The Sparta Aquifer is the major source of groundwater for all or part of sixteen parishes in North-Central Louisiana. Almost a quarter million people rely on the Sparta’s excellent quality water for their drinking water. In 2000, public supply replaced industry as the largest user of the Sparta.
The Sparta is recharged primarily from rainfall on exposed (outcrop) areas in Caddo, Bossier, Webster, Bienville, Jackson and Winn Parishes. The approximate limit of freshwater extends from Morehouse Parish south to Caldwell Parish and then southwest to Sabine Parish. The Sparta becomes confined between clay layers as it flows downward toward the east. In confined aquifers, heavy pumping and substantial pumping reduction have widespread effects. In areas of heavy pumping, the usual east-to-west water flow in the Sparta is altered, and water flows instead toward cones of depression that have formed beneath the pumping centers.
The Sparta has been heavily pumped for more than eighty years. In the past thirty years, well water levels have declined at average rates of one to three feet per year and have dropped below the top of the aquifer in many areas. Water users and managers have become concerned about potential consequences if the trend continues. Consequences may include, depending upon location, expansion of cones of depression, increased cost of drilling and pumping, decreased aquifer yield, deterioration of water quality, intrusion of salt water into the aquifer’s freshwater, and compaction of sands that can permanently reduce the aquifer’s capacity for storing water.
In response to concerns, in 1999 the Louisiana legislature established the Sparta Commission to study the aquifer and how best to manage it. The Commission contracted the Sparta Groundwater Study (2002). The authors re- commended, based upon information at the time, to limit Sparta withdrawals to 52 million gallons per day (mgd) [reducing withdrawals by 18 mgd from the rate since 2000 of about 70 mgd] and to consider developing other potable water sources for another 12 million gallons per day to provide for population and industrial growth.
Several important conservation measures have been completed or are underway. The Union County, Arkansas Ouachita River Alternative Supply Project is an example of the widespread effects of reducing withdrawals. Three El Dorado industries ceased Sparta use in 2004 and2005, resulting in a substantial recovery in El Dorado, Arkansas wells and some recovery in wells in several Louisiana parishes, a recovery that increases with time and diminishes with distance from El Dorado. A City of West Monroe wastewater recycling project promises similar returns.
Because the Sparta aquifer is a limited source of accessible and relatively inexpensive potable water, there will always be a need to protect and conserve the aquifer. Conservation requires cooperation of the public, industries, lawmakers, and government officials. Conservation education is underway to encourage a culture of care for the Sparta. This report closes with a look to the future.