The Colorado River flows through 7 states, 2 countries and 11 national parks and monuments on its path from the Rocky Mountains to the Gulf of California. The Lower Colorado River segment provides drinking water to over 25 million people and irrigation water to agriculture in Arizona, California and Mexico. Along the way water quality data is collected by federal, state, and local agencies, water and wastewater utilities, citizen scientists, non-profits and universities. This data has been, and will continue to be, used to guide the complex management decisions that impact this highly manipulated river basin. The 2 largest reservoirs in the United States, Lake Powell and Lake Mead, are on the Colorado River joined by the river segment flowing through Grand Canyon National Park. The Southern Nevada Water Authority has used water quality data from Lake Powell, Grand Canyon, and Lake Mead to investigate potential changes resulting from a range of management actions.
Results/Conclusions
The Beach Habitat Building Flow experiments conducted in Grand Canyon significantly alter the flow dynamics of the water entering Lake Mead in addition to introducing higher than normal sediment loads. By combining information from Lake Powell, Grand Canyon, and Lake Mead we have worked to predict the impact of these flows in Lake Mead and to plan for water resource infrastructure needs that might arise from these management actions, as well as the transport of sediment further into the system. Similarly, water quality data from Lake Powell is predicative of future water quality in Lake Mead. Increases in salinity in Lake Powell predict subsequent changes in Lake Mead. This information has also been used to evaluate inflow dynamics of the Colorado River into Lake Mead as they are influenced by the temperature of water released from Lake Powell. These temperature changes in turn shift the distribution of dissolved oxygen in the water column, potentially impacting habitat of endangered fish species. The data collected on these systems has also been used to begin to execute mathematical models for changes arising from changes in the climate and the transport of contaminants downstream. Overall this multi-agency, multi-decade data collection and effort has facilitated the management of the Lower Colorado River Ecosystem for the benefit of biological and human systems.