COMPARISON OF OBSERVED AND MODELED STORM RESPONSES IN A MINNESOTA CAVE STREAM: CONNECTIONS BETWEEN GEOMETRY AND RESPONSE

The hydraulic, thermal, and chemical responses of karst springs to storms events are often used to derive information about the flow paths within an aquifer. However, the relationships between spring storm response and flow path geometry are poorly understood. We deploy a system of data-loggers measuring water depth, temperature, and conductivity at locations along a cave stream in southeastern Minnesota. For this system, the geometry of the flow path is known, therefore observed responses are compared against actual geometry. Using the known geometry, we apply two theoretical approaches. First, we use simple theoretical models to estimate geometrical properties and develop further intuition about how signals are modified by the system. Second, we run advection-dispersion simulations to attempt to match the observed responses. An important unanswered question is, "To what extent does a storm response constrain possible geometries?" or similarly, "What are the set of geometries that produce similar responses?" We address these questions through inverse modeling of flood responses and subsequent parameter sensitivity analysis.