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7 . 4 AQUIFER TESTS ~~ ~ ri ~, ~ ~~'~ i <br />Aquifer Tests Reveal Differences in Permeability <br />Among Raton Basin Aquifers. <br />The alluvium is a more permeable aquifer than the bedrock. <br />Aquifer tests measure the ability of a formation to transmit <br />water. Table 7.4-1 summarizes the results of aquifer tests in the <br />Raton Basin. The locations of these tests are shown in figure 7.4-1. <br />The specific capacity of a well, is the discharge divided by <br />the drawdown of the water level in the well during -tAe pumping <br />• peed, as expressed in gallons per minute per foot of drawdown. <br />Aquifers with relatively high permeability, such as the alluvium, <br />have higher specific capacities than aquifers with lower permeability, <br />Tr~n,dcatJ- <br />such as the~Vermejo -. Raton 4y~~~Fcr The low specific capacity <br />oyu~fe,- <br />of the Poison Canyon-C~chwra vindicated in table 7.4-1 results from <br />this :u 9u,~t ~ 's being unsaturated in the area where the tests <br />were performed. Unsaturated aquifers have low specific capacities <br />because they have little water in them and are rapidly drained <br />by pumping, even if, as in the case of the Poison Canyon- CucF~are- o~qu.~e ~ <br />they are known to be highly permeable. <br />The hydraulic conductivity is the rate at which ground water <br />moves through a cross-sectional area of an aquifer, as expressed in <br />feet per day. Table 7.4-1 indicates that ground water may move much <br />faster in the alluvium than in the bedrock and that ground water <br />• --r~,n,JoJ- <br />in the^Vermjeo :- Raton 'aryu,~..~ ' moves at about the same rate <br />through coal and sandstone. The apparently high rate of ground- <br />62 <br />