What will you look for to find the physical properties of a stream bottom?

Question

I'm looking for how to find the physical properties of a stream bottom, how to catch organisms living in fresh water to determine water quality.

Answer 1

Generally look for things like condition of substrate.  Sandy, muddy, rocky, pebbely.  Is there plant matter?  Clarity of the water and to what depth.  Also how fast is the current.    Many biotic counts are two fold.  First use a net to catch a sample of critters visable. Then you want to take a water sample to account for microorganisms too.  The frequency and type of sampling will depend on the type of study you are doing.