The Rancho Murieta Community Services District held the first in a series of workshops last week to meet a state mandate to reduce water use 20 percent by 2020 and to update the community’s water master plan. In the coming months, the CSD will look at the effect of climate change and drought scenarios on the reliability of the community’s water supply and consider ways the community can use water more efficiently.
The state mandate to achieve a statewide 10 percent reduction in per capita water use by 2015 and a 20 percent reduction by 2020 applies to water systems with 3,000 or more connections. Although Rancho Murieta, with 2,500 hook-ups, is under that threshold now, the community isn’t built out, and the next phase of development is expected to add 500 to 600 homes.
“The question is, when does the 10-year window for you to comply start?” General Manager Ed Crouse asked at Friday’s session. “Does it start now even if you reach 3,000 before 2020 and only have two years to go? ... Should (you) just go ahead and bite the bullet, like we are, and plan that you’re going to get 3,000. ... This is the right thing to do, given the direction that the whole state is moving.”
“Your whole water right is predicated on beneficial and reasonable use,” said consultant Lisa A. Maddaus, principal engineer with Brown and Caldwell. “They can actually question that at any time because your water right is a lease.” Making the effort to comply with the mandate is “one way that you can prove that you have been using your water efficiently,” she said.
The community’s water rights allow water to be diverted from the Cosumnes River between November and May, once flows reach high enough levels, and the water is stored in three reservoirs -- Lakes Calero, Chesbro and Clementia.
“Our water right comes up for renewal in 2020,” Crouse said. “So at that time, we need to show that we’re conserving water, using it efficiently to maximize the beneficial use because at that time ... the state can take a look at how well you are using your water, and, if they feel the public isn’t getting a benefit at large versus Rancho Murieta, there’s the potential to reduce your water right, to give that water someplace else.”
It’s unlikely water rights would be granted for aesthetic or recreational reasons. “If you want the aesthetics of your lake, then we need to save the water for the lake,” Maddaus said.
Maddaus said legislation establishing the reduction in water use was spurred by “the downstream crisis in the Bay Delta. ... We extract a lot of water from that ecosystem.”
Consultant Lisa Maddaus took a look at the community's water prospects for the coming years.
Maddaus said state records show April to June run-off has been declining for the Sacramento River since the 1950s, which indicates the snowpack is declining. “When we look back and we analyze these records, we are seeing shifts,” she said.
No growth is expected by 2015, so the district will be asking current customers to reduce their water use by 10 percent. By 2020, there could be 500 to 600 new homes if the next phase of development is built.
When new homes are built, landscaping guidelines will be in place to reduce their water use, Crouse said. According to Crouse, new state guidelines that took effect in January limit planting types, sizes and scope to conserve water.
Maddaus presented a 10-year highest running average that showed daily water use at about 268 gallons per capita in the district. Under one of four methods proposed for complying with the law, it would mean reducing water use by about 53 gallons a day by 2020.
During the workshops, the CSD board will be looking at more than two dozen ways to reduce water use.
Integrated Water Master Plan update
The update of the 2006-07 Integrated Water Master Plan will use dry-year and climate change scenarios to test the reliability of the community’s water supplies. It will also include climate change scenarios for the Cosumnes River and various drought-year scenarios.
“We’re looking at the big picture, and water supply and demand, and when the next big one, in terms of the drought comes, how will you survive?” Maddaus said, outlining the update’s scope.
She said a 50 percent curtailment or more in water demand is a state benchmark in planning for a severe drought like the one in 1976-77. This is the level of conservation proposed for the extreme drought event included in the plan.
A recent peer review of the plan characterized the 50 percent conservation level as aggressive and said it was unclear how it would be achieved.