Water Resources Research Act Program

Principal Investigators: Gregg Guannel

Abstract: Roof rainwater harvesting is common practice in the Caribbean, and in the Virgin Islands (VI) in particular. However, although water quality in cisterns has been regularly investigated, little information exists about rainwater harvesting volumes and cycles (filling, runoff, deficit) in cisterns based on current and historical rainfall values. Here, we investigate the impacts of 3 roof types – wood, sheet metal, and sheet metal with solar panels – on rainwater harvesting potential in the VI. We calibrate the model using measurements from a weather station, and by measuring the volume of water collected by 3 model roofs for at least 1 year. Results provide locally relevant estimates of rainwater roof harvesting capacity in the Territory for common types of roofs, during different climatic conditions. Results also provide estimates of avoided or intensified urban runoffs, and estimates of demand of freshwater from water delivery vendors. The project will also provide the University of the Virgin Islands students and the general public with basic understanding of climatic data measurements, hydrologic principles, rainwater harvesting calculations, and cistern capacity.