HYDROLOGY HYDROLOGY What has a bed but never

HYDROLOGY

HYDROLOGY What has a bed, but never sleeps? What has mouth, but never eats? What always runs, but never walks? What always babbles, but never talks?

HYDROLOGY • Water is possibly the world’s most important commodity. • Water makes life possible on any planet. That’s why we are always looking for water on other planets…where there is water, there is the possibility life.

HYDROLOGY • Water is nearly everywhere on earth. • Even in the desert, there are places we can find water. • How do things in the desert find ways to survive with so little?

HYDROLOGY • Water has a special property of being able to change state readily at natural conditions. • Such conditions are pressure and temperature.

HYDROLOGY • Water is constantly moving from one state to another because of this. • This constant movement is called the hydrological cycle.

HYDROLOGY • When water is drawn into the air from the lakes and oceans, it is called evaporation. • When water is drawn into the air from plants, it is called transpiration. • Over the course of a year, a field of crops transpire enough water to cover the field two feet deep!

HYDROLOGY • When water vapor condenses and falls from the sky, it is called precipitation.

HYDROLOGY • When the water meets the ground again, there are many things it does. • When it is absorbed into the ground, it is called infiltration. You were right, Jenkins. The water has infiltrated the cave! We’re going in!

HYDROLOGY • When the amount of rain exceeds the earth’s ability to absorb it, the water flows off the land into the rivers and other water bodies. • This is called runoff. • If too much rain falls too quickly, what happens?

HYDROLOGY • In very cold areas, water doesn’t always do this. • Since it is too cold, water might freeze on contact and become part of the ice and is stored.

HYDROLOGY • If the glaciers were to suddenly melt, the world water level would rise several dozen meters. • This would be enough to sink Manhattan and submerge most of Florida.

HYDROLOGY • This happening Is the plot of the popular Kevin Costner movie Water World.

HYDROLOGY • We say that the hydrological cycle is constantly balanced. • This is because there is always the same amount of water coming down as there is going up…so to speak.

HYDROLOGY • As we have discussed, water is always on the move. • For this reason, moving water is the single most important factor in sculpting the earth.

HYDROLOGY • Running water is very important to our planet and important to us. • Ancient Egyptians actually depended on floods to grow crops.

HYDROLOGY • The gradient is the way we describe the vertical change in a stream over a certain distance. • The greater the gradient, the greater a river’s velocity.

HYDROLOGY • When there is very little gradient, oftentimes meanders are created. • These are rivers with many bends and turns.

HYDROLOGY • As rivers flow, they rip away parts of the banks and floors, gouging the river deeper into the landscape by a process called erosion. • In meanders, this happens on the outside of a curve.

HYDROLOGY • The source area of a river is called its head. • The area where it flows to the ocean is called the mouth.

HYDROLOGY • As you might imagine, rivers can’t erode down into the earth forever. • They have to reach what is called base level. Ow…

HYDROLOGY • Sea level is considered the ultimate base level. • Lakes and other small bodies of water can be temporary base levels.

HYDROLOGY • Dams work by creating a gradient and using it. • They use the water’s natural movement to run a series of turbines which generate electricity. • Las Vegas is powered largely by Hoover Dam.

HYDROLOGY • Mineral deposits can be created based on how much energy the river has at a certain point. • As the stream loses energy, they drop off various minerals.