Residuum water-table aquifer

Because the residuum water-table aquifer and the upper permeable zone are hydraulically connected, they respond rapidly (within hours) to seasonal fluctuations in precipitation. During winter and spring of 1983, the water levels in the residuum and the upper permeable zone rose in response to increased precipitation and decreased evapotranspiration. Water levels in the residuum and the upper permeable zone declined during the summer and fall as precipitation decreased and evapotranspiration increased. During late fall, decreased evapotranspiration and increased precipitation caused the water levels to rise. 

The primary hydrologic units of interest in this study are, in descending vertical order (1) the residuum which forms the water-table aquifer and acts as an upper confining unit, (2) the Upper Floridan aquifer (formerly the principal artesian aquifer), which consists of the Ocala Limestone, the Clinchfield Sand, and the upper part of the Lisbon Formation, and (3) the basal part of the Lisbon... 

The decreased infiltration of water into the residuum caused a decrease in the vertical leakage through the base of the residuum, and so recharge to the Upper Floridan aquifer decreased. Water levels continued to decline in both the water-table aquifer and the... 

The small head differential, exhibited throughout the year, between the water-table aquifer and the upper permeable zone indicates that although the residuum acts as a confining unit for the Upper Floridan aquifer, vertical leakage does occur through the base of the residuum, and there is some degree of hydraulic connection between the two hydrologic zones. 

The water-table aquifer is hydraulically connected to the upper permeable zone of the Upper Floridan aquifer, and water infiltrates through the residuum to recharge the upper permeable zone. 

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