I just watched her online yesterday. Talk about someone getting ready to run for mayor next round. WOW!!! Talk about one tran thought. She would not answer any questions about the water shortage but she did talk a whole lot about equality, dei, and inclusen. Wonder how she has any time to be head of DWP. I’m pretty laid back but this lady is interested in only one thing, the mayor seat…
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SteepNrocky answered those questions with links to DWP articles that explain the history. I think it is post #21 or #22. It answers many/most of the questions that keep coming up.
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Water - Water - Who Needs Water?
Maybe someone else has already entertained folks with some simple math and I missed it. If so, sorry for the rerun…
Although current Type 1 engines are rated anywhere from 1250 to 2,000 GPM, let’s stay really reasonable for a structure defense mission. Two 1-1/2 lines (not even gonna go with 1-3/4 or using more than two lines) use approximately 125 GPM each–very reasonable and manageable in structure defense. That’s 250 GPM per engine. Per hour that 250 times 60 or 15K per engine. Let’s just use 20-Alpha Strike Teams even though that is grossly under what was there, but hang with me to prove a point. So, 100 engines flowing 15K per hour means we are pumping 15K times 100 or approximately 1.5M gallons per hour. If we do that for a day, we’ve pumped 36M out of the system in just one day. Do you think there is any municipal system designed for a 36M draw in a day on top of the usual demand in the rest of the system? Then lets talk about homes that burn and become unmitigated open-butt flows of water because of melted plumbing. Open up every fixture (shower/tub, toilet, sinks, etc.) and what do you think that flow is per residence per hour? Multiple the number of homes like that and add that to what the engines are pumping and the numbers become completely unrealistic for any system to maintain for any length. I had many rural and not so rural areas where we would tap out our system with 5 hydrants flowing. That’s why you assign someone the position to work with the water department to figure it out – boost pressures and look for alternatives.
Systems are/were designed based on ISO/NFPA fire flows plus normal residential demand, not for an urban fire LA just experienced that is moving block after block in a wide swath for a day(s). If this is going to be more than a complete rarity, to avoid running low or out of water, someone is going to have to design a completely different type of municipal water storage and delivery system and then fund digging up every street in any fire prone area – now with the “urban fire/conflagration” designation.
Just a thought…
For the Way Back Machine
Look at the 1993 Laguna fire and the results of the Times investigation. We (Kern Co) had a Strike Team there and homes burned above where the system couldn’t adequately push water through the distribution system.
Platte, Mark; Brazil, Jeff (November 14, 1993). “Water Pressure Burned Laguna”. Los Angeles Times. Archived from the original on September 19, 2023.
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5" LDH Lays with engines series pumping after they dump their beds. Nah, too much hose, too many engines. Hose wagons?
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Would be nice if some portable pumps or pump stations could of be set up along the coastline. At least to fill up engines. An excavator could put one in place and build a little pad pdq.
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a 1000 3/4 inch water mains flowing are what killed the system, don’t tell the media, it wasn’t fire equipment that drained the system.
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Well… The big city to the north has a different plan… mostly due to earthquakes and water issues. But there are applications in other jurisdictions for ocean, bay, river, reservoir. Give it a watch… they have a couple different plans for long-term water supply including a portable pump ops too. Maybe a water point set up.
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These are great examples as New York, San Francisco, and many other large departments whom have learned by fire have made arrangements near the coast. but It kind of proves my one point,
If this is going to be more than a complete rarity, to avoid running low or out of water, someone is going to have to design a completely different type of municipal water storage and delivery system and then fund digging up every street in any fire prone area – now with the “urban fire/conflagration” designation.
LDH and super pumpers work well near the coastline, not so easy along the Angeles front county like the BurGlePas, Sierra Madre, areas and and all the other communities that fall north of the 210.
…And a thousand 3/4 inch connections at 25 gpm could add another 1.5M per hour - hour after hour after hour.
If it was easy and happened often enough it probably would have been solved by now.
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True, Chief, exactly why we preplan for strengths and weaknesses of specific areas, learning from past issues, our’s or other’s. A plan that doesn’t go exactly as expected is better than no plan.
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I believe the term is
LOW FREQUENCY HIGH RISK
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Rural areas got millions in state fire prevention funds over parts of L.A. that burned
Lots of finger pointing at the LA Times.
L.A. City Council seeks transparency on empty reservoir, dry fire hydrants
L.A. fire officials could have put engines in the Palisades before the fire broke out. They didn’t
Since the 1906 quake, SFD has had a separate hydrant system away from the domestic water supply. Maybe this is something worth exploring.
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Does anyone have a timeline of when hydrants went dry? I think that part of the equation really matters. At some point it became unstoppable do to the speed. Any of these other solutions to bring water are so slow and logistically burdensome. So in the window of initial containment (if there really ever was one) they had water then this is a dead discussion. 80 to 100 mph wind, urban fuels yada yada I dont think there was ever a time someone said man if we could just do X we got this wrapped.
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Right idea, not applicable in all spaces. San Francisco has unique needs and they have created unique solutions. The highest elevation point in the city is 962 feet (twin peaks) It lies more than 6 miles inland from the Marina. (so 6 miles of hose covers the majority of the city on relatively flat ground) The Pacific Palisades/Malibu areas are basically mountains at the oceans edge. Rising to 2000’ elevation within 3 miles. Totally different hydraulics problem, will need a totally different solution. (pre-position the water in a high place)
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I’ve gathered the intel and have been meaning to run through the calcuation, just haven’t gotten to it yet. At an earlier city press conference (day 2 or 3?) A water spokesperson stated that the Palisades was protected by 4 different reservoirs (didn’t name them - haven’t ID’d which she was speaking of) Each contained about 1Million gallons. The Santa Ynez reservoir capacity of 117 million gallons was dry prior to the incident due to failure of the floating roof. That left about 3,000,000 gallons to protect the area. The fire broke out at 10:30 am. The first reservoir went dry at about 4:45 pm. (lasted 6 hours) The second went dry at 8:30 pm (an additional 4 hours) and the last reservoir was reported empty at 3am the next morning (after a 16 hour firefight) … like I said I haven’t completed the math problem, so I can’t show my work here, but I’m actually surprised the water lasted that long.
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… and the LF/HR approach HAS changed our tactics. In the early hours of the firefight, the “leaders intent” was frequently rebroadcast to fire units. (and I’m paraphrasing)… “Save lives first” just as it was during the Tubbs fire and the Camp fire. Instead of engaging, even in defensive operations, the most effective action has become removing the people from the hazard area as a first priority - then deal with the fire after. It will be pretty difficult to develop a successful offensive strategy against the powers of nature aligned against us.
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Time for some great perspectives from Bill Burr.
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We must remember that each reservoir also has a plumbed fill line usually 12 inches plus. As the water level drops in the tank the fill lines open to keep the tank full, under normal usage. There was most likely many millions of gallons of water added into the system beyond the actual tank size.
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Completely agree! Just pushing the water up to storage tanks from sea level to 1,500 feet would require overcoming over 650 psi of back pressure. That’s a lot of design work with relays, piping, and friction loss. Definitely different than SFO area.
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It would be interesting to know the recovery rate. I’m sure they are/need to be great gpm from multiple sources. As long as the primary and secondary power sources remain viable for the pumps to operate. Again, probably not designed back then for the urban fire scenario. That is the pinch point in our local community water system, our recovery rate is only about 8 or 9 gpm. There are dozens of us on a system that is stretched under anything but normal.
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