159° 30' x

159° 20°

159° 40"

22° 00'

if
f

° 5 MILES Hanapepe ~

i} 5 KILOMETERS B 0.22 Mgal/d

Base digitized from U.S. Geological Survey
1:24,000 topographic quadrangles for the
island of Kauai

EXPLANATION
e GROUND-WATER INJECTION
A RELEASE TO OCEAN

Figure 11. Locations of wastewater-discharge sites, iskand of Kaudi, 1990.

16


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ening jeaiBoj089 °S'n wo1} pazi6ip eseg

SS obe

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10


159° 30"
Princeville

a?) A LIHIWAL,’
{ ia / AX, 20201 /
] 7 4 SKILAUEA ”
15940, j ; ( HANALEI 1) 20108.”
“ 20208 ( . a
{ é is Yo ( Bb
22° 10° . . \ \ \ \ . Sy -
NA PALI 4 WAINIHA'\ *. ao So ee

KEKAHA
20301

f \H

j » 20304. 5 5

MAKAWELI \ \ 4 *,
20303 +

22° 00' HANAMAULU give

20102

fe
| —.
Pani we.
° 5 MILES f Pa KOLOA
i) 5 KILOMETERS Hanapepe 20101

Base digitized from U.S. Geological Survey
1:24,000 topographic quadrangles for the
island of Kauai

EXPLANATION

—-—  AQUIFER-SYSTEM BOUNDARY

KOLOA AQUIFER-SYSTEM NAME AND
20101 NUMBER

Figure 14. Aquifer-system areas, island of Kauai, 1990 (modified from George A. L. Yuen
and Assoc., 1990).

20


ESTIMATED WATER USE IN 1990, ISLAND OF KAUAI, HAWAII

By Patricia J. Shade

Abstract

The estimated total quantity of freshwater
withdrawn on the island of Kauai, Hawaii, in 1990
was 370.84 million gallons per day of which 46.29
million gallons per day (12 percent) was from
ground-water sources, and 324.55 million gallons
per day (88 percent) was from surface-water
sources. An additional estimated 40.94 million
gallons per day of saline water was withdrawn for
thermoelectric power generation. Agricultural
irrigation was the principal use, accounting for 66
percent of the total freshwater withdrawals.
Irrigation accounted for about 40 percent of the
fresh ground-water withdrawals, followed by
public supply, thermoelectric power generation,
self-supplied domestic, self-supplied commercial,
and self-supplied industrial withdrawals.
Agricultural irrigation accounted for 69 percent of
the total fresh surface-water withdrawals, followed
by hydroelectric power generation, self-supplied
industrial, public-supply and self-supplied
livestock withdrawals.

A comparison of water-use data for 1980 and
1990 shows total freshwater uses decreased during
1990 by slightly more than 100 million gallons per
day because of decreased withdrawals for
sugarcane irrigation and processing. During this
time, increased domestic, commercial, and
thermoelectric power usage reflects increases in the
resident population and in tourism on the island.

INTRODUCTION

Tremendous growth and change have occurred in
the State of Hawaii since the 1960's. By 1990 the
population had grown from about 634,000 in 1960
(State of Hawaii, 1967) to more than 1 million
residents. Tourism has become one of the principal
economic activities in the State. Agricultural companies
have begun to decrease the amount of acreage planted in

sugarcane, to diversify the type of crops grown, and to
improve the methods of irrigation. Urban development
has rapidly expanded on the island of Oahu, and
residential and commercial development is increasing
on the outer islands of Maui, Kauai, Molokai, and
Lanai.

Coinciding with these changes is an increased
demand and competition for water among all users and
a need for governmental agencies to compile accurate,
uniform, and timely water-use data for planning
purposes. At the national level, the United States
Congress, in 1977, recognized the need for water-use
information and directed the U.S. Geological Survey to
establish a National Water-Use Information Program
(Solley and others, 1988). This program became a part
of the U.S. Geological Survey's Federal-State
Cooperative Program. This report is a product of that
program between the U.S. Geological Survey and the
Kauai County Department of Water.

PURPOSE AND SCOPE

The purpose of this report is to present 1990 water-
use estimates for the island of Kauai, Hawaii. Estimates
of water withdrawn from surface- and ground-water
sources were made from data provided by the Kauai
County Department of Water and the principal self-
supplied users. These data were categorized by type of
use including domestic, commercial, industrial, power
generation, and agricultural as outlined by the National
Water-Use Information Program. These data are
presented on an island-wide basis and by aquifer-
system areas that were delineated by the State of Hawaii
for water-management purposes. A geographic
information system (GIS) was used to disaggregate
these water-use data by aquifer-system areas and to
perform spatial analyses of agricultural data. Water-use
estimates for 1980 and 1990 were compared to
determine the effects from population growth, increased
tourism, and changing agricultural practices.


PRIMARY USE INTERMEDIATE USE FINAL USE
Hydroelectric Sugar mill Irrigation
28.40 12.62 12.62 15.78
Thermoelectric
10.68 10.68 10.68
; TOTAL
Sugar mill 46.20
5.41 5.41
Wastewater
treatment plant
1.71 1.71

(values are in million gallons per day)

Figure 12. Diagram of recycled water, island of Kauai, 1990.

for the domestic category was estimated to be 50
percent (Ernest Lau, Honolulu Board of Water Supply,
oral commun., 1991), which is 4.45 Mgal/d. This
consumptive-use estimate was developed from data on
deliveries to users and inflows to public sewage-
treatment facilities on the island of Oahu. These data are
more complete than data available for Kauai, and
because the climate is similar and the majority of the
populations on both islands are served by a public -
supply system, the domestic consumptive-use factor
was applied to Kauai's domestic-use data. The domestic
consumptive-use factor of 50 percent is comparable to
those reported in 1990 for other areas with warm
climates such as Arizona (50 percent) and Puerto Rico
(44 percent) (Solley and others, 1993, p. 29).

A commercial consumptive-use factor was
estimated in two parts and was also estimated from
more complete data available on the islands of Oahu
and Hawaii. Water use at hotels accounted for 50
percent of the commercial use on Kauai. Few resorts in
Hawaii maintain their own water supply and sewage -

treatment facilities where data regarding water deliveries
to users and inflows to sewage-treatment plants are
available. However, at such a resort on the island of
Hawaii, a hotel consumptive use was calculated to be
68 percent of the water delivered. This 68-percent factor
was applied to the Department of Water hotel deliveries
of 2.07 Mgal/d, and the commercial part of the
Princeville water, 0.71 Mgal/d. Military installations are
another use considered in the commercial category that
sometimes maintain their own sewage treatment
facilities, although not on Kauai. At a small military
installation on Oahu that is publicly supplied and
operates its own sewage-treatment plant, the
consumptive use was 16 percent. The 16 percent factor
was applied to all other Department of Water
commercial deliveries on Kauai of 2.10 Mgal/d. The
estimated total commercial consumptive use was 2.23
Mgal/d, 46 percent of the total commercial use. This
value is similar to the commercial consumptive use
reported for Arizona in 1990, 45 percent (Solley and
others, 1993, p. 33).


SUMMARY AND CONCLUSIONS

The estimated total freshwater withdrawal for the
island of Kauai in 1990 was 370.84 Mgal/d of which
46.29 Mgal/d was from ground-water sources and
324.55 Mgal/d was from surface-water sources. Of this
total, 65.32 Mgal/d withdrawn for hydroelectric power
generation was released back into the streams for
potential use downstream. An additional 40.94 Mgal/d
of saline water was withdrawn for cooling purposes at a
thermoelectric power plant. An estimated total of 46.20
Mgal/d was recycled to various uses such as for
sugarcane processing in the plantation mills, and for
agricultural and golf-course irrigation.

The sum of plantation withdrawals for domestic,
industrial, irrigation, and hydroelectric power generation
uses is about 324 Mgal/d of freshwater in 1990, about
87 percent of the total island withdrawal. Of this 324
Mgal/d, 79 percent, about 257 Mgal/d, was used
directly or recycled for irrigation of more than 33,000
acres of sugarcane, coffee, and macadamia nuts.
Because the plantations are the dominant users on the
island, the changing practices on the plantations,
including the diversification of crops from high water-
use sugarcane to crops such as coffee and macadamia
nuts that have a lower water demand, the reduction in
sugarcane acreage, and the change from furrow to drip
irrigation significantly affect the availability of water for
other purposes.

A comparison of 1980 and 1990 total freshwater
uses shows a decrease of more than 100 Mgal/d in
1990. Of this total, agriculture water-use data indicates a
reduction of about 87 Mgal/d in 1990 after about 8,000
acres were taken out of sugarcane production, 5,000
acres were converted from sugarcane to coffee, and
plantations continued to convert fields from furrow- to
drip-irrigation methods. By using uniform methods for
water-use accounting, the effects of these kinds of
changes can be monitored, and comparisons of water
use for the island between years can be analyzed.

References Cited

Central Electricity Generating Board, 1971, Modern
power station practice, v. 1: Pergamon Press, 512 p.
Chang, J.H., 1968, Climate and agriculture: Chicago,

Aldine Publishing Co., 304 p.

Ekern, P.C. and Chang, J.H., 1985, Pan evaporation:
State of Hawaii, 1894-1983, State of Hawaii
Department of Land and Natural Resources, Honolulu,
Hawaii, 171 p.

George A.L. Yuen and Assoc. Inc., 1990, Water
Resources Protection Plan: Honolulu, Hawaii,

23

prepared for State of Hawaii, Department of Land and
Natural Resources, Commission on Water Resources
Management, variously paged.

Giambelluca, T.W., Nullet, M.A., and Schroeder, T.A.,
1986, Rainfall atlas of Hawaii: Honolulu, State of
Hawaii Department of Land and Natural Resources
Report R76, 267 p.

Hawaii Agricultural Reporting Service, 1981, Statistics
of Hawaiian agriculture 1980: Honolulu, Hawaii
Department of Agriculture, 100 p.

Hawaii Agricultural Statistics Service, 1991, Statistics of
Hawaiian agriculture 1990: Honolulu, Hawaii
Department of Agriculture, 100 p.

Nakahara, R. H., 1984, Water use in Hawaii 1980:
Honolulu, State of Hawaii Department of Land and
Natural Resources, Report R71, 26 p.

R.M. Towill Corporation, 1992, Kauai water use and
development plan: Honolulu, prepared for Department
of Water County of Kauai, 150 p.

Solley, W. B., Merk, C.F., and Pierce, R.R., 1988,
Estimated use of water in the United States in 1985:
U.S. Geological Survey Circular 1004, 82 p.

Solley, W.B., Pierce, R.R., and Perlman, H.A., 1993,
Estimated use of water in the United States in 1990:
US. Geological Survey Circular 1081, 76 p.

State of Hawaii, 1967, The State of Hawaii data book:
Honolulu, State of Hawaii Department of Planning
and Economic Development, 66 p.

———, 1991la, The population of Hawaii, 1990:
Honolulu, State of Hawaii Department of Business,
Economic Development and Tourism, Statistical
Report 219, 28 p.

, 1991b, The State of Hawaii data book 1991:

Honolulu, State of Hawaii Department of Business,

Economic Development and Tourism, A Statistical

Abstract, 657 p.

, 1992, Rainfall trend through August 1992: State

of Hawaii Department of Land and Natural Resources

Commission on Water Resource Management, issued

September 14, 1992, 4 p.



5 MILES

0 5 KILOMETERS

Base digitized from U.S. Geological Survey
1:24,000 topographic quadrangles for the
island of Kauai

EXPLANATION

PLANTATION AGRICULTURAL FIELDS

—40— _ LINE OF EQUAL MEAN ANNUAL PAN
EVAPORATION--Interval 10 inches

Figure 13. Mean annual pan evaporation and plantation agricultural fields, island of Kauai, 1990.

19


159° 30° 3

22° 00°

5 MILES
0 5 KILOMETERS
Base digitized from U.S. Geological Survey

1:24,000 topographic quadrangles for the
island of Kauai

EXPLANATION

— 60 — LINE OF EQUAL MEAN ANNUAL PAN
EVAPORATION--Interval 10 inches
981
d PAN-EVAPORATION STATION
AND NUMBER

Figure 10. Mean annual pan evaporation, island of Kauai (modified from Ekern and Chang, 1985).

14


Water for 1990, 11.18 Mgal/d, were calculated by
averaging the deliveries reported in the 1989-90 and
1990-91 fiscal year metered delivery records. The
deliveries were apportioned by water-use category
using the sewer class codes listed in the records.
Domestic deliveries were 56 percent of the total (6.23
Mgal/d), commercial deliveries were 37 percent (4.17
Mgal/d), agricultural deliveries were 4 percent (0.45
Mgal/d), industrial deliveries were 3 percent (0.33
Mgal/d), and thermoelectric deliveries were zero (fig.
4). Unaccounted-for water was estimated to be 1.68
Mgal/d (15 percent of deliveries); thus, estimated total
withdrawals equaled 12.86 Mgal/d).

COMMERCIAL

AGRICULTURAL
4 percent
INDUSTRIAL
3 percent

TOTAL: 11.18 million gallons per day

Figure 4. Percentages of public-supply
water deliveries, island of Kauai, 1990.

DOMESTIC

The 1990 census data (State of Hawaii, 1991a)
indicate a resident population of 50,947 on Kauai. The
Department of Water supplied domestic water to about
90 percent of this total population, about 46,000
residents. Separate systems on the major plantations
and at Princeville supplied most of the remaining 5,000
residents.

Domestic water use includes water used for
drinking, washing clothes, bathing, food preparation,
watering residential lawns, and flushing toilets. The
Department of Water withdrew 7.16 Mgal/d, 6.84 from
ground water and 0.32 from surface water, for

domestic purposes on the island. Subtracting
conveyance losses of 15 percent (Gregg Fujikawa,
Kauai County Department of Water, oral commun.,
1991), the domestic public-supplied water use was 6.23
Mgal/d, 0.27 Mgal/d from surface-water sources and
5.96 Mgal/d from ground water. There were self-
supplied domestic users on the major plantations and in
the Princeville development. The estimated self-
supplied domestic withdrawals were from ground-
water sources, and in 1990 were 2.77 Mgal/d on the
plantations, 0.35 Mgal/d at Princeville (estimated as 30
percent of the total withdrawal, Gregg Fujikawa, Kauai
County Department of Water, oral commun., 1991),
and 0.01 Mgal/d for all other small self-supplied users
on the island for a total of 3.13 Mgal/d. Subtracting 15
percent as an estimate of conveyance losses, the
quantity of water used by self-supplied users for
domestic purposes on the island in 1990 was estimated
to be 2.66 Mgal/d. The total domestic usage for all
users was 8.89 Mgal/d.

Using a resident population of 50,947, the per
capita water use for domestic purposes was about 174
gal/d, of which 135 gal/d was for public-supplied users
and more than 500 gal/d was for self-supplied users.
The extreme value for self-supplied users indicates the
possibility of error in the reported withdrawal data from
the plantations. Most likely some water reported for
domestic use was used for irrigation or other purposes.
The public-supplied domestic per capita use of 135
gal/d is comparable to the use reported for several states
in 1990 (Solley and others, 1993, p. 29), such as
Arizona, California, Florida and Nevada, which had per
capita public-supplied domestic uses of 150 gal/d, 147
gal/d, 111 gal/d, and 213 gal/d, respectively.

COMMERCIAL

Commercial water use includes water for hotels,
office buildings, restaurants, government buildings,
military installations, and other commercial activities.
Allowing for 15 percent conveyance losses, the 1990
Department of Water commercial withdrawals were
estimated to be 4.80 Mgal/d. The average of the
Department of Water 1989-90 and 1990-91 delivery
figures shows 37 percent of total deliveries, 4.17
Mgal/d, was for commercial purposes. Hotel use
accounted for 2.07 Mgal/d, 50 percent of this
commercial delivery. At the self-supplied Princeville
development, it was estimated that 70 percent (Gregg
Fujikawa, Kauai County Department of Water, oral
commun., 1991) of the water withdrawn, or 0.83
Mgal/d, was for commercial activities, and allowing for
15 percent losses, 0.71 Mgal/d was used. The total


ACKNOWLEDGMENTS

The author acknowledges the cooperation and
assistance of personnel from the Kauai County
Department of Water and Department of Public Works,
the State of Hawaii Department of Land and Natural
Resources, and the University of Hawaii. The
cooperation of the principal water users in providing
data is greatly appreciated.

STUDY AREA

The island of Kauai encompasses 553 mi? and is
located at the northwest end of the chain of major
Hawaiian islands (fig. 1). The topography is varied and
ranges from spectacular sea cliffs and beaches along the
Na Pali coast to mountain peaks higher than 5,000 ft in
the interior of the island. The magnificent Waimea
Canyon is in some places 2,600 ft deep, and the Alakai
Swamp covers more than 10 mi?. This varied and
dramatic topography is the result of an equally extreme
distribution of rainfall. Mean annual rainfall ranges
from less than 30 in. along the coast near Kekaha to
more than 400 in. at Mt. Waialeale (Giambelluca and
others, 1986) (fig. 2).

Several perennial streams (fig. 1) flow from the
summit area in the interior of the island to the shore.
These streams supply substantial amounts of water for
the generation of hydroelectric power and are the
predominant sources of agricultural irrigation water.

ECONOMIC SETTING

Kauai is one of the more rural islands in the State of
Hawaii and has a resident population that has increased
from about 39,000 in 1980 to about 51,000 in 1990
(State of Hawaii, 1991a). The population centers (fig. 2)
at Kekaha, Waimea, Hanapepe, Lihue, Wailua, and
Kapaa are mostly along the coast where rainfall,
topography, and temperatures are moderate and port
facilities are available nearby.

There also are residential and resort developments
at Princeville in a tropical setting on the north shore.
Resorts are similarly located along the southeast and
east coasts where beaches are plentiful and the climate
is mild.

Tourism has more than doubled between 1980 and
1990, as represented by the average number of visitors
per day present on the island, from about 7,300 in 1980
to 17,600 in 1990 (State of Hawaii, 1991b). Statewide
data show that visitor expenditures more than tripled
from 1980 to 1990 (State of Hawaii, 1991b), making
tourism a major source of income for the islands.

Plantation agriculture is the other major economic
activity on Kauai. Five companies have grown
sugarcane on the island since the early 1900's. From
1980 to 1990 there was a decrease of almost 8,000
acres in cultivated sugarcane and a decrease in the value
of total production of raw sugar and molasses of almost
50 million dollars (Hawaii Agricultural Reporting
Service, 1981; Hawaii Agricultural Statistics Service,
1991). To increase efficiency, plantations have
continued to shift from furrow- to drip-irrigation
methods. Recently, one of the plantations started to
diversify by replacing about 5,000 acres of sugarcane
with lower-water-demand crops of coffee and
macadamia nuts. The sugarcane processing mills are
the major industry on the island and most of the power
used on the plantations is generated at hydroelectric
plants owned and operated by the plantations.

WATER USE

Water uses are defined as either offstream,
instream, or miscellaneous (Solley and others, 1988, p.
8). Offstream use includes water that is withdrawn
from ground-water sources or diverted from streams
and conveyed to a place of use. Instream use is water
that is essentially used on-site as for hydroelectric
power generation. The miscellaneous-use category
includes return flows to the environment from
wastewater-treatment facilities and water that has been
recycled from the use for which it was originally
withdrawn to another use.

OFFSTREAM USE
PUBLIC SUPPLY

Water withdrawn by the Kauai County Department
of Water and delivered to many users for domestic,
commercial, agricultural, industrial, and thermoelectric
purposes is considered public supply. Because
pumpage was not adequately metered, the total 1990
withdrawal by the Department of Water was estimated
as the average of the 1989-90 and 1990-91 fiscal year
metered deliveries plus 15 percent as estimated
unaccounted-for water (Gregg Fujikawa, Kauai County
Department of Water, oral commun., 1991) due to
conveyance losses, and public uses such as firefighting
and street cleaning. The estimated total withdrawal by
the Department of Water was 12.86 Mgal/d of which
12.54 Mgal/d was from ground-water sources and 0.32
Mgal/d was from a single surface-water source,
Alexander Reservoir (fig. 3).

The total deliveries (withdrawals minus
unaccounted-for water) made by the Department of


22° 00°

0 5 MILES

-OMETERS

Base digitized from U.S. Geological Survey
1:24,000 topographic quadrangles for the
island of Kauai

Figure 1. Hawaiian islands and island of Kauai.

20°;

159° 30° A

160° 158°

T
rd @ Kauai

Oahu iS)
Lanai ©
Kahoolawe~

PA Chere

Cea, Hawaii
:

156°
— -
HAWAII

Nithau
CS. Molokat

Maui

4



THERMOELECTRIC POWER

The thermoelectric power category includes water
used in the production of electricity generated from
fossil fuels. The public utility company operates a
thermoelectric plant at Port Allen near Hanapepe cooled
by saline ground water. Using a ratio developed from
pumpage data and power generated in 1985, an
estimated 40.94 Mgal/d of saline ground water was
withdrawn in 1990. The power produced from this
plant was 251.83 GWh. A single fossil fuel power
plant on one of the plantations used 10.98 Mgal/d from
a ground-water source in 1990. The power produced at
this plant was 19.89 GWh. Most of the other
plantations have hydroelectric power plants which are
discussed in this report as an instream use. The total
thermoelectric power production in 1990 was 271.72
GWh.

INSTREAM USE—HYDROELECTRIC POWER GENERATION

Water used for hydroelectric power production is
the only instream use accounted for in this report. From
five hydroelectric power plants on the plantations, 47.12
GWh were produced from withdrawals of 93.72
Mgal/d. Of this total withdrawal, 28.4 Mgal/d was
recycled to other uses on the plantations and the
remainder, 65.32 Mgal/d, was discharged back into the
streams.

The various methods used to account for
withdrawals for hydroelectric power can lead to large
differences when comparing various water-use studies.
For example, a recent report (R.M. Towill Corp., 1992)
shows a withdrawal and use of almost 54 Mgal/d for
hydroelectric power generation at one of the plantations.
Two hydroelectric-power plants are at that plantation,
and at one plant all water is returned to the stream.
Therefore, with no accounting for a return to the stream,
there is no accounting for potential use downstream.
This is an example of how applying a uniform water-
use accounting method could result in consistent data
for those making management decisions.

MISCELLANEOUS USE

WASTEWATER TREATMENT

The final element in the water-use cycle of
withdrawals, deliveries, and consumption is the return
of water to the environment either as discharge to
streams, the ocean, or underground by use of injection
wells. Attempting to calculate the quantity of irrigation
water recharging the ground-water sources or the
quantity infiltrating from individual septic systems was

15

beyond the scope of this study. About 20 percent of the
resident population was served by sewer systems in
1990. Water-quality considerations are becoming
increasingly important, and quantifying releases of
treated wastewater to surface- or ground-water sources
is an important element in the resource management.

Data from wastewater treatment facilities also are
useful for estimating consumptive use. For well-
defined small systems such as resorts or military
installations that have their own sewage treatment
facilities and little infiltration of ground water into the
sewers, estimates of consumptive use can be readily
determined by subtracting the amount of inflow to the
treatment plant from deliveries made to users.

Wastewater-discharge quantities and locations are
important to know for health reasons and for potential
recycled-water uses. In 1990, Kauai had two sites of
release to surface water and one site of release to
ground water by injection well (fig. 11). The major
sewage-discharge site into the ocean was at Wailua
where 0.66 Mgal/d was released at a depth of about 30
ft and about 680 ft offshore. On the basis of data
provided by the three treatment facilities, the total
surface-water releases in 1990 were estimated to be
0.68 Mgal/d and ground-water releases 0.22 Mgal/d. In
addition to these releases was 1.71 Mgal/d recycled to
golf-course irrigation and sugarcane irrigation at one of
the plantations.

RECYCLED WATER

An estimated total of 46.2 Mgal/d of water was
recycled to various purposes on Kauai in 1990 (fig. 12).
Of the water withdrawn for hydroelectric power
generation, 28.4 Mgal/d was recycled on the plantations
for use first in the sugar mills and then to irrigation, or
directly from the power plant to the fields. The 10.68
Mgal/d of ground water withdrawn for thermoelectric
power generation was recycled to the mill at one of the
plantations and then to the fields. A total of 5.41 Mgal/d
was used directly in the mills and then recycled to the
fields. Thus, all the water discharged from the
plantation sugar mills, about 28.71 Mgal/d, was
recycled to irrigation. An additional 1.71 Mgal/d was
recycled to plantation and golf course irrigation from
three wastewater treatment plants. The total recycled
water used for irrigation was 46.2 Mgal/d.

CONSUMPTIVE USE

Consumptive-use estimates were made for the
domestic, commercial, industrial, thermoelectric power
generation, and irrigation categories. Consumptive use


159° 30' A

Princeville

159° 20°

°
1333-01 _-e%
1292-01,02

9 1125-01,02

{
|
)
\

0818-0102"

0623-01

0622-01
0623-022 °

b
NC Ay 0421-02
0421-02,
Pro 920-01,08 0
WAS

5923-01,02,
03,04,05,07

5824-02

22°00" 5942-01 " /
e 5939-01, po

5843-01 6" »/7 ie 1 582400 M0

w 5840-02. chad oy Vf Alexander ‘5824-05 ° S088

—2 y © Reservoir 49 5725-01
Waimea aan o
/ 95531-01 Lee
5533-02 / 99500-03

5534-05,

9427-01 102,03

oO 5 MILES G594-08

O 5 KILOMETERS

Base digitized from U.S. Geological Survey
4:24,000 topographic quadrangles for the
island of Kauai

EXPLANATION

5843-01 | = KAUAI COUNTY DEPARTMENT OF
WATER WELL AND NUMBER

Figure 3. Locations of public-supply wells and reservoir, iskand of Kauai, 1990.


Table 3. Water withdrawals by aquifer system, island of Kauai, 1990.

[Values are in million gallons per day; GW, ground water; SW, surface water; --, none.

Aquifer-system names and

numbers are from George A.L. Yuen and Associates, Inc., 1990.]

Amount withdrawn and

Aquifer-system  Aquifer-system used within area

Amount used in area from
withdrawals elsewhere

Amount withdrawn in
area for use elsewhere

name number Gw. SW GW SW GW SW
Koloa 20101 9.64 18.70 -- -- -- 16.43
Hanamaulu 20102 5.24 21.99 -- 6.26 -- --
Wailua 20103 0.75 838.07 - 9.20 0.24 --
Anahola 20104 2.73 19.41 0.24 -- -- 9.20
Kilauea 20105 0.30 6.02 0.12 -- -- --
Kalihiwai 20201 1.22 -- -- -- 0.12 --
Hanalei 20202 0.12 10.71 -- -- -- --
Wainiha 20203 0.10 964.73 -- -- -- --
Na Pali 20204 - -- -- -- - --
Kekaha 20301 22.68 -- -- -- 0.53 53.96
Waimea 20302 0.29 0.17 0.53 953.96 -- --
Makaweli 20303 2.16 36.15 -- -- -- --
Hanapepe 20304 0.17 29.01 -- 10.17 -- --

TOTAL..... 45.40 244.96 0.89 79.59 0.89 79.59

4 Part of surface-water withdrawal was eventually returned to streams

The increase in domestic and commercial water use
from 1980 to 1990 reflects the 31-percent increase in
the resident population, from 38,856 in 1980 to 50,947
in 1990 (State of Hawaii, 1991a), and an increase in
tourism and resort development. Apparent per capita
domestic use increased from 152 gal/d in 1980 to 174
gal/d in 1990.

Because irrigation is the largest use of water on the
island, changes in agricultural practices cause
substantial changes in the water-use data and
significantly affect the availability of water for other
purposes. Diversifying cultivated crops from high-
water-use sugarcane to include lower water-use crops
such as coffee and macadamia nuts, and changing from
furrow irrigation to drip irrigation caused the decrease
in the agricultural water use from 340.22 Mgal/d in
1980 to 252.97 Mgal/d in 1990. Total sugarcane
acreage, irrigated and unirrigated, decreased from
46,000 acres in 1980 to 38,100 acres in 1990 (Hawaii
Agricultural Statistics Service, 1991). Drip-irrigated
acreage increased from 16,077 in 1980 to 19,264 in
1990 and furrow-irrigated acreage decreased from
18,108 in 1980 to 8,837 in 1990.

The decrease of about 5 Mgal/d, or 15 percent, in
the industrial use since 1980 is most likely due to a
decrease in sugarcane processing, the principal

21

industrial activity on the island. From 1980 to 1990
there was a decrease of almost 300,000 tons of
unprocessed sugarcane, about 16 percent (Hawaii
Agricultural Reporting Service, 1981 and Hawaii
Agricultural Statistics Service, 1991).

The increase in thermoelectric water use reflects the
increased demands of a larger resident and tourist
population in 1990, Power production by Kauai Electric
increased by 37 percent from 1980 to 1990. The
decrease in hydroelectric use in 1990 can be explained
by a decreasing demand for power on the plantations
where the hydroelectric power plants are located
because of the decrease in sugar production and
processing.

The values shown in table 4 are estimates, and as
such, assumptions have been made and in some cases,
relationships derived, that are not absolutely accurate.
Therefore, although there are reasonable explanations
for the differences that are indicated by these data, it is
clear that uniform, consistent approaches to compiling
and analyzing water-use data are needed for valid
analyses and results.


ESTIMATED WATER USE IN 1990, ISLAND OF KAUAI, HAWAII

By Patricia J. Shade

U.S, GEOLOGICAL SURVEY

Water-Resources Investigations Report 93-4180

Prepared in cooperation with the
KAUAI COUNTY DEPARTMENT OF WATER

Honolulu, Hawaii
1995


5 KILOMETERS

Base digitized from U.S. Geological Survey
124,000 topographic quadrangles for the
island of Kauai

EXPLANATION

PLANTATION AGRICULTURAL FIELDS

Figure 5. Areas of plantation agricultural fields, iskand of Kauai, 1990.


estimated commercial withdrawals on Kauai in 1990
were 5.63 Mgal/d from ground-water sources, and the
total commercial use was 4.88 Mgal/d.

INDUSTRIAL

Industrial water use includes water for purposes
such as processing, washing, and cooling. On Kauai,
the major industrial process is the milling of sugarcane.
Estimated industrial self-supplied withdrawals for 1990
were 0.03 Mgal/d from ground-water sources and 6.34
Mgal/d from surface-water sources. Applying a 15
percent conveyance loss, 5.41 Mgal/d was the estimated
self-supplied industrial use. From the Department of
Water delivery records, 0.38 Mgal/d was the estimated
industrial withdrawal from ground-water sources, and
0.33 Mgal/d, or 3 percent of total Department of Water
deliveries, were delivered to industrial users. The total
industrial use was estimated to be 5.74 Mgal/d.

MINING

On Kauai, the only activities considered in the
mining category are rock quarrying and concrete
production. Water used in these operations is for
washing, dust control, and in the production of
concrete. Data from users on Kauai in this category
were not available; however, estimates were made from
information compiled from a ready-mix concrete
operation on the island of Oahu. These data indicate that
the water used in concrete production was 15 percent of
the total water delivered to the facility from the public
supply, and that 40 gal was required per cubic yard of
concrete. The estimated quantity of concrete produced
in 1990 on Kauai was 100,000 yd?. Therefore, 4
Mgal/yr was used in concrete production, a quantity
which is 15 percent of the estimated total water required
at the facility. With the additional 85 percent, the
estimated total water used in mining was about 27
Mgal/yr (0.07 Mgal/d).

LIVESTOCK

Livestock water use is a small part of Kauai's total
water use that includes drinking water for animals and
washing water for dairy cattle. Water used in
slaughterhouse operations and egg washing are
considered industrial and commercial uses,
respectively. Livestock water use was estimated from
statistics on the number of beef and dairy cattle, hogs,
and chickens (Hawaii Agricultural Statistics Service,
1991) and from estimates by University of Hawaii
animal science professors (B.A. Buckley, G.G. Gomez,
C.N. Lee, and P.H. Patterson, University of Hawaii,
oral communs., 1991) of the drinking-water

requirements of these animals (table 1). The estimated
total livestock use was 0.2 Mgal/d. Of this total, the
estimated self-supplied livestock use in 1990 was 0.13
Mgal/d from surface-water sources. The Department of
Water deliveries for livestock use were estimated from
applications for lower-price agricultural water rates,
about 10 percent of which indicated some livestock use.
The estimated delivery for these users was 0.07 Mgal/d
in 1990.

Table 1. Estimated livestock water use, island of
Kauai, 1990

Water use
Livestock Number of (gallons per day
type animals per animal)
Dairy 850 80
Beef 11,150 10
Hogs 3,300 5
Poultry 42,400 0.055
IRRIGATION

Water used for irrigation includes water used by
plantations for crop irrigation, small farm irrigation of
fruits, vegetables, flowers, grains, and horticultural
products, and golf course irrigation. Irrigation was the
largest use of water on Kauai in 1990. Data sources
included the Department of Water 1989-90 and 1990—
91 metered delivery records, data from the plantations
on the amount of surface- and ground-water
withdrawals, plantation field maps that indicate location
and size of cultivated areas, type of crop, and method of
irrigation (figs. 5-9), cultivated acreage statistics from
the Hawaiian Sugar Planters’ Association (HSPA)
printed in the 1990 agriculture report (Hawaii
Agricultural Statistics Service, 1991), and private user
withdrawals reported in the Kauai Water Use and
Development Plan (R.M. Towill Corp., 1992).

The total ground-water withdrawals by the
plantations for irrigation was estimated to be 16.62
Mgal/d of which 0.26 Mgal/d was sold to small
farmers. Another 0.45 Mgal/d of ground water was
estimated to be withdrawn for irrigation by the
Department of Water. Estimated total ground-water
withdrawals by self-supplied users other than the
plantations, including small farms and resorts using
water for hotel grounds and golf course irrigation, was
2.15 Mgal/d. The total ground-water withdrawal for
irrigation was estimated to be 19.22 Mgal/d in 1990.
Allowing for conveyance losses of 15 percent, the net
estimated ground-water supplied irrigation water use
was 16.34 Mgal/d.


159° 30° a

Princeville

22° 00"

O 5 MILES

i) 5 KILOMETERS:

Base digitized from U.S. Geological Survey

1:24,000 topographic quadrangles for the
island of Kauai

EXPLANATION

—— 40— _ LINE OF EQUAL MEAN ANNUAL RAINFALL
Interval, in inches, is variable

e RAIN GAGE

Figure 2. Mean annual rainfall, isand of Kauai (modified from Giambelluca and others, 1986).


Industrial consumptive use was a small fraction of
the total industrial water use of 29.11 Mgal/d. Most of
the water in this category, 28.71 Mgal/d, was used to
wash sugarcane in the mills. Because harvested
sugarcane has a high water content that is discharged in
the processing of the cane, the net consumptive use in
the mills probably was zero. For the remaining 0.40
Mgal/d used in other industrial activities such as
cleaning of facilities, the consumptive use was
estimated to be 10 percent, which accounted for about
0.04 Mgal/d, or less than 1 percent of the total industrial
water use. The reported statewide industrial
consumptive use was 4 percent in 1990 (Solley and
others, 1993, p. 45).

The consumptive use of thermoelectric power
generation was estimated at the public utility plant and
at a single fossil-fuel power plant on a plantation. The
public utility plant uses saline water in a "once-through"
cooling process where plant personnel estimated that
the consumptive use was essentially zero. At the
plantation power plant water is used for cooling in a
closed system. Consumptive use at this plant is the
"makeup water" which is estimated to be 3 percent of
the circulating water, 10.98 Mgal/d, (Central Electricity
Generating Board, 1971), or 0.33 Mgal/d. The
consumptive use for this category, 0.33 Mgal/d, is 1
percent of the total saline and freshwater used, 51.92
Mgal/d, and is comparable to the Statewide
consumptive use factor reported for Hawaii and several
other states in 1990 (Solley and others, 1993, p. 53).

An estimate of agricultural or irrigation
consumptive use was made by using data on mean
annual pan evaporation and irrigated acreage. Data
given by Chang (1968) show that a reasonable estimate
of the actual evapotranspiration rate (consumptive use)
of sugarcane is the pan-evaporation rate, and that of
coffee is about 50 percent of the pan-evaporation rate
(P. Tausend, McBryde Sugar Company, oral commun.,
1993). Most of the irrigated acreage was located where
the mean annual pan evaporation is more than 60 in/yr
(fig. 13). Using the total GIS area of irrigated sugarcane
(25,919 acres) and of coffee (5,008 acres) and the
appropriate pan-evaporation factor, the total
consumptive use was estimated at 186.00 Mgal/d:
169.63 Mgal/d for sugarcane and 16.37 Mgal/d for
coffee. If 15 percent of the estimated total ground- and
surface-water withdrawals, 243.26 Mgal/d, is
subtracted to account for conveyance losses, the
remaining 206.77 Mgal/d plus recycled water of 46.20
Mgal/d totals 252.97 Mgal/d applied to the fields. The
consumptive use of 186 Mgal/d represents 74 percent
of the estimated applied irrigation water. This

consumptive use factor is comparable to those reported
for the State of Hawaii (83 percent) and other areas
where sugarcane is cultivated and that have similar
climates such as Alabama (76 percent), Florida (68
percent), and Puerto Rico (74 percent) (Solley and
others, 1993, p. 37).

WATER WITHDRAWALS BY AQUIFER-SYSTEM AREA

Aquifer-system areas (fig. 14) were delineated by
the State of Hawaii for resource-management purposes
(George A.L. Yuen and Assoc., Inc., 1990). The island
is divided into 13 aquifer systems numbered 20101-—
20105, 20201-20204, and 20301-20304. The
withdrawals by aquifer systems and the transfer of
water between systems (table 3) were estimated from
data provided by the plantations, the Kauai County
Department of Water, the State of Hawaii, the U.S.
Geological Survey, and from data reported by R.M.
Towill (1992). The withdrawal by aquifer system is
useful information for resource allocation and planning.

Table 3 shows a total estimated ground-water
withdrawal of 46.29 Mgal/d and a total estimated
surface-water withdrawal of 324.55 Mgal/d for the
island. Of the 324.55 Mgal/d withdrawn from surface-
water sources, 93.72 Mgal/d was withdrawn for
hydroelectric power generation, of which 65.32 Mgal/d
was returned to streams (56.59 Mgal/d in 20203, 1.98
Mgal/d in 20103, and 6.75 Mgal/d in 20302).

COMPARISON OF WATER USE, 1980 AND 1990

Changes in water use during the 10 years from
1980 to 1990 reflect the increased resident population,
increased tourism, increased demand for electricity, and
changes in plantation agriculture, including decreased
acreage in cultivated sugarcane and increased use of
drip irrigation. Rainfall differences in these years do not
appear to be a factor because data from two
representative stations on the island indicate that 1980
was a fairly wet year and 1990 was an average year
with several months showing only a slight departure
from the median rainfall value (State of Hawaii, 1992).
Values for the major water-use categories for 1980
(Nakahara, 1984) and 1990 are compared in table 4 and
show a total decrease of more than 100 Mgal/d: about
39 Mgal/d of ground-water use and about 69 Mgal/d of
surface-water use in 1990. Withdrawals refer to the
quantity of water taken either from a stream or pumped
from ground-water sources. Use refers to the quantity
of water delivered to the point of use; that is,
withdrawal minus conveyance losses.


TABLES

1. Estimated livestock water use, island of Kauai, 1990
2. Estimated sugarcane irrigation requirements, island of Kauai, 1990
3. Water withdrawals by aquifer system, island of Kauai, 1990
4. Estimated water use, island of Kauai, 1980 and 1990........c..cccccssesesseesessescessecneseeseetecesecneeneaeneeneenenseneeneneeass

Conversion factors and abbreviation

Multiply By To obtain
acre 4,047 square meter
foot (ft) 0.3048 meter
gallon (gal) 3.785 liter
gallon per day (gal/d) 3.785 liter per day
gallon per acre per day [(gal/acre)/d] 0.8593 liter per square meter per day
million gallons (Mgal) 3,785 cubic meter
million gallons per day (Mgal/d) 0.04381 cubic meter per second
million gallons per year (Mgal/yr) 3,785 cubic meters per year
inch (in.) 25.4 millimeter
inch per year (in/yr) 2.54 centimeter per year
mile (mi) 1.609 kilometer
square mile (mi?) 2.590 square kilometer

ton 0.9072 megagram

cubic yard (yd3) 0.7646 cubic meter

Abbreviation used:
Units of power are given in gigawatthours (GWh)


159° 40° 159° 35"

oO 1 2 MILES

0 1 2 KILOMETERS,

EXPLANATION

FURROW-IRRIGATED
SUGARCANE FIELDS

DRIP-IRRIGATED SUGARCANE

FIELDS |

|
2t° 55°

a:

Base digitized from U.S. Geological Survey
1:24,000 topographic quadrangles for the
island of Kauai

Figure 8. Types of agricultural fields and irrigation, southwestern Kauai, 1990.

i


The total surface-water withdrawals by the
plantations for irrigation was estimated to be 194.04
Mgal/d. Surface-water withdrawal data were provided
by four of the five major plantations. Withdrawal
estimates were generated for the fifth plantation by
comparing withdrawal data from a_ neighboring
plantation using similar irrigation methods to grow
sugarcane. The analysis showed for a plantation
irrigating 4,740 acres of sugarcane, using drip-
application methods for 95 percent of the acreage, the
withdrawal was about 8,685 (gal/acre)/d. Using this
value, a withdrawal of 23.81 Mgal/d was estimated to
irrigate 2,742 acres of drip-irrigated cane. The total
surface-water withdrawals by other small self-supplied
users was estimated to be about 30 Mgal/d (R.M.
Towill Corp., 1992) for an unknown amount of
acreage, although the area is probably at least 1,500
acres. Some of these smaller operations were growing
taro, which requires a tremendous amount of water, an
estimated 47,000 (gal/acre)/d (University of Hawaii
Tropical Agriculture Experimental Station, K. Gooding,
oral commun., 1992) for the wetland variety. The total
surface-water withdrawals for irrigation were estimated
to be 224.04 Mgal/d for 1990. Subtracting conveyance
losses comparable to those estimated for the public-
supply system of 15 percent, the estimated surface-
water use was 190.43 Mgal/d.

Some differences exist regarding the amount of
irrigated acreage. HSPA data for 1990 showed 19,264
acres of drip-irrigated sugarcane, 8,837 acres of furrow-
irrigated sugarcane, and 10,019 acres of unirrigated
sugarcane. These numbers included 4,337 acres that

were fallow. Using a GIS and digitizing the field maps
from the five plantations the following acreages were
calculated in this study: 18,637 acres of drip-irrigated
sugarcane; 9,414 acres of furrow-irrigated sugarcane;
12,229 acres of unirrigated sugarcane; 225 acres of
drip-irrigated macadamia nuts; 318 acres of unirrigated
macadamia nuts; and 5,008 acres of drip-irrigated
coffee. The difference between the HSPA and GIS-
calculated numbers is probably because some field
maps did not represent 1990 plantings. However,
because the difference in irrigated acreage estimated by
GIS was only about 5 percent compared with the
HSPA totals, the following analysis is valid for
estimating plantation irrigation withdrawals.

The probable irrigation requirements on plantations
where only sugarcane was being cultivated can be
estimated by using mean annual pan evaporation data
(Ekern and Chang, 1985) (fig. 10) and a sugarcane
irrigation application rate equal to a pan coefficient of
1.2 (Michael Furukawa, Vice President and Manager
Lihue Plantation, Kauai, oral commun., 1992). This
analysis showed calculated application amounts
(column A) were within 16 percent of the withdrawal
amounts reported by the plantations (column B) (table
2). Considering that unaccounted-for water such as
conveyance losses, estimated at 15 percent throughout
this study, needs to be subtracted from the amount of
water withdrawn to represent the actual applied
irrigation amount, this method of irrigation and
withdrawal estimation seems to be an accurate
technique.

Table 2. Estimated sugarcane irrigation requirements, island of Kauai, 1990

[GIS, geographic information system; HSPA, Hawaiian Sugar Planters’ Association; pan, mean annual pan evaporation;
Mgal/d, million gallons per day; (gal/acre)/d, gallons per acre per day]

(A) (B) 1990
Estimated need 1990 estimated
(pan X 1.2) withdrawal irrigation GIS area HSPA area Water use
Plantation (Mgal/d) (Mgal/d) (Mgal/d) (acres) (acres) [(gal/acre)/d]
1 58.48 67.76 57.60 8,450 8,413 6,847
2 68.53 81.49 69.27 9,933 7,933 8,732
3 38.63 41.96 35.67 4,705 4,740 7,525
4 22.51 25.25 21.46 2,831 2,742 7,826

Note: The 1990 estimated irrigation values are determined

by subtracting 15 percent from the withdrawal value as a

representation of conveyance loss. The values for water use are determined as the estimated irrigation value
divided by the HSPA area. No calculations were made for plantation 5 because withdrawal data were not

available for comparison.

13


CONTENTS

Abstract .... 1
Introduction 1
Purpose and scope .. 1
Acknowledgment: 3
Study area 3
Economic setting 3
Water USC ........seeeeeeeee 3
Offstream use....... 3
Public supply. 3

Domestic ... 6
Commercial 6

Industrial ... 7

Mining.... 7

Livestock 7

Irrigation 7
Thermoelectric power 15

Instream use—hydroelectric power generatio! 15
Miscellaneous use... 15
Wastewater treatment 15

Recycled water. 15
Consumptive use 15

Water withdrawals by aquifer-system area . 18
Comparison of water use, 1980 and 1990 18
Summary and conclusions 23

References cited ...........

FIGURES

1-2. Maps showing:
1. Hawaiian islands and island of Kauai .
2. Mean annual rainfall, island of Kauai .
3. Locations of public-supply wells and reservoir, island of Kauai, 1990 . .
4. Pie diagram showing percentages of public-supply deliveries, island of Kauai, 1990 00.0...
5-13. Maps showing:
5. Areas of plantation agricultural fields, island of Kauai, 1990.. 8

6. Types of agricultural fields and irrigation, eastern Kauai, 199 9
7. Types of agricultural fields and irrigation, southern Kauai, 990 . 10
8. Types of agricultural fields and irrigation, southwestern Kauai, 1990 11
9. Types of agricultural fields and irrigation, western Kauai........... 12
10. Mean annual pan evaporation, island of Kauai 14
11. Locations of wastewater-discharge sites, island of Kauai, 199 16
12. Diagram of recycled water, island of Kauai, 1990 17
13-14. Maps showing:
13. Mean annual pan evaporation and areas of plantation agricultural fields,
island of Kauai, 1990 19
14. Aquifer-system areas, island of Kauai, 1990 20

iii


Table 4. Estimated water use, island of Kauai, 1980 and 1990
[Values are in million gallons per day. 1980 use from Nakahara, 1984]

1980 use 1990 withdrawal 1990 use

DOMESTIC

ground water 5.44 9.97 8.62

surface water 0.46 0.32 0.27

total 5.90 10.29 8.89
COMMERCIAL

ground water 4.81 5.63 4.88
INDUSTRIAL

ground water 17.76 0.49 0.42

surface water 11.48 6.34 5.39

recycled water 5.11 23.30 23.30

total 34.35 30.13 29.11
AGRICULTURE

ground water 45.49 19.22 16.34

surface water 240.52 224.17 190.54

recycled water 54.21 46.20 46.20

total 340.22 289.59 253.08
THERMOELECTRIC

ground water 5.16 10.98 9.33

surface water 5.93 0.00 0.00

saline water 10.79 40.94 40.94

total 21.88 51.92 50.27
HYDROELECTRIC 100.38 93.72 93.72
TOTALS

ground water 78.66 46.29 39.59

surface water 358.77 324.55 289.92

saline water 10.79 40.94 40.94

recycled water 59.32 46.20 46.20

Note: The recycled water listed under industrial and agriculture includes water that was recycled more than once. To avoid
double accounting, the total amount of water recycled is 46.20 Mgal/d (million gallons per day), see figure 12. Of the
water withdrawn for hydroelectric power generation, 93.72 Mgal/d, 65.32 Mgal/d was returned directly to the streams
and ditches available for other uses. The values in the use column, where different from withdrawal values, account
for conveyance losses. The industrial category includes mining and the agriculture category includes livestock.

22


U.S. DEPARTMENT OF THE INTERIOR
BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY
Gordon P. Eaton, Director

Any use of trade, product, or firm names in this publication is for
descriptive purposes only and does not imply endorsement by the
U.S. Government.

For sale by the U.S. Geological Survey
Earth Science Information Center
Open-File Reports Section

Box 25286, MS 517

Denver Federal Center

Denver, CO 80225

For additional information
write to:

District Chief

U.S. Geological Survey

677 Ala Moana Blvd., Suite 415
Honolulu, HI 96813


22° 10°

22° 05"

22° 00°

| E FURROW-IRRIGATED
SUGARCANE FIELDS

DRIP-IRRIGATED SUGARCANE

FIELDS

[|] UN-RRIGATED SUGARCANE
FIELDS

O 1 2 MILES

2 KILOMETERS

Base digitized from U.S. Geological Survey
1:24,000 topographic quadrangles for the
island of Kauai

Figure 6. Types of agricultural fields and irrigation, eastern Kauai, 1990.


159° 40°

22° 10'

22° 05)

22° 00°

EXPLANATION

FURROW-IRRIGATED

SUGARCANE FIELDS

DRIP-IRRIGATED SUGARCANE

FIELDS

[_]  unarricaten sucarcane
FIELDS

Base digitized from U.S. Geological Su
1:24,000 topographic quadrangles for the
island of Kauai

Figure 9. Types of agricultural fields and irrigation, western Kauai, 1990.

12