Silver Springs 100 year Capture Zone

<div style='text-align:Left;font-size:12pt'><div><div><p><span>100-year Capture Zones represent the distance and direction water particles in the aquifer travel in a 100-year period before reaching a spring head. The boundaries of the geographic area that contributes groundwater to the Silver Springs spring group are dynamic and can be influenced by changing climatic conditions and by anthropogenic conditions, such as groundwater withdrawals. Groundwater within the spring recharge basin (springshed) potentially emerges as discharge from the Silver Springs spring group. The USGS MODFLOW numerical code was the basis for a regional groundwater flow model encompassing north-central Florida. This model was used to simulate the groundwater flow conditions as influenced by groundwater withdrawals that occurred in 1999. The results of the 1999 simulation were then applied to the USGS MODPATH particle-tracking code. This code allows for the determination (mapping) of the origin of groundwater contributing to a specific area of interest within the model by using the reverse particle tracking method. This method traces the flowpaths of a prescribed number of water particles from their points of discharge backward to the original point of origin or to a location determined by the estimated time of travel. In this case, the model grid cell that encompasses the Silver Springs spring group is the particle point of discharge. Further documentation of this methodology is provided in the following SJRWMD special publication: , search https://www.sjrwmd.com for SP/SJ2007-SP4.pdf The delineated 100-year capture zone represent the estimated geographic extent of areas within which it would take groundwater 100 years to travel to the discharge point at the Silver Springs spring group. The capture zone delineations are influenced by the hydrogeologic characteristics of the Surficial aquifer system (SAS) and the Floridan aquifer system (FAS) present within these areas. Horizontal groundwater flow in the Upper Floridan aquifer is, in general, the dominating factor that determines the extent of the capture zone boundaries. Note: The 1000-year capture zone encompasses nearly all of the Silver Springs recharge basin. The 1000-year capture zone in combination with an interpretation of groundwater flow direction within the upper Floridan aquifer is used to delineate the springshed boundary for the Silver Springs spring group.</span></p></div></div></div>