For the first time since 1951, Turlock Irrigation District and Modesto Irrigation District filed a water rights application to divert water during years of ample rainfall — a much-needed adjustment as the region experiences increasingly variable wet weather.
Moments after MID directors approved their end of the application Tuesday morning, the TID Board did the same. The water rights application filed with the State Water Resources Control Board asks that unappropriated flood waters from the Tuolumne River be captured by the districts so that they can be put to beneficial use for customers, communities and the environment.
“Today, we are faced with challenges that we haven’t seen before. Climate change has significantly impacted precipitation and runoff, as you’ve seen in [TID hydrologist Olivia Cramer’s] reports over the years,” TID Assistant General Manager of Water Resources Tou Her told the board Tuesday. “The hydrology within the watershed is very volatile…In the more recent 50 years, you can see that the dry years are getting drier and the wet years are getting wetter.”
The joint application petitions the state to permit the Districts to appropriate up to 2.7 million acre-feet of water Nov. 1 through June 14 annually, when the Tuolumne River is not classified as a fully appropriated stream. A fully appropriated stream is one where there is insufficient supply for new water rights applications; an initial analysis indicates that since 1998, there have been 13 years when water would be available averaging approximately 840,000 acre-feet annually.
The right would be considered junior to all current water rights to appropriate water from the Tuolumne and would complement the Districts’ existing water rights portfolio. A multi-year procedural process now ensues before any water right is issued or flood waters are diverted.
“It’s really a recognition of climate change and also the continued realization that we have to capture every drop that comes down,” TID Board President Michael Frantz said. “In these more and more flashy years that we have, it all seems to come at once, doesn’t it?...So we have to continue to change our system to be able to accommodate those flood flows and keep them around during the dry periods. This is very exciting.”
The filing is consistent with the Governor’s Water Resilience Portfolio while also showing a proactive effort to respond to calls to action for water districts to maintain, increase and diversify water supplies and ensure long-term water availability and reliability. In addition to climate change, state and federal regulatory efforts (e.g. state’s Bay-Delta Plan and federal relicensing of the Don Pedro Project) could likely decrease water supply availability. Implementation of Groundwater Sustainability Plans in response to the Sustainable Groundwater Management Act will also require additional water sources for needed sustainability projects.
“This historic action demonstrates our forward thinking in seeking all avenues of available water to sustain our customers, communities and environment,” MID Board President John Mensinger said. “These water rights can provide us the flexibility and opportunities to collaborate on projects – large and small – to utilize additional water for beneficial use in line with the changing demands of our region.”
Additional water captured from flood flows could also benefit the Tuolumne River fishery, floodplain habitat, flood risk mitigation, groundwater recharge and the provision of drinking water.
“Today’s filing builds on our 135-year legacy of stewardship on the Tuolumne River, we’re constantly on the lookout for regional solutions to regional challenges,” Frantz said. “The watershed is so volatile year to year because of the impacts of climate change. This is a prudent decision that can benefit ag water users, drinking water supplies, the fishery and flood risk management for the next century.”