Impacts of land use change on freshwater runoff into the near-coastal zone, Holetown Watershed, Barbados: Comparisons of long-term to single-storm effects

The Holetown Watershed has undergone extensive land use change since the 19 60s, and is now the mast concentrated center of tourism an the west coast o f Barbados. Local planners perceive that urban expansion related to tourism , and modifications to agricultural land use and drainage systems, are the cause of recent flooding and declines in the nearshore marine environment. A Long-Term Hydrologic Impart Assessment (L-THIA) analysis predicts a 5.5% increase in average annual runoff and a 4.3% increase for peak year runoff between pre-development (1964) and existing (1996) land uses. Urbanization and plugging of sinkholes catered substantial increases in runoff, but this was counteracted by declines in agricultural runoff due to conversion of s ugar cane to pasture. L-THIA results are consistent with short-term streamf low monitoring hut additional information on water quality changes is neces sary to understand the total impacts of land use change on this nearshore e nvironment L-THIA analyses provide quirk, useful insight into hydrologic im pacts as a tool for natural resource conservation efforts.