Thanks to Char for sending this.. here’s an excerpt:
Not all fire’s consequences are as obviously beneficial, at least not for those of us dependent on mountainous watersheds to sustain our thirsty downstream communities. Yet it turns out that in this context too words, and the thoughts and actions they generate, matter.
Although some reports about the Rim fire have highlighted San Francisco’s complete reliance on the Hetch Hetchy reservoir, located within Yosemite National Park, they have been freighted with dire anticipation — will airborne ash clog up its century-old works, imperiling the City by the Bay’s supply of potable water and electricity?
The immediate answer is no, or at least not yet, leading the San Francisco Public Utilities Commission to predict that due “to the rocky, granite terrain and limited brush along the perimeter of the reservoir, there is little risk for direct impacts on the reservoir.”
Whatever relief this response may bring to its anxious customers, it may only be temporary and is certainly partial. That’s because the real question, which compels us to think across a multi-year future, is what happens when rain falls and snow flies in the high-elevation watershed of the Tuolumne River that feeds the threatened reservoir?
This coming winter and spring, and in successive storm seasons, precipitation landing on the burned-over terrain may trigger debris flows that could compromise the water quality within and the functioning of the Hetch Hetchy reservoir as spigot and generator.
Denver had to confront a similar challenge in the wake of the massive Hayman fire of 2002. Then the largest and most intense blaze in Colorado history, it had a major impact on the Mile-High City’s water supply. Ever since, the American Planning Association reports, the tributaries of the Upper South Platte River have experienced an “increase in the number and severity of flooding events” which in turn has let loose “large amounts of sediment and debris threaten[ing] the vitality of watersheds and ecosystems.” These post-fire environmental consequences accelerated public and private collaborations to restore affected riparian ecosystems, an involved and expensive process that continues more than a decade later.
The 2009 Station fire likewise damaged key portions of the Los Angeles and San Gabriel rivers’ watersheds, leading to initial interventions, with more projected, to regenerate forest cover, river flow, and water quality.
It’s unfortunate that San Francisco did not pick up on these broad hints and in advance work with local, state, and federal agencies to reduce the threat that a fire like the Rim could pose to its single-source water supply. But this would have required the city’s Public Utility Commission and Division of Public Works to think proactively, for journalists there and elsewhere to offer more historically informed stories contextualizing fires across time and space, and for us collectively to build a more forward-thinking culture determined to resolve problems before they blow up in our faces.
I did have a quibble with “Set aside the concept that fires inevitably, irreparably destroy forests and consider instead the idea that fire may have regenerative capacity.” I think there are “good” fires from that perspective and “bad” fires. Hayman (photo above) may have been a “bad” fire.
I know it’s not irreparable, but I think people can say they prefer living green forests to this (photo above); knowing it will come back in a couple hundred years provides little satisfaction, and people’s (and certain wildife, bugs, plants, etc.) preferences for living green trees are OK. Aren’t they?