Flow Toward Storage Tunnels Beneath a Water Table: 2. Three‐Dimensional Flow

In the first part of the study (Tal and Dagan, 1983) the problem of two‐dimensional flow of water toward storage tunnels was solved. This case corresponds to a falling water table in absence of sufficient natural recharge. In the present part we consider the case in which the water table is prevented from descending and is maintained in a steady position by a battery of recharging wells. The three‐dimensional flow problem is solved first by a simplified linearization approximation which is valid for flat water table which is sufficiently high above the gallery. The full nonlinear free surface problem is subsequently solved numerically by the boundary integral element method, and the range of validity of the linearized approximation is established. The solution provides the tools needed in order to design an optimal well system (spacing, length, discharge) for given gallery setup, product pressure, and water table height. Both cases of products of low and high vapor pressures are investigated.