Read the following passage.
Demand for Water in the United States
If all of the water in the atmosphere were to fall evenly as rain, the Earth would be entirely covered with one inch of water. But when it rains, it pours. Rain doesn't fall equally on everyone. Unusual weather patterns sometimes create long periods of droughts or disastrous floods. In the United States, the average annual rainfall is 30 inches, and most of the rain falls in the East. Less than 4 inches of rain falls each year on parts of the Southwest, while parts of the Pacific Northwest receive 200 inches a year.
The survival and success of a community frequently depend upon the water it can provide for agriculture and industry. Water has often become the limiting factor in the growth of communities. Although the eastern part of the United States is wet, water supplies are sometimes not sufficient to meet the demand. The high population density along the eastern coast puts great demand upon the region's water supply.
In poor tropical countries, where women must walk several miles for water, each person may use less than one gallon of water per day. It is estimated that Californians use about 100 to 200 gallons a day per person. During recent droughts in New Jersey and California, some residents were required to limit water use to 50 gallons per person per day.
Average Daily Water Use for a Family of Four
| Water Use | Gallons or Litres per Day | Per cent of Total Daily Use | |
|---|---|---|---|
| Gallons | Litres | ||
| Toilet | 100 | 380 | 39 |
| Bathing & Hygiene | 88 | 334 | 34 |
| Laundry | 35 | 133 | 14 |
| Kitchen | 27 | 103 | 11 |
| Housekeeping | 5 | 9 | 2 |
| Totals | 255 | 959 | 100 |
Our demand for water is great and it continues to grow. World water demand has grown faster than the population. Water use is nearly 50 per cent more per person than in 1950. Each day during 1985, nearly 1.3 trillion litres of water flowed through complex systems of pipes to homes, factories, farms and power plants in the United States.
Most water - 141 billion gallons per day - is used for agriculture. A large supply of water is necessary to produce the food that we eat. One hundred and twenty gallons of water is required to produce an egg for your breakfast. A steak for dinner requires 3,500 gallons.
Irrigated agriculture is the number one user of water in the western United States. In California, farmers use about 85 per cent of the available water supply. They grow about half the fruits and vegetables produced in the United States. In California, cotton, rice, and alfalfa rely most heavily on irrigated water. In Kern Country, a farmer can make seven cuttings of alfalfa in an irrigated field. Without water for irrigation, the fields may produce only one cutting.
The second major user of water in the United States is production of electricity at thermoelectric power plants. Power plants use 131 billion gallons of water per day, but 97 per cent of this water is returned to the lake or the river and is immediately available to be used again.
The chart below shows how water was used in the United States in 1985. The charts include only water that is withdrawn from a source. They do not include recreation, power generation, transportation or wildlife uses that do not remove water from the stream.
Daily Water Withdrawal Uses in the Entire United States – 1985
| Use | Litres per Day | Consumed | Returned |
|---|---|---|---|
| Agricultural | 534 | 54% | 46% |
| Thermoelectric | 496 | 3% | 97% |
| Domestic and Commercial | 118 | 20% | 80% |
| Industrial and Mining | 117 | 16% | 84% |