The estimated total quantity of freshwater withdrawn on the island of Kauai, Hawaii, in 1990 was 370.84 million gallons per day of which 46.29 million gallons per day (12 percent) was from ground-water sources,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 An additional estimated 40.94 million gallons per day of saline water was withdrawn for thermoelectric power generation.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.