Before talking about what's being done to reduce TDG, let's quickly review what scientists have found over the years.

Scientists know that the closer to the surface fish travel or are held, the more vulnerable they are. Scientists also know that when TDG travels through slow, flat waters (like Lake Roosevelt), it tends to stay in the water. But if the water moves across rapids or other high turbulent conditions, excess TDG is reduced because the gas makes contact with, and is released, into the air. So one of the things being monitored is how long it takes for the TDG to dissipate (be released) after being created at various projects.

Lastly, scientists know that TDG is minimized if dam's that generate electricity maximize how much water flows through the powerhouse and turbines rather than over the spillway. By water passing through the powerhouse, there is no waterfall. That's less pretty to the human eye, perhaps, but it creates healthier water conditions for me.