geo final

Watershed

“drainage basin” channels rainfall, snowmelt, and runoff into a common body of water, system of water that all comes together

Discharge

How much water is flowing in a certain amount of time

Sediment load

How much deposit is being claimed by the stream

Braided streams

Has too much sediment load

Straight Stream

Straightest path between two points

Meandering stream

Inner moves slower than the outer current

What causes floods?

Heavy rain/percipitation, Melting snow, storm surges, dam & Levee failure

Where does flooding naturally occur?

Floodplains, Rivers changing course

Small floods

are more common than large floods

“100 year flood”

1 in 100 chance this flood occurs

Flash floods (and safety)

Localized, Sudden onset of flooding caused by high precipitation (move to high ground)

Regional floods

Long-term high rain or snow melt over large areas/ regions

Catastrophic floods

Lake Missoula

Floodplains and building location

Stream channelization

Advantages and disadvantages of channelization

Levees

Advantages and disadvantages of levee construction

Dams

Urbanization and flood water runoff

How does urbanization change flooding?

Where are mass movements likely to occur?

How gravity and friction govern mass movements

(Mass movement section) Effects of water

Strength of Geologic Material

(Identifiable features of landslides) Head scarp

Creep

Landslide

(Identifiable features of landslides) Head

(Identifiable features of landslides) Toe

Slumps

Transitional slides

Rock falls

Debris flow

Mudflow

Subsidence

Mitigation Efforts: Building practices

Retaining walls

Channel or Direct flows

Slope armoring, slope protection (shotcrete, etc.)

Catch fences

Reducing slope steepness (slope grading, cut-and-
fill)

Controlling drainage