Laserfiche WebLink
<br /> <br />o <br />.-::~) <br />c::> <br />..... <br />. <br />~ <br /> <br /> <br />Return Flows for Users Takina Oeliverv Above !mnerial Oam <br /> <br /> <br />State of Nevada - All return flows for the State of Nevada, with the <br />exception of those for the Nevada Department of Fish and Game, are returns <br />through the Las Vegas Wash from diversions by the Robert B. Griffith Water <br />Project (formerly Southern Nevada Water Project) and users taking delivery <br />through the BMI system. The flows in the Wash have. in addition to the return <br />flows of Colorado River water, returns from groundwater pumped in the Las <br />Vegas Valley (natural recharge), flows from storm runoff, and subsurface flows <br />from natural recharge. <br /> <br />Since it is presently not possible to separate these flows as to user, the <br />return flow credit is assigned simply to the State of Nevada. It is only with <br />difficulty that the Colorado River water portion of these flows can be. <br />separated. The effort to do this has led to the development of a multi-step <br />procedure worked out in conjunction with the Colorado River Board (CRC) of the <br />State of Nevada. <br /> <br />Recently, Users in the Las Vegas Valley have begun recharge programs. This <br />has led to a proposed modification by Reclamation to the CRC of the multi-step <br />caumputation procedure being used. Copies of the procedure being used, and a <br />copy of the draft proposed modifications to it, are included at the end of <br />'this sec:i:ion. <br /> <br />References to the "North Shore Gage" in the procedure should all be changed to <br />"Las Vegas Wash Above Three Kids Wash Below Henderson Nv". The North Shore <br />gage was los~ after a storm and was only able to be replaced at Three Kids <br />Wash. This ~hanqe. along wi~h others due to commercial development taking <br />place in the Wash. have raised questions about the current methodology. While <br />the proposed Modifications included at the end of this section have only to do <br />with the accoUnting of recharge water, it is clear that other modifications <br />will be needed when development along the Wash is completed. Since the Water <br />Management Branch has had the lead role in development of procedural approach <br />to return flow computation in the Las Vegas Wash, this Branch will continue to <br />do the accounting of the return flows in the Wash. (Computations are done on <br />a Lotus 1-2-3 spreadsheet. The values of 78? and 22?. mentioned on Page a of <br />the procedure for determining return flows. have been, with the concurrence of <br />the CRC, changed to 89? and 117., respectively.) <br /> <br />Flows at Three Kids Wash for monthly and yearly accounting are available from <br />the USGS. Amounts of water recharged to valley aqUifers. groundwater <br />pumping, and sewage effluent, all necessary for return flow computation, are <br /> <br />53 <br /> <br />I <br />