Chuuk


State

Yap State Ponape


State Kosrae


State

20°N

0°

140° 160° E 180° 160° W

0 500 MILES

0 500 KILOMETERS

HAWAII

INDONESIA

AMERICAN


 SAMOA

FEDERATED STATES


 OF MICRONESIA

FIJI Tutuila

Guam

Saipan REPUBLIC


OF


PALAU

COMMONWEALTH


OF THE NORTHERN


MARIANA ISLANDS

REPUBLIC


OF THE


MARSHALL


ISLANDS

PACIFIC OCEAN

AUSTRALIA

The U.S. Geological Survey (USGS) is 

known for its impartial data collection and 

research. The data that the USGS gathers, 

interprets, and presents enable resource 

planners and others to make informed decisions on the basis of objective information. 

Today’s issues related to earth resources 

and natural hazards are more pressing than 

ever, and the USGS continues to address 

these issues in cooperation with State, 

local, and Federal agencies, universities, 

and other public organizations.

The State of Hawaii consists of 132 

islands, shoals, and reefs. The major 

Hawaiian islands are the volcanically 

derived mountain ranges of Hawaii, Maui, 

Oahu, Kauai, Molokai, and Lanai.

Elsewhere in the Pacific, the USGS 

works in the Territories of Guam and 

American Samoa, the Commonwealth of 

the Northern Mariana Islands, the Federated States of Micronesia, and the Republics of the Marshall Islands and of Palau 

(the last three named are all in compact of 

free association with the United States).

Hydrologic Data Collection

The USGS, in cooperation with local,

State, and Federal agencies collects streamflow, ground-water level, water-quality, 

water-use, and rainfall data at sites throughout the State of Hawaii and on all Pacific 

islands where the United States has an 

interest (fig. 1). Data provided by these networks are fundamental to the quantification, management, and protection of the 

islands’ fragile and finite water resources. 

Hydrologic data are used to determine the 

extent and severity of droughts, to identify 

flood-prone areas and potential hydrologic 

hazards, to quantify available freshwater 

resources, to monitor the effects of human 

activities on water resources, and to resolve 

complex legal issues associated with water 

rights. Data collected from these island networks throughout the vast Pacific Ocean 

have global significance by providing a significant part of a worldwide data base for 

climate-change investigations and the study 

of the Pacific El Niño phenomena.

Volcanic and Seismic Hazards

Residents of the island of Hawaii, and, to 

a lesser degree those of the island of Maui, 

face the unique hazards that go along with 

living on the slopes of an active volcano. 

These hazards include lava flows, volcanic 

gases, and earthquakes. Two volcanoes on 

the island of Hawaii, Kilauea and Mauna 

Loa, have erupted repeatedly in this century. 

The current eruption of Kilauea started January 3, 1983 and has since destroyed more 

than 180 houses and buried 8 miles of highway and utility lines. A third volcano, Hualalai, which last erupted in 1801, and 

Haleakala Volcano on Maui, which last 

erupted in 1790, have the potential to erupt 

again within our lifetime.

The youngest volcano in the Hawaiian 

chain is Loihi Seamount, which lies 23 

miles off the southern coast of the island of 

Hawaii below 3,300 feet of water. Loihi 

probably has erupted recently, judging 

from its frequent earthquake swarms (the 

largest ever was recorded in the summer of 

1996) and the fresh lava samples dredged 

from its surface.

To help prevent loss of life and property 

from eruptions and earthquakes, USGS scientists are working to increase our ability to 

predict these natural events and to educate 

the public about the hazards in their area.

The USGS maintains the Hawaiian 

Volcano Observatory (HVO), which is 

responsible for monitoring the activity of 

Index of Subjects

Hydrologic Data Collection

Volcanic and Seismic Hazards

Water Supply for Native Hawaiian 

Homesteads

Effects of Ground-Water Development on 

Streamflow

Topographic Mapping

Hydrologic Studies at Kilauea Volcano

Hydrology of Endangered Species Habitat

Evaluation of Flood Hazards

Beach Loss in the Hawaiian Islands

Water Supply for Domestic Needs

Endangered Ecosystems and Nonnative 

Species Invasion

Water Resources Studies in the Pacific

Figure 1. The Pacific Ocean area includes areas in which the U.S. Geological Survey 

collects data and conducts investigations. (Dashed lines approximate, but do not 

necessarily represent actual, political boundaries.)

Earth Science in the Public Service
Kahului


Bay

Maalaea 


Bay

Wailuku

Kahului

Kihei

Lahaina

Haleakala
 Hana

10,023 crater

KAHIKINUI

MAUI

0 10 MILES

0 10 KILOMETERS

Hawaiian volcanoes and issuing warnings 

of impending eruptions. To assess longterm volcanic hazards, HVO scientists 

study prehistoric lava flows to determine 

the size, frequency, and type of past eruptions. This information forms the basis for 

hazard-zone maps that guide land-use 

planning decisions.

The HVO operates a dense seismic network that records thousands of earthquakes 

each year. Most of these are too small to 

feel, but about once a decade, a large earthquake causes widespread damage across the 

island of Hawaii. These earthquakes cause 

significant economic losses and sometimes 

claim human lives. HVO scientists are 

working with county and State officials by 

providing seismic data and information to 

set building codes that accurately reflect the 

seismic hazards on each island. The HVO 

takes an active role in educating the public 

on how to prepare for an earthquake.

Water Supply for Native 

Hawaiian Homesteads

The State Department of Hawaiian 

Home Lands (DHHL) has responded to a 

desire on the part of Native Hawaiians to 

resettle and restore the land at Kahikinui 

on the island of Maui (fig. 2). The traditional Native Hawaiian approach to land 

use and management was to subdivide the 

land into ahupua‘a, which is an area that 

extends from the ocean to a mountain summit. Those living in an ahupua‘a could 

acquire everything needed for basic survival within that land division. Kahikinui is 

the only intact ahupua‘a on the DHHL 

land inventory. The land was made part of 

the DHHL’s holding by the Hawaiian 

Homes Commission Act in 1920; when the 

lease to ranch the land expired in 1994, the 

DHHL proceeded with resettlement plans. 

Kahikinui covers about 23,000 acres of 

arid land and sustained a population of 

about 8,000 Hawaiians in the 1700’s. For 

the past 100 years, the area has been leased 

out to ranching interests. Logging and 

grazing have affected much of the land’s 

original native forests and habitat, and over 

time, Native Hawaiians were compelled to 

abandon the area.

The Kahikinui area is remote and lacking in readily available water and other 

infrastructure. The USGS is doing a geophysical survey to help define the ground 

water of the area. As part of providing climatological data for the planned restoration 

of Native Hawaiian forest on the upper 

slopes of Kahikinui, the USGS is installing 

and maintaining climatological stations. 

The data collected are helping determine 

the effect of reforestation on the area’s 

hydrology through analysis of precipitation, 

cloud water, canopy throughfall, soil moisture, and evaporation. Climatological data 

also are helping determine the potential for 

fog catchment as a potable water supply.

Effects of Ground-Water 

Development on Streamflow

Most of the known ground-water 

resources in many of the dry, leeward areas 

of the Hawaiian islands have been developed. Pressure has increased to develop 

ground-water resources in the wet, windward areas where perennial streams exist 

to supply the leeward areas. Concerns 

arise because the relation between ground 

and surface waters is not well understood; 

thus, the effect of ground-water development on nearby streams cannot be accurately predicted.

The USGS, in cooperation with the 

State Commission on Water Resource 

Management and the Maui County Board 

of Water Supply, is studying the relation 

between ground and surface waters on the 

windward side of eastern Maui. Results of 

the study are helping determine if future 

water needs for Maui can be met through 

development of ground water in northeastern Maui and have implications for the 

development of ground-water sources of 

water on the islands of Kauai, Oahu, 

Hawaii, and Molokai.

Topographic Mapping

Among the most popular and versatile 

products of the USGS are its 1:24,000-

scale topographic maps (1 inch on the map 

represents 2,000 feet on the ground). These 

maps depict natural and cultural features of 

the landscape, such as lakes and streams, 

highways and railroads, boundaries, and 

geographic names. The state of Hawaii is 

covered by 124 maps at this scale. These 

maps have long been favorites with the 

general public for outdoor uses and with 

scientists and engineers for conventional 

technical applications.

Today, scientists and engineers depend 

on digital (computerized) base maps for 

their research and analyses. Without the 

geographic context provided by digital base 

maps, it would be impossible to understand 

the spatial patterns and changes of natural 

and human distributions. The USGS is 

working with the State of Hawaii to ensure 

and improve digital base data availability 

for the State so that studies in landslides,

ground water, earthquakes, tsunamis, and 

human impacts on the environment can be 

conducted as effectively as possible. 

The USGS, the State of Hawaii Office 

of State Planning, and a private consultant 

are working to prepare digital elevation 

model (DEM) data for the islands of Oahu,

Maui, and Lanai. Cooperative activities 

include data collection, data-base development, technical assistance, and user training. This type of public/private partnership 

can provide essential standardized data in 

a cost-effective manner. The new DEM’s 

will allow the State to perform important 

watershed modeling projects that were 

impossible with existing data. The elevation data are also useful to State, local, and 

Figure 2. Studies are underway at Kahikinui, island of Maui, Hawaii, in preparation for 

resettlement of Native Hawaiians.
Kalaeokahipa Gulch

Kamehameha Highway

Old Railroad

Access Road

Kii Ditch

Ditch

0 0.25 0.5 MILE

0 0.25 0.5 KILOMETER

N

Pacific Ocean

James Campbell


National Wildlife Refuge


Punamano Pond unit

James Campbell


National Wildlife Refuge


Kii unit

Punamano


Spring

Saltwater


aquaculture


ponds

Saltwater


aquaculture


ponds

Aquaculture


fields

Freshwater


aquaculture


ponds

Golf


course

Ditch

Ditch


outlet

Hospital

Artesian


wells Wastewater


injection


wells

Sewage


treatment


plant

Storm drain

Sugar


mill

Study


area

OAHU

private organizations for environmental 

management and planning purposes. 

Because of the need for comprehensive 

statewide data coverage, the USGS is also 

preparing DEM’s and digital contour files 

derived from the 1:24,000-scale USGS 

topographic maps for the islands of Hawaii 

and Kauai. 

Other digital base data being produced 

as part of the National Mapping Program 

include the digital raster graphics (DRG’s) 

for the entire State of Hawaii. With DRG’s, 

the USGS brings the images of traditional 

1:24,000-scale topographic maps to the 

computer screen in raster form. These data 

sets are useful as a base overlaying other 

information themes, updating map features, 

and for other land and resource management applications.

Hydrologic Studies at Kilauea 

Volcano

Recent USGS hydrologic studies at 

Kilauea Volcano on the island of Hawaii 

have increased knowledge of the groundwater flow system of Kilauea, which is one 

of the world's most active volcanoes. Many 

volcanic islands have highly permeable 

rock and scarce surface water, so residents 

must rely on ground water and rain catchments for water supply. Because of the high 

flow rates through volcanic rock, the potential for ground-water contamination problems is high. In addition, hydrologic 

hazards are present in an active volcanic 

area. The results of the Kilauea studies also 

are increasing understanding of groundwater sources and flow patterns on all 

Hawaiian islands.

Stable isotope ratios in water are useful 

in interpretation of ground-water recharge 

areas, and tritium content can be used to 

determine ground-water age. Isotope ratios 

in ground-water samples at Kilauea were 

compared with isotope ratios in rainfall to 

determine the approximate elevation at 

which the water entered the system as 

recharge. The relation between elevation 

and isotope ratios in rainfall obtained for 

the island of Hawaii may be similar to 

those on other Hawaiian islands because 

the temperature and climate patterns are the 

same. If so, then isotopes can be used to 

interpret ground-water recharge areas on 

other Hawaiian islands with minimal collection of precipitation data. This idea is 

being tested by the USGS with a smaller 

scale precipitation isotope study on the 

eastern side of Maui.

Hydrology of Endangered 

Species Habitat

Hawaii has more rare and endangered 

plants and animals than any State in the 

Nation. The survival of endangered species 

often depends on an understanding of the 

water resources of their habitat. The USGS, 

in cooperation with the U.S. Fish and Wildlife Service (USFWS), is investigating the 

water system associated with wetlands at the 

James Campbell National Wildlife Refuge 

(fig. 3). This natural wetland is home to at 

least four endangered species of birds, 

which include the Hawaiian stilt and the 

coot. Water-quality problems exist because 

the refuge lacks a sufficient supply of surface water during extended dry periods. In 

addition, water in the refuge is susceptible to 

contamination from numerous sources. The 

project goals are to identify and monitor the 

quantity and quality of all sources of water 

that enters the wetlands by using gaging stations for measurements of stream and ditch 

flow, rainfall, and well water levels. The 

information obtained from the investigation 

will be used by the USFWS to maintain a 

viable habitat for migratory waterfowl.

Evaluation of Flood Hazards

Flooding on streams in Hawaii is a persistent and often life-threatening hazard. 

Because intense rainfall of short duration is 

common, floods can happen at any time, 

usually with little or no warning. Daily rainfall in excess of 10 inches is expected at 

least once a year somewhere in the State. 

The intense rainfall generates extreme flood 

peaks, which combined with steep, short 

streams, come with little or no warning.

Peak streamflow data collected by the 

USGS are used to estimate the magnitudes 

and frequencies of floods, to identify floodhazard areas, and to design hydraulic structures, such as bridges, culverts, and floodcontrol channels. The USGS publishes 

summaries of the magnitudes of the floods, 

the factors that cause them, and the extent 

of the damage and the areas affected. 

Ongoing evaluations of flood hazards in 

Hawaii by the USGS may help save lives 

and minimize flood damage.

Beach Loss in the Hawaiian 

Islands

Coastal erosion is a widespread, chronic, 

and locally severe problem in the Hawaiian 

islands. The beaches of Hawaii derive most 

of their sediment from the surrounding 

reefs. Factors that affect the growth and 

health of living reefs, such as deterioration 

in water quality or severe storms, can have 

an adverse effect on beach sediment supply. 

Island beach systems are important because 

the people of Hawaii have a very strong cultural attachment to the beaches and because 

tourism in Hawaii is a multibillion dollar 

industry that is inextricably linked to the 

health of the beaches. Loss of beaches 

through erosion can have an adverse effect 

on the economy of the State. 

The USGS, in cooperation with the University of Hawaii, is documenting the magnitude and extent of beach loss and is 

studying the causes of erosion unique to the 

Hawaii environment. Recent activities 

include profiling of eroding beaches on 

Oahu and Maui, establishment of a historical 

shoreline position data base, and comparison 

Figure 3. The U.S. Geological Survey is studying the effects of various land uses on the ground- and 

surface-water systems in the vicinity of the James Campbell National Wildlife Refuge.
For More

Information

of beach profiles and sediment samples 

with those collected in the 1960’s. Results 

from this program provide information 

useful to planners, engineers, and resource 

managers.

Water Supply for Domestic 

Needs

A critical issue in the Hawaiian islands is 

a reliable supply of freshwater. Although 

rainfall, streamflow, and ground water generally are abundant in Hawaii, most islands 

are withdrawing water at rates close to the 

estimated yield of aquifers near the populated areas. In addition, most proposed 

urban development is in the dry, leeward 

areas of the islands. 

The USGS, in cooperation with State 

and local agencies, is conducting studies to 

quantify the availability of ground water in 

five of the six major islands of Hawaii. As 

part of these studies, the USGS has undertaken an exploratory drilling program on 

Hawaii, Oahu, and Kauai.

Studies and test drilling that have led to 

the discovery and quantification of developable ground-water resources have been 

completed in the North Kohala and Kona 

areas of the island of Hawaii, north-central 

Oahu, and southeastern Kauai. Similar studies are currently underway for western 

Maui, south-central Oahu, Lanai, and 

southeastern Kauai.

Endangered Ecosystems and 

Nonnative Species Invasions

The USGS’s Biological Resources Division (formerly the National Biological Service) conducts studies on rare and 

endangered species of animals and plants 

unique to Hawaii and other U.S. holdings 

in the western Pacific, which include 

American Samoa, Guam, and the Marianas 

Islands (fig. 1). About one-third of all listed 

bird, plant, arthropod, and other species are 

found in this area, where competitive invasions of nonendemic plants and animals are 

forcing the collapse of the fragile island 

ecosystems. For example, scientists are 

studying the brown tree snake, which is 

rapidly spreading from Guam to other 

Pacific Islands and poses a serious threat to 

the native ground-nesting birds and lizard 

populations of these ecosystems. The 

Pacific Island Ecosystems Research Center studies the biology of specific species,

such as the Hawaiian crow (Alala), the 

crested honeycreeper, the Haleakala silversword plant, and many others. This 

research is supplemented by studies of how 

introduced diseases and predators take 

their toll. The Center has a geographic 

information system and global positioning 

system node that provides support to its 

island laboratories for location of endangered species, some of which consist of 

only a few individuals. It also contracts 

research for the State, other Department of 

the Interior agencies, and U.S. military 

partners through its Cooperative Parks 

Study Unit. The Hawaii Cooperative Fishery Research Unit is located at the University of Hawaii. The research focus of the 

Unit is on nearshore fish and aquatic 

resource communities other than fish.

Water Resources Studies in the 

Pacific 

The Pacific Ocean area (fig. 1) in which 

the USGS conducts hydrologic work 

encompasses one-sixth of the Earth's circumference and includes a wide range of 

climate, economic development, and local 

forms of government. The most critical 

resource problem for these islands is a reliable supply of freshwater. Many of these 

islands are now near the limit of the known 

freshwater resources, and demand exceeds 

the existing supply on many islands. Rapid 

population growth and expansion of the 

visitor industry have contributed to watersupply problems. In cooperation with the 

governments of the territories of Guam and 

American Samoa, the Republics of the 

Marshall Islands and Palau, the Commonwealth of the Northern Mariana Islands,

and the Federated States of Micronesia, the 

USGS has undertaken water-resource 

investigations. These studies are designed 

to quantify the water resources and to provide a framework for development, management, and protection of these fragile 

resources.

In cooperation with the U.S. Navy, the 

U.S. Air Force, and the U.S. Army, the 

USGS is collecting hydrologic data and 

conducting investigative studies for U.S. 

military installations in Hawaii, Guam, 

Kwajalein, Korea, and Diego Garcia 

(Indian Ocean). This work includes studies 

of ground-water availability and contamination, rainfall/runoff, and the collection and 

analysis of climatologic and hydrologic 

data.

USGS State representative

677 Ala Moana Blvd., Suite 415

Honolulu, HI 96813

(808) 522-8290

Fax: (808) 522-8298

Email: dc_hi@usgs.gov

Additional earth science

information can be found by

accessing the USGS Home Page

on the World Wide Web at

http://www.usgs.gov/

For more information on

all USGS reports and products

(including maps, images,

and computerized data), call

1-800-USA-MAPS

The USGS provides maps,

reports, and information to help

others meet their needs to manage,

 develop, and protect America’s water,

energy, mineral, biological, and land

resources. We help find the natural

resources needed to build tomorrow,

and supply the scientific understanding needed to help minimize or mitigate the effects of natural hazards

and environmental damage caused

by natural and human activities. The

results of our efforts touch the daily

 life of almost every American.

U.S. Geological Survey

Fact Sheet FS-011-96