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Published on: 08/07/2013

Background (text by Charles Batchelor)

Water-related crises are not a new problem in Bangladesh. The discovery of arsenic in drinking water was deemed “the largest mass poisoning of a population in history” threatening the lives of millions. Now Bangladesh is facing another environmental and health threat that is a result of rising salinity levels in drinking water supplies (Khan et al, 2008).  A major cause of increased salinity levels is saline intrusion into groundwater both in exposed and interior coastal areas.  Saline intrusion into aquifers is a slow process that is influenced by a range of bio-physical and anthropogenic factors that include: withdrawal/diversion of water from river systems; inter- and intra-annual rainfall variability and rising temperature; groundwater extraction for irrigation; and, sea level rise due to climate change can all have a strong influence over fresh water distribution, tidal penetration of sea water into estuaries and river systems and the specific hydro-geological characteristics of groundwater systems.

Figure 1: Underground salinity front at a depth of 39m (BADC, 2011)
Figure 1: Underground salinity front at a depth of 39m (BADC, 2011)

Figure 1 shows the current extent of saline intrusion into coastal aquifers in south-western Bangladesh. This map was prepared by the Bangladesh Agricultural Development Corporation (BADC) using data from 100 salinity observation wells. During 2009-2011, BADC also constructed a map using data from 3166 observation wells which shows that groundwater levels have fallen below sea level all over Bangladesh (see Figure 2). The net result being that aquifer conditions have been created that increase the risk of saline intrusion.

There is strong evidence of the link between excessive salt consumption and several chronic diseases (WHO, 2006).  Interventions to reduce population-wide salt intake have been shown repeatedly to be highly cost-effective, hence the urgency to implement strategies/policies/programmes tackling the reduction of dietary salt intake. A technical report produced by WHO and the FAO recommended ingestion of less than 5 g sodium chloride (or 2 g sodium) per day as a population intake permissible limit, while ensuring that the salt is iodized (WHO, 2003). This expert consultation stressed that dietary intake of sodium from all sources influences blood pressure levels in the population and should be limited so as to reduce the risk of coronary heart disease and stroke. Results from a recent study in Bangladesh (Khan et al, 2011) included the following: i) Average per capita estimated sodium intakes from drinking water ranged from 5 to 16 g/day in the dry season, compared with 0.6–1.2 g/day in the rainy season;  ii)  Women who drank shallow tube-well water were more likely to have urine sodium > 100 mmol/day than women who drank rainwater; and iii) The annual prevalence of hypertension in pregnancy was higher in the dry season than in the rainy season.

Figure 2: Locations where groundwater levels have fallen below mean sea level (BADC, 2011)
Figure 2: Locations where groundwater levels have fallen below mean sea level (BADC, 2011)


The problem of saline intrusion into drinking water sources: has multiple causes, is most prevalent in southern Bangladesh and has the potential to be exacerbated by climate change-induced sea-level rise.  Given that the causes of saline intrusion involve multiple factors and feedback loops, it is clear that there are no quick fixes.  Hence, the underlying rationale in this call is that Bangladesh’s salinity challenges are best tackled by preparing (or updating) and implementing water safety plans that consider all contaminants and take a “catchment to consumer” approach to managing water quality.  More specifically, the most cost-effective and protective means of consistently assuring a delivery of drinking water of an acceptable quality is the application of some form of risk management that is informed by sound science and supported by appropriate monitoring systems (WHO, 2005).

Water safety plans should be based on field surveys (or sanitary surveys) that directly link water supply, hygiene, and sanitation, for example, in addressing issues such as open defecation, solid and liquid waste, and safe household storage and handling (WSP, 2011).  It is also imperative that water safety planning is embedded within institutional and governance arrangements that are: participatory; provide relevant training and technical support; review and approve village plans; integrate plans and manage convergence of different development programmes; monitor progress of plan implementation and operational performance, and provide information to stakeholders at all levels on water services levels and the extent and severity of salinity and other water safety challenges. 

Water safety planning is a well-known concept that is already in use in Bangladesh (e.g. Arsenic Policy Support Unit, 2006; Mahmud et al, 2007; Greaves and Simmons, 2011). 

One of the main aims of a BRAC WASH II programme research project on the mitigation of saline intrusion is to add value to existing water safety planning activities by improving the salinity aspects of both water quality monitoring systems and the water safety plans (and water safety plan implementation). 

Another added value is to ensure that water safety plans are an integral part of programmes in Bangladesh that are aimed at “WASH services that last”.  The argument being that “WASH services that last” will not be attainable or sustainable in Bangladesh unless water salinity and other water quality challenges are tackled effectively.

Another aim of the applied research project is to assess different strategies for upgrading existing approaches to monitoring salinity levels in ground and surface water at the local, intermediate and approaches.  

The proposed project needs to address data acquisition, analysis and accessibility issues.  In terms of data acquisition, the utility of using AKVO FLOW as part of salinity monitoring by Government of Bangladesh departments, NGOs and communities will be investigated. 

In terms of data analysis, the proposed project will investigate the possibility of mainstreaming the use of advanced mapping and state-of the-art modelling techniques into water safety planning.  

More specifically the utility of using both commercial and open source mapping and modelling software should be investigated whilst taking account of relevant ongoing studies (e.g. SEI’s SWAT-MODFLOW in Bangladesh (Condappa et al, 2012). 

In terms of data accessibility, particular attention should be given to making information availability in a form that can easily be assimilated and used by stakeholders at all levels via open-access cloud-based management information systems.   

It is also proposed that the project adds value by developing simple decision support tools that help decision-makers decide on the best causes of action as and when salinity levels reach critical limits.  In some cases, actions may involve mitigation (e.g. increasing recharge rates near to borewells that are sources of domestic supply) and in the others the only effective courses of action may involve adaptation (e.g. use of desalination plants or mini-RO plants for water supplies to urban areas or villages respectively). 

All methodologies and recommendations should be piloted and subjected to rigorous livelihood, gender and environmental audits.


The BRAC WASH II research call for mitigation of saline intrusion was won by Deltares, based in the Netherlands. Their project is called SWIBANGLA, managing saltwater intrusion impacts in Bangladesh.

Deltares is working together with two partners: UNESCO-IHE in The Netherlands, and CEGIS Centre for Environmental and Geographic Services in Bangladesh.

The 15-month project runs from 1 May 2013 to 30 July 2014 and has a budget of € 120,000 (US$ 154,000).

Project objectives

Deltares believes that the salinization issue will only become an integral part of water safety planning in Bangladesh when a sufficient level of awareness, knowledge and skills is reached. Towards these aims, their project is focused at fulfilling the following five objectives:

1. Create a better understanding of the process of salinization of drinking water resources in Bangladesh.

Management of and anticipation on the issue of drinking water resources salinization requires an understanding of the actual physical processes behind it. Moreover, awareness of the salinization issue will strongly benefit from an increased understanding of the actual physical process. The project includes the mapping, monitoring and understanding of the groundwater system in Bangladesh by means of innovative complex monitoring techniques, acquisition of local knowledge and density-dependent groundwater modelling. 

2. Provide recommendations for monitoring

It is only through a sound understanding of the cause-effect relationships in the salinization issue that effective strategies for mitigation and adaptation can be defined. Thus, in order to make Water Safety Plans “salinization robust”, a sound insight is necessary in the current salinity levels of the drinking water resources, as well as throughout the (geo)hydrological setting in which these drinking water sources are located. In the case of Bangladesh, this asks for simple but effective monitoring approaches that produce the necessary information at low cost. The cheaper and more simple the monitoring approach, the more successful and widespread its implementation will be.

Monitoring salinization should target both the local and the regional level. Local monitoring information is needed for local-scale water management decisions (where to install a pump, when to shut down a well, what local-scale mitigation and adaptation strategies are possible, etc.). Regional-scale monitoring is needed to increase the understanding of “the bigger picture”, i.e. the ongoing salinization process, in terms of scale and time etc., so that insight is gained into expected problems and regional-scale solutions, enabling the WASH sector to anticipate in a timely fashion.

3. Provide recommendations for adaptation and mitigation

Effective water planning is only possible if water managers are presented with possible courses of action, should salinization indeed hamper the supply of drinking water of a good enough quality. The success of mitigation and adaptation strategies depends on many factors. Guidance is needed as of which mitigation and adaptation measures are applicable in what situation. 

4. Achieve an effective, tailored knowledge transfer between the Netherlands and Bangladesh

The Netherlands has a lot of experience with dealing with salinization issues in low-lying areas, so in terms of knowledge and experience Deltares and UNESCO-IHE can share their expertise with the WASH sector in Bangladesh. Bangladesh has a different setting than the Netherlands but at the same time salinization problems are quite similar. The Bengali setting is well-known by CEGIS, the consortium partner in Bangladesh. The collaboration of all partners in the current project will provide many new and useful insights. It is a challenge to effectively communicate all knowledge to the stakeholders in the WASH sector of Bangladesh. The planned fact finding strategy and workshops will answers questions such as “Who should be targeted?”, “What is the knowledge level of the different stakeholders?“, “What type of communication is most effective and best appreciated?”, and these answers will be used to transfer the needed knowledge and skills to the stakeholders effectively.

5. Advise on the integration of the salinization issue in Water Safety Planning

It is expected that the integration of all new knowledge and information the project will deliver into the Water Safety Plans needs further guidance. The final goal of this project is therefore to provide effective assistance in the translation of the project outputs into “salinization robust” Water Safety Plans.

Project outputs / deliverables

  1. Milestones and major target dates set with the stakeholders; timeline for the 6 work packages
  2. Leaflet/brochure information on salinization processes, monitoring techniques, and mitigation strategies;
  3. Intermediate communication outputs on the project, either with a blog post or short article/paragraph on the IRC site or web site of Consortium Partner(s).
  4. End-user oriented support materials on the causes of salinization and adaptation/mitigation measures (to be included in the Water Safety Plans);
  5. Business case-study of a Smartphone application to convert and transfer EC measurements;
  6. A 3D density-dependent groundwater flow and couples salt transport model of the central coastal zone of Bangladesh;
  7. Peer-reviewed article on 3D model of fresh-saline groundwater flow and coupled solute transport of the central coastal zone of Bangladesh (due to time pressure only submitted, not accepted for publication);
  8. Abstracts to conferences: at least 23rd SWIM (Hamburg, summer 2014), but probably also AGU, EGU or Modflow and More, etc.
  9. Final workshop with BRAC team at which IRC will be personally represented.


Arsenic Policy Support Unit, 2006. Experiences from pilot projects to implement water safety plans in Bangladesh. Arsenic Policy Support Unit, Dhaka, Bangladesh

BADC, 2011. Identification of Underground Salinity Front of Bangladesh.

Condappa, D. et al. 2012.  Application of SWAT and a Groundwater Model for Impact Assessment of Agricultural Water management Interventions in Jaldhaka Watershed: Data and Set Up of Models Technical Report. Stockholm Environment Institute.

Greaves, F. and Simmons. C., 2011.  Water Safety Plans for communities : Guidance for adoption of Water Safety Plans at community level. Tear Fund.

Khan et al., 2008.  Saline contamination of drinking water in Bangladesh.  The Lancet.

Khan et al., 2011. Drinking Water Salinity and Maternal Health in Coastal Bangladesh: Implications of Climate Change. Environmental Health Perspectives.

Mahmud, S.G. et al., 2007. Development and implementation of water safety plans for small water supplies in Bangladesh: benefits and lessons learned.  Journal of Water and Health.

WHO, 2003. Diet, nutrition and the prevention of chronic diseases. Report of a Joint WHO/FAO Expert Consultation. WHO Technical Report Series, No. 916.

WHO, 2005. Water Safety Plans: Managing drinking-water quality from catchment to consumer. WHO, Geneva.

WHO, 2006. Reducing salt intake in populations: report of a WHO forum and technical meeting, 5-7 October 2006, Paris, France.

WHO, 2009. Water Safety Plan Manual: Step-by-step risk management for drinking-water suppliers. WHO, Geneva.

WSP, 2010. Rural Water Supply in India : Policy Issues and Institutional Arrangements. WSP, New Delhi.

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