Summarizing results of their flow model of the Sparta aquifer in southern Arkansas and northern Louisiana and simulated response to withdrawals, McKee, Clark, and Czarnecki wrote in 2003 and 2004 (immediately before three El Dorado industries converted to river water use):   ‘Historically, the Sparta aquifer has provided abundant water of good quality.  In recent years, however, the demand for water in some areas has resulted in withdrawals from the Sparta aquifer that substantially exceed recharge to the aquifer.   Considerable drawdown has occurred in the potentiometric surface, and water users and managers question the ability of the aquifer to supply water for the long term.  Continued heavy withdrawals in the Sparta aquifer, where alternative water sources are not considered or available, will result in continued expansion of the cones of depression as well as increased drilling and pumping costs, decreased aquifer yield, and reduced water quality.’ (Ref.9, p. 2)  ‘Continued pumping at withdrawal rates representative of 1990 - 1997 rates cannot be sustained indefinitely without causing hydraulic heads to drop substantially below the top of the Sparta Sand in southern Arkansas and north-central Louisiana.’ (Ref. 8, p. 1) top

Increased costs of heavy pumping, which can become prohibitive for public and industrial supply, may occur in a number of ways (Figure 23):

• Wells must be deepened or replaced when the head falls below the screened (open) intervals of the well.
• Well yields decrease because of reduced amounts of water in storage.
• Pumping costs increase because of the increase in the vertical distance that groundwater must be lifted to the surface and because of reduced hydrostatic pressure.
• Water treatment costs increase as poorer quality water is drawn from greater depths in the aquifer.  If water becomes saltier, treatment (reverse osmosis or distillation) costs may be prohibitive.
• Less Sparta water is available when sands become compacted; reduced aquifer capacity may be permanent.
• Salt content of drinking water must be counted as salt intake, which may be especially important for individuals on a low salt diet.
• The taste of water declines as poorer quality water is drawn from greater depths of the aquifer.  If water becomes saltier, the saltiness may be appreciated at a concentration of chloride about 395 mg/L. (18)
• Corrosion occurs more rapidly as water becomes saltier, necessitating early replacement of industrial equipment, public utilities equipment, and domestic plumbing fixtures and water-using appliances. (18)
  • In 1968, researchers, estimating costs of corrosion as water becomes saltier, found that using water with TDS concentration of 1750 mg/L compared with 250 mg/L decreased the service life by 70 percent of toilet flushing mechanisms and by 30 percent of washing equipment, adding 50 cents per1000 gallons to the cost of water used. (18)  LDEQ reported that, in 2007, the TDS concentration in water from five of six sampled wells in Morehouse, Ouachita, and Union Parishes exceeded 1000 mg/L. (5)   There are anecdotal reports that in Union Parish near the Arkansas border, where the chloride concentration exceeded 350 mg/L in one well in 2006 (Un-205-Ref. 5), equipment warranties are not offered because of corrosion problems.

• Water in streams and lakes may be reduced, particularly in and near an aquifer outcrop area.
  • Ground-water pumping can alter how water moves between an aquifer and river, stream, or wetland by intercepting groundwater flow that naturally discharges into the surface-water body or by increasing the rate of water movement from the surface-water body into an aquifer. (One consequence may be)… the lowering of water levels below the depth that streamside or wetland vegetation needs to survive.’ (19)