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<br />I <br /> <br />I <br /> <br />I <br /> <br />improvement and maintenance of existing wetlands will be ,obtained as water <br />rights appurtenant to land acquisition. No additional water from the project <br />will be required. The CDW will administer the development, for which funding is <br />included in the mitigation plan. <br /> <br />B. Terrestrial vegetation and habitat <br /> <br />I <br /> <br />1. Studies <br /> <br />I <br /> <br />a. Long-term pump test--A long-term pump test of the shallow <br />unconfined aquifer was conducted in 1979-1982 to monitor the effects of the <br />unconfined water table drawdown on vegetation in the immediate vicinity of <br />the well. The monitored area adjacent to the test well contains the four <br />primary plant species (greasewood, rabbitbrush, saltgrass, and wiregrass) found <br />within project boundaries. <br /> <br />I <br /> <br />I <br /> <br />A total of 43 study plot exclosures were established surrounding the pump test <br />well. Samples from the exclosures were collected at 2-week intervals during the <br />growing season beginning in August 1979 and continuing in 1980. Samples were <br />collected at l-month intervals during the 1981 and 1982 growing season. The <br />long-term pump test began on April 15, 1980, and has since continued to pump at <br />a rate of 575 gallons per minute. The pump test and vegetation sampling will <br />continue through the 1982 growing season. <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />In 1980, only rabbitbrush at exclosures within 1,250 feet of the pump well <br />exhibited what may be a response to the lowering of the water table by a <br />decrease in total productivity. The overall decrease in greasewood appears to <br />be due to the less favorable climatic conditions in 1980 than due to lowering <br />of the water table. The increase in total productivity of saltgrass and wire- <br />grass in 1980 appears to be more directly related to the removal of domestic <br />livestock grazing pressure than to lowering of ground water tables and the <br />more severe climatic conditions that occurred in 1980. <br /> <br />I <br /> <br />1 <br /> <br />During the 1981 growing season, rabbit brush continued to show an overall <br />decrease in total production up to about 1,250 feet away from the pump test <br />well. Greasewood production was significantly decreased in 1981 up to 3,500 <br />feet from the pump test well. Total production measured in wiregrass samples <br />indicated a reduction in exclosures up to 1,250 feet from the pump test well. <br />Saltgrass production was not decreased in 1981 which may still be a response <br />to the removal of grazing pressures. <br /> <br />:1 <br />It <br />I <br />, <br /> <br />r <br /> <br />Preliminary trends obtained from samples during the 1982 growing season are <br />similar to 1981. The effects observed for greasewood, rabbitbrush, and wire- <br />grass continue to show decreases in production. Saltgrass does not appear to <br />be reacting adversely at this time. <br /> <br />I <br /> <br />During the weeks of July 20 and August 31, 1981, infrared photographs were taken <br />of each individual exclosure. This photography indicated in general the amount <br />and vigor of the existing vegetation. Infrared photographs of rabbitbrush and <br />greasewood plants indicated that plants close to the pump test well showed less <br />vigor than those near the control exclosures. Although not substantiated with <br /> <br />I <br /> <br />i <br /> <br />I <br />:1 <br /> <br />r ~ .' ","';\ <br />i , "\,..,,,0.) <br />~-' ... - <br />