By Craig W. Anderson 

San Joaquin County’s groundwater basin should be drinking deep of the heavy winter storms pummeling the area. The most rain since 2017 has alleviated – again –ongoing drought and introduced new water to the aquifer. A sector benefitting greatly from the deluge is that of projects that use excess surface water to recharge groundwater basins.

Aquafer improved

“So far, the indications are that the aquifer’s gone up,” said Joe Valente, president of the North San Joaquin Water Conservation District’s board of directors. “The district’s responsible for making sure the 150,000 acres of land it’s responsible for receives adequate supplies of water.”

That’s being done thus far this year with rainfall on the district’s plentiful vineyards which have, said Valente, “good, sandy soil which absorbs the water really well; it’s gone the next day.”

That is the key to successful filtering down into underground aquifers but while nature receives credit for the beneficial natural recharge provided by rain, it also creates a challenge to determine how much recharge has occurred from the uncontrolled natural rainfall.

A lot of water needed

Whatever the exact amount, Dave Simpson, chair of SJFB’s Water Advisory Committee, said he expects the current storm moisture to be “beneficial” and that “it will take a real good winter to overcome a five year drought. Will winters like this be enough to recover [from our drought]? I don’t think so.’

The lack of reservoirs, ponds and other water-storage/trapping areas allows the water to run down to the Delta or the Bay. “If we were able to capture some of the winter run-off we’d be in great shape. But we don’t have the systems to capture all of this run-off so it goes to the Golden Gate, unused,” Simpson said.

Water capture

One way to capture the currently wasted water is by a voluntary tactic: Flood-MAR or “Flood managed aquifer recharge.”

According to Department of Water Resources Supervising Engineer Jennifer Marr, this method combines floodwater operations and groundwater management to benefit working landscapes and aid local groundwater agencies that are part of the state’s Sustainable Groundwater Management Act (SGMA).

“With recent events, the focus is on flood risk reduction, which includes the use of levees and bypasses to keep floodwater off of land assets – such as agriculture –  and get water out of the system quickly if there is nowhere to store it,” said Marr. “Flood-MAR can help slow down flows and provide prime locations to divert floodwater to maximize recharge.”

Storage needed

Rains as experienced in 2017 and the February/March downpours of 2019 point out the lack of non-winter preparation when ponds, catch basins and other water traps could be installed, including reservoirs and dams, all to catch the winter runoff and store it for use on a non-rainy day.

Plan for future

“In the future, all water rights, conveyance and other infrastructure would be in place and ready for the next event,” said Marr. “Ideally, landowners would be compensated for the public benefits their Flood-MAR project provide.”

Mother Nature has provided Farm Bureau members with examples of on-farm flooding to refill aquifers but, at least for almonds, the February/March downpours have come at the wrong time, said Simpson. “On-farm flooding can work but it needs to take place at the right time. If done at the wrong time, almond trees can be blown down.”

He also suggested setting aside areas specifically as recharging basins, noting, “Stockton East Water District has done a pretty good job with recharging basins.”

Political will lacking

Basins usually require a reasonably large expanse of land onto which the water can be applied; new reservoirs fall into this category, Simpson said, but “our legislators simply do not have the political will to build new reservoirs. We need the legislature to cooperate with a justifiable use of funds so reservoirs and dams can be built. It does us no good to wring our hands and complain about not having sufficient water when it’s our fault.”

He also said that when the will to do it is there and the knowledge is there to build recharge areas “the money isn’t there.”

And all of these elements and a few more, should be on the construction team because groundwater is an essential water source that provides 35 percent of the fresh water used in the state, and significantly more in drought years. And California allows a high percentage of that water to flow away, unused, not recycled, and not used to establish a sustainable use of water. MAR can help prevent negative consequences of groundwater depletion such as subsidence and salt water intrusion by stabilizing groundwater levels and determining the most suitable soil, geologic setting, and aquifer space for recharge and at what rates water can be applied.

Mother Nature intervenes

Of course, Mother Nature enters the picture again because, said Valente, “February was one of the wetter months on record and that meant the relationship between snowfall, the rivers and weather was reasonably in balance.”

Cold weather kept the snow from melting and increasing the water already swelling the rivers and, he said, if storage was available the extra water could be diverted, stored and saved to mitigate drought effects. Unfortunately, the legislature has yet to provide the means for thwarting drought’s effects by pre-planning and proactive management practices.

Orchard removals can help

“As orchards come out, the land could be used to recharge basins until they’re replanted,” suggested Caleb Gervase, Escalon farmer and SJFB board member. “Using newly developed and improved rootstocks could allow more effective on-farm flooding when it’s safe to do so.”

There are, he said, ways to enhance orchard crops and vineyards to make them more amenable to being utilized as aquafer replenishers. But farmers would need to develop means to avoid compacting the soil or equipment creating ruts on softer soil resulting from on-farm flooding.

“I think that as we move forward with SGMA we’ll expand recharge,” Valente said. “We’ve tested this lately with 148 acre feet applied to 10 acres over two to three weeks. The results were very positive.”

If the infrastructure necessary to save water and store it isn’t forthcoming from the legislature it seems the efforts of universities, water districts, irrigation districts and forward thinking organizations such as Farm Bureau hold the hope of making water available throughout the year and over the years.

“It looks like we’ll have to keep working on it until we get it right,” Simpson said.

California Farm Bureau Federation contributed to this story.