AIM: To explain ways in which fresh water is naturally stored as a resource and predict the effects of depletion of an aquifer.

Do Now: Where do we get our water from? Where is our water stored naturally?

HW: Article and Questions #3 due Friday

Water can be stored two ways

1. Dams- rivers and rain runoff

2. Reservoirs- rain runoff, streams, underground sources

Surface Water• Water that is above the ground- does not

seep into the ground– Ex: streams, lakes, ponds

• Runoff– Water that does not seep into the ground-

flows down a slope over land.– Melting snow and glaciers, rainfall– Rills- shallow grooves that runoff carves

into the ground• If deepen and connect, form larger

streams that open into lakes, ponds or oceans

Surface water

Rills

Groundwater-

Some seeps into the ground

between the soil and the bedrock (if

porous)

Runoff

Water table

top of the saturated layer of rocks

Aquiferlayer of saturated rock

• Also called the zone of saturation- the saturated rock layer beneath the water table

• Zone of aeration- where the water enters• Zone of discharge- where the water

leaves• How the water moves depends on

–amount of precipitation–porosity of rocks–slope of aquifer

Overdraft• when a body of water is

drained faster than it is filled

• often times due to an increased demand for water.

• Causes saltwater to intrude into the freshwater making unpotable water

• Subsidence- removing the water weakens the bedrock causing it to sink

Saltwater Intrusion

Ogallala Aquifer

• largest aquifer in the world

• Texas, Colorado, Nebraska, Oklahoma, Kansas, Wyoming, South Dakota, and New Mexico

• Large amount used for agriculture

• Overdraft is occurring due to dry climate

1. What is surface water?

2. What are some sources of surface water?

3. What is runoff?

4. How does groundwater accumulate?

5. What is another name for an aquifer?

6. What determines the rate at which an aquifer moves?

7. What is overdraft?

8. What problems result from over draft?

1. Above ground in streams, lakes and ponds.2. rainfall, melting snow, glaciers, ice sheets3. Water that does not seep into the ground.4. Water that does not runoff seeps through the spaces

between soil particles. If the bedrock is porous or has cracks, the water seeps into the bedrock.

5. The zone of saturation.6. Amount of precipitation, how porous the rocks are,

slope of the aquifer.7. When a body of water is depleted faster than it is

refilled.8. Weakening of the bedrock due to a drop in water

pressure in the aquifer causes subsidence. A drop in pressure also causes salt water intrusion in aquifers near coastal areas.