Thursday, October 1, 2015

Watersheds and why they are important

Contributed by John Cobourn,
Area Water Specialist,
University of Nevada Cooperative Extension




Tau-Gu,Chief of the Paiutes and John Wesley
Powell overlooking the Virgin River, 1873

John Wesley Powell, the first director of the US Geological Survey and the first man to lead a boat expedition down the Grand Canyon, proposed that all political boundaries in the American West should be established along watershed divides. Powell believed that watersheds—also known as basins--are natural units of political and economic community. Powell’s proposal was not adopted.
In the American Southwest, the major watersheds are the Colorado River Basin, the Great Basin (with no outlet to the ocean), the Sacramento and San Joaquin watersheds feeding the Central Valley of California, and the watersheds along the Pacific coastline of California. Within the Great Basin in Nevada, there are four major sub-watersheds, the basins of the Truckee, Carson, Walker and Humboldt River systems.

To explain the importance of the watershed concept, let’s 
The Carson River watershed, shown in light green, flowing
northeast from the Sierra Mountains in California to
the Carson sink in Nevada
look at the Carson River Watershed, which originates at the crest of the Sierra Nevada and flows in two principal forks (East and West Forks) eastward into the Carson Valley, past Minden and Gardnerville, then through Carson City, Nevada’s state capital, and then down through Lyon County and past Dayton to the Lahontan Reservoir. The water is stored in the reservoir for use each summer in the rich alfalfa farming area of Fallon in Churchill County. The reservoir and its water distribution system, known as the Newlands Project, were built by the Federal Bureau of Reclamation in the early twentieth century to “make the desert bloom.”

The State of Nevada created a water resources management agency for the Carson River known as the Carson Water Subconservancy District (CWSD) in 1959. The story of the Carson River Watershed is told by the CWSD Website (www.cwsd.org) and by many publications such as the Carson River Watershed Map (www.unce.unr.edu/publications/files/ag/2003/sp0302.pdf). In 1998, a citizens and interagency watershed management group was formed—called the Carson River Coalition (CRC). Abiding by the principles of Integrated Watershed Management, the CRC attempts to consider and evaluate all issues of water quality, water supply, floodplain management and fish and wildlife habitat in an integrated fashion. Each of these key values within a watershed is connected to each of the others. 

In times of drought, the residents of major watersheds in Nevada are affected differently. The geography, groundwater quality, water rights and Court Decrees are different in each watershed. People suffer in different ways. More about these water supply issues will appear in the next blog. For more information about our drought see www.livingwithdrought.com and www.unce.unr.edu

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