Water summit to discuss state of Carson River
January 9, 2018
This week's wet weather might give them something to talk about at the 2018 Water Summit on Jan. 30.
Hosted by the Carson Water Subconservancy and the Carson River Coalition at the Governor's Mansion in Carson City, the summit offers an overview of the Carson River.
The river's watershed occupies about 3,970 square miles.
Subconservancy Manager Ed James said the river's 184-mile long drainage is home to about 125,000, a number that's expected to more than double by the year 2050.
"We have to be aware of what goes on in the Truckee River basin, because it could have an impact on us," he told county commissioners last week.
A canal joins the Truckee and the Carson rivers at Fernley.
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While 2017 saw a record amount of precipitation, there wasn't as much flooding as in prior years because of the previous dry period, James said.
"The flow was half of what we saw in 1997," he said. "It was not a huge flood event on the Carson. It was between a 20-25 year flood event. We will experience larger floods in the future."
The Carson River is administered by the Alpine Decree, which means the river is fully appropriated. According to James, 95 percent of that use is for agriculture, with floodwaters going to the Stillwater Project near Fallon.
Because there is no storage upstream, Carson Valley relies on snowpack to store water for irrigation.
James compared flows on the East Fork from 1941 through 1974 with those across 1975 to 2009, and found that flows have increased in March, April and May, but have decreased in June and July, indicating an earlier melt-off.
Groundwater in the Carson River watershed is overappropriated, but it's not being overpumped, he said.
"Groundwater levels increased during 2017," he said. "When you put more water on the ground, the groundwater goes up. We did recover. It's a good indicator we're not mining our water."
Groundwater is Carson Valley's sole supply, according to James. Municipal pumping from the Valley's aquifer varies widely depending on how much river water is available.
According to the subconservancy, 18,320 acre feet was pumped for irrigation in 2015, while 12,972 acre feet were pumped for municipal uses. In Carson Valley 3,514 acre feet were pumped from domestic wells.
James said that the various sewer districts provide 5,500 acre feet of treated effluent to Valley ranches.
Email firstname.lastname@example.org for information or to sign up for the summit.