Simple solutions for a complex problem

Water resource management interventions in Delft Island

Location: Colombo, Sri Lanka. 21st May 2017

Water resource management interventions in Delft Island published in the Sunday Times of 21.5.2017.

 Seventy percent of the Earth is covered with water, which is why it is called the Blue Planet. Yet, 96.5% of this water is held in oceans, as salt water. Freshwater — the water that humans need for daily living — is confined to 2.5% of all the water on Earth.  More than 68% of this freshwater is trapped as icecaps and glaciers, and another 30.1% confined as ground aquifers (underground rocks that contain water). Only about 0.3% of freshwater is available as surface water in lakes, rivers, and swamps. It seems inconceivable that of all the water on this Blue Planet, more than 99% is unusable by humans and living beings.

Sharing this meager amount of freshwater among the world’s populace is not an easy task, and a distressing statistic reveals that one in every nine people in the world does not have access to safe and clean drinking water. Climate change will exacerbate these conditions and it is projected that by 2025, about 1.8 billion people will live in water-scarce areas, and two-thirds of the world’s population will live in water-stressed regions.


Although Sri Lanka is not considered a water-scare country, there are sharp temporal and spatial variations of water availability within the island. Much of the island lies in the dry zone where, for several months of the year, water is scarce and this is the area from which 90% of water withdrawals are made. In some districts — in the arid zone of Sri Lanka, in Puttalam and Jaffna — for example, the total available water resources are considerably below the recommended levels for a decent quality of life. This situation will only worsen with the combined effect of the predicted impacts of climate change (a reduction in rainfall), a projected increase in Sri Lanka’s population and changing lifestyles needing more water.

 Adding to the stark picture are human activities that pollute and poison surface water, and over- abstract ground water. Contamination of ground and surface water through agricultural and industrial pollutants is reported to be the cause of several water-related diseases being reported from the dry zone.

 Managing our water resources —  controlling the use of water resources to minimise damage to the environment and to maximise efficient beneficial use — has now become critically important in Sri Lanka. As stated by UN Water ‘Water resource management is complex, as it involves managing an uncertain supply to meet increasing and equally uncertain demands, balancing social needs against ecological and economical needs and management across sectors, policies and physical infrastructure.’

 Two grant recipients of the Small Grants Facility of Mangroves for the Future (MFF) initiative, implemented by IUCN, took a different approach, looking at two simple elements of water management in Delft Island, where fresh water availability is a major problem. There are no rivers on the island; the ground water aquifer in the island is highly saline; and the island receives a mere 750 mm of sharply seasonal rainfall every year. The major source of freshwater for daily human needs is surface water collected in ponds (depressions on the surface which are filled with runoff water), waterholes and shallowly dug wells. Limited supplies for drinking water are provided intermittently by the Sri Lanka Navy and the National Water Supply and Drainage Board and a reverse osmosis plant (where seawater water is desalinised to make fresh water).

The first grantee — the Jaffna Science Association, Faculty of Science, University of Jaffna Association (JSA), a registered charitable organisation engaged in promoting science among the public — installed a 30,000-litre rainwater harvesting system at Delft Maha Vidyalayam, collecting rainwater during the rainy months, instead of letting it runoff, and storing it for later use. To increase awareness about water conservation, they conducted a workshop for 99 middle and upper school students and taught them how to develop and maintain a school garden, using this stored water but managing it carefully, using pot and drip irrigation system for a sand-bag based vegetable garden. (The soil in the school garden is sandy and not suited for cultivation.) Pot irrigation uses clay pots filled with water buried next to growing plants. The porous wall of the clay provides controlled irrigation to the plants and reduces evaporation. Drip irrigation delivers water directly to the roots of plants through a network of rubber hoses. Pot irrigation conserves 50-70% water and drip irrigation, 20-50% water. A hundred clay pots were given with Jambu plants to the students as this species grows well in the dry zone.  Students and teachers are now fully engaged in this school gardening activity and are harvesting 15 kg of tomato,

The JSA then expanded their ambit by recruiting 26 beneficiaries from the Sarapittiya village, training them in drip irrigation, and supplying them with vegetable plants. These 26 farmers are now each trained to cultivate 15’ x15’ plots of lands using a water-saving method. They were also trained in vermicomposting, which uses earthworms to hasten natural composting of garden waste for use as fertiliser. All beneficiaries received a vermicomposting unit. Farmers say they have been able to double their income as a result of these changes.

The simple thrusts of these interventions were to teach children and communities to conserve water, initially by collecting what would be wasted, and then by using that collected water sparingly.

The second grantee — the Department of Fisheries at the University of Jaffna identified all ponds/waterholes in Delft Island based and restored a small pond as a model in order to reduce water scarcity among the community in the Delft Island. Firstly, they identified and mapped 37 ponds and 23 water holes, noting that salt water intrusion and sandy soils, combined with high temperature, results in high natural salinity levels. Next, they tested water samples — both in the dry and wet seasons — from 37 ponds and 23 waterholes, for water quality, such as temperature, electrical conductivity (which measures nutrients, salts or impurities in water), total dissolved solids (again, measuring impurities) and dissolved oxygen (a dissolved oxygen level that is too high or too low can harm aquatic life and affect water quality).

Water quality — such as salinity, electrical conductivity and dissolved oxygen— in these water bodies increased markedly in the dry season, indicating that they were unsuitable for drinking but could be used for agriculture and for livestock.

As the next step, one pond Thoddichchakulam was restored. Traditionally, associated with the ponds are wells and kerny dug by communities. The latter is dug deeper than ground level, for storing and reserving water for livestock and other animals, while the well is deeper still. During the wet season water collects in the kerny and this water remains during the dry season for livestock, and there is a sloping platform through which the animals access the water. 

Researchers from the Department of Fisheries widened the pond, built an earthen ridge to secure it, strengthened and stabilised this ridge by planting Kumbuk/Marudu (Terminalia arjuna) trees on it, cleaned the well and kerny, and raised the wall of the well, preventing pollution during the wet season. Through this physical and ecological  restoration, the water storing capacity of the pond doubled. Water in this restored well was tested for heavy metals and found to be free of them.

Again, this grantee’s interventions were simple: to identify the ponds and waterholes, assess the quality of water during dry season and wet season, and to restore a pond as a model to retain more water to be used in the dry season.

Water resource management in Sri Lanka has been dogged by a lack of a unifying water policy, a surfeit of water-related laws and multiplicity of organisations, with a singularly sectoral focus with conflicting legislation, overlapping mandates and ill-defined responsibilities.  A paradigm shift in thinking has been called for but the process of developing a unified water management policy remained mired in complexity. 

The MFF grantees interventions exemplify Jed Rubenfeld’s (a Yale professor of law) and Robert Collier’s (an American author) combined comments: ‘Don't try to figure it out all at once’ . . . ‘break the problem into parts, and handle one part at a time."

This experience in the Island of Delft may also provide insights into water management in many other parts of the Country.



3.5 kg of chilli and 15 kg of aubergine per a week during the harvesting period. These vegetables are now being used to prepare school lunches.


Testing pond water on Delft I land

Testing pond water on Delft I land, Delft Island, Sri Lanka © Kumudini Ekaratne, IUCN, 2017

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