The cost and availability of energy resources is one key factor in the economic development of and quality of life in any developing country. This is especially true in Kosrae, Federated States of Micronesia (FSM), where nearly all of the energy produced is from costly, non-renewable, and potentially environmentally damaging fossil fuel (oil) resources. The cost of fuel to operate the local power plant has risen dramatically over the past years and no doubt will continue to rise in the future. With these increases of fuel costs, it becomes more and more important to explore other means of providing energy to the islands power grid. Kosrae is blessed with an abundance of surface water resources and because of the extreme topography of the island many of these streams have very high slopes. This combination of abundant streamflow and high stream gradient or slope is ideal for the application of run-of-river-hydropower development. This kind of hydropower development has the least environmental impact and is generally less capital intensive than typical hydropower plants built in conjunction with high dams with large amounts of water storage.

In order to explore the feasibility of using hydropower as an additional energy source for Kosrae, it is necessary to be able to define the variability of flow available in the streams where the hydropower plants might be constructed. This is normally done by direct analyses of streamflow data for the stream in question or by applying some sort of inferential techniques from a gaged to an ungaged stream or from a gaged location on a stream to an ungaged location on that same stream. Of course, the most reliable means is to use actual stream flow data measured at the point of interest. The problem in Kosrae, as in most locations, is that streamflow information is not available for all possible sites where development could occur. In the FSM this problem is even more acute since the streamflow gaging network has been abandoned for almost 20 years. What is needed is a means of predicting the variability of flow at ungaged locations that are likely to become candidate sites for future hydropower development.

This project has developed a means of predicting flow duration curves at ungaged sites in Kosrae. All of the major streams of the island were divided into stream reaches, or homogenous sections of a stream, that have similar flow properties. These reaches were identified on maps developed from the comprehensive Geographic Information System (GIS) map inventory of Kosrae available at the Water and Environmental Research Institute (WERI). Various statistical and analytical methods were applied to the existing streamflow data and physical characteristics of the reaches in order to predict the streamflow in each stream reach.

The final results of this project are a series of maps of the streams of Kosrae with each stream reach identified. The maps will be available for use in the free GIS program ARC Explorer. The user will be able to find the average flow for each stream reach. An Excel application was also developed to perform a preliminary power production and economic analysis for any new proposed site based on the average flow information and the statistical flow duration data developed in the project. The GIS maps, ARC Explorer program and Excel application are available on a CD which is included at the back of this report.