Water-Use Categories

Public Supply: Water withdrawal by public and private water suppliers and delivered to groups of users.

Power Generation: 98 percent of the island's electricity is generated by the Puerto Rico Electric and Power Authority. This company is the sole distributor of electric power on the island, with about 4.397 gig watts of installed capacity in 2000.

Thermoelectric Power water use includes the amount of water used in the production of electric power generated with fossil fuel. Fossil fuel includes coal, oil, and natural gas. Oil is the dominant fuel in Puerto Rico's energy mix, accounting for 97.7 percent of total primary energy consumption. Puerto Rico has four thermoelectric power plants that are fossil-fuel power generation facilities. These facilities are Central Costa Sur in Guayanilla, Central San Juan in San Juan, Central Aguirre in Salinas and Central Palo Seco in Cataño. In 1999, about 16.76 billion kilowatt-hours of electricity were generated in Puerto Rico, nearly all from oil-fired generators.

Water withdrawn requirements at fossil-fuel power generation facilities depend primarily on whether or not the cooling water is re-circulated. Once-through cooling requires the largest amounts of water withdrawal because it is not re-circulated within the facility. In 1995 about 2,260 million gallons per day (Mgal/d) of saline water were used for cooling processes in the four thermoelectric power generation plants throughout the Island.

Hydroelectric Power water use: use is an instream use of water in Puerto Rico. There are ten active hydroelectric power generation plants in the Island, these plants have to be grouped in five individual systems. The systems are grouped as follows: (1) Dos Bocas and Caonillas 1 and 2 (Adjuntas, Utuado and Arecibo); (2) Garzas 1 and 2 (Adjuntas); (3) Toro Negro 1 and 2 (Orocovis and Ciales); (4) Río Blanco ( Naguabo); (5) Yauco 1 and 2 ( Adjuntas, Maricao and Yauco) . These dams generate about 300 million kwh of electricity, and use about 350 Mgal/d of instream freshwater.

Irrigation: The application of water on lands to assist in the growing of crops and pasture toor maintain vegetative growth in recreational lands. Surface-water withdrawals for irrigation use consist of four major irrigation systems: the Guayama and Juana Díaz Irrigation District on the south coast; the Valle de Lajas Irrigation District in the southwest; and the Isabela Irrigation District in northwestern Puerto Rico.

Industrial Water Use: Includes water used to manufacture and package products. Water used for for industrial purpose may be incorporated into products or used for processing, washing, cooling or facility restrooms and maintenance. The five major industrial groups that use the most water per facility are classified according with the standard industrial classification (SIC) codes which are four digit codes established by the Office of Management and Budget and used in the classification of establishments by type of activity in which they are engaged. They are:

• SIC 20 - Food products.
• SIC 26 - Paper products.
• SIC 28 - Chemical products.
• SIC 29 - Petroleum.
• SIC 33 - Metals.