MODELING THE SPATIAL DISTRIBUTION OF GROUNDWATER RECHARGE IN HAITI USING A GIS APPROACH

Haiti is greatly dependent on groundwater resources, as over 90% of drinking water and a large portion of agricultural and industrial water is supplied from groundwater. Groundwater is also necessary to foster economic development, improve food security, and improve water access throughout the country.

Studies and literature have focused recharge estimates at the country-scale as a global metric or at segmented localities associated with specific projects. Such estimates are typically of limited utility to support the scale of planning, modeling, and water management that is of greatest need to inform decision-making in Haiti. The lack or unavailability of climatological, hydrological, and hydrogeological data throughout Haiti presents major limitations to the management of its aquifers.

In response to the scale of investments being made throughout Haiti that rely upon long-term sustainable water supplies, and the lack of resources or guidance to inform integrated water resources management, a custom GIS model was developed to model the spatial variability of groundwater recharge throughout Haiti.

The modeling is achieved with a water balance calculation, and applies a coefficient based on country-wide GIS layers that include soil and geologic permeability, vegetation cover, relief, and karstification. The modeling was calibrated to several basins throughout Haiti where hydrometeorologic and hydrochemistry datasets were available. The results are presented at a catchment scale, however, the model supports the generation of groundwater recharge estimates for any defined area within Haiti. The results suggest that Haiti’s coastal alluvial aquifers have limited aerial recharge, and recharge to Haiti’s largest alluvial aquifers greatly relies on streamflow infiltration. The interior sedimentary limestone aquifer systems are of critical importance for the country’s water security. Not only do the karst aquifer systems absorb most of the country’s direct recharge; they also supply a majority of the streamflow that is responsible for recharging the coastal alluvial aquifers.