Southern Guam geospatial information server
About this map:
This map shows the extent of significant groundwater zones in southern Guam. Only groundwater in limestone and alluvial units is shown because groundwater in volcanic units is not easily extracted due to the rocks' low porosity and permeability. The dataset was derived from the surface geology dataset by generally classifying all non-volcanic areas as either perched (if groundwater bodies sit at elevations above sea level and have no direct connection to the ocean) or basal/parabasal (if connected to the ocean and underlain by seawater or volcanic basement units). This dataset was created by Island Research & Education Initiative for the purposes of this atlas.