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<br />o <br />00 <br />-..:I <br />0) <br /> <br />March 10-11, 1998 <br />Agenda Item l8d <br />Page 2 of 3 <br /> <br />EP A. The Colorado River Basin salinity standard consists of three parts: <br />1) The numeric criteria establishing specific maximum levels ofTDS (annual flow weighted <br />average) at three measuring stations in the Lower Basin (723 mg/l, 747 mg/l, and 879 mg/I at <br />Hoover, Parker, and Imperial Dams respectively), <br />2) A plan of implementation setting out project schedules and funding requirements needed to <br />keep from exceeding the numeric criteria as water development progressed in the Upper Basin. <br />3) Forum dtafted, state adopted policies governing the issuance ofNPDES permits for point <br />source discharges of salinity into the Colorado River system. <br />The standards Were adopted pursuant to the federal Clean Water Act which requires that all water <br />quality standards be reviewed every 3 years to consider the need for modification of the standards. <br /> <br />DISCUSSION <br /> <br />i. Triennial review. <br />The Forum has conducted reviews of the Colorado River Basin salinity standard every three years <br />since 1978 with the most recent review report being issued in 1996. Each of the recent reviews has <br />consisted ofthe'following elements: <br />- determining current salinity and hydrologic conditions, <br />- re-estimating future anticipated depletions ofthe basin water supply, <br />- modeling projected salinity levels at the numeric criteria stations and determining the amount <br />of salt load. which must be controlled to remain below the numeric criteria under average <br />hydrologic conditions, <br />- demonstrating the economic benefits of controlling salinity, and <br />- revising the plan of implementation to remove the necessary amount of salt in a cost-effective <br />mauner. <br /> <br />A schedule has been developed and initial work has begun on the 1999 review, Staff will be <br />participating in the analysis, report writing, and public participation efforts over the next 18 months. <br />The Report docUmenting the review process and findings will be approved by the Forum and <br />submitted to each of the states, which will then adopt the review under each state's own procedutes <br />and submit it to EP A for approval. In Colorado the staffs of the CWCB and Water Quality Control <br />Division coordinate during the review and the Water Quality Control Commission ultimately adopts <br />as a regulation and policy portions ofthe Forum approved Review, and the water quality standatds <br />for salinity thus are reaffirmed as state law. <br /> <br /> <br />ii. Standards <br />In previous reviews the Forum has received little, if any, information that would cause it to re- <br />examine either the numeric criteria or the NPDES policies, and in each review has concluded that <br /> <br />,.1 <br />;~ <br /> <br />r~ <br />!j <br /> <br />C:'SRMlllE~\OOARDMEMI!llIMAR ta.Wl'V <br />Priolod..M"",j,j,l!l9ll <br /> <br />i <br />J <br />.;j <br />, <br />1 <br />" <br /> <br />"'. , '.__ -",.i.. >- ^, _.:, -._ -"..,,- b ' ~ <br /> <br />