A site that produces the typical profile shape will give the most accurate results.  In a majority of the cases, problem sites can be identified by a visual inspection. Site inspection guidelines are as follows: 

	The channel should have as much straight run as possible.  Where the length of straight run is limited, the length upstream from the profile should be twice the downstream length.
	The channel should be free of flow disturbances.  Look for protruding pipe joints, sudden changes in diameter, contributing sidestreams, outgoing sidestreams, or obstructions.  Clean any rocks, sediment, or other debris that might be on the bottom of the pipe.
	The flow should be free of swirls, eddies, vortices, backward flow, or dead zones.  Avoid areas that have visible swirls on the surface.
	Avoid areas immediately downstream from sharp bends or obstructions.
	Avoid converging or diverging flow (approach to a flume) and vertical drops.
	Avoid areas immediately downstream from a sluice gate or where the channel empties into a body of stationary water.

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