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Re: Define drought

Connie Woodhouse (Connie.Woodhouse@noaa.gov)
Tue, 24 Oct 2000 09:31:56 -0600

On the subject of how to define drought - this is a pretty key
question. In my work with reconstructions of streamflow and drought,
one goal is try to make the reconstructed records useful/meaningful for
planning and management. This means a number of things, like explaining
how the reconstruction is related to the instrumental record, but also
it means trying to take the time series of reconstructed flow and
presenting in way that says something about the 20th century droughts in
comparison to prior droughts. To do this, drought must be defined and
quantified. The way it is defined and quantified is definately to
relate to whom is to use this information and the application.
Traditionally, I've looked at the 1950s and 1930s droughts as the
measures with which to gage droughts in the past, but maybe this isn't
the best approach in all cases. I guess it is the 'worst case'
scenario. But I've become more aware that different features of drought
need to be examined and quantified, like duration, mean annual severity
and overall magnitude.

Connie

John Winchester wrote:
>
> Hello, I am John Winchester, a water resources engineer at
> Hydrosphere, a natural resources consulting firm in Boulder.
>
> Of course no discussion on drought would be complete without the
> recognition that a "drought" means different things to different
> people. For water users with no carry-over storage, the drought to
> fear is any year where precipitation is so far below average that
> stream flow becomes insufficient to meet demands. The town of
> Nederland is in this group, as is direct diversion (and dry-land)
> agriculture.
>
> While systems with carry-over storage may be able to go through
> the single really dry year, a string of drier-than-average years may
> deplete storage to the point where supply is inadequate. The city of
> Denver and anyone supplied by a well (with no storage) fall into this
> group.
>
> John
> See http://basin.org/forum/fire-flood.html for more information on this list.

-- 
Connie Woodhouse
NOAA Paleoclimatology Program
National Geophysical Data Center
325 Broadway  E/GC
Boulder, CO  80303
ph: (303)497-6297
fax: (303)497-6513
email: woodhous@ngdc.noaa.gov
See http://basin.org/forum/fire-flood.html for more information on this list.