Carson Valley ponders future of water
For nearly a quarter of a century, Julian Larrouy held the keys to one of Carson Valley’s precious resources, the river which passes through it and irrigates its farmlands.
“You can ask a farmer to lend you his tractor, his pickup and maybe even his wife, but don’t ask him to lend you his water,” said Larrouy, who served as deputy federal water master for the East Fork from 1989 to 2012.
Larrouy talked to a crowd at the Carson Valley Museum & Cultural Center on Feb. 13.
With the county’s population experiencing its first real boom since the Great Recession, there have been renewed concerns about Carson Valley’s water supply.
Engineers working on the 1996 Master Plan projected a population of 47,500 before the Valley would need to find a new source of water besides the aquifer.
While the U.S. Census doesn’t start its annual count until March, its estimated there are around 39,000 people living in Carson Valley. The Nevada Demographer estimates there are 41,000 people living in the East Fork Township, which includes Topaz Ranch Estates and Topaz Lake residents, who live in the Walker River Basin.
Lake Tahoe residents receive much of their water from the Lake, either directly or through wells.
Irrigation has been conducted in Carson Valley since before Nevada became a state, with West Fork irrigators starting in 1852 and East Fork around 1858.
But those farmers were under pressure not to take water from the river by mining concerns downstream, who used the water to run their stamp mills.
“The miners hired a man to go up river to make sure there weren’t any dams on the Carson River,” Larrouy said. “I have to think this man was really brave or not too smart.”
The water master’s office is specific to the Carson and Truckee rivers and was established as a result of the 55-year-long lawsuit that generated the Alpine Decree.
Prompted by a filing in 1925, the decree was settled in 1980 and confirmed by the Supreme Court in 1983, it has been characterized as one of the longest court battles in the history of the Western United States.
Larrouy credited federal Judge Bruce Thompson and Garry Stone with completing the decree. Stone, a former Douglas County commissioner, served as water master until he also retired in 2012.
The Alpine Decree segments the east and west forks of the Carson River and determines the priority of rights along the river.
It does not deal with the streams coming out of the Carson Range or Pine Nuts, nor does it control the aquifer under Carson Valley.
Fed by snowmelt from the Sierra, the river is sensitive to the amount of precipitation that has fallen in the mountains over the winter.
Anyone who has irrigation rights has a headgate on either the river or one of the canals that crisscross the Valley, which includes a measuring device so the water master can determine the use.
Farmers may place 3.5 acre feet of water on bottomlands or 4.5 acre feet on benchlands during their turn irrigating. Larrouy said no farmer may use more than 40 percent of their water allotment in a single month.
Irrigation season typically starts on April 1, though on the West Fork, California users may keep using their water until the first Monday in June, no matter what’s available.
“In most cases the water gets pretty short by the first Monday in June,” Larrouy said. “Once they get to the first Monday, the water is rotated weekly between California and Nevada. “I had one gentlemen who would call me after I closed all the gates in California and remind me it was Nevada’s week, and I would say ‘I know, I’ve got it all taken care of.’”
Upstream storage on the Carson River is limited to small reservoirs in Alpine County and Mud Lake in southern Carson Valley. While most of the small reservoirs are owned privately, the California Department of Fish & Game purchased Red Lake as a fishery, which Larrouy said helps preserve water for use in irrigation on the West Fork.
Carson Valley residents don’t get their drinking water from the river, but that doesn’t mean it’s irrelevant to the supply.
The river and irrigation are responsible for around a third of the estimated annual recharge while the rest comes from precipitation percolating into the aquifer.
When there isn’t sufficient water available for irrigation from the river, many agricultural landowners may dip into the aquifer to supplement their river rights. There are an estimated 49,000 acre feet of supplemental irrigation groundwater rights on paper in the Carson Valley, while there are 38,200 acre feet of municipal water rights. Those rights are administered by the State Engineer.
Larrouy pointed out that farmers may use up to 3.5 acre feet of river water per acre on their land while a home uses about an acre foot. While it’s unlikely that homes would create a solid acre of impermeable space, it will definitely decrease the amount of water that soaks into the soil, and at least partially percolates into the aquifer.
A Town Hall dealing with water and taxes has been canceled, and will be rescheduled for sometime in the coming months.