Guam Watershed Assessment

Study Area
The study area encompasses the entire island of Guam, the southernmost island in the Mariana Islands archipelago. The northern part of the island is a forested limestone plateau with sheer coastal cliffs. The southern part contains volcanic peaks covered in forest and grassland. Coral reef surrounds most of the island, except in the areas where bays exist that provide access to small rivers and streams. The Northern Guam Lens Aquifer (NGLA) is the main source of drinking water for the island.

Guam experiences two seasons: the dry season beginning in December and lasting through June, and the wet season when three-quarters of the annual rainfall occurs. Guam is periodically exposed to the effects of typhoons three times a year on average. The typhoons come within 180 nautical miles of the island. The current population of Guam is approximately 154,000 persons. 

Shared Vision
The Territory of Guam spans 212 square miles of island bordered by 78 miles of coastline in the western Pacific Ocean. Weather related hazards, including tropical cyclones, flooding, high surf, drought, and severe wind are anticipated to intensify with climate change, with a predicted ½- to 1 ½ -foot rise in sea level by 2050. Additionally, anthropogenic stressors, including wildfires, deforestation, introduction of invasive species, erosion, sedimentation, and water quality impacts harm the social, economic, and environmental fabric of life on the island and increase vulnerability to natural hazards. Reducing the consequences of these hazards necessitates a collaborative focus on resiliency among Federal and Territorial agencies and stakeholders. This WA is intended to serve as a strategic roadmap to inform future decisions and actions.

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Submit Public Scoping Comment (12/12/22 – 1/11/23)