AGU: Geophysical Research Letters

 

Editors' Highlight

Using surface topography to predict groundwater flow patterns

Land surface topography governs groundwater flow patterns at both large and small scales, playing an important role in nutrient and contaminant transport and in the water resources available to aquatic ecosystems. The interaction between surface water and groundwater flows is controlled by surface topography through pressure variations that are induced by stream flow over sediment bed forms and, at the landscape scale, the fact that groundwater surface generally follows the ground surface. To study this, Wörman et al. (2006) developed a Fourier series spectrum that estimates groundwater flows in three-dimensions based on known surface topography. This provides a practical tool for quickly calculating the subsurface flow field and offers a theoretical platform for advancing conceptual understanding of the effect of landscape topography on subsurface flow, the authors noted. Their method also shows how the residence time of subsurface flows is affected by surface topography and that hydrologic head in the subsurface decays exponentially with depth, faster than it would in a two-dimensional model. This results in shallower interaction between surface water and groundwater.

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