Rainwater potential for domestic water supply in Grenada

Water resources management in the face of increasing scarcity requires that countries undertake audits of their current resources. The small island of Carriacou (area 34 km(2)), which forms part of the state of Grenada, has no perennial streams and very little groundwater but receives an average annual rainfall of about 1200 mm. The island has traditionally depended on rainwater harvesting, and this offers a sustainable method of providing an adequate quantity and quality of water. Furthermore, rainwater harvesting systems have proven to be resilient in the aftermath of natural disasters. This paper assesses the potential of rainwater harvesting in the islands and shows that, although per capita water demand is dependent on household income levels, rainwater can adequately meet the demands of the island's residents. It shows that the cost of harvested rainwater is by up to nine times lower than that of the recently available desalinated water. The quality of rainwater has not been considered here, as quality is not a concern of the residents. The paper therefore highlights the need for policies that would promote the construction of adequate size storage and quality improvement facilities for achieving the full potential of rainwater as a sustainable water resource on a water-scarce small island.