Here’s this week’s Central Valley water supply headline: We need rain and snow. The storm of a couple of weeks ago did help us get out of what was to that point one of the driest starts to the water year on record. However, the storm pattern was not uniform. A water district official described almost a “wall at the Fresno/Tulare County border,” preventing the heavy moisture from covering the mountains south of there. The data I saw this week bore that out. The San Joaquin River watershed, which is the source of water for the Friant Kern Canal saw a larger boost in water inflow than did the Kaweah, Tule and Kern watersheds. It is still early in the rainy season and a few big storms could dramatically change the picture (in a way I never appreciated until I moved to the Valley in 2018). The fact is that Central Valley agriculture is heavily dependent on each winter’s rain and snow for its sustenance in the coming year.
In the Lake Shasta watershed of the Sacramento Valley, early indications are that there will be some supply, but this will also be a criticality dry year. That designation is meaningful because if the amount of inflow into Lake Shasta falls under a certain threshold, then required deliveries to priority surface water right holders of the Lake Shasta supply are reduced, lessening the threat that San Joaquin River supplies would be diverted away from the Friant Kern Canal.
The surface water priority system has been in place for decades. First in time, first in right, is the basic description of California surface water rights. When irrigated agriculture was developed along the Sacramento and San Joaquin rivers many years ago, those lands owned priority rights to those river supplies. When the major dams were built as part of the Central Valley Project, promises were made to those landowners who owned rights to the Sacramento and San Joaquin Rivers that they would receive priority in obtaining surface water supplies when the projects became operational. In the Sacramento watershed those priority lands are called the Settlement Contractors and on the San Joaquin River the priority lands are called the Exchange Contractors because they exchanged their San Joaquin River supplies for a priority of the Shasta supplies that would be delivered to them through the Delta instead of the San Joaquin River. Part of the legal agreement with the Exchange Contractors is that if there is not enough water available to make them whole from the Delta, then they can call on the San Joaquin River supplies. In that case there is no water available for the Friant Kern Canal. This happens very rarely but did occur in the 2015 drought. The Federal Bureau of Reclamation governs this whole system and must make the call. So far, we are not in a position where this drastic move looks likely. On the other hand, while it looks like there will be a Friant supply, without more precipitation those supplies will be severely limited.
In past decades, shortages in surface water supplies were made up with increased groundwater pumping. But the long-term reliance on that solution has been greatly complicated by the passage of the Sustainable Groundwater Management Act in 2014. SGMA required every part of California that lies over a groundwater aquifer (not mountains) to become part of a new local agency called a Groundwater Sustainability Agency (GSA). Those GSA’s covered lands that were judged by the state to be in a critically overdrafted condition were required to put together a Groundwater Sustainability Plan that must eliminate “undesirable results.” The plans needed to be submitted by January 31, 2020, which they were. What the plans were required to do was outline how the GSA would reach a sustainable condition by year 2040.
This legislation has been a game changer. It is carried out at the local level. Access to supplemental surface water supplies has turned out to be the most important factor for an area to be able to balance its water budget. Without access to surface water supplies, groundwater-only areas are facing the prospect of a significant curtailment of water available for irrigated agriculture. As GSA’s work to implement their plans, capturing additional surface water is a top priority. When we have dry years, it puts increasing stress on the system. There are serious efforts underway to look at increased investment in recharge and conveyance facilities, which would be able to take flood waters in wet years and put them back into the aquifer, but it all starts with ample rain and snow.
Bringing the rain and snow are out of our control, but the Bible says in Zechariah 10:1, “Ask the Lord for rain in the springtime; it is the Lord who sends the thunderstorms. He gives showers of rain to all people, and plants of the field to everyone.” So, we pray for rain and trust in the provision of God.
Geoff Vanden Heuvel
Director of Regulatory and Economic Affairs