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Flooding, Lake Lag, California Water situation - Printable Version

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RE: Palo Alto Flooding - triangle2 - 01-01-2023

(01-01-2023, 10:40 AM)jacket3ree Wrote:  Fishman - 

I went straight to the USGS site: SAN FRANCISQUITO C A STANFORD UNIVERSITY CA[/url]

This is a live link, so I don't know how to copy and paste the hydrograph. There are radio buttons for flow and stage.  The data are provisional (vetting will take months), and the number I reported yesterday was from the memory of looking at my phone while standing on the creek bank in the rain, so it appears 4,300 cfs was low on my part - sitting at my desk this morning on a laptop, I read 6,350 cfs at 9:00 on Saturday.  This is equivalent to the 40-year event. That's better - it means there is a higher level of protection under existing conditions.

Here is a link to the annual peak streamflow data: [url=https://nwis.waterdata.usgs.gov/usa/nwis/peak/?site_no=11164500]Peak Streamflow for the Nation  USGS 11164500 SAN FRANCISQUITO C A STANFORD UNIVERSITY CA

02/03/1998    7,200 cfs

Our flood frequency analysis shows the one-percent peak discharge as 8,000 cfs (YMMV)

Make sure you are looking at peak streamflow data, not maximum daily discharge, which would be lower.

Triangle -

Newell Street is one of those "and then" bottlenecks I described earlier, along with University Avenue.  From upstream to downstream, historically Middlefield Road, Pope-Chaucer, University, Newell, West Bayshore, 101, and East Bayshore cause problems. If all those bridges were removed, with relatively minor improvement, the creek could pass the flow.  Removing, raising or enlarging each of those structures comes with varying degrees of difficulty. That's probably what the City person meant by saying the solution would need to be "elsewhere".  One has to be careful in how one removes a bottleneck, or the problem is indeed moved elsewhere.  The bridge restrictions between Middlefield and Bayshore needed to be remedied simultaneously if possible, or temporary flow restrictions may be necessary if available funding doesn't allow it all to be done at once.

There are four basic things that can be done on any system like this:

1. Increase flow conveyance (enlarge creek, remove vegetation, and/or improve bridge hydraulics)
2. Reduce the flow by storing water upstream.
3. Reduce the flow by diverting a portion of it (bypass).
4. Nothing. But even then, if the creek is not maintained, flow conveyance will lessen and flooding may increase.

Some of the public and NGOs like Friends of the Creek favor the fourth option. As crass as this is to say, we need events like this to remind everyone that doing nothing leads to sorrow.  Alternative 2 (on stream or off-stream storage) and Alternative 3 (giant concrete underground bypass from Middlefield to the Bay through.....EPA?) have been studied to death and appear to be off the table forever due to ineffectiveness and/or expense. That leaves Alternative 1. 

Work should progress from downstream to upstream to avoid induced flooding, and it is.  The reach from Bayshore to the Bay is complete, and with some remaining nuance, Bayshore itself is ready to go. That leaves the reach between Middlefield and Bayshore. The JPA has labeled the reach between Pope-Chaucer and Bayshore as "Reach 2". Kevin does a better job of succinctly explaining it than I can:

Kevin Murray Explains

If anyone has further interest, I encourage you to read about it here: The Reach 2 “Upstream Project” When this work is done, the capacity bottleneck moves to Middlefield Road. I haven't heard anything about fixing that, and the downstream capacity is being set to that of Middlefield, which spills in a 100-year event. It appears that a residual 100-year floodplain will remain, but it will less extensive than under current conditions.

Valley Water put together a flyover after the 1998 flood.  Full disclosure: They retained my firm to help them reconstruct what happened and we did some modeling.  We categorically DID NOT select the background music.

1998 Flood

Remember, a lot of the flooding you see is local - drainage can't get into the perched or leveed creek, so it backs up on the streets.

Jacket3ree, this is great information. Really appreciate you taking the time to share it.

RE: Palo Alto Flooding - Goose - 01-01-2023

(01-01-2023, 03:12 PM)PAsportsfan Wrote:  
(01-01-2023, 02:33 PM)Goose Wrote:  
(01-01-2023, 01:01 PM)jacket3ree Wrote:  Lake Lag is not part of the flood protection plan. It has to be intentionally filled.

Is this even possible after the removal of the Lagunita Diversion Dam? I know that Lag used to get significant runoff that could at least create a swamp for a few months, but it has been a very long time since I have seen it filled, possibly the early 70s?

2017

https://twitter.com/LombardiHimself/status/838903019643121666

It doesn't appear to me that the lake is anywhere close to full in this picture. Take a look at
https://scontent-sjc3-1.xx.fbcdn.net/v/t1.6435-9/88261677_2910970625613149_5119639615703089152_n.jpg?stp=cp0_dst-jpg_e15_fr_q65&_nc_cat=104&ccb=1-7&_nc_sid=2d5d41&_nc_ohc=9-Z5-inq9LIAX-FWPao&_nc_ht=scontent-sjc3-1.xx&oh=00_AfBSoppQrjMKdWKVyWOFLC4itgRGpV-ldE__A_vmO1acrA&oe=63D97275

Note how far up the bank the water is.

RE: Palo Alto Flooding - Maple Leaf - 01-02-2023

(01-01-2023, 01:01 PM)jacket3ree Wrote:  81 -

Lake Lag is not part of the flood protection plan. It has to be intentionally filled.

The Barron Creek Diversion and Matadero Creek Bypass Projects were completed in the late '80s / early '90s.  They were fully tested during the 1998 event. I have that minute-by-minute record stored on our server somewhere. It was dicey. The diversion worked as intended, but the 1998 event identified capacity problems with Matadero Creek between Alma Street and the flood basin, since it is taking the diverted flow from the Barron Creek watershed. We were retained to sort those out. The subsequent remediation project was completed in the early 'oughts. Matadero and Barron should be OK. There are still problems with San Francisquito Creek and Adobe Creek.

A lot of mud out on the streets of Belmont and San Carlos this morning. Belmont Creek may have overtopped near Harbor.

It is my understanding that Lake Lag was constructed way back when to provide irrigation water for the campus. Of course, the lake provided the needed environment for the development of critical social behaviors such as:


RE: Palo Alto Flooding - 81alum - 01-02-2023

(01-01-2023, 03:12 PM)PAsportsfan Wrote:  
(01-01-2023, 02:33 PM)Goose Wrote:  
(01-01-2023, 01:01 PM)jacket3ree Wrote:  Lake Lag is not part of the flood protection plan. It has to be intentionally filled.



Is this even possible after the removal of the Lagunita Diversion Dam? I know that Lag used to get significant runoff that could at least create a swamp for a few months, but it has been a very long time since I have seen it filled, possibly the early 70s?



2017



https://twitter.com/LombardiHimself/status/838903019643121666
That diversion dam has not been operable since the 1930s and was removed to restore the steelhead run in the creek.  So all the times any of us have seen a full Lake Lag it has been after that dam ceased to work.  I hope that means that we can all expect to occasionally see a full Lake Lag from time to time.

I've been up to hike around a full Lake Lag in the past few years--perhaps it was in 2017 when that picture was taken--although the inoperable dam was removed in 2018.  2017 was our last really wet winter.  I'm interested to see what it looks like today, and whether it fills up this winter.  Anyone with eyes on the lake?

RE: Palo Alto Flooding - Mick - 01-02-2023

(01-02-2023, 09:22 AM)81alum Wrote:  2017 was our last really wet winter.  I'm interested to see what it looks like today, and whether it fills up this winter.  Anyone with eyes on the lake?

I think this is going to be a really wet winter. Next two weeks promise lots of statewide precipitation. The larger (500k AF+) California lakes and reservoirs have plenty of capacity. Shasta, Oroville, San Luis and Folsom are about 1/3rd full; Pine Flat, McClure, New Melones and Trinity are 1/4th full; Don Pedro, Berryessa and Almanor are about half full. Some of the others have lesser capacity; Diamond Valley, New Bullards and Friant are around 2/3rds full. Isabella's only 9% full.

RESSW.pdf (ca.gov)

RE: Palo Alto Flooding - BostonCard - 01-02-2023

Sierra snowpack is approaching 200% of normal for this time of year.  However, it is still about 60% of the expected season total.  It’s only December, and more is on the way, but last year we had one of the snowiest Decembers on record, followed by a dry January (no pun intended).  Though we were tracking for a good snowpack, we wound up the year below average.

Would be nice if this next storm is not the last of the season.  In the meantime, stay safe.  This was San Francisco:

[tweet]https://twitter.com/zachklein/status/1609241417410580486?s=61&t=9XxemsycEITgo2VQ6VDxow[/tweet]

And

[tweet]https://twitter.com/johnshrable/status/1609422811164205057?s=61&t=9XxemsycEITgo2VQ6VDxow[/tweet]

Stay safe my friends.


BC

RE: Palo Alto Flooding - 81alum - 01-02-2023

I just took a look at Lake Lag on the way to the game. It is probably only about 15 or 20% full. We will need a lot more rain for it to fill up like 2017.

RE: Palo Alto Flooding - Goose - 01-02-2023

(01-02-2023, 09:22 AM)81alum Wrote:  That diversion dam has not been operable since the 1930s and was removed to restore the steelhead run in the creek.  So all the times any of us have seen a full Lake Lag it has been after that dam ceased to work.  I hope that means that we can all expect to occasionally see a full Lake Lag from time to time.
Do you have a reference for this? While Wikipedia has been known to be in error, take a look at https://en.wikipedia.org/wiki/Lake_Lagunita (which I should have done before I asked my question :-). It says the lake was artificially filled until the "the late 1990s". I guess they could have been getting the water from somewhere else, but I can't imagine where. There was a fish ladder installed on the dam in the 1950s. https://news.stanford.edu/2019/02/27/stanford-removes-lagunita-diversion-dam/ That doesn't prove it was functional at that point, but if it wasn't I would expect just making a big hole would have been the way to go.

In any case the 2017 lake would have been the local runoff, not any "intentional filling". The following is "interesting" in that regard.
https://www.quora.com/Why-is-Lake-Lagunita-no-longer-filled This answer implies that as late as 2017 Stanford had at least the theoretical ability to fill the lake. The problem with the porous lake bottom supposedly goes back a long way. I have heard it was caused by plowing up the bottom of the lake to plant a victory garden during WWII. Have no idea if that is actually so.

RE: Palo Alto Flooding - 81alum - 01-02-2023

(01-02-2023, 12:20 PM)Goose Wrote:  
(01-02-2023, 09:22 AM)81alum Wrote:  That diversion dam has not been operable since the 1930s and was removed to restore the steelhead run in the creek.  So all the times any of us have seen a full Lake Lag it has been after that dam ceased to work.  I hope that means that we can all expect to occasionally see a full Lake Lag from time to time.
Do you have a reference for this?

Quote:The dam created a flume that filled Lake Lagunita with drinking water, but the flume and dam have not been operational since the 1930s, according to the university.

https://www.almanacnews.com/news/2019/03/07/stanford-removes-dam-giving-endangered-fish-room-to-roam

Both statements could be true.  Perhaps Stanford has used different methods to artificially fill the lake that didn't depend on the non-operative dam and flume.  I wonder if such methods could still be used.  I don't believe the flume is still in continuous existence from the creek to the lake--the golf course, Campus Drive, and new developments seem to have been built over it, although I have seen some sections of a dry ditch that look like they might be residual pieces of it.

As for the victory garden, I can believe that.  Many 19th century artificial canals and lakes were carefully lined with clay to retain the water, and piercing the clay would ruin the effect--like opening the drain in a bathtub.

RE: Palo Alto Flooding - 82lsju - 01-02-2023

reading this weather blog over the next ~10 days a really big series of storms could happen (and yes lots can change in a week)

Quote:Overall, this period is looking comparable magnitude to the peak of the extremely wet 2016-2017 winter in Northern California. Impacts, however, could well greater (or less) than those during 16-17, as individual storm sequencing will strongly dictate the magnitude of flooding that will result. There is little doubt at this point that there will be widespread flooding across most of the northern half of California over the next 10 days or so; the only question is whether it remains minor to moderate, or becomes severe and historically significant. Right now, both possibilities appear to be on the table–but recent trends in the ensembles have significantly elevated my personal level of concern regarding a major flood event. Stay tuned.

https://weatherwest.com/

RE: Palo Alto Flooding - Goose - 01-02-2023

(01-02-2023, 08:42 PM)81alum Wrote:  
(01-02-2023, 12:20 PM)Goose Wrote:  
(01-02-2023, 09:22 AM)81alum Wrote:  That diversion dam has not been operable since the 1930s and was removed to restore the steelhead run in the creek.  So all the times any of us have seen a full Lake Lag it has been after that dam ceased to work.  I hope that means that we can all expect to occasionally see a full Lake Lag from time to time.
Do you have a reference for this?

Quote:The dam created a flume that filled Lake Lagunita with drinking water, but the flume and dam have not been operational since the 1930s, according to the university.

https://www.almanacnews.com/news/2019/03/07/stanford-removes-dam-giving-endangered-fish-room-to-roam

Both statements could be true.  Perhaps Stanford has used different methods to artificially fill the lake that didn't depend on the non-operative dam and flume.  I wonder if such methods could still be used.  I don't believe the flume is still in continuous existence from the creek to the lake--the golf course, Campus Drive, and new developments seem to have been built over it, although I have seen some sections of a dry ditch that look like they might be residual pieces of it.

As for the victory garden, I can believe that.  Many 19th century artificial canals and lakes were carefully lined with clay to retain the water, and piercing the clay would ruin the effect--like opening the drain in a bathtub.
Makes sense. They for sure did "fill" the lake back when I was at Stanford, so there must have been a way. That way may still exist if it didn't involve the dam (which is now totally gone). The answer to the question  asked in 2017 implies they could but do not for cost reasons. Due to the significant leakage, I doubt even a big storm can actually fill it, but for sure it has significant water in it at times.

RE: Palo Alto Flooding - M T - 01-04-2023

A couple of the creek gauges are showing higher levels than Dec 28 but most are lower.  San Francisquito has barely budged. 

If you go to the creek cam website, you can see a sequence of the day’s images.

RE: Palo Alto Flooding - BostonCard - 01-04-2023

So far, this storm hasn’t packed as concentrated a whallop as the last one, but it will have staying power; rain is predicted off and on for the next 10 days.  For obvious reasons, that’s much better than a daylong deluge.

BC

RE: Palo Alto Flooding - winflop - 01-04-2023

I'm up in Napa right now. The city and county have poured tons of money into improving flood control both in the city of Napa and upriver. It looks like its working. No flooding last week and predictions are the Napa River will get close to flooding tonight and again on Sunday but will fall a couple feet short.

RE: Palo Alto Flooding - BobK - 01-05-2023

Great to hear about the Napa river that has flooded so many times over the years

RE: Palo Alto Flooding - winflop - 01-06-2023

BTW the creek has flooded upstream from the controls in PA/EPA...I don't know how to copy/paste photos here but I got an email from the Golf Course that shows the creek way way above its banks on the 3rd hole, to the point where the women's tee box can't be seen. The course was closed for three days this past week so that crews could clean up all the debris and downed trees from the overflowing creek.

Sure would have been great if the diversion to Lake Lag were working...

RE: Palo Alto Flooding - Goose - 01-06-2023

(01-06-2023, 08:46 AM)winflop Wrote:  BTW the creek has flooded upstream from the controls in PA/EPA...I don't know how to copy/paste photos here but I got an email from the Golf Course that shows the creek way way above its banks on the 3rd hole, to the point where the women's tee box can't be seen. The course was closed for three days this past week so that crews could clean up all the debris and downed trees from the overflowing creek.

Sure would have been great if the diversion to Lake Lag were working...
It can't. The Golf Course is in the way :-). Maybe they need to look at a "linear" water hazard?

RE: Palo Alto Flooding - Treebound - 01-09-2023

I saw the pictures from the golfcourse that Winflop is referring to.  They were pretty epic and there must have been a pretty bad blockage of the creek at the Sand Hill bridge just north of hole 3.  

For those that know, how did the University fill Lake Lag before?  Did they use the piping near the golf range to pull water from San Francisquito creek or was it filled via a different mechanism every spring?   It was truly a picturesque spot on campus and I have fond memories of taking sailing classes on the lake or hanging out at the "beach!"  I've heard rumors that in addition to the tiger salamander, the University feared that the levies might fail.

RE: Palo Alto Flooding - Goose - 01-09-2023

(01-09-2023, 10:27 PM)Treebound Wrote:  I saw the pictures from the golfcourse that Winflop is referring to.  They were pretty epic and there must have been a pretty bad blockage of the creek at the Sand Hill bridge just north of hole 3.  

For those that know, how did the University fill Lake Lag before?  Did they use the piping near the golf range to pull water from San Francisquito creek or was it filled via a different mechanism every spring?   It was truly a picturesque spot on campus and I have fond memories of taking sailing classes on the lake or hanging out at the "beach!"  I've heard rumors that in addition to the tiger salamander, the University feared that the levies might fail.
The main problem (allegedly)  is that the lake leaks so badly they have to continually pump water to keep it full. I heard, many years ago, that it wasn't so much the University feared the levies around the dam would fail but rather their insurance carriers were concerned about that and were going to charge them an arm and a leg for coverage against such a disaster. I have no idea if that is true or not.

RE: Palo Alto Flooding - 82lsju - 01-10-2023

Quote:In 2001, the University ceased manually filling the reservoir, and several years of drought have left the lake dry year-round. 

Over the course of the past two weeks, heavy rains have brought the water level up to at least eight feet. Signs posted around the lake by the University urged students to not step in. 


https://stanforddaily.com/2023/01/09/so-much-more-alive-stanford-students-rejoice-over-full-lake-lag/?utm_content=Jan-09-2023%3Futm_campaign%3Ddigest&utm_content=Jan-09-2023

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