Incorporating Uncertainty into High-Resolution Groundwater Supply Models

摘要

Groundwater modeling is a useful tool for evaluating whether an aquifer system is capable of supporting groundwater withdrawals over long periods of time and what effect, if any, such activity will have on the regional flow dynamics as well as on specific public water, agricultural and industrial supplies. High-resolution models are necessary for quantification of local processes and phenomena. However, standalone, refined models require more detailed hydrogeological data, are more computationally intensive, and do not provide information on regional flow and dynamics. We are currently involved in a groundwater modeling study of the Chicot Aquifer in southwestern Louisiana where we are using a low-resolution groundwater model to study the regional flow in the Chicot aquifer and to provide boundary conditions for higher-resolution inset models created using telescopic mesh refinement (TMR). These high-resolution models allow us to incorporate more data and information into the study region, including aquifer heterogeneities, recharge rates, and pumping locations and rates. Despite increasingly sophisticated techniques for quantifying and incorporating these data and information into groundwater models, there are still many uncertainties. The objective of this paper is to describe the regional Chicot Aquifer model, the high-resolution Acadia Parish inset model, and the use of geostatistical tools to incorporate uncertainties in the hydraulic conductivity field into the inset model. The regional model is able to reproduce the regional flow dynamics and the boundary conditions necessary for the local model, while the local model incorporates many of the aquifer heterogeneities and water use details. This allows us to determine the impact of these processes on the groundwater flow dynamics (e.g., drawdowns, capture zones, etc...).