Drainage Patterns

Question 1

Dendritic

Answer 1

Tributaries join at acute angles, pointing downstream.

Uniform rocks of similar gradient and hardness. E.g. Massive Igneous or horizontal sedimentary

Question 2

Trellis

Answer 2

Short tributaries join main stream at right angles

Folded sedimentary or alternating layers of hard and soft rock that are tilted.

Question 3

Radial/centrifugal

Answer 3

Rivers radiate out from a central point.

Rivers flow away from central point, e.g. a dome, volcano, butte or mesa.
E.g Karoo

Question 4

Rectangular

Answer 4

Rivers have 90 degree bends.

Hard rock with joins e.g igneous rock

Question 5

Centripetal

Answer 5

Rivers radiate in towards low lying area.

Rivers flow towards central basin or low lying area such as a marsh, lake or pan.

Question 6

Deranged

Answer 6

Small streams with no specific pattern- Marshy areas with many small lakes.

Flats areas undergone recent glaciation.

Question 7

Parallel

Answer 7

Streams flow parallel to each other following dip of the land.
May join larger river or flow into a lake.

Common along ridge of hills or part of trellis drainage pattern.
Constant gradient.