Laserfiche WebLink
<br />1- <br />~ <br />I- <br />I- <br />~ <br />~ <br />t <br />~ <br />~ <br />~ <br />~ <br />J <br />J <br />J <br />. <br />. <br />J <br />J <br />1- <br /> <br />376~ <br /> <br />Summary <br /> <br />As in the other Colorado subbasins, the USGS and EPA have <br />attempted to account for total basin salt loads by source during <br />their respective study periods. As shown below, the reports <br />differ somewhat in the portion of total basin salt yield <br />attributed to man caused and natural sources. <br /> <br />USGS <br /> <br />Man caused <br />Natural <br /> <br />24.5 percent <br />75.5 percent <br /> <br />EPA <br /> <br />Man caused <br />Natural <br /> <br />11.2 percent <br />88.8 percent <br /> <br />The EPA report gave much more consideration to industrial sources <br />and natural runoff sources. The USGS report attributed a much <br />larger portion of the total salt yield to irrigated agriculture. <br /> <br />The EPA estimate of salt yield from the Sinbad Valley-Salt <br />Creek area was developed during the 1965 and 1966 study period <br />and appears to be significantly lower than the BLM estimate of <br />over 13,000 tons per year. This is partially explained by the <br />fact that the EPA measurements of TDS concentration were much <br />lower than the BLM measurements. The EPA also references <br />unquantified additional amounts of salts that enter the Dolores <br />River as underflow from alluvium in Salt Wash Canyon. <br /> <br />The three sources which considered salt loading in the <br />Paradox Valley were relatively close. The Bureau of <br />Reclamation's determination of 205,000 tons of salt per year <br />appears to be the most accurate since it reflects the most <br />current information. <br /> <br />-33- <br />