[Atomic-S (OP)]

I wonder what the cost of fighting California wildfires by means of a permanently-installed sprinkler system covering all lands within a quarter of a mile of civilization, would be compared to present methods. (To say nothing of improved effectiveness).

[Don_1]

I think you would need more than a sprinkler system to stop fires like those.

Just one glowing ember whipped up by the wind and carried 100yds into fresh, dry locations can start a new fire.

[Don_1]

Perhaps it would be better to consider a ring firebreak.

It would need to be very wide, perhaps 500yds or more, constructed of concrete and regularly maintained to ensure it is kept free of any combustibles.

Although it wouldn't look very nice, it would have the advantage of serving two purposes if it were to double-up as a ring route freeway around the town/city.

Should Arnie wish to take up my brilliant idea, please tell him I require a huge wad of dosh for my advisory service.

[Bored chemist]

In the long run it might be cheaper to move the population to an area that is less affected by wildfires.

[tuttut]

Wouldn't all that concrete make local temperatures higher and help the fires?

[Don_1]

It probably would have a localised effect on the ambient temperature, but I doubt it would start any fires.

If Arnie dosen't like this idea, then I shal require an even larger wad of dosh for my other plan. Don't tell him until I receive a plain brown envelope stuffed with pictures of Benjamin Franklin.

A MOAT!!!

[peppercorn]

In the long run it might be cheaper to move the population to an area that is less affected by wildfires.

Yes. It's even more insane than building on flood-plains!

Wildfires (to some degree) are part of a natural cycle of certain forests - I imagine people are accelerating the process in some cases though!

[SkepticSam]

Wouldn't covering vast area's with impervios surfaces such as concrete cause more problems than leaving it vegetated? The thermal and conductive storage capacity of all that concrete would be large and could generate enough heat to evaporate a lot of the precipitation that would normally fall on vegetation, grass, soil and wooded area's.
Not only that but large concreted area's are also a cause of flash flooding where torrential rain runs off the concret instead of soaking in to the ground. This would affect the water table and the soil moisture. A dryer environment would lead to more fires as the trees and vegetation would be dryer and one stray cigarette accidentally discarded or not could prove disasterous.
Wouldn't it be cheaper and easier to regulary burn the vegetation and for firebreakes that way?

[Atomic-S (OP)]

good thoughts; a concrete ring does pose the stated problems. Regular thinning of the forest would also obviously be of value; that is in fact done in some places in the American West; however there is the problem of cost -- it often does not pay for itself with the harvested materials -- and there have been legal and political obstacles. The removal of which has been recommended by some knowledgeable observers, but easier said than done. Similar problems have attended controlled burns, which may account for the severity of certain fires in recent years. Granted that all this should be done, using a wide concrete barrier poses, among other things, the difficulty that if the land is ever to be used for any thing else, there is all that concrete that may have to be removed. My suspicion would be that a super sprinkler system covering the same territory would be much nicer, and may well cost less than installing concrete (just a guess). Of course, we are talking about installing a MAJOR system, way bigger than anything in a building. The question of where the water would come from, comes up. My first suggestion would be to draw it from major reservoirs or rivers. My second suggestion would be to build additional reservoirs that would slowly fill during non-fire conditions, that would expand the peak load capacity of the water system, so as to be able to handle this.