Northern Guam geospatial information server
About this map:
This map shows the extent of areas that capture rainwater that goes to recharge the Northern Guam Lens Aquifer (NGLA). The surface of the aquifer is considered to provide autogenic recharge (because limestone units of the aquifer itself receive direct rainfall and convey it downward). Adjacent non-limestone surfaces provide allogenic recharge (because they capture rainwater and conduct it to lower-lying limestone areas via surface drainage networks guided by land surface topography). The delimitations on the map were developed by Taboroši and Kottermair in 2013 for the purposes of this atlas and are based on information from USGS Geologic Map, 2007 LiDAR data (JALBTCX), and watershed boundaries by Natural Resources Conservation Service (NRCS).