Evaluation of spatio-temporal dynamics of water table in NW Bangladesh: an integrated approach of GIS and Statistics

Abstract

The aims of this study are to determine and evaluate the spatial and temporal changes in the groundwater table for the period of 1991-2009 and probable causes of changes of water table depth in northwest (NW) Bangladesh. Trends analyses have been done by linear regression, Mann-Kendall Trend Test and Sen's slope estimator; and spatial analysis by Geographical Information Systems (GIS). The results show decreasing trends in dry and monsoon seasons and annual average groundwater level except a few discrepancies in NW Bangladesh, though the magnitudes of changes very spatially and methodically. Very strong declining trends with high magnitude of changes in all three series that are significant at 99 % confidence level found in the central part of the area where the rate of changes vary from 0.82 to 0.2 m/ year in dry season, from 0.67 to 0.2 m/year during monsoon season and 0.6 to 0.1 m/year in annual average time series. Declining trends with low rate of changes are found in the rest of the areas except some pocket areas. The drop of groundwater level is also very high in the central part. Falling trends and drop of groundwater level indicate unsustainable withdrawal of groundwater over the study area. Findings of study indicate rigorous abstraction of groundwater for irrigation, decreasing trend in rainfall and surface geology of the area are attributed to rapid declining trend in groundwater level. Situations will be irreversible if necessary steps are not taken beforehand. Keywords Groundwater table dynamics Á Mann-Kendall trend test Á Sen's slope estimator Á Linear regression Á GIS Á North West Bangladesh

Sustainable Groundwater Management in Context of Climate Change in Northwest Bangladesh

“…These data have also been collected from the BWDB. Details of groundwater level monitoring data can be found in Rahman et al [7,9].…”

“…In the present study, trends have been detected by non-parametric Mann-Kendall [15,16] (MK) test. MK test shows a good performance for identifying trends in hydrological variable [7][8][9]. If there is a significant serial correlation at lag-1 in the climatic data, MK test cannot calculate the exact value of test statistic [17].…”

“…The rate of change has been calculated by Sen's slope estimator [19]. The details of the methods can be found in [7][8][9][15][16][17][18][19].…”

“…Hence, the present study has given the main attention to the sustainability of groundwater resource by integrating drought characteristics, and climate change effects and status of the groundwater resource. Our previous studies [7][8][9] investigated the groundwater level scenario, drought characteristics, and dynamics of drought in the northwest Bangladesh. However, the impact of climate change on rainfall pattern which is the main source of groundwater recharge and potentiality of surface water resource have not been investigated comprehensively yet.…”

Evaluation of Aus Rice (<i>Oryza sativa</i> L.) Production in Less Irrigated Situation in Northern Region of Bangladesh

“…The Agriculturists 15 (1):110-115(2017) ISSN 2304, ISSN 1729-5211 (Print) A Scientific Journal of Krishi Foundation Indexed Journal Impact Factor: 0.568 (GIF, 2015) season as an additional and substitute cereal crop to gradually replace cultivation of more irrigation water consuming and costly Boro farming (Rahman et al, 2016). Hence groundwater utilization will be reduced in Rangpur region under climate change situation and food security will be stable with the upscaling of Aus instead of Boro rice.…”