maddog48 wrote:
I just got this e-mail from Arkansas G&F.

Over the last 2 days, D.O. levels below Greers Ferry during nameplate
capacity generation have fallen below 6 ppm

Per the D.O. plan, vacuum breaker vents should be blocked open.


Mike





6 ppm, or 6 parts per million, is the minimum necessary for a healthy trout population. This is a number set by ADEQ (Arkansas Department of Environmental Quality) which is ratified by the EPA. 6 ppm is the standard that has been accepted by other states from around the United States. Interestingly the COE (Corps of Engineers) and SWPA (Southwest Power Administration) have suggested that Arkansas lower its standard to allow for more efficient power generation.

In an effort to remedy low oxygen water on the dam side, the COE has installed air inlets in the turbines. These suck in air while they are generating power and raise the oxygen levels when trout are at risk. Unfortunately they also intake nitrogen which is not necessarly a good thing for fish. When levels behind the dam get back over 6 ppm they will close off the vents.

The major complaint from the COE is that injecting air into the turbines lowers their ability to produce electricity because it lowers the density of the liquid.