Surface Water and Groundwater Fusion Text: Pages 30-38
Where on the Earth is fresh water found? • On the Earth’s Surface (Surface Water) • Beneath the Earth’s surface (Groundwater)
On the Earth’s Surface (Surface Water) • Streams, Rivers, and Lakes. • Comes from precipitation or fresh water streams (springs). • Water that flows across the Earth’s surface is called runoff. Runoff can enter streams, rivers and lakes.
Beneath the Earth’s Surface (Groundwater) • Water drains down through the soil because of gravity and collects in the spaces between rock particles. • Most drinking water in the U.S. comes from drilling wells down into the water table or aquifers. • The water table is the upper boundary, or surface, of a location’s groundwater.
How does water move on the Earth’s surface? • Precipitation hits the Earth and flows from high to low ground forming streams. • Streams erode rocks and form channels. • Channelsare paths that streams follow. • Tributaries are small streams that feed into river systems. • A river system is a network of streams and rivers that drain an area of runoff called a watershed.
Watersheds • A watershedis an area of land that is drained by a river system. • Watersheds are separated from one another by a ridge or an area of higher ground called a divide. • A large part of Pennsylvania lies within the Chesapeake Bay Watershed. http://techalive.mtu.edu/meec/demo/Watershed.html
Rivers and Streams • Gradient describes the steepness of the ground that a stream or river runs down. • Steep gradients, rainstorms and rapid snow melt increase the flow rate of streams and rivers. • The flow rate is the amount of water that flows through a channelin a given amount of time. • The flow rate determines the stream load, or the size and amount of particles carried and deposited.
How does groundwater flow? • Water from precipitation or streams may percolate or seep below the Earth’s surface to become groundwater. • An aquifer is a body of rock or sediment that stores groundwater. • Recharge occurs when water seeps through the ground and enters an aquifer. • Discharge occurs when groundwater becomes surface water which pools to form wetlands or flowing as a spring. • Groundwater is also discharged where water is extracted from wells which are drilled into the water table.
How do people use surface water and groundwater? • Drinking and Home Use • Agriculture • Industry • Transportation and Recreation
Drinking and Home Use • Surface water and groundwater are both important sources of drinking water. • In a typical home, 50% of all water is used for washing clothes, bathing, washing dishes and flushing toilets. • About 33% of all water used is to water lawns and gardens. • The remaining 12% is used for drinking, cooking and washing hands.
Agriculture • 40% of the fresh water in the U.S. is used for growing crops and raising livestock. • These activities account for about 70% of all groundwater use.
Industry • Almost half of the fresh water used in the U.S. is used for industry. • Almost half of the water used in industry helps cool elements in power plants.
Transportation and Recreation • Surface water is used to transport products and people from place to place. • People use rivers, streams and lakes for recreation. • Water Skiing • Sailing • Swimming • Fishing