Frequently Asked Questions
This information excerpted Natural Resources Law Center at the University
of Colorado School of Law. If you have any questions or need further clarification email us.
How much is Colorado expected to grow in the next two decades?
Projections from the State Demographer suggest approximately 1.7 million
new residents by 2020. Most of these new citizens will locate along the
Front Range, although growth rates in western Colorado will actually be
higher in percentage terms.
Do Coloradans use much water?
According the U.S. Geological Survey, Coloradans use about 208 gallons/day
for domestic uses, compared to a national average of 179 gallons.
Largely due to agricultural irrigation, total per capita offstream water
use in Colorado is 3,690 gallons/day, a figure exceeded by only four other
states (Idaho, Montana, Nebraska, and Wyoming), and nearly three times
the national average of 1,280 gallons/day. (Offstream use
includes water used for domestic purposes,
commercial and industrial applications, thermoelectric power generation,
irrigation, livestock, and mining. Figures are from 1995.)
Who uses the most water?
Over 90 percent of water consumed through human activities in Colorado
occurs in agriculture.This is typical of arid and semi-arid western states.
Agricultural water use in Colorado is not expected to increase, and is
likely to decrease slightly in coming decades as a result of increased
irrigation efficiencies and additional agricultural-to-urban water transfers.
How much water is used in lawn irrigation?
Roughly half of municipal water deliveries in the summer are for landscape
irrigation, particularly Kentucky blue grass.
How does population growth in Colorado influence water demands?
Population growth and increasing economic wealth result in increased municipal
demands for water. Recent research suggests that over the next two decades,
municipal water demands in Colorado could grow by more than 250,000 acre-feet/year
(roughly the amount of water used by a.2 million municipal residents).
(An acre-foot is approximately 326,000 gallons, enough to flood an acre
of land to a depth of one foot.) Over the next 100 years, this demand
for new municipal
water could exceed 1.2 million acre-feet. Political demands and legal
requirements calling for water to be left instream for environmental and
recreational purposes will also likely increase in coming decades.
Overall, are Colorados water resources sufficient?
Despite its semi-arid climate and public perception, Colorado is a water
rich state. Winter snowfall provides an abundance of water. The challenge
for water providers is to adapt the timing and location of snowmelt to
meet the timing and location of water demands. Generally, this means storing
spring snowmelt in reservoirs for use in other seasonsespecially
the summer irrigation season. It also means moving water from resource-rich
areas like the West Slope to demand-intense areas like the East Slope.
This has been done extensively in Colorado.
How and why do cities get water from farms?
Colorado law allows water rights to be bought, sold and transferred. It
is very common for cities to purchase water rights from farmers. For example
in the Colorado-Big Thompson project along the northern Front Range, agricultural
ownership of water shares dropped from 85 to 47 percent from 1957 to 1998
as growing Front Range cities bought agricultural water. For cities, this
is often the cheapest and easiest way to acquire new water. For farmers,
selling water is often more profitable than farming. Thus, it is a simple
matter of supply and demand.
What are trans-basin diversions, and what role do they play in Colorado
A trans-basin diversion is a water project or management scheme that moves
water from one river basin into another. Most of the major trans-basin
diversions in Colorado move water from the Upper Colorado River basin
on the West Slope to the South Platte basin on the East Slope. These are
sometimes known as trans-mountain diversions. The largest trans-mountain
diversion in Colorado is the Colorado-Big Thompson Project, which moves
over 200,000 acre-feet/year from
the Granby area primarily to Weld and Larimer counties. Many municipalities
plan future trans-basin diversions, although this may be unrealistic given
environmental and area-of-origin concerns.
Why does the Front Range (particularly Denver, Aurora and Colorado
Springs) turn to the West Slope and to agriculture for additional water?
In Colorado, most residents live on the Front Range, while most precipitation
falls on the West Slope. Front Range rivers are typically unable to satisfy
local demands. Consequently, water imports are a practical necessity.
The two most abundant sources of water for urban demands are undeveloped
West Slope water and water already used in agriculture.
What role does groundwater play in meeting new municipal demands?
In recent decades, groundwater has emerged as a major water supply source
for new growth, especially in Douglas and Arapahoe Counties. Over 90 percent
of Castle Rocks water supply, for example, comes from deep groundwater.
Groundwater reserves in the Denver Basin aquifers are vast, but are largely
nonrenewable. If future growth follows its recent pattern, there could
500,000 people dependent on Denver Basin groundwater in the next few years.
What are the impacts of growth on the aquatic environment?
Impacts vary widely. Construction of dams can have a devastating ecological
impact on stream ecosystems. Similarly, human uses can dramatically deplete
streamflows, and can introduce pollutants into water bodies. Not all impacts
are negative, however, as alterations to streamflow regimes often provide
unexpected benefits to some species and locations. For example, the South
Platte River is a perennial stream only due to human activity and, particularly,
diversions that feed the river with flows from the Upper Colorado system.
In general, the protection of instream flows and the environmental restoration
of systems impacted by dams, diversions, and related activities, have
traditionally not been high priorities in western water law, policy, and
management. That is slowly changing.
If growth continues, will Coloradans run out of water?
The vast majority of Coloradans live in cities served by water systems
with the economic, political, and technical resources to ensure a continuing
water supply. The ability of engineers, politicians, lawyers, and business
leaders to keep water in the taps of homes and businesses should not be
underestimated. For most Coloradans, the real issue is not one of impending
shortages, but rather is the increasing environmental, economic, and social
costs that must be paid
to keep the water flowing to growing regions.
Will water become more expensive?
The cost of water will likely go up as competition increases for limited
supplies. However, there is no reason to expect dramatic price increases
for most users. Colorado water bills are well below the national average,
and relatively insignificant for most consumers.
Will neighboring and/or downstream states try to claim Colorados
Colorado shares several rivers with other states. Major interstate rivers
include the Colorado, Arkansas, Rio Grande, and Platte. Colorado is a
party to nine interstate compacts that specify the rights of each state
to shared interstate rivers. As long as these compacts are not modified
by congressional action or a Supreme Court judgment, Colorados rights
to interstate rivers are quite secure.
Will rapidly growing Front Range cities be able to meet future demands?
Some municipal water providers face greater challenges than others in
responding to the water demands of growth. Established cities, such as
Denver, with well-developed water systems, abundant and old water rights,
and limited room for new population growth are best positioned. Many newer
communities, such as those on the southern edge of the Denver-Metro area,
must scramble to overcome their lack of developed water resources or water
rights, and their explosive rates of growth. In these situations, however,
the challenge is primarily one of finding water of
low cost and high quality, rather than finding a sufficient amount of
Will rapidly growing mountain resort communities be able to find adequate
Although water is physically plentiful on the West Slope, unclaimed water
is often in short supply during the snow-making season. Several mountain
resort communities, particularly those in Summit County, are finding water
difficult to secure, as local water resources are already claimed by Front
Range cities and by environmental protection programs.
What comes first: water development or growth?
The relationship between water and growth in the modern West is often
misunderstood. Historically, it has been assumed that water development
was a necessary precursor to growth and, similarly, that a lack of water
development could act as a deterrent to growth. While these premises may
have been true at one time, recent experience in Colorado and other western
states shows both ideas are now unsupportable. To the contrary, many of
the regions showing the highest rates of growth in the Westfrom
Douglas County, Colorado to Las Vegas, Nevada
show the opposite trend; growth is actually highest in some of the driest
regions. Similarly, the veto of the proposed Two Forks dam on the Front
Range by the Environmental Protection Agency in 1990 certainly did not
deter growth in the Denver-Metro area. Examples also suggest that an abundance
of water is often insufficient to stimulate growth. The experience of
Pueblo is illustrative.
What are Colorados options for developing new water supplies?
Developing additional water through new dams and reservoirs has become
increasingly difficult, largely due to concerns over environmental protection
and the fact that the most obvious water projects have already been built.
Moving already developed water from one location to another is often a
more practical option, but can bring negative consequences for rural agricultural
areas steadily losing water to cities. Development of deep (mostly non-renewable)
groundwater is also an attractive option in some situations, but is not
a permanent solution to the water demands of growth.
What are the most practical ways of increasing municipal water supplies?
In order to maintain adequate water supplies in the face of continued
growth, it is generally recognized that the realloaction of water from
the agricultural to the municipal sector will.5 continue. Ultimately,
the physical limits of natural water supplies must be recognized, and
management strategies must be refocused on controlling demands, as well
as conservation and efficiency.
Can we meet future water demands through water conservation alone? Water
conservation practices cannot satisfy future water supply needs alone,
but are an important piece of the puzzle. Conservation strategies allow
water providers to avoid the economic, environmental and political costs
associated with new development and with reallocations.
Will the East Slope and West Slope ever stop fighting over trans-basin
Several recent efforts suggest that a new era of cooperation may be emerging
between the East and West Slopes. The most promising examples include
the Wolford Mountain Reservoir, the Eagle River MOU, and Clinton Gulch
project. Increasingly, it is easier to cooperate on trans-basin water
development than to fight.
What is conjunctive use?
Conjunctive use describes a water management strategy that uses both groundwater
and surface water in a coordinated fashion. In a conjunctive use scheme,
an aquifer can be a water source during dry periods, and a storage reservoir
during wet periods. Colorado has relatively little experience with conjunctive
use, but this is likely to change in future decades. The strategy is used
extensively in California, which is both drier and more populous.
Can water policy be used as a growth management tool?
Water policy does not appear to be a useful tool for growth management.
Decisions about where or how to grow are rarely influenced by the availability
of water. It does appear possible, however, to influence water development
and management through growth management policies. If growth management
policies suggest lower rates of growth, or rates of growth that can be
predicted with greater certainty, then the need to pursue new water supplies
can be reduced.
What are the most exciting areas of innovation in Colorado water law,
policy and management?
For the most part, the positive innovations deal with emerging water management
strategies, more so than formal legal or policy reforms. At the heart
of these strategies are increased cooperation, an attempt to minimize
adverse impacts of water development and use, and a commitment to stretch
existing supplies further. Specific tools include cooperative/joint water
developments, small-scale and off-stream water storage, market-based water
reallocations, temporary water transfers, groundwater development and
conjunctive use, integration and coordinated operation of water systems,
wastewater reuse, conservation and demand management, and cooperative
solutions to environmental problems.
Will the possibility of future water shortages hurt economic growth
In the short term, there is no reason to believe that water concerns will
hurt economic growth in Colorado, except perhaps in a few isolated communities.
In the long term, maintaining the economic vitality of the state will
require finding better ways to meet growing municipal and industrial demands
while simultaneously protecting agricultural activity and the environmental
and recreational amenities of the state.
Does Colorado need to build more dams?
Additional dams would undoubtedly be useful in serving some new demands
and in taking full advantage of the states entitlements to interstate
rivers, such as the Colorado and South Platte Rivers. Additional dam building,
however, generally runs counter to the goal of protecting and restoring
aquatic ecosystems. Most parties agree that the era of big dams is over,
or at least has entered a dormant period of indeterminate length. Nonetheless,
several opportunities still exist for smaller projects and for modifying
the operation of existing projects to increase storage.
Is Colorado vulnerable to drought?
Most water users in Colorado are protected from droughts by water storage
reservoirs and the availability of groundwater. Another source of protection,
ironically, is wasteful water-using practices that provide plenty of opportunities
for conservation in tough times. As water conservation becomes more of
an everyday management practice, our vulnerability to drought may actually
be increased. Additionally, climatic research suggests that recent decades
have been unusually wet in many parts of Colorado, including the South
Platte basin. Consequently, ost
Front Range residents have little or no experience with drought, and some
water sers may be unprepared.
What is the role of the federal government in Colorado water management?
The federal government is a major player in Colorado water management
for several reasons. Much of the land in Colorado is federal public land,
including most mountainous regions where major rivers originate and where
many water projects, both federal and non-federal, are located. Additionally,
federal law is particularly important in the areas of water quality management
and endangered species protection.
Who paid for this study?
Primary support for this project came from the William and Flora Hewlett
Foundation, and from the Western Water Assessmenta study of western
climatic variability funded by the National Oceanic and Atmospheric Administration
(NOAA) and administered at the University of Colorado by the Cooperative
Institute for Research in Environmental Sciences (CIRES).
Who/what is the Natural Resources Law Center?
The Natural Resources Law Center is a non-profit research and educational
organization housed with the University of Colorado School of Law. The
mission of the Natural Resources Law Center is to promote sustainability
in the rapidly changing American West by informing and influencing natural
resource laws, policies, and decisions. The Natural Resources Law Center
was established in 1982. For further information on the Natural Resources
Law Center,: contact Doug Kenney; 303-492-1296; Duglas.Kenney@colorado.edu.