Water-table dynamics of Dhaka city

What is it about?

The groundwater condition of Dhaka city is reported to be very alarming as the water table (WT) of the city goes down, down and down. So, seventeen years (1988-2004) WT data of the city was analyzed for assessing the WT fluctuation and predicting its trend using a computer model, "MAKESENS". The procedure of the model is based on the non-parametric Mann-Kendall test for trend and non-parametric Sen's method for slope (Salmi et al., 2002). In the computation of statistical test, the model exploits both the so-called S statistics and Z statistics (the normal approximation) given in Gilbert (1987). The results revealed that at different locations of the city ground water level drastically declined during the study period. The worst WT condition was found at Mirpur, where the maximum WT declined from 14.2 m in 1988 to 60.5 m in 2004 (about 46 m depletion in 17 years). Analysis of WT declining trends showed statistically significant at level α = 0.0001. Moreover, the model also predicted that WT would further decline 9 to 25 m by the year of 2015 and 18 to 40 m by the year 2025 when most of the wells would possibly be inoperative, if the pumping rate is not reduced. This might cause more crucial groundwater situation in the city. Hence, there is an urgent need to find alternate source of water supply to mitigate the blooming crisis.

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Why is it important?

For remedial measure of the groundwater mining.