Click here for an animation The Water Cycle                                               Click here for an animation

Increase in runoff with urbanization Decrease in infiltration

Groundwater Groundwater is simply water under the ground where the soil is completely filled or saturated with water. This water is also called an aquifer.

Groundwater moves underground from areas where the elevation is high, like a hilltop, to places that are lowland areas. Water movement is slow and might move anywhere from less than a millimeter up to a mile in a day.

Groundwater Where the water table meets the land surface, a spring might bubble up or seep from the ground and flow into a lake, stream, or the ocean.

Groundwater Ground water that meets the land surface also helps keep rivers, streams, lakes and wetlands filled with water.

Zone of Aeration: area where the pore spaces in the rock/soil are empty of water Water Table: boundary between zone of saturation & zone of aeration; wells must go below the water table to reach water Zone of Saturation: area where the pore spaces in the rock/soil are filled with water

Porosity and Permeability Permeability: how quickly water can travel through a material Porosity: the percent of a material’s volume that is pore space

Groundwater

Dangers Associated with Groundwater

Effects of Over-Pumping a Well

Sinkholes from groundwater overpumping, Antelope Valley, CA Dust storm during Dust Bowl in Kansas, when overpumping from wells & a drought caused farmers to ‘overspend’ the water budget Sinkholes from groundwater overpumping, Antelope Valley, CA

CONTAMINATED?!

Caves Limestone is a common bedrock that dissolves more easily than some types of rock. The carbonic acid found in groundwater dissolves the calcite found in limestone, increasing the porosity of the limestone that remains.

Caves Over time as more and more water flows through cracks in the limestone bedrock, the carbonic acid dissolves the limestone and carries it away in solution. After thousands of years, these cracks become larger eventually forming a network of underground tunnels. These caverns, or caves can be many miles long and hundreds of feet deep.

Cave Formations When water drips from the roof of a cave, calcite is deposited. Slender deposits called stalactites hang like icicles from the roof. On the cave floor beneath the stalactites, a rounded mass called stalagmites form. When they meet, a column is formed.

Entrance to Mammoth Cave National Park-Kentucky

Soda Straws

Helictites

Chandeliers

Flowstone is sheet-like which includes draperies/curtains.

Cave “Bacon”

Luray Caverns, VA Observe an animation of cave formation.

Karst Topography They are regions characterized by caves, sinkholes, lost rivers or sinking streams, and underground drainage caused by the dissolution of soluble rock.

Karst areas of the U.S. shown in green.

Development of Karst Topography Step 1: Acidic groundwater dissolves limestone. Then the water table drops, leaving empty caves. Step 2: Ground above the caves is eroded away. Step 3: Thin rock above the cave collapses, creating a sinkhole.

Winter Park, FL

Sinkhole, Shenandoah Valley, VA

Because rainwater drains through sinkholes, there are few surface rivers in Karst regions.

Lost or sinking streams form when the surface stream disappears underground and flows out of a cave many miles away.

Watershed :The geographic land area on which runoff water from precipitation gathers and flows into a single body of water. Precipitation: falling products of condensation within the atmosphere.

Four types of Precipitation: Rain, sleet, hail, snow.

Freshwater accounts for only 3% of Earth's total water Freshwater accounts for only 3% of Earth's total water. Freshwater is stored as ice, in lakes, ponds, rivers, and streams.

Wetlands are areas where the ground is saturated and water is apparent Wetlands are areas where the ground is saturated and water is apparent. They are sometimes characterized as swamps, mashes, or bogs.

Rivers and streams are flowing bodies of water Rivers and streams are flowing bodies of water. A river’s source is often referred to as headwater, which may be a glacier, pond, lake, or a spring.

A delta is a fan-shaped pattern of sediment that has been deposited by freshwater flowing into the ocean.

Why is too much nitrogen and phosphorus bad for the environment???

Too much nitrogen and phosphorus can lead to eutrophication – out of control algal growth as a result of too many available nutrients.

Eutrophication leads to a loss of oxygen and the death of more complex organisms such as fish and crustaceans.

pH (percent hydrogen) – a measure of how acidic or basic a substance is. The ocean is slightly basic and most organisms require a pH range of 6.5 to 8.0.

Riparian vegetation– type of vegetation along the banks of a freshwater body.

Turbidity– measure of how cloudy or clear water is Turbidity– measure of how cloudy or clear water is. Turbidity is measured using a secchi disk.