About this map:

This map shows only high gradient flow portions of streams and rivers in southern Guam. More specifically, it indicates areas where 1) flow is relatively fast across steep or sloping terrain, 2) is characterized by presence of cascades and waterfalls, and 3) is beyond influence of any saltwater intrusions typical in more lowland areas. Such portions of streams and rivers represent unique freshwater habitats distinct from downstream lowland portions characterized by lower gradient flow. The GIS data used to create this map was derived from drainage network data developed by Government of Guam Bureau of Statistics and Plans, by removing portions of all streams that are downstream from the lowermost cascades or waterfalls. The GIS layer was made by Island Research & Education Initiative specifically for the purposes of this on-line atlas.