Hydro-Environmental Associates, Inc. (HEA), in association with Atkins North America, Inc. were selected by the Suwannee River Water Management District and St. Johns River Water Management District, to conduct a hydrogeologic assessment of north central Florida. The purpose of the study was to identify and evaluate various concepts to protect, maintain, and restore regional aquifer levels by recharging the Upper Floridan Aquifer (UFA) at strategic locations. The areas of focus include the upper Suwannee River and Santa Fe River watersheds, and the Keystone Heights potentiometric high. Replenishment of the UFA in these areas could benefit surface water features including lakes, springs, and rivers; as well as contributing to the development of a sustainable water supply for the region.
HEA initially identified and evaluated numerous aquifer recharge options within the upper Suwannee River basin, and conducted groundwater flow modeling on several pre-screened sites to further assist in the evaluation process. HEA used the updated U.S. Geological Survey MegaModel to conduct the groundwater flow analysis. The groundwater flow model was used to establish the benefits to the river systems, major springs within the Suwannee River, Ichetucknee, and Santa Fe Rivers, as well as the potentiometric level of the UFA from each of the pre-screened options. HEA modified the existing MegaModel to include each of the proposed recharge options, and simulated the recharge characteristics of three indirect recharge options and three direct recharge options. The direct recharge options mainly consisted of aquifer recharge wells completed within the UFA, and the indirect options included the use of RIBS, sinkholes, and other natural geologic features.
The model was used to predict the benefits of each potential recharge option into selected target springs, including: White Sulphur Springs, Suwannee Springs, Ichetucknee Springs, Blue Springs, Ginnie Springs, Poe Springs, and Hornsby Springs. Many of these springs have shown evidence of declining base flows.