Large-scale high-resolution groundwater modelling

Abstract:

Groundwater is the world's most important freshwater resource. Despite this importance, groundwater flow and interactions between groundwater and other parts of the hydrological cycle are often neglected or simplified in large-scale hydrological models. One of the challenges in simulating groundwater flow at continental to global scales is the lack of consistent globally-available hydrogeological data. This input data is needed for a more realistic physical representation of the groundwater system, enabling the simulation of groundwater head dynamics and lateral flows. A realistic representation of the subsurface is especially important as large-scale hydrological models move to finer resolutions and aim to provide accurate and locally relevant hydrologic information everywhere.

The aim of this study is twofold. First, to improve and extend on current available large-scale data-sets providing information of the subsurface. This is done by integrating local hydrogeological information into representative aquifer parameter values applicable to the continental scale. Second, to extend current global-scale model evaluation strategies focussing on the groundwater system. Results of a hyper-resolution aquifer parameterization for Northern America and the results of an inter-scale model comparison study will be presented. The latter evaluates model results using the new continental-scale aquifer parameterization against model results using regional specific aquifer parameterizations, focussing on groundwater flow. This provides new insights into model sensitivity and robustness of the continental scale parameterization. The methods used are simple and can be extended to other parts of the world.