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How Hydrology Works


Hydrologists
Leonard Malczynski, a hydrologist, software engineer and economist with Sandia National Laboratories, creates models using system dynamics to help water planners predict how different factors can alter use by consumers.
Leonard Malczynski, a hydrologist, software engineer and economist with Sandia National Laboratories, creates models using system dynamics to help water planners predict how different factors can alter use by consumers.
Andy Nelson/The Christian Science Monitor/­Getty Images

Hydrology is the study of the flow of water through the hydrologic cycle, and Hydrologists are the people conducting the research. While most people don't think much about water, hydrologists examine every aspect of it -- where it comes from and in what quantities, where it goes, how it gets there and what happens to it in the process.

To do this, they use a lot of math and some really cool gadgets, and they even get a little wet sometimes. The results are astounding. Hydrologists help designers and engineers construct dams and levees to keep towns safe from flooding, track pollution and find new water sources -- they even help track water

in space.

Because water is everywhere and is so critical to nearly everything we do, hydrologists span almost every branch of science, from physics and geology to astronomy and ecology. There are so many ways to study the Earth's waters; here are just a few.

Spatial hydrology is the study of the movement of the waters of the Earth through the hydrologic cycle using a spatial database developed in a geographic information system (GIS). This means that they try to connect the varying space that is the land with the varying time and flow that is the water

[source: Purdue University].

Hydrogeology, or groundwater hydrology, tracks the flow of water through the soil and into underground systems. Hydrogeologists help find underground sources of water (aquifers) that we can tap into for drinking water. They monitor these, as well as the flow of water into underground sites to determine how much is taken out. They also figure out how water flows through soil. This may sound boring, but if you're a farmer who needs the right amount of soil moisture to grow your crops, it's vital information. Hydrogeologists help with irrigation practices and monitor pollution that seeps down through the soil into our wells.

Vadose zone hydrology is a subset of hydrogeology that focuses on the layer of earth directly above an aquifer, called the vadose zone. This zone is important because it acts as a final filter and aeration device before rain becomes groundwater, which is sometimes taken straight from the ground through wells and used without purification methods. If the vadose zone is unhealthy, so is much of our drinking water.

Hydraulics has nothing to do with making your car do really cool tricks (well, it does, just not in this context). This is the study of the physical flow of water. Hydraulics professionals use mathematical modeling to track the flow of water from one source to another. The major purpose of this is to track not the water but contaminants in it. For example, if a factory is dumping industrial waste into a river, it will flow downstream and eventually get dispersed into the ocean. Who knows where it will end up? The people who study hydraulics do.

Hydrometeorology, also known as hydroclimatology, uses meteorological instruments to figure out how much rain will fall and in what specific areas. This is useful for many reasons -- not just so you know when to take your umbrella when leaving the house. Hydrometeorology can help determine how much water will reach one area in a given year. This helps with the building of flood-control devices and

irrigation systems.

In a form of science known as dendrohydrology, dendrohydrologists use tree rings to help determine historical rainfall and drought conditions, stream flow, runoff, and much more. Knowing this information can help regions without reliable historical records predict the hydrological future.

If the world's water supply contains the same amount of water today as it did in the beginning, then how is it possible to waste water? Won't it just come back? Why do people fight over water? Find out on the

next page.