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<br />1 2 <br /> <br />I,"':) <br />OJ <br />.."" <br />""'" <br />,-7) <br />r:.) <br /> <br />Question: <br /> <br />Will the Closed Basin Project turn San Luis Valley into a dust Bowl? <br /> <br />Ans\ver: <br /> <br />No, the operation of the Closed Basin Project will not turn the Valley <br />into a dust bowl. <br /> <br />, <br /> <br />The fears which many people have expressed on this subject are based on <br />misunderstanding. This misunderstanding focuses on two official state- <br />ments about the project. These official statements are: (1) "the <br />Project will salvage water now being lost to evapotranspiration. . .," <br />and (2) "decreased plant vigor may result (from the operation of the <br />project) in some areas. . . . II Some people have interpreted these <br />statements to mean that operation of the project will result in the <br />loss of existing vegetation from a vast part of the valley. That is <br />not what the statements say, and it is not reasonable to believe this <br />will happen. <br /> <br />In the Closed Basin sump area, the water table is generally 2 to 6 feet <br />below the surface. A large amount of water evaporates from the project <br />area every year. Project facilities are designed to salvage some (not <br />all) of this evaporated water by lowering the water table in the Closed <br />Baisn sump area (only within the project boundary). A lower water <br />table will reduce the amount of water transferred from the soil surface <br />and from some of the vegetation to the atmosphere. <br /> <br />Water is transferred to the atmosphere from leaves of growing plants <br />(transpiration) and from the soil surface (evaporation) by a process <br />called evapotranspiration. Plants in the San Luis Valley and the area <br />of the Closed Basin (not including wetlands) are well adapted to 10" <br />rainfall and moisture levels; however, they can and do use large <br />amounts of water "hen it is available. The efficiency with which a <br />plant uses soil moisture often decreases with too much available water. <br />A point can often be reached where high moisture levels reduce plant <br />growth and survival. Where there are always very high water tables, <br />the rate of plant growth will likely be less than if the water table <br />and available water were lower. towering high water tables within pro- <br />ject boundaries will not automatically result in the death of all <br />existing vegetation. Some plants will be adversely affected by <br />lowering water tables. Others will be helped and increased plant <br />gro"th will occur, Evaporation of soil moisture can be very high when <br />water levels are near or at the soil surface. The evaporation rate <br />from a "et soil surface generally exceeds that transpired by plants <br />under the same climate conditions. Reducing water levels "ill decrease <br />total water lost from the soil surface and "ill often maintain greater <br />plant growth rates. <br />