Water & Drought

Paso's wells could collapse into the Salinas River. Here's how the city is preventing that

After two winters of downpours, the resources that supply Paso Robles with two-thirds of its drinking water are on the verge of collapsing into the Salinas River.

The city's Thunderbird well field — used to extract water that's percolated under the sandy riverbed — and the equipment used to process Lake Nacimiento water are located on a dangerously eroded riverbank.

Although the river looks dry now, it's become swollen with water during the past two rainy seasons — more so than during the previous five years of drought.

"When the river was flowing, it looked like a chocolate milkshake," said Christoper Alakel, the city's water resources manager.

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In one extreme case, 10 people were rescued from the Salinas in late March after heavy rains filled the channel with water and flooded homeless encampments.

These sudden influxes of water have eaten away parts of the riverbank, threatening the wells and treatment facility, which are located off Ramada Drive just behind Firestone Walker Brewing Co. Farther down the river, the force of the water felled large cottonwood and oak trees.

"We're seeing erosion increase at rates we haven't seen in the past," Alakel said.

The Paso Robles City Council recently approved an emergency $750,000 plan to shore up the riverbank by grading it and then stabilizing it with stones to prevent further erosion.

Dick McKinley, the city's public works director, said the money will come out of his department's $3 million reserves fund. "You have emergency reserves for emergencies," he said.

"It's nothing compared to what it would cost if we lost those well fields," he said.

Paso Robles Wells Salinas River113888
Large cottonwoods and oaks have been felled by the erosion. Christopher Alakel Water Resources Manager of Paso Robles shows the Thunderbird wellfield beside the Salinas River, which was threatened by the Salinas River after heavy winter rains 2017-18. The city is paying $750,000 to protect the wellfield, which is a major source of water for Paso Robles residents. David Middlecamp dmiddlecamp@thetribunenews.com

Significant real estate

On Tuesday, bulldozers scooped up chunks of the riverbank, turning the steep drop-off into a gradual slope.

Down the river from the construction site, pipes sprayed water from Lake Nacimiento into the sand to percolate through and help replenish the underground stream from which the five river wells draw water.

The Nacimiento Water Project — which pumps water from the reservoir on the northwest edge of the county to North County cities and San Luis Obispo — went online in Paso Robles in 2015, helping to reduce groundwater pumping.

During hot summer months, some of the lake water is sent underground and some is processed through the treatment plant located near the wells.

The city's drinking water comes from three sources: the river wells, the Paso Robles groundwater basin and the Nacimiento Water Project. Since the city began using lake water, it's been able to shift away from groundwater, Alakel said.

Only about one-third of the city's potable water now comes from deep water wells, with lake and river well resources accounting for the majority of the water residents consume, he said. This means the wells and surrounding facilities are more valuable than ever.

"We just want to get a handle on it and mitigate the real estate loss," Alakel said.

Lindsey Holden: 805-781-7939, @lindseymholden