I think the biggest effect will be dissolved oxygen issues that will probably show up later in the year.
E. coli itself doesn't directly affect the fish much unless you get really high levels. You actually get some coliform bacteria in the environment nearly all the time from farm runoff, goose poop, etc. You might get a little increased mortality from high levels but not a lot. It also doesn't stick around in the flesh like chemical contaminants and heavy metals do. In theory, you could eat a fish right out of a sewer discharge and be okay as long as it's cooked, though you wouldn't want to drink the water.
E. coli a much bigger problem for humans, since it can make you sick if you ingest the water or get the bacteria in an open cut.
The biggest problem is not the bacteria itself, but the oxygen consumed by the bacteria. All that sewage in the water is like a major blast of fertilizer. It causes big algae blooms and the number of bacteria explodes overnight. Eventually the algae dies and provides food for even more bacteria. Bacteria don't photosynthesize, so they consume a lot of dissolved oxygen. Right now that's not a big issue, because the lakes aren't really stratified and more oxygen gets absorbed from the surface and mixed through the system. However, once the thermocline forms, the deeper, cooler water doesn't get oxygen replenished from the surface. Increased amounts of bacteria will eat up all the oxygen from the deeper water.
Hopefully they can limit discharges and let most of the poop settle out in Woods. If it gets into Tim's Ford, it will be VERY tough on the stripers there. In the hot summer, the stripers move down below the thermocline in search of cool water. However, if increased bacteria loads have eaten up all the oxygen in the deep water, the fish are forced back up into warmer surface water where they become temperature stressed. If you get low enough DO and warm enough surface temps, you will get a fish kill on the cooler water species.
Depleted DO will also hurt the trout in the tailwater because the water discharged through the dam will have very little oxygen and poor quality. However, it's my understanding that Tim's Ford Dam has some modifications to oxygenate the water as it comes through. Hopefully that will be enough to keep DO at an acceptable level, but only time will tell.
Usually late summer is when you really see the impacts of depleted oxygen from a spill like this. Surface temps are at their peak around that time, and bacteria have had all season to deplete the available oxygen in the deep water. At that point you have to wait for fall turnover for new oxygen to be introduced into the deeper water.
bd
