good dam pix

It's made of dirt. Once the water starts cutting into the structure of the dam, things get bad in a big, big hurry. The canyon cut in the emergency spillway in just a few days is scary.

Fortunately the spillways are not on top of the dam itself, but off to the side on a hillside that would take a lot of eroding--there's rock underneath, but apparently not very good rock. So the lake wouldn't empty if the emergency spillway failed, but its level would drop 30 feet in a big hurry. You wouldn't want to be downstream if that happened.

Cheers

Phil Hobbs

Just give everybody a life jacket.

What makes them think the dam is going to "fail" (meaning collapse) anyway? Things don't often collapse, especially dams. Terrorists would need an impossibly large bomb.

Impossibly large? Well, 3000kg of torpex has famously destroyed a couple of dams :)

Apparently there was fairly dramatic and obvious erosion in the spillway.

How on earth that got missed until it got big enough to threaten the integr ity of the dam is an interesting question, but the point has been made that US politicians are much happier spending money on new dams, which offer th em photo-opportunities at opening ceremonies, than they are about spending money on preventing existing infra-structure from falling down, which doesn 't generate any column inches at all.

The problem has been that the usual spillway isn't large enough to empty the lake as fast as the rain has been filling it, so the lake level keeps rising. There is an emergency spillway that's _supposed_ to handle this contignency, however the emergency spillway is earthen, rather than concrete. Since it has never before been used, no problem. The first time it was used, it washed away, AIUI, undercuting the concrete dam cap. This has compromised the dam and it could fail at any time. The forecast rain will again raise the lake level to where the dam may fail. This had been predicted but the fix is expensive and California has better things to do with its money (like keeping people impoverished). Good going California!

The dam could be destroyed if the damaged regular spillway erodes up to its base. That's looking unlikely. The real hazard is that if the water gets too high, the emergency spillway tops and water falls onto the dirt hillside below. That would undercut the spillway (it almost did last week) and dump all the lake on the towns below, while the dam stands proudly over a dry lake.

One thing I'm seeing, that nobody has mentioned so far, is water dumping on (or maybe through?) the dirt slope from the flooded parking lot beyond the emergency spillway. Once a tiny trickle of water finds its way underground, it eats a tunnel and pretty much can't be stopped.

Water is nasty stuff. If there's a way, it finds it.

Some engineers are idiots, and some are cowards.

What about the politicians and bureaucrats who were told, decades ago, about this potential problem but chose to do nothing?

We KNOW that they are usually idiots and cowards, but the engineers should have been public and noisy about the hazard.

Californica set aside funds designated for infrastructure maintenance, and used them instead for important things, like "high-speed" rail from San Fransicko to Lost Angels... which no one will ride since there's ample air shuttles every half-hour or so.

And then there's the infamous "Saving the Snail Darter" need for funds. ...Jim Thompson

They should have been forced to live directly in front of the dam.

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Don't forget the many millions spent on importing illegal immigrants to help the vote for hillary. Too bad they lost on that one. One might feel some small amount of pity. Or not.

I feel their pain >:-} ...Jim Thompson

so terrorists could steal a bomber, or maybe use a boat or side-tipping truck, or on a dam that allows public traffic.

Tipper truck sounds best, and if they buy army surplus then I would have thought it could turn the road into a public access road for a few minutes :)

We have too much experience of such American/Ghadaffi funded bombs over here.

All impossible for them. Terrorists are idiots when they don't have an intel officer telling them what to do. They can manage a small bomb, but aren't smart enough to aquire the torpex or the delivery system. Their attempt to get a crop dusting plane as a delivery system in 2000 was a good example of their incompetence.

Of course there are lots of opportunities for attack that they could manage but are too stupid to think of, so I won't help them by elaborating.