown.Tri- River, wren wnfa, quality specialist at the CSU Cooperative Extension said, "Irrigation efficiencies were much lower than necessary with losses from canal seepage, deep percolation on the farm and tail water ranging from 50 percent to '90 percent of the water diverted from the river. The er scrutiny program documented that reducing these losses. would reduce salt load- ing ' to the Colorado River, and it follows that. selenium loading would be reduced. as well since the mecha- nisms are very similar." o, See Salinity page 24 M N 0 0 C11 Cq ..o o�i