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<br /> <br />Above the layers which confine the artesian aquifer, the sands and gravels also <br />bear water. This "unconfined" aquifer can be conceived of as a large sponge on <br />the surface of .the Valley. The "sponge" is kept moist by spring runoff from the <br />mountain slopes, irrigation diversions, and to a small degree by upwa'rd leakage <br />from the artesian aquifer. Like a dry sponge left on a wet kitchen counter, <br />capillary action slowly distributes water, through the whole system. The sponge <br />becomes evenly damp. In the sump area of the Closed Basin, the effect of the <br />sun on the surface of the land is like a heat lamp being focused on our <br />"sponge." The top surface feels dry but, in fact, water mOves through it all <br />the time and evaporates into the atmosphere. The Project is, quite simply, <br />designed to capture some of this water before it evaporates. <br /> <br />A pipe appropriately slotted below the water table"which is inserted into the <br />unconfined aquifer, will fill. up with water to about the level of the water <br />table. If the water is to reach the surface, it must be pumped. The Project <br />wells are designed to work this way. Project effects to the unconfined aquifer <br />are limited to the area within the Project boundries. This is the second way <br />that the Project will minimize local economic effects. By law, the operation of <br />the Project cannot lower the water table more than 2 feet outside the Project <br />boundaries. Observation wells have been established around the periphery of the <br />Project area. Except for about 30 minutes a year to clear out sediments, these <br />wells are not pumped at all. They are strictly there for allowing monthly <br />measurements of the water table to be made. These measurements are a public <br />record. The Project salvage wells inside the boundaries work by creating a <br />drawdown in the water table (see figure B-1). The design calls for them to be <br />spaced and pumped at a rate so that over the whole 130,000-acre Project area <br />the water table will 'be lowered by an average of 4 to 8 feet while not dropping <br />more than 2 feet at or beyond the boundaries. The water below and the vegeta- <br />tion on top of all land outside of the Project boundaries will not be signifi- <br />cantly affected by the operation of the Project. <br /> <br />Some people find the scale of some of the Project's statistics to be alarming <br />(150 to 180 wells, 130,000 acres of Project area, 104,000 acre-feet of yearly <br />salvaged water). In fact, these statistics should be reassuring. The Project <br />design calls for an average of less than one well per section. Virtually no <br />place else in the Valley are wells so widely spaced. The Project's planned <br />104,000 acre-feet annual yield is tiny when compared to the water produced by <br />only the new center pivot systems introduced in the Valley for anyone year in <br />the 1970's (see section VI, question 2). The reason that there are-SO many <br />wells is because they will be widely spaced and each one will recover only rela- <br />tively small amounts of water. This is the aspect of the Project's design which <br />allows only the amount of water to be salvaged which would evaporate naturally. <br /> <br />The third aspect of the Project which relates to minimizing local economic <br />effects has to do with the character of the land which is within the 130,000- <br />acre Project boundaries. Water has continuously evaporated from the surface of <br />the Clos,ed Basin sump for centuries. The minerals dissolved in that water are <br />left behind on the ground surface. As a result, much of the land surface is <br /> <br />{' _ ' "'11:,'':\ <br />,',',' 1..0 <br />"-. . -' <br /> <br />7 <br />