UW's Ogden to Create Computer Model of Upper Colorado River Basin's Hydrology
For nine decades, the Colorado River Basin Compact has provided the water allocation blueprint for communities located in the Upper and Lower basins. While that 1922 water distribution agreement remains intact, other factors -- climate, land use and population -- in the seven states that comprise the region have undergone vast changes over the years.
For Fred Ogden, that long hydrological history is ripe for review. But rather than peruse old maps, Ogden will use advanced technology.
Ogden, the Cline Distinguished Chair in the Department of Civil and Architectural Engineering and Haub School of Environment and Natural Resources at the University of Wyoming, is working to create a computational model of the hydrology of the upper Colorado River Basin - roughly 112,000 square miles that run from Wyoming and Colorado down to the Gulf of California. The Green River, a Colorado River tributary, is the first area that will be modeled, Ogden says.
"No one's ever tried to do this before at this scale. If we can help inform communities about future sustainability, we will have accomplished a lot," Ogden says. "It's (modeling) a way to test future outcomes."
Ogden spearheads UW's efforts with the CI-WATER project, which is funded with an EPSCoR Research Infrastructure Improvement Program (RII) Track-2 cooperative agreement that focuses on the hydrology of the Colorado River Basin.
The CI-WATER project will develop a high-resolution, physics-based hydrologic model that is applicable over large areas to help assess long-term impacts of water resources management decisions, natural and man-made land-use changes, and climate variability -- with an emphasis on the Rocky Mountain west region, Ogden says.
"The CI-WATER project includes significant funding ($1 million) that will be used to purchase computing hardware for the UW campus," Ogden says. "The UW computing cluster will provide a place for our project to develop and test our code. Once things are running correctly, we will run larger simulations on the NCAR-Wyoming supercomputer."
The campus cluster, or on-campus high-performance computing site known as the Advanced Research Computing Center (ARCC), will be housed in UW's IT Data Center and is expected to be operational this fall.
The CI-WATER project is a joint collaboration among UW, the University of Utah, Utah State University and Brigham Young University. Cooperators include the U.S. Army Corps of Engineers and NCAR. EPSCoR Track-2 cooperative agreements, distributed through the National Science Foundation, are designed to provide research funding to states, including Wyoming, that typically receive lesser amounts of NSF research and development funding.
Through computer simulations, Ogden wants to determine how much water is available in the Colorado River Basin, including Lake Powell, which straddles the Arizona and Utah border. It is the second-largest man-made reservoir in terms of maximum water capacity. The lake stores 24.3 million acre feet of water for Upper Basin states of the Colorado River Compact, Ogden says. Those states are Wyoming, Colorado, Utah and New Mexico.
Under the compact, Upper Basin states have to provide a minimum of 7.5 million acre feet of water annually to the Lower Basin states, which include Arizona, California and Nevada, Ogden says. One acre foot of water is defined as one acre of water a foot deep, which translates to roughly enough water for a family of four for one year, Ogden says.
"The Lower Basin has a guaranteed amount (of water) to use. The Upper Basin doesn't really have such a supply guarantee, and are limited by actual availability while meeting downstream demands," Ogden says.
While the Upper Basin doesn't have a water-use limit under the compact, that basin's population is approximately 936,000, Ogden says, citing U.S. Bureau of Reclamation numbers. That population increases to 10 million when you include those who live around the Upper Basin. When you add in the populations of Los Angeles and San Diego, both in the Lower Basin, the number of people who rely on water from the basin balloons to more than 30 million, Ogden says.
Ogden described Lake Powell as a "bank account to take care of lower states' (water needs)."
"If that ever goes dry, we're at the whim of snowfall and runoff for water there (Lower Basin)," he says. "It raises questions of long-term stability if there is continued warm weather."
In addition to climate change, land-use decisions by city, state and federal officials, and population increases in communities, can have potential adverse effects on water usage and long-term supply.
For example, Colorado diverts water from the basin for use in big cities, such as Denver, and irrigation of crops at lower altitudes on farmland east of the Front Range, Ogden says. Water from the basin also is used for watering lawns and golf courses.
"All of these (water) decisions you make at this scale are based around risk," Ogden says.
Even if there had been no change in climate, land use or population since the compact's origin, Ogden says there is still no real answer to how much water from the basin can actually be used safely on an annual basis.
"There is a lot less water than was originally thought when the basin compact was created," Ogden says. "Everyone has a good idea that there is less water available than what was thought in 1922."
Ogden envisions his computer simulation models could be used by city managers or other officials interested in learning what future water availability will look like 10 or 20 years out, and beyond.
The model also could be used to interface with other scenarios that could affect water use. For example, the model could be run to show what climate change occurs after a forest burns. Computer scenarios can be run 100 years in the past to 50 years in the future, Ogden says.
"We have a three-year schedule. It's a fantastic project for the University of Wyoming, and it comes at the right time for the state," Ogden says of the CI-Water project. "I'm really jazzed about it."
The NWSC is the result of a partnership among the National Center for Atmospheric Research (NCAR); the University of Wyoming; the state of Wyoming; Cheyenne LEADS; the Wyoming Business Council; Cheyenne Light, Fuel and Power; and the University Corporation for Atmospheric Research. NCAR is sponsored by the National Science Foundation (NSF).
The NWSC will contain some of the world's most powerful supercomputers (1.5 petaflops, which is equal to 1.5 quadrillion computer operations per second) dedicated to improving scientific understanding of climate change, severe weather, air quality and other vital atmospheric science and geo-science topics. The center also will house a premier data storage (11 petabytes) and archival facility that holds irreplaceable historical climate records and other information.
Fred Ogden, the Cline Distinguished Chair in UW's Department of Civil and Architectural Engineering, poses with his laptop at the north fork of the Little Laramie River, above Centennial, in Medicine Bow National Forest. Ogden will use the NCAR-Wyoming Supercomputing Center to create simulation models to study the hydrology of the Colorado River Basin.