How Does Topography Control Topography-Driven Groundwater Flow?

Abstract

How topography controls topography-driven groundwater flow is investigated with varying rainfall and topography using a two-dimensional groundwater-surface water coupled model. Results show that the penetration depths of local flow systems present a good relation with capture zone size (Cl) and topography rise (Hl) of local flow systems, but poor and opposite relation with the two topographic indices of the surface water watershed. The stagnant zones are formed due to the movement of stagnation points, whose velocity magnitude is almost zero. The area and depth of stagnant zones below the mountains have a good or no relation with the mountain size, depending on the hydraulic conductivity. The fractal behavior of penetration depth variations with rainfall presents a good or no relation with Cl and Hl, depending on the rainfall rate and hydraulic conductivity. The topography control may be less important when rainfall rate or hydraulic conductivity is significantly reduced.