TEMPORAL VARIATIONS OF THE OZARK AQUIFER CONE OF DEPRESSION

The geometry of the cone of depression formed in the karst Ozark aquifer underneath Springfield, Missouri has been documented at irregular intervals since the expansion of deep wells in the area, which occurred in the fifties. From 1990 to the present, groundwater levels were expected to recover due to the shifting of population from urban to rural areas and efforts from the Springfield City Water Utilities to add more surface water. Even so, in 2002 private well owners within and near the City of Springfield reported low levels and water problems, which prompted mapping the new cone of depression.

Well data were collected in 2003-2004 and contoured using GIS mapping tools. This new cone of depression was compared to previously reported cones of depression. The results show a cone of depression extending towards the recently developed areas south of Springfield while the potentiometric levels of some areas within the city had returned to levels measured in the late eighties. The extent of the cone of depression has changed significantly in the past few decades while its maximum depth has changed only slightly.