Last known photo of St Francis Dam before it collapsed, © scvhistory.com

You know when you hear something you never noticed before, and then hear about it again the very next day? (It’s known as the Mandela Effect.)

I mean, I saw Chinatown many years ago and so understood that there was a rotten heart to Los Angeles’ water supply, but I never thought about where the water comes from – or understood how it trashed a valley and its communities in the 1920s.

Originally called Payahǖǖnadǖ, meaning ‘place of flowing water’, Owens Valley is a now dry valley north of LA.

I work with enough hydro dams to be curious about dam failures – there have been a few catastrophic failures in the 20th century – so wanted to watch a PBS documentary about the total failure of St Francis Dam in the valley. It failed because of hubris. It did not make it past its first day in operation. But the documentary was about much more than the immediate collapse and the hundreds of people who died that day.

Los Angeles basically stole the water, buying up water rights surreptitiously and sometimes illegally.   For some reason I can’t comprehend, it even memorialises the engineer responsible for the dam failure (and the overall aqueduct, which does still exist): Mulholland, of the Drive.

And the day after I watched the documentary, I read a review of a book titled Dust, by Jay Owens, using the Owens Valley as a 20th century example of humanity creating arid dust bowls where there were once thriving ecologies.

Metropolitan LA is a funny old place. I have spent plenty of time there as my brother moved to Azusa in the late 1970s, and retired to Orange County to the south. It was hailed as the city of the future once, but water is the big question mark, still. You would have to conclude that the LA basin is well beyond its carrying capacity, and perhaps always was.

Owens Valley, and St Francis Dam, seem suitable reminders of the challenge of sustainability. enshrined in the original BSI PAS 55 definition of Asset Management. The valley and its people – original and immigrant – paid the price for the development of a vast city region.

Not the first and surely not the last example, but a sobering reminder that water engineering is both hard, and not always on the side of the angels.