The term skimming well is used for any technique employed with an intention to extract relatively freshwater from the upper zone of the fresh-saline aquifer. The types of skimming wells include: the conventional single strainer well, multi-strainers wells, scavenger wells, radial collector wells and dug wells. The skimming wells are low discharge (less than 28 l.p.s.) cluster of wells drawing groundwater from relatively shallow depth. Skimming wells are generally designed for irrigation(Saeed et al., 2002a) or drinking water supply (Rao et al 2006, 2007) purposes.
Rates of pumping of saline groundwater is a crucial decision variable, especially when sustained pumping have to be done on a long term basis. Unregulated pumping often results in up-coning phenomena resulting in increased salinity of pumped groundwater. Therefore regulated pumping along the planning horizon must be carefully implemented such that relatively least saline water is skimmed from upper unconfined aquifer system. Groundwater management models embedding numerical flow and transport (salt) models with in simulation-optimisation frameworks are often employed for this purpose (Rao et al 2007).
For more details:
Rao, S V N., Sudhir Kumar, Shashank Shekhar and D Chakraborty (2006). Optimal pumping from skimming wells. ASCE J. of Hydrologic Engineering, Vol. 11, 5, 464-471.
Rao, S V N., Sudhir Kumar, Shashank Shekhar and S K Sinha (2007) Optimal operation of skimming wells – A case study in river Yamuna flood plain at Palla in north India 15:6 of Hydrogeology Journal , 1157-1167.
Rao S V N (2007). Optimal locations of skimming wells. Hydrological sciences Journal, 52(2), 352-361.
Saeed MM, Ashraf M, Bruen M. 2002a. Diagnostic analysis of skimming well technologies in the Indus Basin. Irrigation and Drainage Systems 16, 139-140.