ASSESSMENT OF SPATIO-TEMPORAL FLUCTUATIONS IN GROUNDWATER LEVEL AND ITS IMPACT ON TUBEWELL ENERGY NEXUS

Abstract

Over exploitation of groundwater to fulfill the crop water requirements due to insufficient canal water supply can pose a major threat of water table lowering in semi-arid regions like Pakistan. So, it is necessary to analyze the seasonal groundwater level variations for appropriate management strategies to sustainable groundwater use. Water table declining has adverse economic impacts on total cost of agricultural inputs, as more than 50% of irrigation demand is being fulfilled from groundwater resources. Therefore, this research was aimed to draw the groundwater level zones and to determine the impacts of lowering water table on tubewell energy nexus in district Hafizabad, Pakistan. Water table depth was categorized in three zones i.e., shallow (<10 m), moderate (10-15 m) and deep (>15 m) for years 2003, 2008 and 2013. It was found that water table was shallow on north-east boundary, moderate on the Centre and deep on west-south boundary. During the study period, the area under shallow water table zone reduced from 38.6 to 23%, moderate area expanded from 52.3 to 59.2% and deep area increased from 9.1 to 17.9%. The difference between total cost of shallow and moderate water table was minor. The total cost (construction and operational) of tubewell for 36 m deep water table was 3 times higher than shallow depth (9 m). Thus, lowering of water table should be controlled by increasing share of canal water in deeper zone and introducing artificial recharge methods