FAS Abstracts 2004 Meeting Page

Geological & Hydrological Sciences (GHS): GHS-3

|search by author| |return to GHS 2004| |return to FAS 2004|

Doline and aquifer characteristics within Hernando, Pasco, and northern Hillsborough Counties.  B ARMSTRONG (1), A COLLAZOS (2), J MALLAMS (1) and D. CHAN (1).  (1) Geology, University of South Florida, Tampa, FL 33620, (2) Parsons Brinckerhoff, 5405 West Cypress St., Tampa, FL 33607. An investigation to examine the relationship between the spatial distribution of doline features and the hydraulic conductivity (K_x) of the underlying Upper Floridan aquifer was conducted in a 4,400 km² area of west-central Florida. Hydraulic properties of an aquifer are traditionally estimated from field tests and the values obtained are often more site-specific in nature than a regional characterization of the aquifer. Using depression data derived from U.S. Geological Survey (USGS) maps, doline densities (D_D) were calculated over the study area, and doline-area ratios (R_D) were generated and compiled by county, physiographic province, and model-derived K_x zones. Results from these analyses indicate that areas of high D_D coincide with northern portions of the study area where aquifer confinement is poor. Values of R_D calculated by county also support the observation of increased karst activity in the north. Establishing a relationship between karst geomorphology and the characteristics of the underlying aquifer could provide a useful technique for estimating regional-scale values of hydraulic conductivity or other hydraulic properties which could then be applied to a groundwater model.