Pile drivers constructing coffer dams for the intake facilities will cause a lot of underwater noise. This will not be good for the fish, affecting early and late portions of some runs. Intake construction also has the “potential for substantial increase in predation” for a small part of the fish population.
“Surge towers” will be needed at the head of each tunnel or pipeline “to absorb the pressure surges following the sudden shutdown of the pumps.” (See page 59 or the PowerPoint.) These towers are supposed to ensure the safety of the equipment. In response to a question from the audience about handling the momentum of that amount of water, the presenter from DWR said it would take up to 48 hours to get past the danger stage and 5 to 7 days before you could dewater the system enough to allow for repairs. An audience member suggested that all that sloshing of water underground might cause earthquake-like disruptions at the surface. Presenters had no answer for that.
Listening to planners describe the BDCP, one has the sense that for them, this is an interesting (and probably well-compensated) academic exercise, with no serious connection to the real world.
(An interesting side note: ICF is coordinating both the effects analysis and the Environmental Impact Report (EIR) for BDCP. And the SWRCB has extended an existing contract with ICF to work with them on developing Delta flow standards. So with one thing and another, the Delta is keeping those folks really busy.)
Another example of the academic nature of this exercise is the fact that BDCP planners are working with a projected 55-inch rise in sea level because that is what the legislation requires. So, asked attorney Osha Meserve, who represents North Delta reclamation districts, when do you abandon South Delta facilities?
Said Meral, “We don’t assume that South Delta levees will fail. We just decided that we won’t assume levee failure. We assume continued operations.”
We guess that means they actually think Delta levees aren’t doomed to fail after all.