The Colorado River is a vital water source for the western United States, providing drinking water, irrigation, and hydroelectric power to millions of people. However, the river is facing a crisis, as climate change and over-allocation have led to declining water levels.

One of the key factors contributing to the Colorado River crisis is an overlooked study conducted over a century ago. In 1902, the U.S. Geological Survey published a report titled "The Water Supply of the Colorado River Basin." This study estimated the average annual flow of the Colorado River at Lee Ferry, Arizona, to be 16.4 million acre-feet (MAF).

This estimate was based on limited data and was later found to be inaccurate. The actual average annual flow of the Colorado River is closer to 13.5 MAF. This discrepancy has had significant implications for water management in the basin.

The 1902 study overestimated the amount of water available in the Colorado River, leading to the development of water projects and agricultural development that exceeded the river's sustainable yield. This has resulted in declining water levels in Lake Mead and Lake Powell, the two largest reservoirs on the Colorado River, as well as increased salinity and other water quality problems.

Another factor that contributed to the overallocation of water in the Colorado River Basin was the lack of coordination among the seven basin states. Each state has its own water laws and regulations, and there is no comprehensive framework for managing the river as a whole. This has led to conflicts over water rights and disputes between states over how to allocate water.

The Colorado River crisis is a complex problem with no easy solutions. However, addressing the inaccurate estimates from the 1902 study and promoting cooperation among basin states are important steps towards finding a sustainable solution.