Options for Skimming Fresh Groundwater in the Indus Basin of Pakistan: A Review

抄録

The aquifer under the Indus basin of Pakistan is of marine origin and the native groundwater is saline which is overlain by a freshwater layer. The upper freshwater layer is formed as a result of seepage from rivers, canals, field irrigation losses and precipitation. About 6.42 million ha area has freshwater layer of variable thickness. The exploitation of upper freshwater layer is hindered by saline water intrusion and saline upconing under pumping wells. To extract this freshwater for agricultural, domestic and industrial purposes, different techniques are being practiced in the Indus basin to minimize the saline water intrusion. These include; shallow tubewells, skimming tubewells, scavenger wells, dug wells, and radial collector wells. The adoptability of these techniques depends upon the thickness of the freshwater layer, availability of local material, availability of technical personnel for installation and maintenance, local customs and traditions, and the affordability. The present paper reviews the skimming well technologies used for extracting freshwater in various parts of the Indus basin of Pakistan, their feasibility in different part of the basin, the present status of these techniques and associated constraints.