Facing what could be another historically dry winter, North Marin Water District is set to study options to expand its water supply for Novato, including increasing reservoir capacity and considering desalination.
“We need additional supply,” district board Vice President Stephen Petterle said during a board discussion on the study this week. “There is no doubt about it.”
The $150,000 study is set to explore several possible supply options, including expanding the district’s recycled water production, which currently makes up 8% of its Novato supply; capturing stormwater runoff from nearby areas such as Bowman Canyon; increasing the capacity of its Stafford Lake reservoir by raising lake elevation by 3 feet; and groundwater banking, in which the groundwater aquifer can be recharged during wet years and drawn from during drought years.
Board members also voiced support for exploring desalination, especially should its larger neighbor to the south — the Marin Municipal Water District — consider temporary desalination plants as one of its emergency water supply projects if this winter is as dry as the last.
North Marin Water District directors Mike Joly and Rick Fraites voiced support for exploring desalination, even if it is not their preferred option, based on potential growth in the county in the coming decade and the potential for longer drought periods, especially given climate change impacts.
“Our mission is to meet the expectations of our customers in providing potable water,” Joly said during the Tuesday meeting. “That is a clear, evident mission and that mission is something that is our obligation to make happen where we can, within reason. I personally love conservation, but for this director and this customer, I believe we’ve passed the flashpoint where conservation as a marginal return is a climate change solution.”
“I don’t think we should take it off the table,” Fraites said of desalination.
District General Manager Drew McIntyre said his intent is to bring back a contract for the study to the board for a vote by September. The study would begin in October and potential options would be brought back to the board by March.
In the meantime, the district can still consider additional changes to its water use restrictions depending on how much rain the region receives closer to the end of the year, McIntyre said. Novato ratepayers have been required since July 1 to collectively reduce water use by 20% compared to 2020 water use. Ratepayers were exceeding this target as of last week at 22% conservation.
The discussion comes after the district, which serves about 61,000 residents in Novato and 1,800 residents in parts of West Marin, experienced its driest year on record with just more than 8 inches of rain falling at its only reservoir at Stafford Lake. The reservoir was 43% full on Thursday with about 1,780 acre-feet of water. The lake would be closer to 15% full had the district not paid $405,000 to pump 1,100 acre-feet of Russian River water into the reservoir earlier this year in preparation for the dry winter.
Stafford Lake makes up about 20-25% of the district’s supply for Novato, with the remaining water coming from imported Russian River water from the Sonoma Water agency. Sonoma Water is facing its own supply crisis and reduced water imports by 20% beginning July 1. The cuts could increase to 30% should Sonoma Water’s reservoir at Lake Sonoma dip below 100,000 acre-feet later this year. The lake had about 126,200 acre-feet of supply as of Thursday.
A larger regional study led by Sonoma Water is already taking place and set to be completed by September 2022. However, given the drought conditions, parts of the study addressing drought risks are being put on a fast-track schedule and are set to be completed by October, according to McIntyre.
One potential fast-tracked option could be restoring currently dry wells owned by Sonoma Water that could be refilled during wet years and used during dry periods such as this drought. The wells could produce about 4.5 million gallons of water per day, McIntyre said.
While he said he prefers these types of regional solutions more, McIntyre said, “At the same time we need to look at what we can do locally here within our region.”
