Proceedings of the International Symposium on Efficient Water Use in Urban Areas


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INTERGRATED APPROACHES
FOR
EFFICIENT WATER USE IN MALDIVES

By Farooq Mohamed Hassan
Maldives Water and Sanitation Authority
Male’, Republic of Maldives

1.Introduction

The Maldives archipelago lies in the Indian Ocean; approximately 600 kilometres south-water supply and environmental sanitation of Sri Lanka. The islands are spread over a geographical area of some 90,000 square kilometres. The total land area is approximately 300 square kilometres.

The climate is tropical, warm and humid all year round. The temperatures fluctuate between a daytime maximum of 32 degrees Celsius and a night-time low of 26 degrees Celsius, with a mean annual temperature of 28 degrees Celsius. The mean annual relative humidity and the mean annual wind speed are 80 % and 4 m/s, respectively.

Unlike many small island nations, surface water such as lakes, rivers, ponds or streams are not available in Maldives. However, almost all the islands of the Maldives have groundwater aquifers. The quality of the water in these aquifers generally varies from very fresh to very saline. The quality may also be impaired by human activities such as mode of sanitary and wastewater disposal and agricultural practices. Until very recently, the people of Maldives have been dependent on the shallow groundwater aquifers for all their freshwater requirements, including drinking.

Historical records show that rainwater harvesting was not practised in Maldives until after 1906. And it was not widely practised until 1978, following the epidemics of cholera (1978) and shigella (1982). Although the country is blessed with a relatively regular and high rainfall, its usefulness as an adequate and dependable source of freshwater is rather limited. This limitation is imposed mainly by the unavailability of sufficient storage facilities and land space.

Desalination was first introduced into Maldives in 1985. Presently, all houses, institutional and commercial establishments have been provided with piped water. The basic cost of providing this water is US$ 4.64. Although it is now a major source of freshwater, especially for Male’- the capital of the Maldives and in the tourist industry, it is still considered far too expensive to be considered as an economically viable source of freshwater for most small island communities.

Freshwater is undoubtedly a scarce resource in Maldives. If scarcity is defined as less than 600m³ per million people, then Maldives clearly falls under this category. The scarcity is both temporal and spatial. The problem is aggravated by saltwater intrusion and pollution of groundwater resulting from release of sewage, industrial effluents and poor agricultural practices. This makes integrated water resource management more urgent and more important in the Maldives.

2.Rainfall characteristics and rainwater harvesting

2.1. Rainfall characteristics

The Maldives is blessed with plentiful rainfall; over 1900mm a year. The mean annual rainfall is 1900 mm. The storms are normally of high intensity and of short duration. The frequency and intensity of these storms vary across the country. Except for the dry period, which normally occurs from January to March, the rainfall is very evenly distributed throughout the year.

An analysis of the rainfall records of the past 20 years shows that 43.86 percent of days in a year are dry days. The storms are normally of high intensity and of short duration. The frequency and intensity of the storms vary across the country. On an average, 8 - 10 percent of the storms occur at intensities higher than 25 mm/hr., and 2 - 4 percent of storms occur at intensities higher than 50 mm/hr. Since high intensity storms occur very rarely, rainfall harvesting is difficult to practice and its utilisation is very low.

2.2. Rainwater harvesting

The first concrete decision to provide safe drinking water to the people of the Maldives was made in 1904. This was in response to the recommendation of the 19^th century British historian and writer, Mr. H.C.P. Bell, following his first visit to Male’- the capital of the Maldives. Between 1906 and 1909, the GoM constructed two rainwater tanks. The first tank was completed in August 1906 and the second tank was completed in June 1909.

In spite of the deteriorating condition of the groundwater, and the associated health risks involved, no serious attempt was made to even encourage people to harvest rainwater. This was perhaps that many were not convinced of the link between contaminated water and disease. This may also be that many were used to drinking groundwater, which at the time was good in terms of salinity and other chemical parameters. This may also be that many could not afford to build their own rainwater tanks. According to a study carried out in 1974¹, only 15 percent of the 2600 households in Male’ had private rainwater tanks.

However, following the frequent outbreaks of cholera and shigella throughout the country, the GoM began to promote and invest in rainwater harvesting. Gradually people in Male’ began to construct their own private rainwater tanks. In 1985 the GoM launched the first major water supply and sewerage project in the Maldives. The project allocated more than 2.5 million US Dollars; roughly 33 percent of the total project cost, for the construction of steel tanks with a total storage capacity of 9900 m³ and the construction of 1154 private rainwater tanks in 1116 households providing a total storage capacity of 4157.5 m³. The private tanks were provided on cost recovery basis, payable over a period of 5 years.

To provide freshwater for the rural population, the GoM, with financial assistance from UNICEF, constructed 1925 ferrocement tanks with a total capacity of 19,3000 for community use in 200 islands, serving a population of 234,008. In addition, 222 households have been provided with construction materials for the construction of private rainwater storage tanks. Since 1994, the program has focussed on providing HDPE tanks instead of the ferrocement tanks. Todate, 2914 HDPE tanks with a total capacity of 14,520 m³ have been distributed free of cost for community use, and 1588 HDPE tanks with a total capacity of 3,176 m³ have been distributed to the households on cost recovery basis.

The HDPE tanks, because of its durability, ease of handling and mobility, are proving to be more acceptable and popular among the rural population.

¹ Binnie and Partners, March, 1975; Water Supply and Sewerage for Male’, Final Report.

3.Groundwater

Groundwater aquifers formed by the accumulation of the recharged rainwater on top of the saltwater are found in all islands. These aquifers normally lie at a depth of 1-1.5 meters below the surface. The thickness of an aquifer is normally dictated by several factors including net rainfall recharge, size of the island and permeability of the water through the soil column. Since these parameters vary from island to island, the quality of the aquifer also vary from island to island. Moreover, the proximity of the aquifers to the surface also makes them highly susceptible to pollution and contamination from human activities. Thus, the availability of the groundwater as a freshwater resource is also limited. This limitation is imposed by the quality of water rather than its quantity.

Presently 76 percent of the urban freshwater requirement and almost 98 percent of the rural freshwater requirement is met by these shallow groundwater aquifers.

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