Southern CA, dont come this way... big storms on the way

[Carl L]

This first storm sure dumped a lot of rain on us since last evening and was accompanied by some high winds. Some stats/observations:

• Highest rainfall: 10" in the Santa Cruz mountains. Lots of flooding. More flood watches in effect.
• Highest winds: 105mph in Los Gatos Hills, 87mph at Angel Island (SF Bay).
• Bay area power outages: Approx 500,000 homes. 91 power poles down. 30 miles of power lines down. 34 transformers out.
• Numerous roads closed due to trees down and big rigs overturned.

Haven't seen updated numbers for the Sierras, but Truckee was expecting 10 feet of snow.

The news just announced that CalTrans has just closed I-80 east and west of Truckee. 

 

[Bob Buchanan]

Haven't seen updated numbers for the Sierras, but Truckee was expecting 10 feet of snow.

I'm looking out of our family room window. Normally we'd be looking down at the boat, but today we're looking up. We clearly have a higher water level, but I can't imagine it's because they're letting water out of the high country reservoirs. Way too early for that.

They well may be releasing from some of the reservoirs, Tom. Though DWR and USBR hate to put water anywhere if not through generators vs. over spillways from Trinity, Shasta, Orville, or Folsom the threat of warm rains after a heavy snow pack like the one developing now is always a danger. Though rare, if it does happen they need empty reservoirs to hold back all that melting snow. If I recall, the last one happened in a late December -- and hardly a flake of snow remained in the Sierras.

That kind of one, two punch could be our next CA dilemma.  Let's hope the jet stream doesn't become the Pineapple Express again. 

 

[Tom]

Thanks Bob. I know that you are far more knowledgeable than most folks on this subject.

The reason I assumed they weren't releasing water was because of the desperately low state of the reservoirs. We were extremely surprised when we drove by Shasta several months ago and saw the very low water level. Also, the American River around Sacramento has had very low flows, presumably because of low water in Folsom Lake.

I know in prior years (early/mid 80's), they'd allowed the lakes to fill to capacity before unanticipated snow fall, and we ended up with huge amounts of water released into the rivers, resulting in extensive flooding. We had something similar a few years ago. So it must be quite a challenge balancing the need for stored water early in the winter with the possibility of flooding later.

 

[Bob Buchanan]

So it must be quite a challenge balancing the need for stored water early in the winter with the possibility of flooding later.

Well -- living in the Delta experiencing the results of the weather and the official response to it make you very knowledgeable as well. From your reports over the years, it appears someone has done a pretty good job of keeping the Delta healthy.

They have control centers with the entire CVP outlined in lights and such -- much like a subway control center - with movement of water vs. trains. If it's raining in the Trinity Alps and dry around Folsom, they may adjust releases accordingly. If I recall, they set priorities -- such as flood control takes precedence over drought.

Initially, Folsom was built for flood control - whereas it has since also become the main source of releases to push the salinity back at high tide so it does not get into the delta -- and down to the San Luis reservoir for summer travel to LA. So flood control and high tide abatement takes precedence over fishing the American River or water skiing Folsom lake -- and keeps Carl L. from having to drink salt water.    It's has been interesting over the years noting the complaints by those downstream from Folsom complaining about heavy releases during a drought w/a low water level behind the dam -- not realizing the catastrophic consequence of SF Bay salt water getting into the Delta.

 

[Tom]

.... not realizing the catastrophic consequence of SF Bay salt water getting into the Delta.

Agreed Bob. There's now some concern over "Arnold's plan" to save the Delta levies; Essentially resurrecting the peripheral canal project to divert Sacramento/American fresh water to LA, which would result in what you described. OTOH the process is likely to take so long that we might not need to worry about it.

I was interested to stumble across a number of links on the Central Valley Project, including these historical photos. Also the Department of Reclamation web site and their Reservoir Operations Reports. Unless I'm misreading these, it doesn't appear that there was any increase in outflow from Shasta or Folsom for Jan 1-3. It will be interesting to see if this changes when today's (1/4) data is added.

 

[Bob Buchanan]

OTOH the process is likely to take so long that we might not need to worry about it.

Unless I'm misreading these, it doesn't appear that there was any increase in outflow from Shasta or Folsom for Jan 1-3. It will be interesting to see if this changes when today's (1/4) data is added.

Probably so. In the early sixties when I arrived in Sacto, my initial programming assignments were involved with the testing of rock core samples on the abutments of the Auburn dam = that would feed the peripheral canal. The environmentalist stopped the project and have not let it begin again. Reclamation has charts that show the daily increase in total project cost for every day it has been delayed vs. having been completed back then. You can imagine the incremental amount the project will cost today vs. in the mid sixties.

Releases from the major dams will fluctuate during the course of a day -- mainly because of the variation in power demands from their power plants. Reclamation repays the cost of a Dam project thru the sale of water and power -- so every drop through the power plant is critical -- whereas DWR will pass a bond issue to assist in repayment (such as the Orville dam and the pumping plant into LA). They want little or no water to be released thru the dam or spillway. The power plant fluctuation in releases would play havoc with down stream water rights so control dams are built below each major dam. Releases from the control dams keep the releases to down stream stable during the course of the day and night regardless of the major dam releases.

Below Folsom is Natoma Dam (or is it Nimbus), below Trinity is Lewiston, below Shasta is Keswick and so forth. Let's see, below Parker dam is the Davis dam just above Laughlin and so forth.

Enjoyed the pictures link. The delta mandota was before my time - but I was totally invovled in the San Luis dam and power/pumping plant project. I believe that is the longest earth fill dam in the world and the largest dam not fed by a river or stream behind it -- but rather by water pumped from the canal in front of it during the wet winter months to be released during the summer to Carl L. in LA. 

 

[Tom]

Bob,

Having listened to your stories and read your comments over time, I continue to be amazed at the scale, complexity, and interdependencies of California's water system.

 

[Ron]

When the levies break which according to a TV program they most likely will we can always remember what we read right here.

 

[Jim Godward]

Bob,

You might want to go by the newer dam near Hemet and take a look at it.  I haven't seen it my self but intend to try and get there this year.  My daughter used to live near where it is and I would like to see the changes.  BG  It is a collection type like San Luis one.

 

[Ned]

A levee in NV broke yesterday and flooded Fernely, NV, about 30 miles from Reno.

 

[Tom]

A few gave way in NO too.

 

[Ned]

NO was already below sea level.  Who expects a flood from a broken levee in NV?  Parts of the town are under 8 feet of water and now it's freezing.

 

[Ray D]

Maybe they could get the Mayor of NO to come in as a consultant, to help solve the problems. And, there might be some Katrina trailers still available.  8) :

Ray D  ;D

I'm a bad boy!! Right?  :-[

 

[KodiakRV]

Maybe they could get the Mayor of NO to come in as a consultant, to help solve the problems. And, there might be some Katrina trailers still available.  8) :
Ray D  ;D
I'm a bad boy!! Right?  :-[

I vote they send Harry Reid home to fix it -- and keep him there until it is.  ;D

 

[Bob Buchanan]

NO was already below sea level.  Who expects a flood from a broken levee in NV?  Parts of the town are under 8 feet of water and now it's freezing.

That's for sure, Ned. When I first heard that a levee failed, I assumed it was in the Sacto area -- and was surprised that it was in NV. Actually tho, sea level has little to do with it vs. the elevation of the water on one side of the levee and of the ground level on the other side (8' in Fernley). Regardless of location, poor or out dated construction is the culprit. I would consider it foolish to purchase in NO or in the flood plane areas of Sacto such as North Natomas. However, many are doing that as we write . . .

All in all -- a levee "anywhere" scares me. They are really just long earth filled dams -- that are not constructed to the specs of an earth fill dam.

 

[Tom]

We have a secret weapon right here on the forum. Chris Pennings has offered to put his finger in the dyke aka levee should we get a leak. He has prior experience from when he was a boy in his home country, and is now a living legend there.

 

[Tom]

They are really just long earth filled dams -- that are not constructed to the specs of an earth fill dam.

I'm sure that's true Bob, although I don't have the relevant technical knowledge or experience to make that judgement (you OTOH do). We know that the initial Delta levees were built manually by large numbers of Chinese laborers, before the clamshell dredge came into play. OTOH I do know that many of the levies have large amounts of rip rap (rock) protecting them, but I've heard stories of levees failing because of damage by gophers and other animals.
[edit]Fixed typo.[/edit]

 

[Karl]

And, there might be some Katrina trailers still available.

On my way from Hattiesburg, MS to Slidell, LA I saw hundreds, if not thousands, of them parked almost one on top of the other, in various states of disrepair. You wouldn't believe what some of them looked like!

 

[Ned]

It's possible that burrowing rodents were a factor in the levee failure according to the news reports.

 

[Bob Buchanan]

I'm sure that's true Bob, although I don't have the relevant technical knowledge or experience to make that judgement (you OTOH do). We know that the initial Delta levees were built manually by large numbers of Chinese laborers, before the clamshell dredge came into play. OTOH I do know that many of the levies have large amounts of rip rap (rock) protecting them, but I've heard stories of levees failing because of damage by gofers and other animals.

When I first read that, I thought it read, Golfers. We "do" have to keep Golfers off the levee's.

The rip rap is the outer protective "zone" of material in an earth fill dam. The innermost zone is a clayish, impervious, material that sits on a concrete core . The zones then continue outward of less and less impervious soils, then rock that is smaller in size than the rip rap - then the rip rap. The design is such that the water actually flows though the dam over the core. The idea is to keep the soil zones moist and less likely to fail. They develop what they call a "flow net" that shows exactly how the water will move over the core.

During the upgrading of the levees along the American River a few years back I was staying at the CalExpo RV park in Sacto. My bike ride each evening allowed me to play inspector on the process (until they ran me off ). They had a huge back hoe removing the inner part of the levee, then replacing it with what I assumed was a better material for that purpose. So tho I have no experience with levee design, this appeared far below the intricate design of an earth fill dam that I am somewhat familiar with.

OTOH, the pressures on an earthen dam are much stronger than on a levee -- so the design doesn't need to be as elaborate. However, the way they are designed leads to the problems we are seeing around Sacto and the Delta. So I guess it's like air line seats. We can make them to withstand not so severe crashes, but that costs too much . . .