Water is one of our most important and necessary natural resources. Without water, there would be no life on earth. This fact makes water quality a huge concern. Hydrology is a science in response to the need to understand the complex water system of the earth and help solve water problems. Hydrologists are the scientists who are in the trenches playing a vital role in finding solutions to water problems.
How much water do we use? Using data from the year 2000 by the United States Geological Survey, the United States withdrew 408 billion gallons of water per day (Bgal/d) for all uses. The two largest uses are thermoelectric power and irrigation. Fresh ground-water withdrawals were 83.3 Bgal/d and fresh surface- water withdrawals were 262 Bgal/d in 2000. There is a lot of hidden water use that we normally do not think about. Think about what you may have for lunch. A hamburger requires water to raise wheat for the bun, to grow hay and corn to feed the cattle and to process the bread and beef. If we add French fries and a soft drink, this all-American meal uses about 1,500 gallons of water – enough to fill a small swimming pool. How about what you wear? To grow cotton for a pair jeans takes about 400 gallons of water. Same amount of 400 gallons for a shirt. To produce the amount of steel in a car that takes you to school or the mall requires about 32,000 gallons of water. A 30 pound bicycle requires 480 gallons.
The hydrologic cycle or water cycle was one of the first articles in this series. Earth’s water is finite. Water is not created or manufactured, it is recycled. There is a continuous cycle of water coming down as rain or snow. It can be collected in rivers and oceans. It can seep down into the aquifers of the earth. It can be part of our polar caps. The water eventually evaporates back to the atmosphere and then returns as rain or snow. This process of recycling is also treating and purifying the water for safe use.
Hydrologists are instrumental in studying this water cycle and identifying any problems. Problems can be quantity of water, quality of water, and availability of water. During years of drought, quantity of water can be a huge concern for farmers, industry, and highly populated regions. We know water can be contaminated by run-off from agricultural fields, industrial waste, and human waste. The natural purification of water through wetlands and seeping through the soil can only handle so much contaminated water. Hydrologists can help by detecting problem areas through field investigations. This field work includes collecting basic data, overseeing testing of water quality, directing field crews, and working with equipment. By knowing what the problem is, they can provide possible solutions to deal with improving water quality.
Withdrawal of water for use comes from two basic sources - surface water and ground water. Most cities meet their needs for water by taking it from the nearest river, lake, or reservoir. Hydrologists assist cities by collecting and analyzing the data needed to predict how much water is available and whether it will be sufficient to meet the city’s future needs. Managing a reservoir can be a complex process. A reservoir normally serves several purposes. They increase the reliability of local water supplies. Deciding how much water to store and how much to release depends on the time of year and the weather conditions. More may need to be released during times of irrigation and for downstream use such as hydroelectric power and recreation. In a year of ample rain and snow, reservoir management is somewhat easier. In a year of drought, management of storage and release is much more crucial. Surface water is also more susceptible to pollution than ground water.
Ground water is commonly used for public water supplies. It also provides the largest source of usable water storage in the United States. Underground reservoirs contain far more water than the capacity of all surface reservoirs and lakes, including the Great Lakes. Hydrologists can again assist by estimating the volume of water stored underground and determine the most efficient pumping rate to avoid over pumping the aquifer.
Before the increase of earth’s population by man and man’s use of water for irrigation and industry, Mother Nature was able to keep up with purifying earth’s fresh water. In 2014, it is becoming more and more of a concern to understand the water cycle and use our knowledge to protect the quality of our water. It is not a doomsday situation, but it is an issue we need to be aware of as earth’s population increases and the demand on earth’s resources increases.