Sea water for fire fighting?

[gfh77665]

Maybe this is wild idea. Cal has allowed so many reservoirs to go dry and the fires are raging out of control. So why, in an extreme, catastropic emergency only, can't sea water be used for fire fighting? Yes, I am well aware the salinity content in the soil would rise, but it could wash out in time. Wouldn't that still be better than the whole region burning to the ground?

Also, a desalinsation plant was once proposed in Huntington Beach, IIRC.

 

[cptbarkey]

Iron oxide has been dropped all over (the red stuff), also be interested in this saltwater information but been too busy to google reasons other than the obvious Roman tactics of killing fertile land.

 

[MNgopher]

Saltwater is being used in some cases. The CL-415 water bombers are an example that can scoop ocean water and drop it. However, most water bomber aircraft are not set up to handle the corrosiveness of salt water.

Many of the water supply issues are not issues caused by dry supply reservoirs (thinking big dams/lakes, etc). Instead, these are classic firefighting water use issues faced by any water system supply designer. All that water flowing in pipes faces resistance by friction losses and other losses in the pipes. Open enough spigots and the water pressure goes down everywhere and you can't force more water into the system. Most systems are driven by water towers, who are sized to supply water to put out a fire or two at one time, and sized to store enough water to bridge high demand times by filling during low demand. Constant wildfire suppression will drain this type of system... Wildfires strain water supply systems like no other when a fire hydrant system is available.

 

[gfh77665]

Yes, the water bombers is what I had in mind. The corrosion could be handled or fixed later, or even replacing the whole plane is better (cheaper) than letting a major US city burn to the ground.

 

[Mechanician]

Saltwater is being used in some cases. The CL-415 water bombers are an example that can scoop ocean water and drop it. However, most water bomber aircraft are not set up to handle the corrosiveness of salt water.

Many of the water supply issues are not issues caused by dry supply reservoirs (thinking big dams/lakes, etc). Instead, these are classic firefighting water use issues faced by any water system supply designer. All that water flowing in pipes faces resistance by friction losses and other losses in the pipes. Open enough spigots and the water pressure goes down everywhere and you can't force more water into the system. Most systems are driven by water towers, who are sized to supply water to put out a fire or two at one time, and sized to store enough water to bridge high demand times by filling during low demand. Constant wildfire suppression will drain this type of system... Wildfires strain water supply systems like no other when a fire hydrant system is available.

Many have simple answers to complex problems, but rarely a solution.

 

[MNgopher]

Yes, the water bombers is what I had in mind. The corrosion could be handled or fixed later, or even replacing the whole plane is better (cheaper) than letting a major US city burn to the ground.

I don't think anyone has said the fire fighting aircraft have not been able to source enough water. The issue has been firefighters using the fire hydrant system and essentially draining the systems of water...

In addition, there are times the firefighting aircraft simply cannot fly, due to weather conditions.

Also easy to say that ignore what can happen for now, but I'd be willing to bet there is a pretty solid safety culture behind wildfire aviators - despite taking risks, they are calculated risks.

 

[Hall]

....and another that will get locked up. Leave this part out, "Cal has allowed so many reservoirs to go dry" and ask the question in general (next time).

 

[KGMtech]

The salt water will damage the soils preventing regrowth, however some eggs get broken for an omelet. If there is not enough regrowth of whatever on those hills, then the risk is bigger for mudslides. Not trying to be negative, but this will be hard to deal with eventually.

 

[Hirev]

The are and have been using some sea water to fight the fires.

 

[y_p_w]

There's nothing preventing sea water from being used. The city of Los Angeles has fire boats that spray saltwater. Some have noted that they are using scoopers to bring in saltwater.

Here's a guy who has a unique skill set as a former merchant seaman, but also a volunteer or professional firefighter at one time or another. He said that it's not that big a deal to either spray saltwater into soil nor to pump saltwater into dedicated hydrant systems. When done the equipment and pipes can be flushed out and saltwater doesn't turn soil into a wasteland. There's constant sea spray all along the coast, and that doesn't prevent grass from growing on golf courses, nor does it kill trees. Heck - the Lone Cypress at Pebble Beach has been hit by saltwater over and and over for well over a century, and it's not dead yet. However, they probably won't pump saltwater into the drinking water system, which feeds many hydrants.





The problem with hydrant pressure was related to altitude, tank placement, and water level, and had nothing to do with lack of available water. Water levels are very high at Southern California reservoirs right now, especially those fed by the California Aqueduct.

 

[64bawagon]

The pumps on the apparatus will require a thorough flush with fresh water when they are done. Prolonged use of salt water will attack the pump packing and deteriorate it. Salt water is commonly used in the middle east. They learned the hard way that the typical truck mounted pump would not tolerate extended salt water.

 

[skyactiv]

I think the high winds made this an impossible fight. When someone's home is on fire, a fire department will usually send 2 fire trucks. They just didn't have the equipment and manpower for this battle and that is no fault of anyone.

 

[daves87rs]

I assume this will only get worse……

 

[Hall]

the drinking water system, which feeds many hydrants.

I can't imagine anyplace that has separate systems for drinking water and hydrants. It is the same water. Fire departments routinely flush out hydrants and this churns up sediment that settles in the piping and residents will be told to let their water run until it runs clear.

 

[y_p_w]

I can't imagine anyplace that has separate systems for drinking water and hydrants. It is the same water. Fire departments routinely flush out hydrants and this churns up sediment that settles in the piping and residents will be told to let their water run until it runs clear.

One of the videos I linked had an explanation of how San Francisco has two water systems for fire hydrants, and the hydrants are different when attached to each system.

https://sf-fire.org/our-organization/division-support-services/water-supply-systems​

High Pressure Auxiliary Water Supply System​

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The Auxiliary Water Supply System, more commonly known as the San Francisco Fire Department High Pressure System, is a system of mains and 1889 High Pressure Fire Hydrants, independent of the domestic water supply, built solely for the purpose of firefighting. The system is supplied with fresh water, by gravity, from a reservoir and two tanks located at high elevation in the city.​

I suppose one of the questions was probably about why not pump to the maximum height in the area. I guess that sounds great in practice, but how much is it going to cost? I know where I live (on a hillside) there's an elevation surcharge for water. This explains how they "stratify" water storage to bridge between water needs at higher elevations and the cost of pumping. I guess people can make all the claims about overengineering a system for an absolute worst case scenario, but in reality, who wants to pay for that?

http://www.firehydrant.org/info/cascade.html​

Water delivery becomes more complicated in hillside communities. The East Bay Municipal Utility District (EBMUD) distribution system covers over 1500 feet of elevation changes throughout the Oakland-Berkeley hills. If all water storage was kept at the highest point of the system, water pressure at the lower levels would be about 650 p.s.i. and the cost of pumping the water supply to such a high storage elevation would be prohibitive.​

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To provide water to hillside communities, the distribution system has to be stratified into multiple zones with each zone serving a specific elevation area. This stratified design is known as a "cascade system."​

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Each zone is served by one or more reservoirs and is its own self-contained distribution system. Reservoirs are designed to provide at least two days of domestic consumption plus have a reserve capacity to provide between two and three hours of required fire flow.​

 

[dbias]

As a retired firefighter I can attest that most hydrant/water systems are designed to supply normal water usage and also flow maybe four hydrants for fires per sector. They can, and I have called the water company to increase pressure for large fire events but this has to be done in a controlled manner or blow outs will occur.
The fires around LA are catastrophic and the water system is not designed for this and no one is willing to pay for a system that could handle this type of situation.
The wind is the limiting factor here. Most Aerial apparatus cannot be used above thirty mile an hour winds and this affects the planes too. They’ve had 100 mph winds and there is simply nothing they can do in this situation.

 

[JHZR2]

The corrosion is an issue. But the salt water can destroy the local areas too. This happened in some places in the country where too much dissolved solids in water was used for irrigation. Though this is a last ditch effort so what’s worse…?

 

[4WD]

Prevention means more - how about non flammable roofs in these areas going forward … (metal, tile, etc)
Anyone read about the guy who pumped pool water on his roof ?

 

[burbguy82]

You would have to have a pretty serious system that could handle sea water on demand to serve the hydrants. At least a 400 series stainless steel service line, branches, valves and hydrants. A pretty serious network of either pumps or pumps and water towers, again, all in at least 400 series stainless.

All of which would not look good.

Just like the covering of oil pump jacks in the middle of a neighborhood, with a nice looking shell.

 

[alarmguy]

Maybe this is wild idea. Cal has allowed so many reservoirs to go dry and the fires are raging out of control. So why, in an extreme, catastropic emergency only, can't sea water be used for fire fighting? Yes, I am well aware the salinity content in the soil would rise, but it could wash out in time. Wouldn't that still be better than the whole region burning to the ground?

Also, a desalinsation plant was once proposed in Huntington Beach, IIRC.

Seawater is being used to fight the wildfires.
However, it has own set of problems, both on equipment and the environment.

Pumping it up from the ocean is a major problem and that is not done. Salt is highly corrosive and damages the environment, possibly for years to come. But when the ocean is calm, planes are using seawater to dump on the fires.

This is a pretty good explanation;
https://theconversation.com/firefig...g-saltwater-is-typically-a-last-resort-247188