OFR 03-448

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Shoemaker, W.B., O’Reilly, A.M., Sepúlveda, Nicasio, Williams, S.A., Motz, L.H., and Quing Sun, 2004, Comparison of Estimated Areas Contributing Recharge to Selected Springs in North-Central Florida by Using Multiple Ground-Water Flow Models: U.S. Geological Survey Open-File Report 03-448, 31 p.


Areas contributing recharge to springs are defined in this report as the land-surface area wherein water entering the ground-water system at the water table eventually discharges to a spring. These areas were delineated for Blue Spring, Silver Springs, Alexander Springs, and Silver Glen Springs in north-central Florida using four regional ground-water flow models and particle tracking. As expected, different models predicted different areas contributing recharge. In general, the differences were due to different hydrologic stresses, subsurface permeability properties, and boundary conditions that were used to calibrate each model, all of which are considered to be equally feasible because each model matched its respective calibration data reasonably well. To evaluate the agreement of the models and to summarize results, areas contributing recharge to springs from each model were combined into composite areas. During 1993-98, the composite areas contributing recharge to Blue Spring, Silver Springs, Alexander Springs, and Silver Glen Springs were about 130, 730, 110, and 120 square miles, respectively. The composite areas for all springs remained about the same when using projected 2020 ground-water withdrawals.



Purpose and Scope
Hydrogeologic Setting
Description of Ground-Water Flow Models
Peninsular Florida Model
Lake County/Ocala National Forest Model
North-Central Florida Model
Volusia County Model
Estimation of Areas Contributing Recharge
Description of Particle-Tracking Analyses
Areas Contributing Recharge
Blue Spring
Silver Springs
Alexander Springs
Silver Glen Springs
Effects of Projected 2020 Ground-Water Withdrawals
Appendix I (on CD and not included online)