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Trout Creek
west of Cody, Wyoming

Trout Creek - Wyoming

As you can see from the photo, this is a single-thread channel.  Field measurements determined an entrenchment ratio of 1.7.  The ratio of bankfull width to mean bankfull depth is 16. The sinuosity, calculated from aerial photographs is 1.3. At this point in the classification process, it can be seen that this reach classifies as a B channel, commonly called a step-pool stream.

Single-thread Channels

Stream exampleThe measured slope on this reach is .034 feet per foot. The slope numbers on the diagram are in feet per foot units. These numbers multiplied by 100 will yield percent slope; or multiplied by 5,280 will yield feet per mile slope. Measurements of channel materials, commonly called "pebble counts", indicate that 50% of the surface substrate is equal to or less than 52 millimeters in size. This size material falls within the gravel range. This reach is therefore a B4 stream type.

Comparison of measured values from this stream with values from known B4 references reaches provides the basis for determining if this reach is stable.   The reference reach concept is beyond the scope of this presentation.   However, all the measurements in the exercise presented here indicates the B4 reach is a stable B4, and will tend to adjust back towards a B4 as a consequence of alteration.

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