Picture provided by Andrea Yarberry
Andrea Yarberry
One of Humboldt State’s senior ERE students, Annie Yarberry, took a summer research position at the University of Colorado Boulder this summer working for Professor Rajagopalan Balaji. Annie traveled to Boulder, Colorado for 2 months and $2500 to work on the Colorado River. Annie was faced with a problem along the Colorado River regarding sections of the river’s water consumption and distribution. She was in charge of determining the best possible water reservoir system that would result in the highest yield of water for the consumer, as well as carry the least risk in the event of a drought.
Annie discovered her research opportunity through her major advisor at HSU, who referred her to theResearch Experience for the Undergraduates program. This organization matched her with Professor Balaji and UC Boulder, hopefully increasing her chances of being accepted into graduate school this spring. She already had experience in probability, programming, and modeling skills from her ERE courses at HSU. Classes like Probability and Statistics, Computational Methods 1, 2, and 3, as well as ENGR115 all aided her in receiving and excelling at her research position. She used her knowledge in MatLab and R (modeling programs); to complete her required work with Professor Balaji. She spent about 20 hours a week working on her data, and met twice a week for 1-2 hours with the professor going over her data for the week and to discuss further research.
Research Topic
The Colorado River is a major source of water for many regions in the United States and Mexico. In order to control consumption and distribution, the Colorado River Compact was created in 1922. This was an agreement among seven U.S. states in the Colorado River basin governing the allocation of the water from the river system. The states were divided into the upper and lower basins, the upper consisting of Colorado, Utah, Wyoming, New Mexico, and Arizona. The lower consisting of California, Arizona, and Nevada. Both the upper and lower basins are allocated 7.5 million acre-ft/year of water and Mexico is allocated 1 million acre-ft/year. Along the river, reservoirs are installed to collect and store the water that is going to be used.
During the past 8 years there has been a large drought along the river and the reservoirs are becoming greatly depleted. Annie was responsible for determining the reliability and risk of the flow rates associated with the present reservoir system. She would have to consider input, evaporation, precipitation, leaks in the reservoir, overflow, and output in order to predict the reliability. Professor Balaji used data from tree age lines to trace back 400 years worth of water flow along the Colorado River and calculated the natural annual stream flow of the river. He created a linear regression model of the natural stream flow in order to estimate further depletion. Using this data and data from the reservoirs, Annie was able to use a Heuristic Model to determine the risk and reliability of the reservoirs. Her work consisted of modeling 10,000 different possible yields from the reservoirs. Each yield used 50 years worth of data from Professor Balaji in order to estimate the best possible yield from the reservoirs without waste or risk. In plotting this data as a risk value on the x axis, against overall yield from the reservoir on the y axis, Annie was able to approximate the best yielding scenario carrying the least risk. In doing so, she was able to display the most practical and efficient reservoir setup possible. 
Figure provided by Andrea Yarberry
Conclusion
Annie is presenting her final research data in December (2010) at the American Geophysical Union (AGU) Conference in Washington D.C. Not only is Annie’s name being recognized at the conference, but her final research paper may be published, further expanding her network in the engineering field. Annie spoke highly of the professor and UC Boulder as an excellent research opportunity and skill builder. Annie would love to do it all again as she had a great time and learned a great deal under Professor Balaji, although mathematical modeling may never be her lifelong career.