C. A. Couch William Wilber 2002 <p><span class="EXLDetailsDisplayVal">In 2001, the <span class="searchword">National</span> <span class="searchword">Water</span>-<span class="searchword">Quality</span>Assessment (NAWQA) Program of the U.S. Geological Survey (USGS) began its second decade of studies. A total of 42 study units (major river basins and aquifers across the nation) will be reassessed in three groups of 14 on a rotating schedule. Each group of study units will be studied intensively for three years, followed by six years of low-intensity assessment. One of the primary goals in the second decade is to improve understanding of the key processes that control <span class="searchword">water</span>-<span class="searchword">quality</span> conditions in order to establish the links among the sources of contaminants, their transport through the hydrologic system, and the effects of contaminants and physical alterations on stream biota and ecosystems and on the <span class="searchword">quality</span> of drinking <span class="searchword">water</span>. An improved understanding of these links will provide the basis for predicting <span class="searchword">water</span>-<span class="searchword">quality</span> conditions in unmonitored areas and for predicting the likely effects of contemplated changes in land- and <span class="searchword">water</span>-management practices.</span> </p> application/pdf en ProQuest Assessing five national priorities in water resources article