Springs have historically played an important role in Florida's history, and the Wekiva River is a spring-fed system associated with many, possibly 19, springs connected to the Floridian aquifer. Maintaining groundwater recharge to the aquifer is a key factor of the viability of the regional water supply as well as the Wekiva ecosystem. A first principle, physics-based watershed model WASH123D has been applied to conduct the study of Wekiva "springshed", which is the recharge area of the spring. We first briefly introduce the basic hydrogeologic characteristics of the study area. The mathematical concepts of WASH123D are presented in succession. The development of the numerical model is detailed, followed by the discussion of hydrologic data input. The Wekiva WASH123D model was run to evaluate the average steady-state 1995 hydrological conditions. The distribution of simulated Floridian aquifer system groundwater levels using WASH123D shows very good agreement with the field observations at corresponding locations. Also identified are the areas of recharge to and discharge from the Floridian aquifer system as well as decreases of the spring discharge due to urbanization.