Laserfiche WebLink
<br />U.: <br />c.n <br />c.c <br />o <br /> <br />Construction of the west end of the Government <br />Highline Canal began in the fall of, 1986, and cons,truction <br />of the west end laterals is scheduled to begin in the fall <br />of 1988. The remaining lateral systems will be implemented <br />in the approximate order of cost effectiveness, with <br />construction to be completed about the year 2005. <br />To date, USDA's onfarm and off-farm lateral <br />improvements in Stage One and Stage Two of the Grand Valley <br />have been accomplished primarily through the annual <br />practice cost-share provision of the Agricultural <br />Sabilization and Conservation Services (ASCS) ACP program. <br />The total onfarm pipe and ditch lining installed from <br />1979 to date includes approximately 163 miles of pipeline <br />and 44 miles of ditch lining. This represents about 31 <br />percent of the total Grand Valley project goal for these <br />practices. The total onfarm average annual salt load <br />reduction is 17,900 tons. <br />USDA's off-farm lateral improvements, for the period <br />1980 to date~ amount'to 40 miles of pipeline and 11 miles <br />of ditch lining. These off-farm lateral improvements <br />account for about 27 percent of USDA's overall goal with an <br />average annual salt load reduction of 15,600 tons. <br />, -USDA's total on farm and off-farm improvements since <br />1979 amount to a total average annual salt load reduction <br />of 33,600 tons. <br />Las Vegas Wash (Reclamation). Las Vegas Wash is a <br />natural drain'age channel pro\"iding, the onl~' surface water <br />outlet for the entire Las Vegas Valley. The lower portion <br />is now a perennial stream as a result of waste water <br />effluent and ground water discharges. Flow in the Wash has <br />increased steadily in recent years due primarily to <br />increased sewage discharges resulting from a rapidly <br />growing population. This wastewater carries a salt load of <br />150,000 tons per year and leaches an additional 80,000 tons <br />of s~lt per year as the water flows into the Wash. <br />One alternative salinity control strategy would be to <br />prevent seepage of waste water and minor storm runoff by <br />placing them in a bypass channel running parallel to the <br />Wash for about 4 miles, circumventing salt deposits in the <br />Wash alluvium. The bypass channel has been viewed by some <br />local entities as being in conflict with nutrient and <br />toxics control and plans for a wetlands park. The seepage <br />prevention strategy is being studied in the Pittman <br />Verification Program. Once-through cooling water formerly <br />discharged to the Wash from unlined ditches is now diverted <br />into a pipeline. Several wells in the Pittman area are <br />being used to monitor ground water levels and quality. The <br />curtailment of seepage from the unlined ditches was <br />followed b~' a drop in ground water levels, which is a good <br />indicator of reduced saline ground water inflow to the <br />Wash. A long term reduction of 7,000 tons per year is <br />expected. <br /> <br />-32- <br />