Several components of a hydropower facility may be affected by zebra mussels. (Figure 6) shows an infestation at the condenser cooling unit at the Detroit Edison Power Plant; there was heavy zebra mussel infestation on all surfaces. (Figure 8) is a closer view of this same infested surface. These components include trashracks, penstocks, turbine headcovers, imbedded piping, raw water cooling systems, instrumentation, gates, and fish ladders. The problems associated with each component are described below along with suggested control strategies.