Please fill out and return this sheet after viewing Program #20.   If you are unsure of an answer, give your best intelligent guess.

1.  What is baselevel?

The theoretical limit of downward erosion in a river.  This would typically be equal sea level (if that's where the river ends), lake level, or the elevation of the confluence of the rivers (where one river feeds into another).

2.  What are three stages of river landform development?

Youthful, mature, and old age

3.  What are features of youthful streams?

V-shaped valleys, generally higher gradients (slopes).

4.  What are features of mature streams?

The development of meanders, the development of floodplains, the overall widening of the river valley.  The gradient is a little lower in this stage.

5.  What are features of old age streams?

Very broad floodplains

6.  What are the different stream drainage patterns, and in which types of rock do they form?

Dendritic - flat landscapes; trellis - parallel resistent ridges and valleys between; rectangular - fractures meeting at right angles; radial - water draining from an isolated mountain or volcano; anular - forms from an impact crater or an uplifted structural dome.

7.  How does rejuvenation occur?  What are features of rejuvenation?

Rejuvenation occurse when baselevel drops or the land is uplifted.  Two features of rejuvenation are incised meanders and stream terraces.

8.  What river feature forms at its mouth?

Deltas

9.  How do distributaries form?

River channels near the mouth of a river become choked (filled in) with sediments.  At some point the river breaks out another channel to the ocean or lake.  When this happens several times, a distributary system develops.

10.  Why do we not allow the Mississippi River to change course naturally?

Because it would then bypass Baton Rouge and New Orleans, and their economies would be devastated.  An alternate course would also result in the flooding of towns and farmlands.

11.  Which river is trying to capture the Mississippi?

The Atchafalaya