Assessing Groundwater Level Declination in Dhaka City and Identifying Adaptation Options for Sustainable Water Supply

Abstract

Dhaka city, having a population of about 18 million, depends heavily on groundwater as a source of quality water. However, the city is encountering a rapid depletion of groundwater, and its groundwater-based water supply is at risk of failure. This study was carried out to analyze the groundwater depletion scenarios occurring from 1970 to 2019 in the city and to find suitable options to sustain its water supply. The trends in groundwater levels (GWLs) were quantified by the non-parametric Sen’s slope and their significances were assessed by the modified Mann-Kendall test. Contour maps of GWL were generated to develop the contemporary GWL scenario in the city. Key informant interviews (KIIs) with the Dhaka Water Supply and Sewerage Authority (DWASA) officials, groundwater experts and researchers, in addition to semi-structured interviews with the DWASA consumers were conducted to assess current adaptation practices and to develop potential adaptation options. The effectiveness of the options was assessed by strengths, weaknesses, opportunities and threats (SWOT) analysis and the options were ranked through a normalization process of the weights given by the KIIs for future adaptabilities. The GWLs were found to be decreasing all over the city, varying from 0.6–2.4 m/year. The contour maps demonstrated that the groundwater of the central area had depleted more than the peripheral areas. The locations vulnerable to severe groundwater depletion were identified to be the Khilgaon, Sobujbagh, Motijheel, Dhanmondi, and Sutrapur areas and some parts of the Cantonment and Mirpur areas. Potential options identified were adopting more surface water treatment plants, rainwater harvesting, implementing a block tariff system, reducing non-revenue water, metering water consumption, and promoting public awareness. Spatially-varying adaptation strategies were also suggested for different zones. Some measures adopted by DWASA were not supported by the respondents.

Quality Assessment of Condensate Water Generating from Air Conditioning Units

“…Over the last five years, DWASA has managed to increase daily production by 3.5 crore liters by installing deep tube wells [12,13]. However, excessive groundwater extraction, coupled with inadequate aquifer recharge in the city, is leading to a rapid and concerning decline in groundwater levels [20][21][22][23]. To address the increasing water demand in Dhaka, the DWASA is increasingly prioritizing the use of surface water sources for providing clean drinking water.…”

The impact of climate change, population growth and development on sustainable water security in Bangladesh to 2100

“…Urban water supply in Bangladesh’s biggest city, Dhaka, is also based on the unsustainable use of groundwater, with rapid depletion threatening both the quantity 22 – 24 and quality 25 of the resource. Population increase will again exacerbate the problems 26 .…”

Potential Impacts of Industrialization on Coastal Fresh Groundwater Resources in Bangladesh

“…In Bangladesh, groundwater is the major source of freshwater supply for irrigation, industrial, and domestic water supply in both the urban and rural areas [19][20][21][22]. However, Bangladesh is one of the worst affected countries in the world for groundwater arsenic [23,24].…”

“…Away from the coast, extensive irrigation and use of pesticides and other chemicals in the northern part of Bangladesh is deteriorating the groundwater quality [30,31]. Apart from groundwater quality issues, many urban centers and agricultural hubs in the country are experiencing a rapid decline in groundwater levels [21,22], and its impacts are being felt in areas that are tens of kilometers away from the urban center [32][33][34].…”