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Unformatted text preview: EAS 44600 Groundwater Hydrology Lecture 11: Regional Groundwater Flow Dr. Pengfei Zhang Steady Regional Groundwater Flow in Unconfined Aquifers A groundwater basin is defined as a three-dimensional closed system through which groundwater flows from areas where the water table is recharged to areas where the groundwater is discharged (Fig. 11-1). Recharge areas are typically topographic highs where the groundwater flows downward away from the water table, whereas discharge areas are usually topographic lows where the groundwater moves upward with respect to the water table (Fig. 11-1). On a flow net, flow lines tend to diverge from recharge areas and converge to the discharge areas. Water table usually mimics the topography of the land surface, but the relief on the water table is generally less marked than the relief of the land surface. Figure 11-1. Cross-sectional flow net of a homogeneous and isotropic aquifer (Hubbert, 1940). In early 1960s Tóth studied extensively the influence of water table configurations on groundwater flow. His first case was flow in a basin with a sloping linear water table ( h = h o + cx , where h is the hydraulic head, h o the head at x =0, and c the slope of the water table). An analytical solution to the flow problem was given by Tóth, and two flow nets constructed from this analytical solution are presented in Figure 11-2. With the linear sloping water table this analytical solution are presented in Figure 11-2....
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This note was uploaded on 12/29/2010 for the course EAS 44600 taught by Professor Pengfeizhang during the Spring '10 term at CUNY City.
- Spring '10