Physics‐based continuous simulation of long‐term near‐surface hydrologic response for the Coos Bay experimental catchment

Abstract

The study reported here employed the physics‐based Integrated Hydrology Model (InHM) to conduct continuous hydrologic‐response simulation from 1990 through 1996 for the Coos Bay experimental catchment. The uniqueness of the boundary‐value problem used to simulate three sprinkling experiments was assessed, via model performance evaluation against observed piezometric and discharge data, for 33 events extracted from the continuous record. The InHM simulations could not adequately reproduce the distributed observed pore water pressures, suggesting that detailed characterization of the locations and connectivities of bedrock fractures is critical for future efforts designed to simulate distributed hydrologic response at the field scale for locations where bedrock fracture flow is important. The simulations presented here suggest the potential for interaction between the deeper water table and near‐surface hydrologic response. The results reported herein suggest that while uniqueness can be reasonably achieved with respect to the integrated response (i.e., discharge), the integrated response uniqueness is no guarantee that the distributed response (i.e., pressure head) is either unique or well simulated.