| Volumes and Issues Contents of Issue 3 |
www.hydrol-earth-syst-sci-discuss.net/6/4125/2009/
doi:10.5194/hessd-6-4125-2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
Recent trends in groundwater levels in a highly seasonal hydrological system: the Ganges-Brahmaputra-Meghna Delta
1Department of Geography, University College London, London, UK
2Department of Statistical Science, University College London, London, UK
3Department of Geology, University of Dhaka, Dhaka, Bangladesh
Abstract. Groundwater levels in shallow aquifers underlying Asian mega-deltas are characterized by strong seasonal variations associated with monsoon rainfall. To resolve trend and seasonal components in weekly groundwater levels in the Ganges-Brahmaputra-Meghna (GBM) Delta, we apply a nonparametric seasonal-trend decomposition procedure (STL) to observations compiled from 1985 to 2005 in Bangladesh. Seasonality dominates observed variance in groundwater levels but declining groundwater levels (>1 m/yr) are detected in urban and peri-urban areas around Dhaka as well as in north-central, northwestern, and southwestern parts of the country (0.1 to 0.5 m/yr) where intensive abstraction of groundwater is conducted for dry-season rice cultivation. Rising groundwater levels (0.5 to 2.5 cm/yr) are observed in the estuarine and southern coastal regions. This novel application of the STL procedure reveals, for the first time, the unsustainability of irrigation supplied by shallow aquifers in some areas of the GBM Delta and the hydrological impact of seawater intrusion of coastal aquifers associated with sea-level rise. Our findings provide important insight into the hydrological impacts of groundwater-fed irrigation and sea-level rise in other Asian mega-deltas where monitoring data are limited.
Discussion Paper (PDF, 2723 KB) Supplement (1030 KB) Interactive Discussion (Closed, 4 Comments) Final Revised Paper (HESS)
Citation: Shamsudduha, M., Chandler, R. E., Taylor, R. G., and Ahmed, K. M.: Recent trends in groundwater levels in a highly seasonal hydrological system: the Ganges-Brahmaputra-Meghna Delta, Hydrol. Earth Syst. Sci. Discuss., 6, 4125-4154, doi:10.5194/hessd-6-4125-2009, 2009. Bibtex EndNote Reference Manager XML
