Becoming skilled at reading water is essential to becoming a successful steelhead fisherman.  Steelhead are very specific about what type of substrate they prefer and what type of water speed they'll hold in.  In this section we'll discuss the substrate they prefer to hold over and why they'll hold there opposed to other areas in the river.

When steelhead enter the river they want to exert as little energy as possible to get from point A to point B.  In addition, steelhead like to have at least some current, as opposed to salmon who will often sit in "frog" water or swirling back eddy's with little to no current. 

Water flows down river over a myriad of different substrates, some of which cause turbulence along the bottom that actually reduces the current flow near the river bottom to almost nothing, and some cause a minimal reduction in flow.  All of these substrates create a zone of turbulence of varying depths along the bottom. 

A sandy bottom, like the one in the first diagram, causes very little disturbance to the flow of water and has a very shallow zone above it.  Steelhead will move over an area like this, but there is no incentive for them to hold here for an extended period of time, since they would have to exert energy to stay here.     

A bottom made up of rocks, however, creates more disturbance in the water and results in a much wider zone of reduced current along the bottom.  The bigger the rocks, the deeper this area of turbulence will be along the river bottom.

In medium to large sized rivers like the Bogachiel or Skagit it's best to look for a bed of rocks roughly the size of basketballs.  An entire run may look good, but find an area within the drift that has rocks like this and you'll probably find steelhead holding there.     

Areas of the river with the right mix of current and rocks will hold fish on a regular basis.  Once you find the winning combination of current speed, cover, and substrate, your trips to the river in pursuit of steelhead will be much more successful.