PUB00106

• Year: 2000
• Title: A History of Drought in Colorado: Lessons Learned and What Lies Ahead
• CWCB Section: Water Conservation & Drought Planning
• Author: Colorado State University
• Description: Lessons learned and what lies ahead
• Publications - Doc Type: Tech Report

~Water in the Balance ~

Red Dawn II: What May Lie Ahead
(Colorado's "Worst Case Scenario" Drought)

Colorado has come a long way since the "dust howl"
years. We manage OUf crop and grasslands with soil and
water conservation in mind. We store large volumes of
water from wet years for use in dry years, and from wet
seasons for use in dry seasons. We divert water from areas
with lower demands to areas with higher demands. Still we
know, history has a way of repeating itself.

OUf study of past droughts has shown that the worst
droughts are multi-year droughts. Vegetation dries up,
soils blow, stored water reserves are gradually depleted,
wells go dry. What begins as a minor inconvenience can,
for many people. end in the loss of revenues, property, and
livelihoods.

Sometime and somewhere in Colorado's future, a climato-
logical scenario may unfold that goes something like this:

For two to four years, winter and spring precipitation.
in Colorado s mountains will fall far short of the
average we have become accustomed to. <<i"nter
precipitation totals of 60 to 70 % of average in the
high cowmy will be followed by hot, dry summers on
the Eastern Plains and Western Slope.

The combination of diminished supplies along with
heavy use of irrigation water will gradually deplete
surface reserves and make ground water pumping
more necessary. The Ogallala aquifer will again
show signs of rapid depletion like it first did in the
1970s. and the cost of pumping groundwater will
increase.

Dryland vegetation will grow shorr and sparse. Bare
patches will appear on sandy soils. Plant residue on
unirrigated crop land will decrease each year.
Despite efforts to retain soil moisture, crops will suffer
and more topsoil will blow.

Then along will come a winter like the winter of
1976-77 with snowpack accumulations less than
50% of average over most of the Colorado mountains,
shutting down some ski areas.

Spring will not bring its nonnal series of widespread
rain and snow stonns to the
Front Range and Eastern
Plains. A few storms will
tease and appease us, but
onlyafew. Forthe months
of April through June, only
about half of the average
moisture will fall.

Strong westerly and southwesterly winds will blow
frequently, kicking up more and more dust as
agriculture production falters. Giant dust clouds will
blow through our cities and across fields.

Water rights conflicts over municipal uses, agricul-
tural uses, and instream flows will intensify, as will
conflicts over interstate compacts and agreements.

Finally, with reservoirs already very low, a long, hot
summer will bring frequent temperatures near or
above the 100 degree mark at lower elevations.
Reservoirs will be too low to provide hydropower to
meet demands for electricity to run air-conditioners
and relieve us of the heat. Blackouts or brownouts
will occur in some cities.

Forestfires will race through thousands of acres of
dry timber, and clouds of smoke will turn suftsets Oft
the Front Range a deep blood red.

Do you believe this? Will we be ready ifitreally does
happen? Colorado's water planners think long and hard
about drought. They know it is a part of life in the semiarid
west. But most of us never give it a thought. Frankly, we
haven't had to. The last multiyear Colorado drought ended
in the late 19705, and the last severe and widespread year-
long drought Colorado ended in 1981. Yes, there have
been local droughts since then, some quite severe, such as
the drought southwestern Colorado experienced in 1989-
1990 and again from the late summer of 1995 to early 1996.
But droughts of that duration are not uncommon.

Overall, since 1982, Colorado has enjoyed the longest spell
of wet (compared to historic averages) weather statewide
since the favorably cool and wet period from 1905 through
1929 when so much of Colorado was settled and farmed.
For portions of southeastern Colorado, the decade of the
1990s is the wettest decade since weather observations
began in the late 19th century.

The heavy precipitation of the 1980s and 1990s does not
guarantee that wet weather will continue into the 21st
century. Neither does it assure us that drought is immi-
nent. But one way or another, we know that drought will
return. The longer we go
without drought, the mOre
likely we will be ill-prepared
when drought makes its
inevitable next visit to Colo-
rado.

Are we ready?

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