Los Osos diverts water from failed basin, neighbors call foul

January 16, 2023

Flooded intersection of Pecho Road and Grove Street


Floodwaters flowed into homes in the Cuesta-by-the-Sea neighborhood in Los Osos on Saturday, prompting neighbors to question if an earlier basin failure caused the flooding.

While an atmospheric river pummeled Los Osos on Jan. 9, floodwaters did not flood into homes in the Cuesta-by-the-Sea neighborhood. But after the Los Osos Community Services District diverted water from a basin that failed during the Jan. 9 deluge, floodwaters quickly rose in the Cuesta-by-the-Sea neighborhood during a milder storm on Jan. 14.

Decades ago, contractors built a retention basin at the base of the Cabrillo Estates, a subdivision on a hillside on the way to Montana de Oro. The retention basin was constructed in an attempt to protect neighboring, lower-elevation properties.

However, on Jan. 9, the basin burst, leading to hundreds of thousands of gallons of water and mud crashing into Vista de Oro Estates. A raging river of water and mud filled homes with up to three feet of mud, water and debris.

At a community meeting on Jan. 12, Los Osos Community Services District staff told attendees they planned to temporarily remedy the Cabrillo Estates’ drainage issue by diverting the stormwater runoff down Pecho Valley Road, and away from Vista de Oro Estates.

“We are turning Pecho Valley Road into a drainage canal basically,” said one of the Los Osos Community Services District board members off camera.

In response to questions about the diversion causing unintended consequences to downstream residents, General Manager Ron Munds said the district would monitor those areas during any new storms.

“There are potential places with the constant flow that might be unintentionally impacted so we will look at armoring them with sandbags,” Munds said.

Staff then diverted stormwater from Cabrillo Estates, towards Pecho Valley Road, to Los Osos Valley Road where it was expected to drain into an inlet, and then through pipes that lead to the bay. However, drainage through the pipes slows depending on the tides.

Cuesta-by-the-Sea residents noticed rapid flooding at the intersection of Pecho Road and Grove Street on Jan. 14, at a higher and faster level than during the Jan. 9 deluge. A group of neighbors worked together in an attempt to keep the floodwaters out of their homes.

Decades ago, resident Paul Van Meel made changes to his property after flood waters breached his home. Van Meel voiced concerns that diverting water from Cabrillo Estates to his neighborhood could be “catastrophic.”

On Jan. 14, for the first time in approximately 30 years, stormwater again flowed into Van Meel’s home.

“The rising water level at the intersection of Pecho and Grove was inconsistent with the amount of rain,” Van Meel said.

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The changes the county made to Arroyo Grande Creek also resulted in flooding of areas that have been safe for decades. Where the creek bed had been maintained previously by managers of the agricultural land below the mesa, the county banned their activity and created bare earth ‘levees’, with the side effect of killing many of the trees that stabilized the natural creek bed. County ‘improvements’ also raised the bank on the south side that had resulted in periodic flooding of the agricultural fields south of the creek when we had heavy rains. Flooding of deltas creates some of the richest soil in our country. When the earth levee failed, water was released in amounts and areas not previously affected.

I would like to see environmental studies done previous to the ‘fixes.’

Was the inspector a Certified Flood Manager, a SCM inspector, a licensed PE qualified to inspect flood control devices? Did the inspector, just inspect the water level? Did he or she inspect the structural integrity of the flood control device as required by law during and post significant rain events? Has the CSD met these requirements and numerous others? If not, then criminal liability may rest with the CSD Manager?

Sounds like Mr. Munds needs be handed his walking papers.

Great idea, even though we’ll have to cough up an incredibly generous severance package typical of bozo administrators that SLO County is getting rid of.

You are right on the money. Fire him today and don’t give him a severance package. He failed to do his job and his actions have created untold liability for the CSD and risk to members of the community.

Time for LOCSD management to learn to read a tide table, it will serve them well in deciding when to let large amounts of storm water run into the bay.

My guess is that no LOCSD member lives in any of these flooded areas.

It is a good thing LOCSD has deep pockets.