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<br />primary plant species (greasewood, rabbitbrush, saltgrass" and wiregrass) found <br />within project boundaries. <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 I-month intervals during the 1981 growing season. The long-term <br />pump test began on April 15, 1980, and has since continued to pump at a rate of <br />575 gallons per minute. The pump test and vegetation sampling will continue <br />through the 1982 growing season. <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 />During the 1981 growing season, rabbitbrush 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 />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 />data, saltgrass and wiregrass photographs generally indicated that the total <br />density of vigorous plants could be less near the well. Infrared photographs <br />of all exclosures will be obtained periodically during the 1982 growing season. <br /> <br />b. Long-term monitorinR proRram--A long-term vegetation monitoring <br />program will be established in Stage 1-2 initially and expanded to each succes- <br />sive stage as the project is constructed. This monitoring program will con- <br />tinue during project operation to determine the overall effects of pumping on <br />preproject vegetation, the capacity to graze domestic livestock, the value of <br />the wildlife habitat, etc. The monitoring program for Stage 1-2 has been <br />developed but will be physically established on the ground by December 1982. <br />The plant species selected and monitored in the study plots will be greasewood, <br />rabbitbrush, saltgrass, wiregrass, and a variety of other plant species. The <br />program will help determine if project pumping will significantly affect <br />existing plant species and, for example, the carrying capacity for grazing of <br />domestic livestock in a given area. Data collected from the vegetation study <br />and the analysis at that time will be available to the general public at the <br />project office in Alamosa, Colorado. <br /> <br />i <br /> <br />r::C~8 <br />