Background:

The Colorado River Basin is the most heavily regulated river system in the world with 83 reservoirs in its upper basin and 10 reservoirs in the lower basin. It provides over 30 million people with some part of their water supply, irrigates 3.5 million acres of farmland, and produces 10 billion kilowatt hours of electricity each year. Lake Powell has experienced a drop in water level elevation that is unprecedented. Prolonged drought conditions have heightened the need for interdisciplinary research efforts that apply predictive climate science to river operations modeling for water supply planning purposes.

A section of Lake Powell can be seen to the left displaying a significant decline in water level elevation.

Overview of the Project:

This project further develops research partnerships and extends two prior years of work on a multi-pronged approach to preparing for and responding to variable Colorado River supply reliability in Arizona. The Surface Water Hydrology Group's Matt Switanek, working with Peter Troch, is honored to be an integral part of this important research.

There are many important questions that this research hopes to address:

• Is it possible to establish a stronger link between sea surface temperatures, sea level pressures and the hydrology of the Lower Colorado River basin?
• With a greater understanding of past climatic and oceanic conditions and the ensuing hydrologic implications, can that knowledge be used to help quanitify the runoff variability of the Lower Colorado River basin?
• In effect, can we improve the predictive capacity and lessen the uncertainty that managers of the river are faced with?

The atmospheric and hydrologic sciences have recently used climate indices in an attempt to account directly for runoff variability or indirectly by using precipitation and temperature. Climate indices are oscillations of the ocean-atmosphere system having important consequences for weather around the globe. An El Nino event can be described as sea surface temperature departures of significant magnitude from the long-term mean sea surface temperature in the tropical Pacific Ocean. There seems to be a positive correlation between El Nino events and an increase in precipitation throughout parts of the Lower Colorado River basin. The challenge now is to develop a stronger quantified relationship between the ocean's variability and the runoff that we see in the Lower Colorado River basin.