Investigation of operational efficiency and up-coning problem of scavenger wells in lower indus basin of Pakistan

Abstract

Groundwater in lower Indus Basin of Pakistan is available in thin aquifers. If groundwater is exploited to unsustainable level, up-coning problem can occur. Up-coning is the saline water intrusion in the fresh water aquifer. Once quality of fresh water is deteriorated because of upconing of saline water, it is very hard to make it again fit for irrigation usage. Thus, it is always advised to abstract groundwater without bringing saline water into the fresh water aquifer. In this study, we have investigated the operational efficiency of 79 scavenger wells installed at right side of Jamrao canal, lower Indus Basin Pakistan to check whether these wells were performing with the design operational efficiency. We found that majority of scavenger wells were running quite below the design operational efficiency. We also performed a constant rate pumping test on one of the scavenger wells to check whether any chances of up-coning were happening if the both pumps (fresh water and saline water) of the selected scavenger wells were operational. The pumping test results reveal that chances of up-coning were negligible if the pumps are run within the design operational hours (14.4 hrs per day).