Oficina Regional de la FAO para América Latina y el Caribe |

IRRIGATION IN ST. KITTS & NEVIS

Climate

Both islands have a tropical climate influenced mainly by the northeast trade winds of the Inter-tropical Convergence Zone. Average annual rainfall in St. Kitts ranges from 1 270 mm to 1 905 mm. Most of this precipitation occurs from September to January.

Water Resources

Annual average yields for St Kitts are 3.6 million m3 for surface sources and 20 million m3 for groundwater sources. Currently the island experiences water shortages in some rural communities during the dry season. Nevis experiences lower annual rainfall than St. Kitts, and has lower yielding water sources.

Water withdrawal

St. Kitts' water supply system comprises six surface water intakes which supply five mainly independent water distribution systems. There are also five wells, which supplement the water supply with a coastal aquifer of maximum safe yield of 16 million m3/y as the major groundwater source. Nevis' water supply available from the mountain spring intakes has to be supplemented (seasonally) by water from several earthen dams (total capacity 90 million m3). Roof catch is also utilized to supplement domestic supplies.
The entire population of both islands has some degree of access to domestic water supplies. Where water is supplied by public standpipes, the standpipes are located within 400 m of the households served.

Irrigation and drainage development

The irrigation potential of the island is estimated, based on water resources and topography, at 200 ha (180 ha for St. Kitts and 20 ha for Nevis). There has been limited experience of irrigation within the sugar industry. In the late 1970 and early 1980 the sugar manufacturing company used a rain gun fed from a shallow well on one estate. In the case of vegetable production, a 3-ha vegetable production, demonstration plot utilizing sprinkler irrigation was established on the same estate and the Caribbean Agricultural Research and Development Institute (CARDI) also undertook some experimental work. The CARDI initiative utilized drip irrigation for a total of seven farmers on the islands.
Generally, in St. Kitts, because vegetable production is carried out on the lower hillslopes, access to irrigation water is very limited. Some 8 ha are irrigated mainly on government demonstration plots and private farms utilizing the domestic supply. Also, the construction of tanks (average capacity 341 m3) has been encouraged on some farms to extend the production season as far as possible. In Nevis, approximately 10 ha are irrigated from surface water and half from groundwater. Schemes are small and are operated by a total of eight households; 4.5 ha are privately-owned schemes, 2 ha are smallholder/government enterprises, and the remaining 3.5 ha are government schemes.

Trends in water resources management

Over the last five years, house connections for water have averaged 500 per year. An expanding tourism/hotel sector is expected to create the largest need for increased water supply in the near future. The Water Department does not cater for irrigated agriculture, but has however accommodated the requests of some livestock owners. Because of the relatively high consumption and water scarcity situation, requests from crop farmers are rarely given consideration.
The Department of Agriculture, St. Kitts, considers the lack of water for supplementary irrigation in the dry season as the major constraint to achieving one of its primary goals: year round production of selected vegetables. The Department has investigated mountain springs which formerly fed sugar estates. The use of polymer-lined reservoirs is presently being evaluated.
The Nevis Water Department gives an estimate of 360 house connections per year over the last five years. Tourism expansion is also considered to be the area of increased demand in the immediate future.
Because of the minimal size of irrigation schemes and farms in the Federation, there have not been any significant environmental concerns. Drip irrigation predominates and the water table does not come into play in the areas presently irrigated.
Constraints to water and irrigation development include:

high cost of exploratory drilling;
high cost of irrigation development per unit area;
difference in altitude between farms (foothills above sugar cane fields) and the groundwater aquifers near sea level;
high construction cost of polymer-lined reservoirs;
small catchment areas which limit maximum size of reservoirs;
inaccessibility of mountain springs.