The illustrated map below was part of a presentation given by state officials this week to bring attention to the tremendous opportunity that exists right now to recharge vast amounts of surface water into the San Joaquin Valley groundwater aquifer. The numbers that stand out to me are these:
The Southern Sierra mountains show nearly 3.5 million acre-feet of projected runoff anticipated to flow through the Southern San Joaquin Valley over the next several months.
Groundwater depletion in the last two years has been over 7 million acre-feet in the Valley. There is a lot of room for this surplus flood water to fill up the aquifer if we can slow the water down and disperse it over the landscape, hopefully in an organized and safe way.
The Central Sierra mountains are predicted to generate nearly 9 million acre-feet of projected runoff. Here too, the last couple of years have seen groundwater overdraft and this is the year to recharge the aquifer.
The fact that we have wet and dry cycles is normal for California. We have had the dry years; now we have this unbelievable opportunity with this incredible wet year. As the Groundwater Sustainability Agencies (GSAs) wrote their sustainability plans over the past several years, all of those plans depend upon recharging surface water in the wet years to get through the dry years. The BIG UNKNOWN has been when those opportunities arise – and they are here now – what will farmers do?
The greatest opportunity to change the water future of the Valley is if we can maximize the recharge of these wet year flows. We are about to find out what we are capable of. If you are in a position to take water onto your farmland and let it percolate into the ground, now is the time to act. If you are in a GSA with a water allocation and you want a groundwater credit for your recharge, you will need to call your local GSA for instructions. Most of them have adopted recharge policies and they can direct you to what you need to do to earn recharge credits. If you are in a GSA where there is not a groundwater allocation yet, then you are probably in an area where your access to groundwater is less threatened in the near term, but certainly your action to recharge the aquifer will keep your area closer to sustainability and soften pumping restrictions in the future.
Governor Newsom did issue an Executive Order that helped to facilitate the diversion of this flood water. In many areas in the Southern San Joaquin Valley, the local water districts and conservation districts already had authority to divert this water and did not need the Executive Order to facilitate its capture. But other areas of the Valley are benefiting greatly from the Governor’s order. Contact your GSA to find out what the rules are in your area. Remember, whatever water is not captured will be lost.
Geoff Vanden Heuvel
Director of Regulatory and Economic Affairs