Water Table Trend-A Sustainability Status of Groundwater Development in North-West Bangladesh

Historical trends of the annual maximum and minimum depths of groundwater tables (GWTs) that are indicative of sustainability status of groundwater resources still remain inadequately studied in the North-West (NW) hydrological region of Bangladesh. This study aimed at evaluating long-term (1985-2016) trends of GWTs of 350 monitoring wells and their impacts on groundwater development status in that region. The trends of the annual maximum and minimum depths of GWTs were determined and evaluated by using MAKESENS trend model. The functionality of suction-mode pumps was identified based on the annual maximum depth of GWTs. A significant (p <= 0.05) falling trend of the annual maximum depths of GWTs in 65.71% of the monitoring wells revealed continuous increase in groundwater abstraction. A significant falling trend of the annual minimum depths of GWTs in 69.71% of the monitoring wells revealed groundwater mining. GWTs remained below the suction limit (approximate to 6 m) for 3 to 6 months in each year in 59.72% of the monitoring wells and for the whole year in 15.14% of the monitoring wells, making suction-mode pumps inoperable and creating domestic water scarcity. Therefore, groundwater extraction in many locations has become unsustainable, and hence, measures such as artificial recharge to the aquifers and water-saving technologies are needed to prevent groundwater mining.