Chapter 11, Section 1: Water Resources

Standards: SEV5e

The Water Cycle The same amount of

water had been on the planet for billions of years.

The water you drink today is the same water dinosaurs drank!

Water is a renewable resource that is recycled through the water cycle.

The Water Cycle Evaporation

Water evaporates when heated by sun (leaves salts behind)

Transpiration- water evaporation from plants

Condensation As water vapor rises it cools,

condenses, and collects on dust particles in the sky (condensation nuclei) and forms clouds.

Precipitation When clouds get too full of water

they drop it as precipitation

Infiltration and Runoff Water either

Infiltrates the soil- pass slowly through soil to recharge an aquifer

Runs off into a nearby lake or stream.

How much water is on Earth? 97% is saltwater in

oceans & saltwater lakes.

3% is freshwater

2% frozen in ice caps & glaciers (unusable)

1% groundwater & surface water (usable)

How is our usable water distributed? Surface water

Groundwater

What is surface water? Fresh water above

ground.

Important for

Drinking water

Transportation of goods via ships

Irrigation

Aquaculture

Power for industry

What are the types of Surface Water? Rivers & streams

Fast moving Cold, highly oxygenated Insect larvae, trout, long narrow

plants, algae

Lakes & ponds Slow moving Warm, less oxygenated Bass, catfish, cattails, leeches

Wetlands Covered with water most of the

year Absorb and slow water flow Filter pollutants & sediment Provide breeding ground for

water birds, shellfish, fish

What is a river system? Streams form in higher

elevations from rainfall or melting snow.

As they move downhill they combine with other streams to form rivers.

Streams that feed rivers are called tributaries.

This interconnection of streams to form rivers is the river system

Ex: McEachern creek flows to Noses Creek to Sweetwater Creek to Chattahoochee River

Lake Lanier

West Point

Lake

Walter F.

George

Lake

Lake

Seminole

Apalachicola

River

Flint River

Chattahoochee

River

What is a watershed?

Area of land that drains into a stream/river.

Pollution anywhere in the watershed could end up in that river.

We live in the Chattahoochee River watershed

What is groundwater Fresh water stored

underground in aquifers

Most fresh water resources are stored here

Aquifer- area underground with rocks & gravel that have spaces where water can accumulate.

What is the water table? Top layer of water in

aquifer where soil is saturated.

In wet regions the water table may reach surface and create a natural spring.

If aquifer is confined by layer of rock may be under pressure and squirt out of ground as artesian well

In desert regions water table is usually very deep.

Ogallala Aquifer One of the largest in the world. Supplies 1/3 of groundwater used in

the U.S. Used mostly for irrigating crops. Now being used at increasing rate

(faster than can be recharged) Water table has dropped 100 ft in

some places of Ogallala. Wetlands rely on water table of

Ogallala where it comes to surface. If water table decreases, wetlands

dry out, water birds (sandhillcranes) lose feeding & breeding site.

Farmers are trying to limit their use by switching to crops that require less water (wheat & sorghum)

What factors affect aquifer recharge rate?

Porosity Percentage of total volume of a

rock that has spaces Water is stored in these pore

spaces More porous the rock, the more

water it can hold.

Permeability Ability of rock or soil to allow

water to flow through it. Sand- high permeability- lets

water flow through quickly. Clay- low permeability- holds

water so it flows slowly. Limestone, sandstone are

permeable materials that often form aquifers.

How does an aquifer recharge? When it rains, water

percolates through region of soil called recharge zone.

Recharge zone is determined by what is on surface of soil above Buildings, parking lots

reduce recharge zone Pollution can contaminate

recharge zone & contaminate aquifer.

Can take 10’s of 1,000’s of years to recharge

How do wells impact groundwater sources? Well- hole dug/drilled to

reach groundwater Well water is filtered by soil

before it reaches aquifer-relatively clean. (usually filters are added on the pump that draws the water up)

Must reach way below the water table b/c water table changes seasonally.

If water is pumped out quickly it will create a cone of depression that may prevent other wells from reaching water.

You should be able to… Describe the distribution of water on Earth. Where is

most of the freshwater located?

Explain why fresh water is considered a limited resource.

Explain why pollution in a watershed poses a potential threat to the river system that flows through it.

Describe how water travels through rocks and soil.