Report Number: 111
Year: 2007

Water Resources Analysis of Fais Island, Federated States of Micronesia: The Analysis of Small Water Distribution Systems

Fais Island is an elliptical, uplifted carbonate platform with an area of approximately 0.75 square miles (2.0 km2) and an elevation of approximately 66 feet (20 m). Although the approximately 310 residents of Fais rely almost exclusively on rainwater catchment systems for potable water, the island contains an aquifer with a viable freshwater lens. Currently, the rainwater catchment network is insufficient to collect and store enough water to meet the needs of the islanders during major droughts, especially those following El NiƱo events. The network is also vulnerable to the inevitable typhoons that could render it inoperative for many months. To enable us to prevent these natural disasters from affecting the health and quality of life of Fais Islanders, we studied their rainwater catchment systems and the island's basic geology and hydrologic features including its caves.

We conducted a comprehensive survey of all rainwater collection and storage components; a water usage and distribution survey of the residents; a visual inspection of all coastal areas, both on foot and by boat; a complete survey of all known caves and cave features; and well documentation and testing. To facilitate these tasks and assist in future studies we developed a series of GIS coverages and maps that include: previous maps of the geography, the land and water uses, and the three villages; GPS points of well locations, caves, and hydrologic features including freshwater discharge points; the topography of an ancient dug well; and a digital elevation model (DEM). We studied the well data and calculated the approximate properties of Fais' freshwater lens. We analyzed the rainwater catchment network using a modified multi-level version of RoofRain, a spreadsheet model developed by Dr. Leroy Heitz. We ran several potential solutions through this model to develop recommendations for system upgrades, modifications, and maintenance, as well as the development of Fais' groundwater as an emergency resource.

Robert S. MacCracken
John W. Jenson
Leroy F. Heitz
Donald H. Rubinstein
John E. Mylroie