The Colorado River is the seventh longest river. In the 1920s, Western states began dividing the Colorado River's water by building dams and diverting the river's flow to San Diego, Phoenix, and other large cities to supply water to these cities. In the past the river was known to be an important source of water and electricity. The Colorado River flows through Utah, Arizona, Colorado, Nevada, California, Baja California, and Sonora. Over the past decade, a drought has hit the southwest, causing river levels to drop. The Colorado River still runs through the Grand Canyon. The river is a total of 1,450 miles long. The headwaters of the Colorado River are located at La Poudre Pass Lake in Rocky Mountain National Park in Colorado ("Geography of the Colorado River"). The delta of this river is located in the Gulf of California in Mexico; today this delta is mostly dry due to the removal of water for irrigation and urban uses (“Geography of the Colorado River”). Humans have lived around the Colorado River Basin for thousands of years. The river was first mentioned in documents in 1539 and was first given the name Colorado in 1743 ("Geography of the Colorado River"). During the 1800s and 1900s explorations of the river took place, and in 1921 it was dug from the Grand River to the Colorado River ("Geography of the Colorado River"). The flow of the Colorado River has created numerous canyons. One of the most notable canyons that have been created is the Grand Canyon. Uses of the river include energy production, irrigation, municipal and industrial use, flood control, and recreation. This water is used by people in the areas surrounding the river as the water is diverted for their use. Some of the policies on...... middle of paper ......groundwater harvesting (“Water Returns to Dry Colorado River”). The pulsed flow leads to the rehabilitation of the river bed and an increase in the water level. The biggest water quality issue in the Colorado River is salinity and selenium (“Water Availability: A Question of Quantity, Quality and Use”). These problems pose long-term threats such as water availability, effects on plant growth and crop yields, damage to infrastructure, reductions in water quality, and taste and odor issues (“Water Availability 'water: a question of quantity, quality and use'). To reduce this problem, federal agencies and Colorado Basin states are working together to implement salinity control projects to reduce the amount of salt entering the river; This process is said to save approximately $100 million in economic damage per year (“Water Availability: A Question of Quantity, Quality and Use”).