Describe the major drainage patterns. What will be an ideal ...

[geoffrey]

Describe the major drainage patterns. What will be an ideal response?

Question 2

Briefly explain the trade-offs that accompany any flood control project. What will be an ideal response?

[l.stuut]

Answer to Question 1

In dendritic drainage, a network of channels resembles tree branching. The pattern develops on gently
sloping surfaces underlain by material that erodes roughly equally. Tributaries join larger channels at
various angles. In rectangular drainage, tributaries join larger channels at right angles; this pattern is
controlled by geologic structures, such as joints. Trellis drainage is a network of nearly parallel
streams with tributaries joining them at right angles because the streams follow easily eroded rocks
and are separated by resistant rocks. In radial drainage, streams flow outward from a high point like a
volcano. Deranged drainage patterns are irregular, with streams flowing into and out of swamps and
lakes.

Answer to Question 2

The obvious benefits of controlling flooding are offset by loss of sediment deposition area, loss of
wetland habitat, loss of the natural evolution of a drainage basin (natural changes in the stream channel
such as meandering), increased soil erosion, and decreased natural ability to moderate effects of
floods.