River Systems Part 2 Features of a Meandering River Levees Shaping of River Channels

Running Water The Work of Streams When a stream meanders, its zone of maximum speed shifts toward the outer bank. A point bar is deposited where the water on the inside of a meander slows. Here we see erosion of a cut bank . By eroding the outer bank and depositing material on the inside of the bend, a stream is able to shift its channel.

Formation of a cutoff and oxbow lake

Oxbow lakes occupy abandoned meanders Oxbow lakes occupy abandoned meanders. As they fill with sediment, oxbow lakes gradually become swampy meander scars.

Erosion and deposition along a meandering stream Figure 5.10

This distinct meander loop on the Colorado River will eventually lead to an oxbow lake.

Formation of Natural Levees by Repeated Flooding Rivers and Streams Formation of Natural Levees by Repeated Flooding Figure 5.21

A stream valley’s sides are shaped by three processes: Rivers and Streams A stream valley’s sides are shaped by three processes: weathering overland flow mass wasting

A Narrow, V-Shaped Valley Some characteristics of narrow valleys v-shaped channels down-cutting toward base level rapids waterfalls Figure 5.17 A

Continued erosion and deposition widens a valley Figure 5.17 B

Features often include A Wide, U-Shaped Valley Some characteristics of wide valleys: stream is near base level downward erosion is less dominant stream energy is directed from side to side floodplain Features often include meanders cutoffs oxbow lakes