Runoff is water that doesn’t soak into the ground or evaporate, but flows across earth’s surface

Factors that affect runoff1.Amount of rain2.Length of time Light rain over an hour has time to soak up

Heavy rain over less than an hour will run off because it can’t soak into the ground fast enough

3. Slope of land Gravity causes water to move down slope Water moves quickly down steeper

slopes Water moves slowly down gentler slopes Slower movement=water soaked up by

ground4. Vegetation Plants slow down runoff and help prevent

soil from being carried away Runoff will carry more soil and sediments

in places lacking vegetation

Streams are parts of river systems Can compare to a tree Water comes from rills, gullies and small

streams Drainage basin is the area of land from which a

stream or river collects runoff All the water in a river system flows to the

trunk (main river)

Stages depend on the slope of the ground over which the stream flows

3 classifications:1.Young2.Mature3.Old The stages of development do not always coincide with the actual age of the river

Flows swiftly Slope is steep Has a rough bottom High level of energy Erodes bottom of stream faster than its side

Flows smoothly through its valley Rocks in the streambed over time are eroded by running water and sediments

Erosion takes place more on the sides than the bottom

This causes curves to develop called meanders

Flow through broad, flat floodplains Drops load of silt near its mouth Dropping of sediments forms a delta A delta is an area of flat, fertile land extending into the ocean

As water moves through a river system it loses energy

This lose of energy causes sediments to be dropped along the way

Some sediments are carried a long way, while others only short distances

When sediments are deposited as the water empties into an ocean or lake, a deposit called a delta forms

Deltas are triangular or fan-shaped

When a river empties from a mountain valley into a flat plain, the deposit is called an alluvial fan

Water that soaks into the ground collects in the pores and empty spaces in the soil or rock is called groundwater

14% of all water exists as groundwater Groundwater system has connecting pores

Soil and rock are permeable if pores are connected and water can pass through them◦Water flows easily through◦Ex: sandstone-permeable rock

Impermeable rock or soil doesn’t have well connected pores or few pore spaces◦Water doesn’t flow easily through◦Ex: granite, clay

Groundwater keeps going deeper into Earth’s crust until it reaches a layer of impermeable rock

Zone of saturation is where all the pores in the rock are filled with water

The upper surface of this zone is the water table

The amount of groundwater is limited Many people get their water from wells that have been drilled into the zone of saturation

During a draught, the water table drops This is why it is important to conserve water

A good well extends deep into the zone of saturation

Groundwater flows into a well and a pump brings it to the surface

If water is taken out of well faster than it can be replaced, wells can go dry

If too much water is pumped out in area, the land can drop or sink

Artesian well-doesn’t need a pump to bring water to the surface

Water in an artesian well rises to the surface due to pressure

Artesian wells are very rare because the aquifer needs to be located between 2 impermeable layers that are sloping

Water enters at the high part of the slope and exits through a well at the low part of the slope due to the pressure created by the higher part of the aquifer

Springs are found on hillsides where the water table meets a sloping surface

Water flows out of the spring Source of freshwater Usually water comes to the surface as a cool temperature

When water comes to the surface after being heated by hot rocks, it is called a hot spring

Is a hot spring that erupts periodically Groundwater is heated to high temperatures causing it to expand underground

The expansion forces some of the water out of the ground

Most of the water turns into steam Ex: Old Faithful, Yellowstone National Park

1. Groundwater mixes with carbon dioxide to form carbonic acid (weak)

◦ CO2 is absorbed by groundwater in the soil

◦ CO2 is absorbed by rainwater from the air

2. Acidic water flows through rocks, dissolving the rock (limestone)

3. Cracks in the limestone get bigger until an opening is formed. This is called a cave!

Stalactites form from deposits of calcium carbonate.◦Water dripping inside the cave has calcium

ions dissolved in it◦This water evaporates and deposits calcium

carbonate.◦When this happens over and over stalactites

form. Stalagmites form when the drops of water

fall to the floor of the cave A sinkhole is a depression on the surface

of the ground that forms when the roof of a cave collapses or when material near the surface dissolves

3 forces shape shorelines1.Waves Crash against the shorelines Very powerful force Erode and move away large amounts of material

2.Currents Longshore currents are created by waves that hit at a slight angle

Carry tons of loose sediments3.Tides Outgoing tides carry sediments away from the shore

Incoming tides bring new sediments to the shoreline

Work with waves to shape shorelines

Rocky Sandy

Consist of rocks and cliffs

Waves and sediments slowly wear away rocks

Rock parts that break off are carried away by longshore currents

Smooth, gently sloping beaches

Made up of grains of quartz or shell fragments

Fragments range from stones to fine sand

Some beaches have different colored sands

Ex: Hawaii-black, made of basalt

Ex: Jamaica-white, made of coral and shell

Are sand depositions that lay parallel to the shore but are separated from the mainland

Start out as underwater sand ridges Hurricanes and waves help form the islands

Last only a few years to a few centuries Storms and waves also erode the barrier islands and cause erosion to beachfront developments