John K. Lovelace Paul A. Ensminger Dan J. Tomaszewski 2002 <p><span>In 2000, approximately 10,400 mgal/</span><span class="searchword">d</span><span> (million gallons per day) of </span><span class="searchword">water</span><span> was withdrawn from </span><span class="searchword">ground</span><span>- and surface-</span><span class="searchword">water</span><span> sources in </span><span class="searchword">Louisiana</span><span>, an increase of 10 percent from 1990. In 2000, about 16 percent (1,600 Mgal/</span><span class="searchword">d</span><span>) of the </span><span class="searchword">water</span><span> withdrawn was </span><span class="searchword">ground</span> <span class="searchword">water</span><span>. Approximately 93 percent of the </span><span class="searchword">ground</span> <span class="searchword">water</span><span> withdrawn was from four aquifers or aquifer systems: the Chicot aquifer system (49 percent), the Mississippi River alluvial aquifer (22 percent), the Sparta aquifer (4 percent), and the Southern Hills aquifer system (18 percent). Three of these, the Chicot aquifer system, the Sparta aquifer, and the Southern Hills aquifer system, contain areas where declines in </span><span class="searchword">ground</span><span>-</span><span class="searchword">water</span> <span class="searchword">levels</span><span> from 1990-2000 are 1 ft/yr (foot per year) or greater. The Chicot aquifer system in southwestern </span><span class="searchword">Louisiana</span><span> is the most heavily pumped aquifer or aquifer system in the State. By 2000, </span><span class="searchword">water</span> <span class="searchword">levels</span><span> in areas of Calcasieu, Jefferson Davis, and Acadia Parishes had declined to 50 feet or more below sea level. </span><span class="searchword">Water</span> <span class="searchword">levels</span><span> in areas of largest withdrawals declined as much as 1.7 ft/yr during the period 1990-2000. The Sparta aquifer in north-central Louisiana is the fourth most heavily pumped aquifer in the State. Approximately 68.2 Mgal/d was withdrawn in 2000. Water levels in the aquifer declined to more than 200 feet below sea level in the Monroe area by 1997. During 1990-2000, water level declines ranged from 0.1 to 5.2 ft/yr at monitor wells screened in the aquifer. The Southern Hills aquifer system of southeastern Louisiana is composed of numerous freshwater aquifers. This aquifer system is the third most heavily pumped aquifer or aquifer system in the State (291 Mgal/d in 2000). By the 1970's saltwater encroachment had been documented in major aquifers in the Baton Rouge area. Water levels in deep aquifers having largest withdrawals declined about 0.2 to 3.5 ft/yr or more during the period 1990-2000. In 2000, about 84 percent (8,700 Mgal/d) of the water withdrawn in Louisiana was surface water. Stream discharge data were analyzed for 59 continuous discharge stations. Eleven stations on nine streams had decreasing mean annual discharge during the period 1990-2000.</span></p> application/pdf en Louisiana Department of Transportation and Development, Office of Public Works Water withdrawals and trends in ground-water levels and stream discharge in Louisiana reports