Field Trip - Northern Guam Lens Aquifer Jun 2014 | Página 4

Abstract
This field trip takes you to four sites, each of which is a premier example of the
four basic components of the Northern Guam Lens Aquifer: the tight, nonproductive volcanic basement rock that constitutes the floor of the aquifer; the
porous and soluble water-bearing limestone bedrock that is the source of our
drinking water; the surface catchment that captures the recharging rainwaters;
and the features of the surface that control and distribute the entry of water into
the aquifer. At each site, we observe and discuss the geological and hydrological
properties that control the capture, storage, and production of potable water, and
the opportunities and challenges faced by geologists and engineers in exploring,
developing, and managing groundwater production. While traveling between
sites we observe features of regional importance to groundwater development and
aquifer protection. We also discuss basic facts and statistics related to drinking
water production, consumption, and conservation on Guam and nationwide.

Table of Contents
The Northern Guam Lens Aquifer (NGLA)

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Basic Facts 6
Water Processes 7
Surface of the Aquifer 8
Groundwater Basins and Zones of the Aquifer
9
Production and Observation Wells 10
Idealized profile of a Carbonate Island Karst Aquifer
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Cross-section of the NGLA along the Yigo Trough
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Stop 1
The Floor of the Aquifer – the Volcanic Basement Rock

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Stop 2
The Core of the Aquifer – the Limestone Bedrock

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Stop 3
Plumbing of the Aquifer – Surface and Internal Drainage

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Stop 4
The Roof of the Aquifer – the Water Catchment System

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Field Trip Map and Schedule of Stops

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From Sustainable Yield to Sustainable Management
26
Managing Supply and Demand 28
Further Reading 30
Authors 32
Acknowledgments 33

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