A programme for Promoting Rainwater Harvesting in the Caribbean

Caribbean Rainwater Harvesting Programme2. Introduction2.1. Water and developmental issues – Global to Small Island DevelopingState perspectivesWater is life! It is undisputed that water is the most vital natural resource and all of life andlife support processes are dependent on this liquid medium. Many scientific theories postulatedthat life itself originated in an aqueous medium and even though it evolved to survive underdrier conditions, the role of water as a medium and conveyance of biochemical reactions thatsupport survival and propagation of life remains a critical one. The finiteness of availablewater on this earth is very discernible when we consider that of the 1,400 million cubickilometers of water on earth and circulating though the hydrological cycle, only onehundredthof 1% of this amount is readily available for human use (FAO, 1995). It is believedthat this quantity is sufficient to meet humanity’s needs if it were evenly distributed; however,this available 9,000 cubic kilometer volume is very unevenly distributed across the planet. Inareas where the indigenous water supplies average less than 1,000 cubic meters per person peryear, these areas are categorized as water scarce (FAO, 1995).The amount of water available to each person is falling considerably as growing humanpopulations continue to place tremendous pressure on diminishing water resources. Waterscarcity is exacerbated by pollution. According to the FAO (1995), 450 cubic kilometers ofwastewater pollute the world’s surface waters each year reducing utility of these waters forsafe human consumption. This not only has implications for human populations but also forthe natural environment, offsetting the delicate balance of ecological systems, and in severecases unleashing irreversible consequences which may have direct adverse socio-economicconsequences.This situation is of particular concern for developing countries and Small Island DevelopingStates (SIDS) where nearly one-third of the population has no access to safe drinking water.The Caribbean region has the least water available per capita as compared to other SIDSregions; just 13.3% of that available in the Indian Ocean SIDS and 1.7% of that available in theSouth Pacific SIDS on a per-capita basis. The island of Barbados for example, is rankedamong the ten most arid countries in the world. The geomorphology of most Caribbeanislands limits the physical availability of freshwater reserves on account of relatively smalllandmass areas and typical mountainous terrain. The impacts of relatively frequent naturaldisasters (typically hurricanes and floods) exacerbated by human activity, compromise watersupply systems for extended periods, placing populations at risk under water scarce conditions.The potential impacts of climate change and climate variability on the water regime in SIDScannot be underestimated and constitutes an additional threat to water security.2.2. Rainwater Harvesting – a practical water augmentation measureAvailable literature cites many variations on the definition of rainwater harvesting. Acomposite definition used in this document is:2