Vernon
concept saved a lot of people's lives probably and a lot of money. The Cherry Creek Dam
in Denver is one of them where they got a huge flood after the project had been built for
a while.
There were enough benefits from that one flood to more than pay for the project, not to
have to worry about any other floods paying for it. So the economics, even though it
looks good on paper, why you can't really be sure. Even though what has happened in
the past is a pretty good indication of what might happen in the future, we have such a
short time span for looking at the past compared to what the future is going to be that we
don't have that good of a fix on what is going to happen in the future.
Besides that, when you're looking in terms of hydrology, probability analysis--if you had
thousands and thousands of years of record you could get a real good indication of what
the probability of flooding was going to be in the future. But that doesn't necessarily
mean the probability of flooding in the next 30 years. It may be real good for an infinite
period. But for the next 30 years or the next years that you're really concerned about
in your life span, that probability may not be right at all. The next 30 years may be wet
years, they may be dry years.
So, even though you have the best possible analysis of what the probability conditions
might be in the future, is that right for the next 30 years. Is that right for the next hundred
years? You say it is, you know in a lot of cases on the average it will be, but it's not
going to be for a particular project or a particular area, it is probably not going to be right.
Like having one foot hot and one foot cold, but on the average you're comfortable.
Q ..
So in your side of the business, you really have to be more conservative.
A
Well, we
or most of us, feel that you should be conservative because to error on the
low side or I mean to error on the one side, the consequences are more severe than they
are in the other direction.
Dam Safety and the Big Flood
Q ..
Do you want to continue your comments on the conservative nature of hydrologists?
A
Well, of course, I guess one of the biggest areas where conservatism comes into the
picture is in dam safety and the probable maximum flood. Are you familiar with the
probable maximum flood, have you heard about that?
Previous Page
