Laserfiche WebLink
<br /> <br />Consumptive Uses and Losses Report includes a qualification that within Arizona, Interior cannot <br />distinguish between tributary surface water uses and groundwater withdrawals. <br /> <br />The point is that in the Colorado River Basin, states where there is considerable agricultural <br />uses, all of the states except Nevada, there is not necessarily a correlation between population growth <br />and increases in water use. Much of the new growth has been and will continue to be served by the <br />conversion of agricultural supplies to municipal uses. <br /> <br />For example, in Colorado, two transmountain diversion projects, the Colorado-Big <br />Thompson Project (C-BT) and the Twin Lakes-Independence Pass Tunnel Project were at one time <br />almost entirely used for agricultural purposes. Today the C-BT Project is approaching 65% <br />municipal and industrial on a share ownership basis and the Twin Lakes Project is about 95% <br />municipal. <br /> <br />Nevada is an exception. Nevada has a little bit of irrigation in the Muddy River and Virgin <br />River Basins, but this water is not readily accessible by Las Vegas, therefore there has been a direct <br />correlation between population growth in the Las Vegas area and Nevada's mainstem water use. 139 <br /> <br />The following table shows historical and projected populations for California, Nevada, <br />Arizona and Colorado (in millions). <br /> <br />TABLE V-I: State Population (in millions) <br /> <br />State 1960 1970 1980 1990 2000 2030 Projection <br />Arizona 1.30 1.78 2.72 3.66 5.13 10.71 <br />California 15.72 19.97 23.67 29.76 33.87 46.44 <br />Nevada .29 .49 .80 1.20 2.00 4.28 <br />Colorado 1.75 2.21 2.89 3.29 4.30 5.79 <br /> <br />The following graph (Figure V-I) shows Arizona's tributary water uses which, as previously <br />mentioned, includes groundwater overdrafts on the Gila River system. The graph clearly shows the <br />impact of Arizona's legislative efforts to reduce groundwater uses which began in 1980. <br /> <br />139 One of the great ironies is that under the Arizona v. California ruling, if Las Vegas builds an expensive pipeline to convey retired <br />agricultural water from the Virgin and Muddy Rivers to Las Vegas it is tributary water, but if Las Vegas tries to convey this water <br />down these rivers to Lake Mead and pick it up at its pumping plant, then it is mainstem water and counts as a part of Nevada's 300K <br />apportionment. The Seven States agreement gives Nevada access to pre-compact agricultural water in the Virgin Basin. <br /> <br />Page -53- <br />