Siltation & Dams

[Tim Bousquet <chicoexaminer@xxxxxxxxx>]

Now that I think about it, siltation is a big problem
even here in CA. All these huge dams we've built don't
last forever; they have projected lifetimes that
depend on the rate of siltation. Shasta Dam, for
example, was given a projected lifetime of 100 years
when it opened in 1939-- after which the area around
the dam will be so silted that water will flow over
the top. There's also a down-stream matter of
increased erosion as river bottoms are scoured but not
replaced with new deposits, which are left behind the
dam. I think I see how the problem could be at least
mitigated with dredging, but I don't know why they
would give a lifetime for the dam in the first place
if the problem could be solved. Interestingly enough,
2039 is about when all the projected problems with
global warming and the need for increased capacity
kicks in. I'll find out more on this.

tim

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