Ground-water consumption for industrial use at Nikiski increased from about 1 million gallons per day in 1968 to 4.2 million gallons per day in 1979. Water managers and local citizens are concerned that industrial pumping may reduce the esthetic and recreational value of local lakes. Some lake levels have declined as much as 8 feet since pumping began; the greatest declines occurred in lakes nearest the center of pumping.
Ground water occurs in three aquifers. The upper aquifer is unconfined and is hydraulically connected to most lakes and streams in the area. The upper two aquifers are hydraulically connected through a leaky confining layer, and water levels in the two aquifers fluctuate synchronously with changes in precipitation and changes in pumping from either aquifer. The hydraulic connection of the lower confined aquifer, the deepest of the three aquifers, to the other two aquifers is poor. Drawdowns caused by pumping have stabilized in all three aquifers. This indicates that the pumping is in equilibrium with the hydrologic boundaries. In the lower two aquifers, the potentiometric surfaces near some production wells are below sea level; however, no salt water has intruded the aquifers as far as the pumped wells. If intrusion occurs or if additional water supplies are needed, another potential site for ground-water development is the middle Beaver Creek basin, 7-10 miles east of the industrial area.
