Streams (Rivers)

Runoff:• H20 that does not sink into ground

• Most ends up in streams

• How much, depends on terrain + amount of precip.

Assume same precipitation for both. Which place would have

More runoff?

Assume same precipitation for both. Which place would have

More runoff?

Assume same precipitation for both. Which place would have

More runoff?

People can increase runoff by:• Removing vegetation

(road building, bad farming, clear cutting)

Clear cut forestin Canada

• Building large parking lots/buildings

Silt fence Water retention pond

Extra runoff can lead to:• Loss of top soil

• Aquifers not being replenished (wells going dry)

• Flooding downstream

Load:• Sediment carried by water

• Faster moving water carries more load

3 main types of load:1. Dissolved: minerals like NaCl

2. Suspended: silt, clay (makes water look muddy)

3. Bed: sand, gravel

Bed

Dissolved Suspended

Types of streams:1. Meandering streams: on low slopes, fine sediment

Point bar: sediment deposited in slow water

Cut bank: where sediment is carried away in fast water

Draw and label

fast slow

fast

slow

slow

fast

Oxbow lake: remnant of stream

2. Braided streams: bars and islands in middle

3. Mountain stream: steep slope, no floodplain, straighter

Drainage basin:• area drained by a stream

Divide:• separates basins• Ex.: Rocky Mnts. called Continental Divide

North Carolina river basins

Tributary:• smaller stream that empties into a larger one

Canyon formation:• River cuts down as land is uplifted

Uplift of the Colorado Plateaus forced rivers to cut down faster

Stream Deposition:erosion load deposition

produces produces

Delta:• Sediment deposition when stream reaches its base

level

Alluvial fan:• deposition when a stream flattens out

Stream discharge:• Volume of water flowing in m3/s (or cfm)

Floodplain:• Land next to stream that floods periodically

Dealing with floods has its problems.

1. Levees:• ridges (natural or artificial ) that contain a stream

2. Channelizing can:• Create flooding downstream• Increase erosion• Warm water by removing trees

• Trap river organisms

• Trap sediment

• Expensive

• Flood land upstream

3. Dams: