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Description:
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The Southern High Plains region of Texas and New Mexico contains more than 20 ,000 small , circular depressions called playa lakes or playas . These playas create a unique physiographic phenomenon where many watersheds in the region are small closed basins in which no outlet from the watershed is present (Gustavson et al . , 1994 ) . The presence of playa lakes implies that runoff from the contributing watershed is focused into the playa lake , including chemical constituents associated with the runoff . Also , the fate of the runoff has only two possibilities , evaporation or infiltration . The chemical constituents are therefore treated naturally in playa waters , bound to playa sediments , or transported to the groundwater flow system .
At one time , researchers believed that evaporation , rather than infiltration , controlled the fate of water entering playas in the High Plains . This includes work done by C V . Theis (1937 ) and the Texas Water Development Board (1965 ) . However , more recent investigations are revealing that not only is infiltration significant in playa lakes , it is the primary source of recharge to the groundwater (Wood and Osterkamp , 1984b ; Wood and Sanford , 1994 ; Wood , Rainwater , and Thompson , 1997 ) .
In an urban environment , such as the city of Lubbock , the existence of playa lakes is essential to storm drainage as well as recreation (Hertel and Smith , 1994 ) . Little information has been collected concerning the hydrology of these urban playas , some of which have altered bed sediments due to development . In addition , rising groundwater levels and runoff quality concerns are major considerations for city engineers and administrators as well as researchers . Detailed investigations of urban playas will be a valuable tool for determining the interaction of stormwater runoff and groundwater flow systems . |