California Drought

[downsizingnow48]

Meta bunk is commendably focused on empirical practical circumstances and avoids the foolish emotional blather that infects most forums.

 

[NoTrespassing]

'Biggest storm of winter' to unleash flooding rain in California at week’s end

'Biggest storm of winter' to unleash flooding rain in California at week’s end


"The late-week storm has the potential to be the biggest of the winter in terms of rainfall and impact to much of Southern California," according to AccuWeather Meteorologist Jim Andrews.

The storm will bring enough rain and excess runoff to cause flash flooding, which can cause major delays for motorists. Along with the heavy rain will be the potential for mudslides in some neighborhoods, especially in recent burn scar locations.


"We expect 3 to 6 inches of rain to fall in the lowlands along the coast and over the Los Angeles basin," according to AccuWeather Senior Meteorologist Ken Clark. "From 6 to 12 inches of rain is likely below snow levels in the mountains, especially along the south-facing slopes."

In the Los Angeles and Santa Barbara, California areas, much of this rain may fall in 24 hours from early Friday morning through Friday night. In San Diego, the heaviest rain will fall Friday evening into Saturday morning.

Good Luck CA
Kevin

 

[buckeyefarmer]

Hopefully the heavier rain stays south then.

 

[k0ua]

Good luck out there guys..stay safe..

 

[California]

Thanks k0ua, from everyone out here.

 

[ForestGrump]

My concern with this issue is that the geology of the dam, the spillway and the emergency spillway seem to be conflicted. It has been stated that these were built on a solid rock face. Evidently not in the case of the two spill ways, they eroded overnight. That's not solid rock. So what is the dam built on if the spillways were not built on rock. It is my opinion the geologic studies of the dam complex are suspect. I would re-evaluate the old studies and to conduct new studies. Especially since a compression earthquake has already occurred in the immediate area.

Face it, mistakes have been made both in the geology and in the construction of the dam resulting in two rather massive failures.

The dam in Big Bear is 100 years old. It was retrofitted just prior to the Landers/Big Beartwin quakes in '92 and then again after the quakes. It is now designed I believe to withstand an 8.5. It is time to do a thorough review of that dam, its geology and its construction based on current technology.

 

[aczlan]

My concern with this issue is that the geology of the dam, the spillway and the emergency spillway seem to be conflicted. It has been stated that these were built on a solid rock face. Evidently not in the case of the two spill ways, they eroded overnight. That's not solid rock. So what is the dam built on if the spillways were not built on rock. It is my opinion the geologic studies of the dam complex are suspect. I would re-evaluate the old studies and to conduct new studies.

Time will tell. When they put in the emergency spillway, they ripped down 10 feet into the rock to get to "suitable rock" for the base of the emergency spillway. That rock has not eroded, nor has the erosion reached the base of the emergency spillway.

On the main spillway, it eroded to a point, then it held up to 100,000cfs (as much water as flows over Niagara Falls every second) for 5 days before they started throttling it back today.
I suspect that the under-slab drainage for that section failed which let the fill wash out and leave the concrete unsupported. In the construction notes, they also talked about needing a different anchor system for some sections of rock (the orangeish rock) as it was weaker.

Face it, mistakes have been made both in the geology and in the construction of the dam resulting in two rather massive failures.

Massive, perhaps but not fatal to that dam and not sufficient to cause a complete dam failure like some of the chicken little crowd would have you believe.

Aaron Z

 

[coldsteelva]

The new/repaired/rebuilt spillway needs to be supported by poured columns not just the local geology (more like an aqueduct than a rain gutter)

 

[houstonscott]

Time will tell. When they put in the emergency spillway, they ripped down 10 feet into the rock to get to "suitable rock" for the base of the emergency spillway. That rock has not eroded, nor has the erosion reached the base of the emergency spillway. On the main spillway, it eroded to a point, then it held up to 100,000cfs (as much water as flows over Niagara Falls every second) for 5 days before they started throttling it back today. I suspect that the under-slab drainage for that section failed which let the fill wash out and leave the concrete unsupported. In the construction notes, they also talked about needing a different anchor system for some sections of rock (the orangeish rock) as it was weaker. Massive, perhaps but not fatal to that dam and not sufficient to cause a complete dam failure like some of the chicken little crowd would have you believe. Aaron Z

I haven't seen one post predicting the dam failing. There are many concerns that the lake could indeed drain from a failure of the emergency spillway, and cut a new channel right there.

 

[TemporaryKubotaOwnerMark]

It is my opinion the geologic studies of the dam complex are suspect. I would re-evaluate the old studies and to conduct new studies.

Agreed. We have learned a lot since those studies were done. It's just prudent to apply that knowledge by re-examining the work.

The dam in Big Bear is 100 years old. It was retrofitted just prior to the Landers/Big Beartwin quakes in '92 and then again after the quakes. It is now designed I believe to withstand an 8.5. It is time to do a thorough review of that dam, its geology and its construction based on current technology.

Just on the north side of Landers is a batholith which presents as a hill rising above the town. It's rather like an iceberg in that most of it is underground. IIRC it's around 1500 feet above the surrounding terrain, so that's a pretty big rock. I was present when a geology team from one of the big-name universities (can't remember if it was UCLA or USC) measured it to see how the quake affected it. It had moved 18 feet south and 12 feet up, IIRC. The terrain north of town showed "stretch marks", the classic horror movie cracks in the earth that swallow cars. Well, none of them was quite big enough to swallow a car, but several were big enough for a car to fall partially in. I saw them a few days later when they had gotten filled in to make the highway passable.


All that to say, given the right earthquake at the wrong place, no dam will stand. There is just too much energy involved. We should do all we can, but "all we can" has to include the recognition than an earthquake can completely take out any dam in just a few minutes.