Nearing the end of the San Bernardino Basin area’s first water year with above average precipitation since 2010-11, San Bernardino Valley Water Conservation District reported more than 20 billion gallons of water captured, a new record for captured groundwater recharge.

This milestone was reached the last week of July, with two months left in the water year, and represents enough groundwater to serve 180,000 families for one year, according to a conservation district press release.

This is a 30-year record with 1987 being the last year this much groundwater was stored into the region’s aquifers. Prior to that, 20 billion gallons of storage had not been achieved since the late 1940s.

According to SBVWCD General Manager Daniel Cozad, the high recharge collection is the result of greater cooperation among local agencies in purchasing state project water, a more aggressive strategy for collecting storm water and a wet winter.

The establishment of the San Bernardino Basin Groundwater Council in 2017 played a major part in the effort, as local cities and water agencies joined efforts and resources in the purchase of water imported from Northern California through the State Water Project (SWP). The council includes participation by East Valley Water District, San Bernardino Valley Municipal Water District, Yucaipa Valley Water District and the cities of Redlands, Colton, Loma Linda and Rialto.

“We are excited and encouraged to see the large amount of storage achieved in such a short amount of time,” said Douglas D. Headrick, general manager of San Bernardino Valley Municipal Water District, which imports SWP water to supplement recharge.

“The combination of everybody cooperating, putting money together for state project water, and planning far enough in advance that we could do the aggressive recharge was half the magic of what came together this year,” said Cozad. “The other half was that it rained.”

Rain year

After seven straight years of below-average rainfall, the San Bernardino Valley Municipal Water District recorded approximately 38 inches of average annual rainfall at its three main watersheds during this season.

San Bernardino Valley Municipal Water District Deputy General Manager Robert Tincher advised that while, after 10 of the past 11 years had below average rainfall, this might feel like an especially wet year it actually represents a slightly above average rainfall.

According to Tincher, the district’s area depends on local rainfall for 72 percent of its water supply and about half of that recharge comes from the Lytle Creek, Santa Ana River and Mill Creek watersheds. As a result, the district monitors those areas to gauge local rainfall and recharge potential.

Another 23 percent of the district’s supply comes from the State Water Project, dependent on Northern California rainfall.

Aggressive recharge

According to Cozad, the conservation district staff developed the aggressive recharge plan about five years ago but was unable to implement it until this year due to lack of rain.

The plan involved opening gates to the district’s spreading basins sooner after a storm, partnering with local agencies and businesses to spread water over more land and other operational changes aimed at collecting water that was previously allowed to flow downstream because of the increased difficulty, costs or risks associated with capturing it for groundwater recharge.

Cozad explained that these costs are associated with the increased force, debris and sediment that water diverted from streams and rivers can carry into the district’s recharge facilities during and for a short period after a storm.

The more aggressive approach resulted in the district diverting more than 43,000 acre-feet of snowmelt and rainfall from Mill Creek and the Santa Ana River this rain year, Oct. 1, 2018 to Sept. 30, 2019. It’s the 16th highest streamflow recharge year since the conservation district started recording measurements 106 years ago.

The district also recharged nearly 20,000 acre-feet of imported watt, bringing the total recharge to about 63,000 acre-feet.

The record year was 1922 when 104,545 acre-feet of water was captured. Previous years of substantial recharge include 53,986 acre-feet in 2011, 30,565 acre-feet in 2010, 56,980 acre-feet in 2005 and 55,576 acre-feet in 1998.

All of the district’s spreading ponds ⎯ 52 at Mill Creek and 19 in the Santa Ana River Wash ⎯ were filled to capacity.

In addition to this, the district arranged to spread additional water on land used by the Redlands Conservancy preserve and into an unused Cemex mining pit.

There were some damages including a levee that was quickly repaired and debris that that had to be cleared during storms and more debris and silt that will have to be removed from recharge basins as they dry up. If silt is left coating a basin it reduces the effectiveness of the basin, holding the water on the surface, preventing it from percolating into the ground.

According to Cozad, thanks to the sand and gravel make up of the local basins they can recharge up to 10 feet of water a day when clean. This can be reduced to 2 to 3 feet per day at the height of silt and debris build up, the end of a season.

In anticipation of these increased maintenance costs, the groundwater council budgeted an additional $50,000 for maintenance and cleanup costs.

The wet winter, full basins and water spread into the Redlands Conservancy also benefitted the native ecosystem spurring a healthy bloom of the endangered Santa Ana River Woolystar as well as a spike in toads, which in turn attracted egrets.

The district also took measures to control and prevent increased mosquito and midge hatches.

Basin storage

Once it seeps into the ground, the water will be stored in the San Bernardino Basin, a 5.69 million-acre-foot underground reservoir that holds the vast majority of the San Bernardino Valley’s water supply.

The basin is larger than Lake Shasta, California’s largest surface reservoir, and is larger than the neighboring Yucaipa Valley, Rialto-Colton Riverside North basins combined.

According to Tincher, the basin now holds approximately 4,716,000 acre-feet of water. If the water storage were to drop to 3,236,000 acre-feet some wells would need to be deepened. The average annual demand for the district is 250,000 to 300,000 acre-feet.

“We have nearly 5 million acre-feet in storage so are we in panic mode?” Tincher said. “No, we’re not in panic mode, but we don’t know how long this drought is going to last.”

Tincher added that tree ring studies give evidence that California has experienced historical droughts that were a century long. (Thick tree rings indicate wet years while narrow tree rings indicate dry years.)

“Even though we have these great storage supplies we never want to rest,” Tincher said. “We’re always trying to find and diversify supplies because we never know what can happen next.”

The main supplemental supply is State Water Project, a supply that the area has come to depend more and more on during the drought.

In 2017 Valley District received a record amount of SWP water, just under 80,000 acre-feet, and it took all that was available in 2018, approximately 45,000 acre-feet.

This water is purchased and delivered to local districts through Valley district for use as groundwater recharge and retail to residents.

Availability of this supply had been on the decline due to concerns for the critically endangered Sacramento River Delta smelt.

To ensure water can continue to be imported from Northern California, the Southern California agencies invested in the state water project are planning for the construction of two major projects ⎯ new conveyance tunnels that will allow the pumping of water from the Sacramento River without altering the flows of the smelt’s native waterways and a new off-channel reservoir.

Each of these projects is expected to be completed in 10 to 15 years.

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