Crisis of safe drinking water in coastal areas

In Bangladesh, approximately 20 million people are living in coastal areas, continuously struggling for safe potable water. The majority of them depend on surface water for drinking purpose.  Seasonal calendar shows that pond water is generally used from mid-November to mid-June, while rain water from mid-June to mid-October. Regardless of enough tube-wells, only a few are apparently suitable to ensure year-round access due to excessive salinity in groundwater as stated by the DPHE.
Admittedly, coastal people drink pond water either tested by filtration process or not.  Generally, pond sand filter (PSF), solar system PSF (SSPSF), pipeline solar system PSF (PSSPSF), managed aquifer recharged (MAR) and desalinisation reverse osmosis (RO) plants are found here. Of these technologies, hand-pumped PSF is the most convenient because of its economic feasibility and easy to use. On the contrary, solar system PSF is found little effective during the winter season; PSSPSF is ineffective to ensure door-to-door water supply due to its technical complexity and improper local communication system; and MAR technology couldn't come into effect due to high salinity and turbidity in aquifer. In addition, very small number of private business-oriented RO plant aren't found economically viable for the poor community. Astonishingly, the number of functional water technologies is lower than the local demand. As a consequence, coastal communities have to collect drinking water from ponds.
Meanwhile, all existing drinking water ponds are unable to ensure year-round water supply owing to water loss for environmental uncertainty. A study of Rupantar in Dacope Upazila (2015), revealed that 89 ponds with water option are effective out of total 319 drinking water ponds, holding about 239 million litres of water for about half of the total population. Of the total water, around 35 per cent water loss takes place for seepage and evaporation. Considering water loss and unused water free from microbial impurities, 2.5 feet water from the bottom, only 65 per cent and 56 per cent ponds are able to create access to safe water for three and 6 months respectively. Besides, for reducing water depth, the rest of the ponds are at risk of creating blockage in filtration chamber of water options due to higher concentration of turbidity and TDS in water. Therefore, non-functional water technology is not only the said management issue but also the environmental issue. Considering the environmental factors, we should install water technology following standard size and depth of pond.
During cyclone Aila and Sidr in coastal areas, all ponds were flooded with tidal surge, creating scarcity of drinking water badly. Pond water is also contaminated by rotten leafs as pond bank is dominated by deciduous and semi-ever green trees that lose their leaves before the next growing season. The pond adjacent to latrine and cow house within 30 feet is polluted by microbial impurities like E.colibacteria when it comes to the pond water through surface runoff. In addition, solid, suspended particle and inorganic salt go into the unprotected pond stimulating growth of the bacteria. Interestingly, it is commonly found in the lower intestine of warm-blooded organisms, causing intestinal infection when it enters the stomach using oral route.
As a developing country, Bangladesh is facing challenges in financing of drinking water. The Department of Public Health Department (DPHE) and local government institutions are trying hard to supply safe drinking water because of lower budget allocation although they have a mandate to supply water to the communities. Likely WaterAid, very few NGOs are working in the coastal areas. Financing in water sector as part of Corporate Social Responsibility (CSR) of banks and industries is found to be insignificant. According to the UNDP, every $1 invested in water and sanitation will yield return of up to $8. So, the country should go for funding in this sector in order to improve community health, empower women, and foster economic development.
The writers work in the Environment and Disaster Management Programme of Rupantar
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