Guam Water Resources Monitoring Program

The water resource monitoring program for the Northern Guam Lens Aquifer (NGLA), designated a Sole Source Aquifer in 1978 by the U.S. EPA, had been established in the 1950s by the USGS. However, in the 1990s, this program was forced to downsize when funding from the local government could not be met, which resulted in data disruption to deep well monitoring for saltwater intrusion in the north and stream gage data in the south. In 1998 the Comprehensive Water Monitoring Program (Guam Public Law 24-161) became a permanent program of the Water and Environmental Research Institute (WERI) of the Western Pacific and resulted in the refurbishment of the deep monitoring wells and a renewed program of water resource monitoring on Guam. In the same year, the Guam Hydrologic Survey (Guam Public Law 24-247) was made a permanent program, administered by WERI, to develop an inter-agency cooperation for gathering and publicly providing water and environmental information. Current withdrawals from production wells estimate to 40 Mgal/d. Over the next decade, population growth, inclusive of the proposed military forces relocation, projects a production increase as much as 25 percent. Increased withdrawals, in the long-term, were modeled to result in a decline in water levels and a rise in the freshwater-saltwater transition zone. To assist with water-resource management, an inter-agency framework for information sharing and decision making has been established with a Memorandum of Understanding, signed in 2010, under the Monitoring System Expansion and Rehabilitation Program. 7 new deep monitoring wells will be drilled, and 12 existing monitoring wells will be rehabilitated to expand groundwater monitoring from only two NGLA sub-basins to include the remaining four sub-basins. As partners in the island's technical/scientific experts group, WERI and the USGS will assume data collection, analyses, and reporting, to provide best practices for sustainable management.