SPATIAL DELINEATION OF SUBAQUEOUS KARST SPRINGS IN BELTON LAKE ALONG THE EASTERN BORDER OF THE FORT HOOD MILITARY INSTALLATION, BELL COUNTY, TEXAS

Belton Lake is located on the Leon River in the northern part of Bell County, Texas, with the western shoreline of the lake forming the eastern boundary of the Fort Hood Military Installation. Surface features along the shoreline indicate previous conduit and fracture porosity development within the Cretaceous-age Edwards and Comanche Peak limestone, however no evidence exists of surface springs along the shoreline today.

In order to determine subaqueous contributions to the lake, a multi-parameter YSI 6920 sonde was used to collect five sets of geochemical data along the shoreline in order to delineate subaqueous spring discharge. Physiochemical characteristics such as temperature, dissolved oxygen, pH, and conductivity were continually measured by the sonde; during data collection the sampling equipment was coupled with a GPS unit for spatial reference. Data gathered from the sonde were spatially analyzed along the collection route by means of the inverse distance weighted interpolation algorithm available in ArcGIS.

Although lake levels fluctuated during the sampling period, geochemical analysis of the data indicates physiochemical anomalies associated with subaqueous karst springs discharging along the sonde route. These subaqueous springs contribute to lake volume through conduits and fractures in sub-surface lithologies and are further evidence of the complex hydrogeology exhibited in this karst system.