After almost 70 years, San Luis Obispo County’s use of water from Lake Nacimiento will no longer be restricted—a shift in policy that could be key to helping cities across the county meet new state sustainability standards.
The April 7 change to the Monterey County-based permit affects Nacimiento Water Project participants, including the city of Paso Robles, Templeton Community Services District, Atascadero Mutual Water Company, Santa Margarita Water Company, the city of San Luis Obispo and some parts of Cayucos, according to SLO County Engineer Wes Thompson.
Before the restrictions were lifted, participants were limited in where they could apply their Nacimiento water allocations: on up to 7,000 acres of urban land and 500 acres of agricultural land in the county. Now, water agencies can continue using the water within their service areas, and they can also sell excess water to regions that wouldn’t have been allowed to use the water before.
SLO County Groundwater Sustainability Director Blaine Reely said the impact of the change can’t be understated—especially in the Paso Robles Groundwater Basin, a basin the state considers to be critically over-drafted and recently received state approval for its groundwater sustainability management plan.
“This is a critical restriction that needed to be removed—especially considering participants in the program weren’t using upwards of 50 to 60 percent of the water each year,” Reely told New Times. “Now participants can explore the use of that excess water—which, frankly, is a higher quality than traditional groundwater—to help meet those new goals and take our sustainability programs into the future.”
Thompson told New Times that current Nacimiento Water Project participants have roughly 3,000 to 6,000 acre-feet of water they aren’t using out of the 15,750 acre-feet allocated to them per year. While the lifted restrictions will free up how that leftover water is used, Thompson clarified to New Times that the county—across all participants—is still only allowed to use that maximum of 15,750 acre-feet of water from the project.
“The change approved by the State Water Board did not increase the amount of Nacimiento water available annually to SLO County, or change the allowable uses,” he said. “It only clarified where the contracted water could be used within SLO County.”
Regardless, the county still sees the change as key to complying with the California Sustainable Groundwater Management Act (SGMA), which requires medium- and high-priority basins—like the Paso Robles basin—in the state to develop long-term agencies and sustainability plans to manage groundwater.
“Water users in Paso Robles are exploring the possibility of blending Nacimiento water with recycled water to maximize water supply for certain crop types,” Thompson said. “This change in water rights is just one piece of the puzzle to the idea of water uses like this being a viable option for long-term groundwater sustainability.”
Paso Robles Resource Manager Kirk Gonzalez sees the lifted restrictions as able to both directly and indirectly help balance water use in the city and across the county—especially in helping maintain water suitability guidelines mandated by SGMA.
“The changes allow water from Lake Nacimiento to be used for several purposes including municipal, domestic, industrial irrigation, and recreational use,” Gonzalez told New Times. “All of these uses can benefit the Paso Robles Groundwater Basin where they would offset groundwater pumping or result in a return flow to the basin.” Δ
This article appears in Apr 20-30, 2023.