High sediment transport can fill pools and cause spawning gravesl to be embedded. Reeves et al. The statistical rigor of pool frequency was not significant statistically in one of three study areas. Consequently, repeated habitat typing is not a valid way to monitor change in stream habitats over time. It is preferable to use habitat typing to help determine limiting factors and then choose quantitative monitoring tools.
Riffles are areas of swifter flowing water, where the surface is turbulent.
Young of the year steelhead like low gradient riffles but coho generally do not. The flowing water delivers insects for food and the broken surface provides cover from predators. Glide are slow moving areas in the stream, where the surface is smooth. Often, streams suffering from cumulative watershed effects have a large percentage of flatwater habitats, such as glides and runs, and riffles. Pools often have filled in, and represent a small percentage of habitat types.