December 2016 January 2017
Figure 7 GWS in Bankura District as water Equivalent (monthly)
All the above results are relative to maximum value of 17.687852 cm and minimum value of -24.306836 cm. It is observed that the month of September 2011 has experienced maximum positive groundwater change with a value of 17.6722 cm and June 2013 is observed with maximum negative change of -24. 16828 cm. From the observation of above images, it is found that the months of September, October and November showing positive variations and April, May, June months are showing negative variations of groundwater storage. Graph between time period and mean GWS variations of Bankura district are displayed in figure 8.
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Figure 8 Groundwater storing variations in Bankura district as Equivalent thickness of water
From the graph, it is observed that the trend line of GWS variations in Bankura district is decreasing at a rate of 0.0298 cm/ month (slope of the trend line) during time period from November 2007 to January 2017. It means groundwater depleting in the region at an average rate of 0.3576 cm/year. Reasons behind this groundwater depletion might be agriculture. Because the district has Kangsbathi reservoir as major surface water source which is distant from many places of the district.