Paper Title
GROUNDWATER PROTECTION ZONE IN GUAM, USA

Abstract
Guam, a strategic unincorporated territory of USA, is the largest and southernmost island located in the Mariana archipelago chain. The Northern Guam Lens Aquifer (NGLA) provides about 90% drinking water in Guam. Most of the groundwater protection zone (GPZ) is located atop the NGLA.The GPZ was delineated based on John Mink’s work more than 40 years ago. Due to new data, and emerging technologies for the past four decades, it’s time to update the GPZ so that the water resources in the NGLA can be better managed and developed. This research focuses on a GIS based method applied to update the existing GPZ in the NGLA, Guam. The history of GPZ in Guam and local laws/bills related to GPZ are addressed, methods for delineating GPZ are described, and those methods for delineating the GPZ suitable to Guam are discussed. Keywords – Ground water Protection Zone, Northern Guam Lens Aquifer, GIS, Spatial Analysis and modeling.