Identify drought vulnerable sectors: Colorado
Climate Patterns and Water Sources
Colorado is a semi-arid state. The statewide annual precipitation averages only 17
inches, and many areas receive less than 10 inches. Colorado is a headwater state, which
is the source for several major rivers that flow out to many other states. Meanwhile, there
are no major rivers that flow into Colorado. Consequently, the only source for new water
supplies to the state is from natural precipitation in the form of rain or snow. Although
the majority of the state is arid or semi-arid, more than 25 inches of water falls as snow
annually in the highest elevations of the Rocky Mountains,. The water is stored within
snowpack and later becomes available as streamflows. The level of winter snowpack is a
major determinant of water supplies in the following spring and summer. To adapt to this
dry climate and inconsistent precipitation, the state has constructed more than 2000 dams
and reservoirs to manage water supply.
Colorado is divided into seven water divisions by major river basins. They are the
South Platte, Arkansas, Rio Grande, Gunnison-Uncompangre, Colorado Mainstem,
Yampa-White, and San Miguel-Dolores-San Juan. Each division has its unique
precipitation patterns and seasonality. Some divisions’ wet seasons might be another
division’s dry season. Even within a water division, precipitation varies greatly by
elevation. Due to such climate diversity, it is not common that drought would spread over
the entire state. Most droughts were localized. Multi-year droughts occurred but
infrequently.
Major Water Users
Water use can be divided into two main categories for the state: consumptive use
and nonconsumptive use. The former includes: agriculture, industrial and residential
water uses; and the latter includes: recreation, hydropower and environmental uses.
Agriculture
Agriculture in Colorado accounts for a smaller share of the state economy
compared to Nebraska, but it is still a large and important industry. According to BEA
2004 data, agriculture produced 2,015 million dollars and created 14,547 jobs,
encompassing 1% of the Gross State Product and 0.7% of total employment, respectively.
Colorado’s four leading crops are corn, wheat, hay and potatoes. They accounted for
about 90% of the total value of crop sales. Cattle and calves are Colorado’s number one
agriculture commodity with the total sales value over $2.5 billion.
Agricultural production gets water from four sources: precipitation, groundwater,
water from streamflows and reservoirs. Dryland crops and pastures rely solely on
precipitation, and thus are most vulnerable to meteorological drought. Colorado has a
large acreage of dryland crops (8.9 million acres) as well as pastures and rangeland (17.3
million acres). Major dryland crops include winter wheat, sorghum and corn.
Irrigation makes crop growth rely less on direct precipitation, and thus more
resilient to drought in most cases1. Irrigation dominates freshwater consumption in the
state. There are about 2.5 million acres of farmland irrigated, ranking number 4 in
western states (44% of Nebraska). According to a USGS 2000 water use report, irrigation
alone accounts for 90% of total freshwater consumption in Colorado, with 18% from
groundwater and another 82% from surface water sources (Figure 1). Eastern Colorado
has few surface water supplies but large groundwater resources mostly from the Ogallala
Aquifer. Because of the low recharge rate, groundwater in this area is considered
nonrenewable. Colorado also has large nontributary groundwater resources stored in deep
underground rock aquifers. (More information is needed to understand the impact of
drought on nontributary groundwater resources.)
Municipalities
Colorado has a fast growing population and expanding municipal areas. Drought
poses a threat to both industrial and residential water consumption, especially during the
summer as about 50% of municipal water is used for watering of lawns and landscapes.
Restrictions on water use may be triggered when severe drought occurs.
Recreation and Tourism
Colorado is one of the most popular destinations for both domestic and
international visitors. Tourism and recreational industry is a major part of the state
economy. According to the Colorado data book, the tourism industry generated
approximately $7.3 billion from domestic overnight visitors in 2004, and an additional
$900 million from international travelers. Since many of the recreational activities are
water related, drought could bring critical damages to the business.
Drought impacts exist for both winter and summer recreational activities. In
winter, lack of snow precipitation by November is critical to ski resorts, because a large
portion of their profits are generated during the Dec/Jan holiday season. With the
technology of snowmaking, many resorts have managed to lessen the winter drought
impact, but it increases costs and competition over water rights.
Each year, snow precipitation is stored as snowpack at higher elevations. Snow
melts and becomes streamflows during the following spring. White-water rafting
business is affected by the level of in-stream flows. Reduced streamflow will result in
less visits and shorter rafting season.
Other summer recreational activities, like fishing and boating, can be affected by
drought as well, especially a multi-year drought which depletes water in lakes and
reservoirs. Drought also increases the number of wildfires, which result in the closures of
national and state parks, health threats due to smoke and flames, and declined visits to
neighboring places that are not on fire (because the images of wildfires on state-level and
national media influence people’s vacation choices).
Schneckenburter and Aukerman (2003) have studied the economic impacts of the
2002 drought on Colorado’s recreation and tourism, through a series of one-on-one
interviews with representatives from various sectors. Specifically, drought effects are
reviewed and described for Colorado state and county parks, the boating industry, the
rafting industry, and the fishing industry. The study confirms that drought impacts are
1
There is argument that irrigation might increase the production risk if water supplies are uncertain.
enormous and severe on the local resort communities, especially for those small
businesses.
Hydropower electricity
In Colorado, the annual net electricity generation from hydropower averaged
around 1.6 million Megawatt hours, accounting for only 0.3% of total hydroelectricity
generation in U.S. The hydroelectricity generation data from 1990 through 2005 are
plotted in Figure 3. Since 2001, the net hydroelectricity generation has been declining,
and it is probably due to the reduced streamflows and low levels of reservoirs caused by
recent droughts.
Conclusion
Because precipitation is highly variable in both time and space, there are different
dry and wet seasons within each river basin and sub-river basin. Multiyear drought
encompassing large areas of the state is rare. What is most common is a single season
drought in a local area. Therefore, the industries affected by drought and the magnitude
of impacts differ greatly by timing and location; drought impacts can be severe locally
but limited at statewide.
Dryland agriculture and water-related recreational business are the most drought
vulnerable sectors in Colorado. Our study can focus on these sectors and analyze the
specific impacts of drought in each river basin.
Lack of data is a major problem of estimating drought impacts in recreation and
tourism sector. The secondary data is either not available or collected inconsistently by
private parties. Although primary data can be obtained through interviews and surveys, it
costs a lot of time and effort. An estimation of general effects at state level would be a
difficult task. In addition, as most droughts are local and there is a variety of recreational
activities in Colorado, we expect that the negative and positive effects may even out at
statewide level. Therefore, our study might be focused on some specific recreational
activities in local areas.
Figure 1: Freshwater Use in Colorado
Total freshwater use by source, Colorado 2000
(w ater use are in thousand acre-feet per year)
Ground w ater,
2,595.0, 18%
Surface w ater,
11,569.0, 82%
Freshwater use by category, Colorado 2000
(w ater use are in thousand acre-feet per year)
Thermoelectric,
154.8, 1%
Public Supply,
1007.5, 7%
Irrigation,
12792.4, 90%
Domestic, 74.8,
1%
Industrial, 134.5,
1%
Figure 2: Colorado Gross State Product and Employment by Industry
Industry Composition_CO
Agriculture,
1.00%
Government,
12.01%
Minining&Constr.,
9.57%
Manufacturing,
6.55%
Services, 25.92%
Trans. & Util.,
3.87%
w holesale, 5.44%
Retail, 6.36%
FIRE, 20.36%
Information,
8.91%
Colorado Employment by Industry
Government,
15.95%
Agriculture, 0.68%
Minining&Constr.,
7.74%
Manufacturing,
7.21%
Trans. & Util.,
3.22%
Services, 38.82%
w holesale, 4.30%
Retail, 11.27%
Information, 3.79%
FIRE, 7.02%
Figure 3: Hydroelectricity Generation in Colorado
Hydroelectricity Generation_Colorado
2500000
1500000
1000000
500000
Year
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
0
1990
Megawatthours
2000000