WSP04876 - Laserfiche WebLink

Home Browse Search

PART V COLORADO RIVER WATER QUALITY ASSESSMENT . .... Heavy m~tals, trace elements, and organl':s (phenyls) have also been found In drainages associated ~lth all shale depOSits. The Colorado and ....tllte RIvers could be Impacted by future 011 shale development. There are several major sources of salt loading to the Colorado River that are found ~Ithln Colorado. They Include salIne springs that naturally dlScharge to the Dolores River In the Paradox Valley and Glenwood-Dotsero Springs that discharge to the rnalnstt:m. Irrigation of saltne Mancos Shale SOils In the Grand Valley, McElmo Creek, and lo~er Gunnison areas also contribute substantially to the salt loading. "> ," ..... W 4. Anzona(5] Water quality along the Colorado River IS protected for agn- culture, aquatic life, drinking water supply, fishIng, full body contact recreation, and ~Ildllfe uses by Arizona water quality standards. Documented water qualIty problems along the rlller and In nearby ground ~ater Include elevated bacterIa counts and the presence of some agrIcul- tural chemicals. Eutrophication has long been suspected In Anzona, and the EPA has promulgated ambIent nutrIent standards on the Colorado River malnstem under Section 303(c) of the Federal Clean Water Act. . Chlorlnat Ion of eutrophiC surface waters for dnnklng W'ater systems frequently produces trlhalomethanes. Federal standards have been promulgated for total tnhalomethanes In public drinkIng W'ater systems and these substances could become a publiC health concern for W'ater systems supplied With Colorado River water. There IS concern related to unquantlfled health Impacts of several secondary drinking water quality crltena other than salinity, Including alkalinity, chloride, hardness, sodium, and sulfate. Though the role of these constItuents IS not fully understood at thiS tIme, some are suspected to have POSitive or negative Impacts on publiC health. 5. Nevada[b) The level of organIC precursors ln Las Vegas raw W'ater Intake frum Lake Mead IS Increasing so that after chlorination there is the potential of creating trlhalomethanes. ThiS may be connected to a local eutrophIcation problem ln Las Vegas Bay of Lake ~ead due to the Inflo~ of Las Vegas wastewater. SuI fates make up about 300 mg/L of the IDS In Lake ~ead, which exceeds the secondary drinking wllter cnterla. Nevada ~ould like to see Federal emphaslS on suI fate removal In salinIty control programs. 6. Cal,forn18{7] . Present Colorado River sallnlly levels are marginally suItable for such key benefICial uses as agriculture and domestIc water supply. Most of the salIne con.::entrat Ions In the Colorado River derive from sources upstre.am from Callfornla, but, to .a lesser degree, there are local Influen.::es In the Palo Verde Valley RegIon. 18