Rivers

Question 1

What are tributaries?

Answer 1

All of the small streams that flow into a large river

Question 2

Drainage basin/watershed

Answer 2

Area below a divide from which all water drains down into the same river system - the geographic area which supplies water to a network of streams

Where water collects for river (watershed)

Source from higher elevation basically

Question 3

Divide

Answer 3

High ground or ridge that separates two drainage basins

Question 4

Describe the three types of drainage patterns

Answer 4

Dendritic: resembles the veins of a leaf and can be found in areas where rock layers are of uniform hardness

Trellis: water flows in each fold, parallel to each other
(established in areas where folding and tilting of rock layers may confine rivers to parallel valleys that meet a larger stream at right angles)

Radial: occurs on cone shaped mountains (volcanoes) > water flows away from the high point equally in all directions

Question 5

Name and describe the four stages of a river

Answer 5

Youth/young: dominated by erosion and turbulent water (vertical erosion creates steep slopes)

Mature: meanders and floodplains start to take shape

Old age: widened floodplains and extensive meandering

Rejuvenated: land uplifts and river returns to a period of vertical erosion

Question 6

What features can you find at each of the river stages?

Answer 6

Youth/young: V-shaped valleys, gorges, waterfalls, potholes, canyons

Mature: start of floodplain, small meanders

Old age: wide meanders and floodplains, oxbow lakes, natural levees from flooding, deltas

Rejuvenated: River terrace (process starts again)

Question 7

Meander

Answer 7

Curve of a slow moving mature river

Question 8

Point bar (slip off slope)

Answer 8

Area of the river bank along which deposition occurs (those pile dumps of sediment, gently sloping)

Question 9

Nip (undercut bank)

Answer 9

The side of a meandering river where the water moves the fastest and greatest erosion occurs (the hard side)

Question 10

Levees

Answer 10

Natural mound of debris along a river bank created by flood waters (help hold flood water in the river channel)

Question 11

Dikes

Answer 11

Man made mounds designed to limit river flooding (artificial levees)

Question 12

Flood plain

Answer 12

Formed in lowland areas when the river has reached an elevation which is close to sea level

(Area along meandering river that is flooded when the river overflows its banks)

Question 13

Channel

Answer 13

Carries water from drainage basin to larger river/lake/sea/ocean

Question 14

Riverbed

Answer 14

Bottom of the channel (river floor)

Question 15

Riverbanks

Answer 15

Sides of the river

Question 16

Oxbow lakes

Answer 16

A crescent shaped lake formed when a river straightens by cutting through a meander

Question 17

River terraces

Answer 17

Part of an original floodplain that has undergone uplifting (now sits high above the river banks)

Question 18

What are the erosional actions of rivers?

Answer 18

Hydraulic action, abrasion (rubbing), attrition (hitting), corrosion

Question 19

What ways do rivers transport sediments?

Answer 19

Solution: dissolved materials are carried away by river water (looks invisible, but can have many soluble materials)

Suspension: very light materials are carried in water and does not touch the bottom of the river

Saltation: some heavy rocks bounce and roll along the bottom of the river - depends on the speed of the flow

Traction: very heavy rocks drag along the river

Question 20

Pothole

Answer 20

Pebbles trapped in a small depression keep spinning around. Abrasive action deepens the hole

Question 21

Delta

Answer 21

Created when river meets ocean