On The Colorado

Colorado River Open Source Simulator

CROSS logo Want to know how much water may be available in the Colorado River in the future?

Do you have concerns about climate change and its impacts on reservoir levels, the likelihood of water shortages or hydropower generation?

Ever wonder how much water needs to be conserved to guard against prolonged drought?

The Colorado River Open Source Simulator (CROSS) has your answers.

Developed for OTC by Niklas Christensen, one of the first researchers to simulate climate change impacts on Colorado River flows, CROSS employs many of the same assumptions and operating rules used by the Bureau of Reclamation in its modeling. In fact, despite CROSS being a very simplified version of the government’s model, their results are nearly the same.

The difference lies in what you can do with CROSS. In November 2007, after two years of analysis, Reclamation released new plans for managing the Colorado River should water shortage occur. However, this analysis neglected to evaluate the full range of independent estimates for the Colorado River’s annul flow, assuming instead, that future flows will likely mimic those of the recent century--among the wettest in the past 1200 years. Also absent were allowances for the impacts scientist predict climate change will have on Colorado River flows and reservoir levels. As a result, these new shortage polices are based on a narrow spectrum of potential risks, leaving the public unprepared for the kinds of shortages many experts fear. CROSS enables you to investigate what the government has not.

Once you've experimented with CROSS, please share your findings with others in the CROSS Forum. Also, let us know how CROSS can be improved to help further the public’s understanding of the Colorado River and the limits to what we can expect from it.


To operate CROSS, download the Excel file below and open it on any computer with Microsoft Excel 2003 or 2007 installed. No prior knowledge of the Colorado River or Microsoft Excel is assumed or required.

CROSS [14mb Microsoft Excel File]

Your Excel security settings might have to be changed to enable CROSS programs to operate. Locate this message box at the bottom of the CROSS main page to learn more.

Excel security warning

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