Seepage Face Height, Water Table Position, and Well Efficiency at Steady State

Abstract

When a fully penetrating well pumps an ideal unconfined aquifer at steady state, the water table usually does not join the water level in the well. There is a seepage face inside the well, which is a key element in evaluating the well performance. This problem is analyzed using the finite-element method, solving the complete equations for saturated and unsaturated flow. The seepage face position is found to be almost independent of the unsaturated zone properties. The numerical results are used to test the validity of several analytic approximations. Equations are proposed to predict the seepage face position at the pumping well for any well drawdown, and the water table position at any distance from the pumping well for any in-well drawdown. Practical hints are provided for installing monitoring wells and evaluating well efficiency.

Water flow and nitrate transport through a lakeshore with different revetment materials

“…Many simulated and observed results have reported the existence of a seepage face and its effects on water flow and solute transport (Vachaud et al, 1973;Simpson et al, 2003;Rushton, 2006;Chenaf and Chapuis, 2007). For example, in a sand box experiment involving radial flow and transport, Simpson et al (2003) found that the flow velocity through the seepage face was about 30% higher than at the base of the aquifer, while the solute transport patterns were strongly influenced by the flow characteristics of the system.…”

Sustainable yields from large diameter wells in shallow weathered aquifers

“…An essential feature of an agrowell is the formation of a seepage face (Fig. 5(b)) between the water table at the edge of the well and the pumped water level (Simpson et al, 2003;Rushton, 2006;Chenaf and Chapuis, 2007). This is represented in the groundwater model by modifying the hydraulic conductivity for the four grid lines connected to the well by a factor of 0.28; this factor was adjusted for best-fit.…”

述评:水井水力学—水流定律和几何学的影响

“…Several authors developed purpose-specific numerical models (e.g. Cooley and Cunningham 1979;Kaleris et al 1995;Von Hofe and Helweg 1998;Rushton 2006;Chenaf and Chapuis 2007), while others relied on commercially available groundwater modeling programs, such as MODFLOW (e.g. Barrash et al 2006;Horn and Harter 2009;Houben and Hauschild 2011;McMillan et al 2014), FEFLOW (Rubbert and Treskatis 2008) and HYDRUS-2D (Yakirevitch et al 2010).…”

“…The red bar shows the area suitable for the linear approximation (Eq. 51) proposed by Parsons (1994) and Rushton 1989;Rushton 2006;Chenaf and Chapuis 2007;Yakirevitch et al 2010;Behrooz-Koohenjani et al 2011).…”

“…This approach was questioned by Kawecki (1995) and Wise and Clement (1995). The problem of the Kozeny approach is that it assumes a unit gradient for the maximum flow velocity at the well screen (Chenaf and Chapuis 2007).…”