Implementation of a linear optimization water allocation algorithm into a fully integrated physical hydrology model

Connections between groundwater and surface water are well-established and remain the focus of significant ongoing research. Within the water management community, stream-aquifer interactions are widely acknowledged and often subject to regulation. Yet, the tools most commonly used by water managers often have limited physical hydrology and a resulting inability to represent feedbacks between elements of the physical system. This paper presents the development of a water allocation module (WAM) for an integrated hydrologic model, ParFlow. The module presented here is designed to maximize the satisfaction of demand subject to a system of priorities, preferences and constraints. Because ParFlow solves the groundwater and surface water systems simultaneously, the coupled management model can explicitly incorporate groundwater surface water interactions into management decisions. Proof of concept for the new module is demonstrated for a hypothetical water management scenario, utilizing moisture dependent irrigation, in a real world basin, the Little Washita.