Water is taken out of the Colorado River through a phenomenal network of dams, reservoirs, and diversions. Over 100 dams have been built on the Colorado River and its tributaries for flood control, to create hydroelectricity, to store agricultural and municipal water, and to harness the river’s widely varying flows to generate a steady water supply for people and crops. Despite the widespread benefits of dams and reservoirs, over-allocation and drought have placed significant stress on storage. The water levels of the river’s two largest reservoirs – Mead and Powell, stored behindy Hoover and Glen Canyon Dams – have dropped significantly in recent years. Although dams and reservoirs provide enormous benefits for human populations, they are also threats to water supplies – over 10% of the flow in the Colorado River evaporates every year in reservoirs along its path.
The Colorado River is often called one of the most controlled and plumbed rivers on the planet. In addition, more plumbing, and dams, and diversions are planned, especially in the upper basin in Colorado. Currently multiple projects are being proposed along the Front Range of Colorado that would remove over 300,000 acre feet of new water from the Colorado River and its tributaries – all of this would be removed even before the river reaches Lakes Powell and Mead. Currently, more water is requested from the river than the river can provide, and thus the river has been drained dry for the last decade before it reaches the Sea of Cortez.