Protecting a Fragile Freshwater Lens
Thoddoo Island is famous in the Maldives for its fresh produce, particularly the watermelons that are harvested and enjoyed during the holy month of Ramadan. Now, an innovative demonstration project is seeking to protect the fragile freshwater resources on which farmers and islanders depend.
In common with low-lying islands around the world, The Maldives is not endowed with an abundance of freshwater – inhabitants of the archipelago depend on rainwater and groundwater aquifers to meet their needs. In the capital city of Malé, and the smaller towns of Villingili, Hulhumale desalinated water is supplied to households via a metred network, but on the most of the outlying islands (only five have water networks) water is drawn from shallow, hand-dug wells and household or community-owned rain-water tanks. The transportation of water is also common in the Maldives, especially during the dry months of March and April. For example, between 2011 and 2015, the government transported 23 307 tons of water by boat to 27 islands, an extremely costly endeavour.
land is used for the cultivation of papaya, watermelon, betel, chillies and leafy vegetables and approximately 100 farmers tap into Thoddoo’s freshwater lens on a daily basis, using the water to irrigate their crops. However, the groundwater aquifer is extremely susceptible to contamination from wastewater and agricultural chemicals: it is often foul smelling and discoloured, and in some areas farmers have abandoned fields because the salinity of the groundwater makes it unsuitable for irrigating crops.
Both farmers and citizens of Thoddoo have expressed concern about the contamination of the island’s freshwater lens and an Integrated Water Resources Management (IWRM) demonstration project has been initiated to resolve the freshwater pollution and over abstraction on the island, and ultimately address the challenge of saltwater intrusion. The project is jointly financed by the Global Environment Facility (GEF), through the United Nations Development Programme (UNDP) and the government of Maldives.The Ministry of Environment and Energy through its Water and Sanitation Department is the lead agency responsible for the implementation of the project, with the United Nations Office for Project Services (UNOPS) as the executing UN agency on behalf of the donors.
A major constituent of the demonstration project was the establishment of an integrated water supply system. This comprises the infrastructure required to collect and store rainwater, a desalination plant and a water distribution network that will see every household on Thoddoo Island receiving clean drinking water. A 1 000m3 rainwater collection tank connected to 10 public buildings was built. Rainwater collected from the roofs of these buildings is channelled through a pipeline to a lifting station from which it is pumped to the rainwater holding tank. Water in the tank will be filtered and cleaned before being pumped to a second holding tank where it is mixed with fresh water produced by a desalination plant. This water is sterilised one more time before being channelled to households via a newly designed and constructed distribution network. The idea is to supplement and mix the water that is produced by the desalination plant with rainwater. Not only is desalination very costly, it also produces water with a somewhat slightly salty taste – mixing desalinated water with rainwater will make it more palatable for the people of Thoddoo.
The rainwater collection system is fully now operational on Thoddoo Island and is expected to supply at least 25 percent of the water that is distributed to homes. However, on other islands in The Maldives, similar systems are supplying up to 75 percent of piped water, so it is possible that rainwater could supply a much higher percentage of piped water to Thoddoo islanders in the future.
It is worth noting that the government demonstrated ownership of this demonstration project and decided extend the reach of the water distribution system to the 2000 islanders, financing 70% of the total cost of the new system.
Although the IWRM demonstration project includes a large infrastructure development component, it also has a “soft” component that will educate and sensitise the people of Thoddoo Island about the fragile nature of the freshwater lens and the need to protect its integrity.
One of the first steps taken towards this end was the establishment of a Water Committee for Thoddoo Island. The newly constituted Committee includes representatives from every walk of island life, from the chairperson of the Island Council to farmers, women, schools and non-governmental organisations. The Water Committee is expected to play a key role in the management of water resources on Thoddoo in the future. One of its biggest challenges is to address the excessive abstraction of water from the freshwater lens which is causing its depletion and increased salination. Another challenge is to curb the irresponsible use of chemicals and fertilizers: these are sometimes mixed inside wells which makes it easy for farmers to dispense them to their crops, but causes serious contamination of the lens.
Watch the video about the project:
Working with the Water Committee and in partnership with extension officers from the Ministry of Fisheries and Agriculture, the demonstration project team has addressed problems like these through a concerted education and awareness campaigns targeting schools students and farmers. It is aiming at changing the behaviours that are known to contaminate the freshwater lens.
The establishment of a participatory water quality monitoring programme – that involves farmers and other island residents in the routine sampling and testing of water quality – will allow islanders to constantly keep an eye on pollution and salinity levels in the water they use for farming, washing and drinking. Sampling and testing equipment and training will be provided to Thoddoo islanders by the IWRM demonstration project, so that they can play a leading role in protecting the fragile freshwater lens on which they depend.
This initiative will dovetail with a nation-wide water conservation campaign that that aims to encourage all citizens of The Maldives to use water sparingly and responsibly.
The IWRM demonstration project that has been implemented on Thoddoo Island has not only helped to protect the island’s precious freshwater lens from contamination and improve the quality of life of Thoddoo islanders, it also has the potential to protect freshwater supplies on other islands through the testing of new technologies and the introduction of IWRM approaches to the agricultural sector. In a bid to protect its citizens from climate change impacts, the government of Maldives recently secured USD 28 million dollars from the Green Climate Fund to improve and replicate the water supply system built on Thoddoo island on 49 other islands of the Maldives where water supplies run out during the dry season.