Dynamic Response of a Freshwater Lens to Natural Variations in Recharge
The hydrographic analysis of a composite island aquifer’s phreatic zone with climatic effects on contributing hydrologic processes provides insight to a freshwater lens’ storage capacity. The observation wells in the Yigo-Tumon Aquifer Basin in the Northern Guam Lens Aquifer (NGLA) was scoped to conduct an empirical hydrologic study that characterized the dynamic response of the lens to natural climate variations. Results showed the actual thickening and thinning of the lens in response to rainfall and drought. This is the most comprehensive hydrographic analysis of the NGLA, capitalizing on decades of data collection through the Guam Hydrologic Survey and Comprehensive Water Monitoring Program. The techniques here may be applicable for determining capacities in similar aquifers.
Keywords - Freshwater Lens, Island Karst Aquifer, Phreatic Zone