Scientists wrap up groundwater testing, quality analysis to come next

Scientists wrap up groundwater testing, quality analysis to come next
Scientists built several test wells in October at the San Elijo Lagoon in hopes of tapping into a local water source. Currently, equipment from the project is being removed. Depending on further analysis, the Olivenhain Municipal Water District could build a series of long-term wells and a desalination facility a mile or two east of the lagoon. Photo by Jared Whitlock

CARDIFF-BY-THE-SEA — For two months, scientists drilled a test well at the San Elijo Lagoon with the aim of finding potable water for the Olivenhain Municipal Water District (OMWD). 

With testing complete, officials are in the process of removing a 40-foot drill structure that was used to tap the well. Other work includes returning the environment to its prior state.

Next, the district will decide whether the groundwater meets quality and quantity standards. If the groundwater is viable, OMWD could build a series of long-term wells and a desalination facility a mile or two east of the lagoon, which could supply the district for decades.

“There are millions of pieces of data that will take months to sort through,” said Joseph Randall, management analyst with OMWD. “After that, we’ll take the next steps.”

OMWD partnered with the U.S. Geological Survey (USGS) for the project in hopes of securing another long-term water source to draw from. Currently, Southern California is largely reliant on imported water, leaving water districts in the region open to price hikes and supply disruptions.

“This was a big undertaking and exploratory by nature,” Randall said. “That said, we’re feeling pretty solid about the results so far.”

On the better-news-than-expected front, the groundwater doesn’t have as much salt as originally anticipated.

The groundwater’s salinity is around 1,800 parts per million, lower than the estimates of 3,000 parts per million.

As such, treatment — putting the water through reverse osmosis — would potentially cost less, according to Randall.

Randall said the amount of water underground in the aquifer isn’t necessarily an issue, because water moving from the mountains to the ocean provides a continuous supply. What’s important is how much the district can pump from the ground.

To that end, the test well produced 50 gallons per minute, which wasn’t quite as high as estimated before the project began.

Why? Drilling 1,200 feet into the earth at the spot was more difficult than thought, and pulling up water didn’t come up quite as easy as anticipated.

But Randall said that might not be a major source of concern, as the yield from a test well is typically less than that of a production well. And should the water flow remain less than desired, building additional wells is an option.

Originally, the district estimated a future desalination plant and wells for treating the groundwater could generate up to 1.5 million gallons of groundwater per day, making up as much as 10 percent of OMWD’s potable water, and also a portion of the district’s recycled water.

Based on results so far, Randall said it’s early, but the groundwater could measure up or exceed those numbers.

“One piece of the puzzle is in place, and there’s still more to go,” Randall said.

Should the district green light long-term groundwater wells, the earliest the project would go online is 2018, Randall said.

Wesley Danskin, a research hydrologist with USGS, called the testing phase of the project “successful.” But he noted it was hit by some setbacks, including breaking a drill bit, which required extending the project by several weeks.

Now finished, officials are packing up.

“Right now we’re removing everything and mitigating any impacts to the area,” Danskin said.

But some equipment will remain in one of the shallow wells. According to Danskin, it will be used to monitor water levels.

The $450,000 project was funded by $300,000 in grants from the U.S. Bureau of Reclamation and the California Department of Water Resources, as well as $150,000 from OMWD and USGS.

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