Estimate of Recharge to the Freshwater Lens of Northern Guam

摘要

The groundwater hydrology of Guam has been studied by a number of investigators over several decades. In 1964, Davis estimated a range of 0.73 to 0.89 mgpd reaching the freshwater lens of Northern Guam. In 1968, Davis and Huscel estimated the recharge rate at 0.97 mgpd per square kilometer in an administrative report prepared for the Air Force. Also in 1968, Sheaham estimated that 50% of rainfall infiltrates the soil as recharge. In a report to the Public Utility Agency of Guam in 1970, Auston, Smith, and Associates, Inc. estimated a recharge rate of 1.04 mgpd per square kilometer. The present study was based on the chloride-ion concentration in the rainwater. The chloride ion was used as a tracer which is concentrated evapotranspiration.