Since 2000, the Colorado River Basin (Basin) has been
experiencing a historic, extended drought that has impacted regional
water supply and other resources, such as hydropower, recreation, and
ecologic services. During this time, the Basin has experienced its
lowest 16-year period of inflow in over 100 years of record keeping, and
reservoir storage in the Colorado River system has declined from nearly
full to about half of capacity.
This application was developed by the U.S. Geological Survey and
the Bureau of Reclamation in support of the Department of the Interior’s
Open Water Data Initiative
(OWDI). This visualization is part of a multi-agency effort to showcase
the usefulness of open data (i.e., data provided in a discoverable,
sharable, and machine-readable format) by exploring the current 16-year
drought and its effects on the Colorado River Basin.
Read More >>
The Colorado River is a lifeline.
Water from the Colorado River is essential for life in
parts of the southwestern United States and northwestern Mexico.
According to the Colorado River Basin Water Supply and Demand Study
(2012), the Colorado River and its tributaries:
Supply more than 1 in 10 Americans with some, if not all, of their water for municipal use, including drinking water.
Provide irrigation water to more than 5.5 million acres (approximately 8,590 square miles) of land.
Support 4,200 megawatts of electrical generating capacity, providing power to hundreds of local areas and millions of people.
Are directly linked to nine National Park Service units and seven National Wildlife Refuges, supporting over $1 billion in tourism revenue associated with outdoor recreation and wildlife.
Provide habitat for a wide range of species, including threatened and endangered species, as well as other species of wildlife and vegetation.
One river, two parts.
Approximately 1,400 miles long and flowing through seven U.S.
States and into Mexico, the Colorado River drains roughly one-twelfth of
the land area of the contiguous United States. The Colorado River Basin
is divided into the Upper and Lower Basins at the Lee Ferry Colorado River Compact
Point (Compact Point) located in northern Arizona. The Upper Basin
spans portions of Wyoming, Colorado, New Mexico, Utah, and northern
Arizona. The Lower Basin covers parts of Nevada, Arizona, California,
southwestern Utah, and western New Mexico. The Colorado River also
supplies water to parts of the states of Baja California and Sonora in
northwestern Mexico.
The Upper Colorado River Basin supplies approximately 90
percent of the water for the entire Basin. This water originates as
precipitation and snowmelt in the Rocky and Wasatch Mountains. About 50
percent of streamflow comes from baseflow, which is surface water that
percolates into groundwater aquifers and then resurfaces as streamflow (Rumsey et al., 2015).
The Lower Basin is arid, with little tributary runoff reaching the
mainstream of the Colorado River except during occasional rain events.
Read More >>
Learn about the Colorado River Basin's network of reservoirs, water delivery infrastructure, and water delivery service areas.
The Colorado River is managed with a series of dams and
canals that provide flood control, water conservation, and hydropower
benefits.
The dams and canals in the Colorado River system provide
storage for regional water supply, facilitate water deliveries, provide
flood control benefits, improve navigation, and generate hydroelectric
power. These facilities are operated in coordination with adjacent or
nearby water delivery systems that also provide a variety of other
economic, cultural, and ecologic benefits.
Read More >>
Hover over sections of the diagram below to get additional information
The diagram above depicts the major dams, reservoirs, and control structures of the Lower Colorado River.
View real-time data and take a journey through major dams on the Lower Colorado River.
Water supply varies over time.
Due to year-to-year differences in precipitation and snowmelt,
the natural water supply of the Basin is highly variable. Long-term
drought like the Basin has experienced since 2000 reflects natural
climate variability coupled with the likely impacts from changing climate.
Since most of the Basin's water supply comes from the Upper Basin,
drought conditions in the Upper Basin impact water supply and resources
in both the Upper and Lower Basins of the Colorado River.
The U.S. Geological Survey (USGS) stream gage at Lees Ferry,
Arizona, is the lowermost mainstream gage in the Upper Basin, located
about 12 miles downstream of Glen Canyon Dam and about 1 mile upstream
of the Compact Point between the Upper and Lower Basins. Natural flow at
this stream gage location is used as a proxy for the hydrologic
conditions in the Upper Basin and the overall hydrologic health of the
Basin. Natural flow is defined as the streamflow that would have
otherwise occurred without the effects of human activities such as
reservoir regulation and river diversions.
Hover over sections of the graph below to take a closer look
In the graphic above, the 10-year average natural flow
at Lees Ferry shows periods of below and above average annual flow
(approximately 14.8 million acre-feet [maf]). The most recent drought
for the 2000-2015 period (indicated by the brown shaded area) was the
driest 16-year period in the past 100 years and one of the driest
16-year periods in the past 1,200 years. The graphic also depicts how
the early part of the 1900s, which corresponds to the period of
reference used to set the apportionments for the Upper and Lower Basins
in the 1922 Colorado River Compact,
was an unusually wet period (indicated by the green shaded area). At
the time the 1922 Colorado River Compact was signed, the average annual
inflow at Lees Ferry during the pre-Compact period (1906-1921) was
approximately 18.0 maf.
USGS observations of the Colorado River at Lees Ferry (USGS site 09380000) have been recorded since 1895. For more information and data on this site, visit the U.S. Geological Survey National Water Information System Lees Ferry stream gage website.
Real-time gage height, discharge, water temperature, sediment, and
water-quality properties can be accessed from the U.S. Geological Survey
Grand Canyon Monitoring and Research Center website.
The Lees Ferry gage is distinct from the Lee Ferry Compact Point: Lees Ferry refers to the USGS-operated stream gage
located near the town of Lees Ferry, Arizona; whereas Lee Ferry refers
to the Colorado River Compact Point, as referenced in the 1922 Colorado River Compact. The Lee Ferry Compact Point is located 1 mile downstream of the Lees Ferry gage.
Historical observations are extended by a tree-ring reconstruction
of streamflow going back approximately 1,200 years, as estimated by
Meko et al. (2007a). Because trees grow less during dry years and more
during wet years, tree-ring cores can be used to estimate historical
streamflow conditions going back many centuries. Tree-ring core samples
were collected from locations throughout the Upper Basin to estimate
historical natural flow. These estimates were validated using the
observed natural flow record developed by the Bureau of Reclamation.
Explore more about reconstructed natural flow based on tree-ring data.
The western U.S. is experiencing an extended drought.
Since 2000, the Colorado River Basin has experienced the driest
16-year period in over 100 years of historical natural flows (Bureau of
Reclamation, 2015). This period also ranks as the fifth driest 16-year
period in the last 1,200 years (Meko et al., 2007a and 2007b).
While the current drought is severe and historic, the most
extreme drought in the Colorado River Basin occurred in the mid-1100s
(Meko et al. 2007a). The 1100s drought was characterized by a 25-year
period of flows that were 15% lower than the long-term average of 14.8
maf and no higher-flow years (greater than 125% of average) for six
decades. By comparison, the current drought is characterized by flows
that are 16% lower than the long-term average with one year of higher
flows (135% percent of average in 2011).
The U.S. Drought Monitor shows the extent and intensity of drought conditions in the Western U.S. from 2000 to 2015. The Esri Drought Tracker provides a means to view drought conditions in the U.S. over time, using data from the U.S. Drought Monitor.
View more information about drought in the U.S. and Colorado River Basin.
The Colorado River Basin's abundant water storage capacity has made the Southwest more resilient to drought.
The basin-wide storage capacity of the Colorado River totals
about 60 million acre-feet (maf), approximately four times the average
annual inflow in the Upper Basin (14.8 maf). The Basin’s two largest
reservoirs, Lake Powell and Lake Mead hold about 50 maf combined, which
is approximately 83 percent of the total system storage capacity. This
large storage capacity creates a buffer against year-to-year hydrologic
variability and longer-term drought periods by allowing excess water to
be stored during wet years and used during dry years.
It is this large amount of basin-wide storage capacity that has
allowed the Bureau of Reclamation to continue to meet water delivery
requirements during the current drought period. It should be noted,
however, that headwater reaches in the Upper Basin can experience
localized shortages due to insufficient in-stream flows during dry
years.
The volume of water that can be stored in the Colorado River
system reservoirs (60 million acre-feet) is enough to cover the State of
Utah in about 1 foot of water. Dimensions shown above are not to scale.
Development in the West continues, leading to increased water demand in the Colorado River Basin.
Since the early 1900s, water demand in the Colorado River
Basin has increased while water supply has, on average, decreased. For
the 16-year period preceding the signing of the 1922 Colorado River Compact,
when the beneficial consumptive use of 7.5 million acre-feet (maf) per
year was apportioned to both the Upper and Lower Basins, the average
annual natural flow in the Upper Basin was about 18.0 maf (1906-1921).
When the 1944 U.S.-Mexico Water Treaty was executed, the average annual
natural flow in the Upper Basin was about 16.3 maf (1906-1944). The
current average annual natural flow in the Upper Basin is about 14.8 maf
(1906-2015).
Read More >>
Hover over sections of the graph below to take a closer look
Trends in water supply and water use in the Colorado River
Basin are shown above. When water use (red line) exceeds water supply
(blue line) in a given year, the amount of water stored is reduced.
During the past 20 years, average water supply and average water use
have been about equal. Under these conditions, reservoirs are
replenished more slowly. Water-supply and water-use data shown in the
graphic above are estimated by the Bureau of Reclamation using water
accounting information, U.S. Geological Survey stream gage data, and other sources.
In this graphic, water use is shown as “consumptive use”
(surface-water diversions and groundwater pumping minus measured and
unmeasured return flows) as estimated by the Bureau of Reclamation in
its annual water accounting reports.
Other estimates of water use that account for withdrawals of surface
and groundwater and incorporate water that is used and returned to the
stream, are made by the USGS.
Because of reduced water supply during the current drought, the elevations of Lakes Mead and Powell have declined.
As the reservoir levels of Lake Mead and Lake Powell decline,
other resources, such as hydropower, recreation, and water quality, are
also affected. 2014
1999
In the photo slider above, the change in the surface area of Lake
Powell can be seen from the pre-drought conditions in 1999 to the
current drought conditions as of 2014. The red area that emerges
represents the loss in the reservoir’s surface area as lake elevations
have declined. These maps are based on U.S. Geological Survey Landsat satellite
surface reflectance-corrected images acquired in the month of June in
1999 and 2014. Landsat images acquired within 16 days of each other have
been merged together to generate cloud-free composite satellite images
suitable for measurement and change comparison.
2014
1999
In the photo slider above, the change in the surface area of
Lake Mead can be seen from the pre-drought conditions in 1999 to the
current drought conditions as of 2014. The red area that emerges
represents the loss in the reservoir’s surface area as lake elevations
have declined. These maps were prepared using the U.S. Geological Survey
Landsat satellite data as described in the Lake Powell caption above.
2015
2001
Between 2001 and 2015, Lake Mead’s elevation dropped from 1,196
to 1,075 feet, a decline of 121 feet. Move the slider on the upper photo
to see the decline in the reservoir elevation during this time. The
decline in water elevation has exposed a white band of mineralized rock
around the shoreline. The declining reservoir level has also exposed
portions of Hoover Dam’s four intake towers, two on the right side and
two on the left side. These intake towers channel water from Lake Mead
into penstocks that serve Hoover Dam's 17 hydroelectric generators.
Water moves through the generators, creating electricity on the way, and
is released back into the Colorado River below the dam.
Read More >>
2015
2003
The photo slider above shows Hemenway Harbor, located in the
southwestern portion of Lake Mead, and the location of Las Vegas Marina
at an elevation of 1,152 feet in January 2003, and the new location of
Las Vegas Marina at an elevation of 1,078 feet in May 2015. The photos
also depict the increased exposure of Lake Mead’s shoreline and the
emergence of the Boulder Islands, located on the right side of the
photo, as the reservoir elevation has declined.
Read More >>
The possibility of a shortage condition in the Lower Basin may result in reduced water deliveries.
In keeping with the Bureau of Reclamation 2007 Interim Guidelines,
if Lake Mead's January 1 elevation is projected to be 1,075 feet or
lower based on an August projection, a Lower Basin shortage condition
would be determined. Monthly projections made by the Bureau of
Reclamation through an operational model called the "24-Month Study" are
used to set the operational conditions for Lake Mead and Lake Powell.
Continue with the visualization to learn more about Lake Mead's
operational conditions, how operational conditions are determined, and
the potential impacts of drought on water deliveries in the Lower Basin.
Hover over sections of the graph below to take a closer look
The graphic above shows Lake Mead's historical
elevations (on a monthly basis) since 2000, projected elevations for
2016 and 2017, and annual operating conditions.
As Lake Mead's elevation declines, the Lower Basin comes
closer to its first-ever shortage condition. Since the drought began in
2000, Lake Mead's elevation has dropped by nearly 140 feet, declining
every year except in 2005 and 2011. The Bureau of Reclamation makes
projections of Lake Mead elevations and summarizes them in the Colorado River Basin 24-Month Study reports.
The 24-Month Study model simulates operations of 12 major reservoirs in
the Colorado River Basin. The projections are used to support annual
and monthly decisions about how to operate the system looking out 1 to 2
years. The annual operating conditions for Lake Mead and Lake Powell in
the upcoming year are based on projected January 1 reservoir elevations
from the August 24-Month Study consistent with the 2007 Record of
Decision on Colorado River Interim Guidelines for Lower Basin Shortages
and the Coordinated Operations for Lake Powell and Lake Mead (2007 Interim Guidelines ).
Read More >>
Lake Mead
The Colorado River is one of the primary sources of water for
irrigation and domestic use in Arizona, southern California, southern
Nevada, and portions of northwestern Mexico.
To learn more about Lower Colorado River water entitlement
holders and consumptive use data from the Bureau of Reclamation, click
button below.
An era of hope - communication, cooperation, and collaboration.
In the Colorado River Basin, stakeholders, States, and
Federal and local agencies are collaborating to develop creative
strategies to reduce the impacts of drought and increase reservoir
storage at Lake Powell and Lake Mead. Activities related to drought
response include a system conservation program and drought contingency
planning efforts in both the Upper and Lower Basins. Additional ongoing
activities are being conducted with stakeholders through the Basin Study
Moving Forward process and with Native American Tribes through the Ten
Tribes Partnership Tribal Water Study. Lastly, the implementation of
Minute 319 and related binational discussions also underscore the
importance of the partnership and continued collaboration between the
United States and Mexico.
Read More >>
This product is an activity of the Advisory Committee on Water Information Open Water Data Initiative (OWDI),
and was developed collaboratively by the Department of Interior, U.S.
Geological Survey, and U.S. Bureau of Reclamation, and with
contributions from the U.S. Environmental Protection Agency, Oregon
State University, and the Western States Water Council. The OWDI seeks
to integrate currently fragmented water information into a connected,
national water data framework and leverage existing systems,
infrastructure and tools to underpin innovation, modeling, data sharing,
and solution development. Application design was inspired by the 2014 National Climate Assessment.
Any use of trade, firm, or product names is for descriptive purposes
only and does not imply endorsement by the U.S. Government.
Learn about the Colorado River Basin's network of reservoirs, water delivery infrastructure, and water delivery service areas.
View real-time data and take a journey through major dams on the Lower Colorado River.
Explore more about reconstructed natural flow based on tree-ring data.
View more information about drought in the U.S. and Colorado River Basin. 
To learn more about Lower Colorado River water entitlement
holders and consumptive use data from the Bureau of Reclamation, click
button below.
No comments:
Post a Comment