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How Hydrology Works


Water Supply Control and Pollution Control
Hydrologists continually search for ways to improve water treatment plants.
Hydrologists continually search for ways to improve water treatment plants.
Flip Chalfant/Getty Images

While the Earth still has the same amount of water it has always had, the demand for water is greater than ever. The population keeps growing, and everyone needs to be fed and clothed with materials that have to be grown using water. The same people need to live in houses built with steel, lumber, or other various building materials -- again, these materials take a large amount of water to manufacture or grow. Of course, people also have to bathe and wash their clothes and go to the bathroom … all of this

takes water.

You want to know the real kicker? Water doesn't fall evenly over the entire Earth. One place may get too much rain, causing floods and devastation, while another might get very little, causing a drought. Once the water goes down the drain, it takes a while for it to be processed back into something that can be used again. If there is not enough rainfall for your area and the population uses too much water, the reserve levels go down faster than they can be replenished.

Hydrologists are constantly looking for ways to find more water to keep up with current demands. Water treatment facilities take the water that has been used for waste and turn it back into fresh, local water that can be consumed again. Hydrologists not only look for ways to improve these facilities, they also try to find new underground wells of water and, perhaps even more importantly, figure out how to maintain these supplies with the ever-growing threat of pollution.

Pollution is industrial waste, emissions from cars, runoff of pesticides and animal wastes from farms, and extra nutrients in the soils that cause an imbalance. These can run into lakes, rivers and streams; seep into the groundwater; or collect in the air and fall back to the ground as acid rain. Mapping the course of these contaminants through environmental hydraulics is one way hydrologists help locate and clean

up pollutants.

Don Moseley, Director of Experimental Projects for Wal-Mart, shows off the absorbent asphalt in the parking lot of a new, more eco-friendly experimental Wal-Mart Super Store in Aurora, Colo.
Don Moseley, Director of Experimental Projects for Wal-Mart, shows off the absorbent asphalt in the parking lot of a new, more eco-friendly experimental Wal-Mart Super Store in Aurora, Colo.
Thomas Cooper/Getty Images

Another way is through innovations like permeable pavement materials. When rain falls, it sometimes contains pollutants. In places with a lot of people, like most cities, there also tends to be a lot of concrete. This washes out all of the pollutants on the road and puts them into the nearest sewer, drain system or river, which overflows with water and has no place else to go. Concrete is impermeable -- it won't allow water to pass through it into the ground. This poses a problem, because filtering the pollutants out with rocks and sand is the first natural water filtration system for our groundwater.

One answer to this problem may be permeable concrete. This surface allows water to pass through it, sort of like soil. It takes the pressure off of the sewage systems in urban areas where all of the water and waste have to drain during a big rain. It also helps with flood control as well as pollution control. The costs, however, are sometimes prohibitively high. Digging up streets and replacing the concrete is no small task. The best way to begin the process of permeable planning is to start during the planning phase of a project.

This is just one of the many ways hydrologists work to keep our ground water safe. Other hydrologists research pollution levels in snow, soil and even glaciers.

On the next page, find out how hydrologists can predict, and sometimes even prevent, floods.


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