68 replies to this topic

[Carl G]

I believe a news report talked of rewriting the rulebook once the new spillway in complete.  Part of that would be to use the improved long range weather models to help determine appropriate water levels.

[tony]

I believe a news report talked of rewriting the rulebook once the new spillway in complete.  Part of that would be to use the improved long range weather models to help determine appropriate water levels.

Exactly.

While it is easy to bash the bureaucracy of the federal government, the reality is that their primary mission in operating Folsom Dam is flood protection, also known as life safety. If they get the flood control part wrong, they potentially endanger hundreds of thousands of lives in the Sacramento region (and parts of Folsom in particular). Uncontrolled releases from a dam can result in a complete dam failure; it has happened before. So, those bureaucratic engineers at the "bureau" take that responsibility very seriously. It's a matter of risk versus potential consequences. They take very little risk with regards to flooding because the consequences of being wrong are devastating in terms of life and property. Conversely, the risk of releasing too much water too soon is extending the consequences of the drought -- consequences that are almost entirely economic in nature.  Or, in an oversimplified and ever so slightly sarcastic comparison: if they don't release enough water and the dam overtops, people potentially die; if they release too much water and extend the consequences of the drought, grass dies.  As a result, they are very careful about making changes to operational protocols that have worked for many years. Having worked with folks in the dam safety arena in the past, and working in a field where mistakes can cost lives, I understand and appreciate the caution practiced by the bureaucrats at the bureau. And being one year away from opening the new spillway, which will necessarily change their operations of the dam (and improve it's ability to store water while providing improved flood protection), I can understand their reluctance to make dramatic changes now.  And, there is enough snowpack in the mountains this year that at this point, even without further rain, it is likely the lake will reach capacity or near capacity in May/June, so there isn't much point in trying to hang onto every drop now.

[Steve Heard]

Exactly.

While it is easy to bash the bureaucracy of the federal government, the reality is that their primary mission in operating Folsom Dam is flood protection, also known as life safety. If they get the flood control part wrong, they potentially endanger hundreds of thousands of lives in the Sacramento region (and parts of Folsom in particular). Uncontrolled releases from a dam can result in a complete dam failure; it has happened before. So, those bureaucratic engineers at the "bureau" take that responsibility very seriously. It's a matter of risk versus potential consequences. They take very little risk with regards to flooding because the consequences of being wrong are devastating in terms of life and property. Conversely, the risk of releasing too much water too soon is extending the consequences of the drought -- consequences that are almost entirely economic in nature.  Or, in an oversimplified and ever so slightly sarcastic comparison: if they don't release enough water and the dam overtops, people potentially die; if they release too much water and extend the consequences of the drought, grass dies.  As a result, they are very careful about making changes to operational protocols that have worked for many years. Having worked with folks in the dam safety arena in the past, and working in a field where mistakes can cost lives, I understand and appreciate the caution practiced by the bureaucrats at the bureau. And being one year away from opening the new spillway, which will necessarily change their operations of the dam (and improve it's ability to store water while providing improved flood protection), I can understand their reluctance to make dramatic changes now.  And, there is enough snowpack in the mountains this year that at this point, even without further rain, it is likely the lake will reach capacity or near capacity in May/June, so there isn't much point in trying to hang onto every drop now.

 

Excellent post! 

[The Average Joe]

So why not build the Auburn dam for better flood control, water storage, recreational opportunities and green power (oh wait, CA does not consider hydroelectric green power, go figure). More storage means more water to use.

And I still don't see how the spillway will protect anything. Isn't the capacity of the downstream levees the limiting factor? yes, the spillway could dump 300,000cfs, but the levees are only capable of 120,000. So what am I missing?

[2 Aces]

We are in Calif...liberals and environmentalists control the state, and that's why the Auburn Dam will never happen, even though it makes perfect sense. People who oppose it don't have common sense, and they can't even articulate in a rational way WHY they oppose it.

The inmates are running the asylum.

[Carl G]

I forgot to mention, the Folsom Dam built 60 years ago has a design flaw.  The flood gates are too high.  The new spillway's gates are considerably lower allowing water to be released before it becomes a crisis.

 

Yes the new spillway if fully open will top the existing levees, but a dam failure would do the same but much worse as well as forcing the dam to be rebuilt at a huge cost.

[4thgenFolsomite]

Remember that Folsom Lake receives all the water run off for a huge area. Pretty much everything west from Lake Tahoe and north and south of hwys 80 and 50,. That is a huge area draining into the lake. So when you have a big snowpack and you get a big warm rain, there is going to be a tremendous volume of water flowing into the lake. The capacity to let water out of the lake safely is limited to its flood gates and spillway. You never want a concrete dam to overtop. All the estimates of how much water would be released if the dam failed had a 20-foot tall wall of water hitting the state Capitol. The new spill gates will prevent that. Until they are operational, the dam will still be operated as originally planned. I imagine what the bureau does is as much art as it is science since they have to rely on the same forecasts we do, supplements with real time measurements. It's a huge responsibility. And, yes, I know I used the word huge three times.

[2 Aces]

A 20-foot-tall wall of water slamming into the State Capitol?? Hmmm...let me ponder that for a moment...

[Carl G]

A 20-foot-tall wall of water slamming into the State Capitol?? Hmmm...let me ponder that for a moment...

 

I see where you're going with this.  If only we could guarantee the "trash" gets swept out...