​Conceptual Model
Based on a preliminary assessment of all available data, the following conceptual model describes the controlling influences of surface- and ground-water interaction within the SEW. It should be emphasized that these interpretations are based on the early results of our studies, and likely will undergo revision as we gain understanding and additional data from longterm assessment. Ground-water recharge (from precipitation) within SEW is distributed areally, yet our preliminary data suggest that runoff, lateral flow in the soil and rocks, and even temporal directions of flow are a function of many factors which are highly variable. Surface-water basins (wastersheds) and ground-water basin boundaries do not coincide. This means that if a contaminate were spilled on the ground in one watershed, it may not necessarily show up in wells or springs in the same watershed; it may be “pirated” along unseen underground flow routes to discharge at another resurgence point. Permeability contrasts within the soil, at the soil-rock interface, and within the solid rock aquifer concentrate flow and distribute it down gradient along the flow paths of least resistance. These are a reflection of purity of rock type (limestone at SEW), and are a dominant control on the hydrology. Springs in watershed 1 represent the interception of these flowpaths with the land surface, and these range across a continuum of intermittent, infrequent flowing seeps that barely trickle to continuous springs that flow year round. The soil/rock contact (epikarst) developed on the Boone Formation, and the relatively-pure limestones of the St. Joe Formation represent the dominant zones in which continuous springs and seeps occur. Hydraulic gradients of the groundwater, which generally appear to follow the tilt (structural dip) of the rock formations, act independently (are decoupled) from surface-water bodies where confinement by chert layers in the Boone Formation is effective. This decoupling is also lithologically controlled, but in areas of faults and major joints, exhibits strong structural control. Stream piracy is one manifestation of combined structural and lithologic control that is obvious in watershed 1.