Several years ago, as the state was in yet another period of drought, state lawmakers decided one way to improve the ground water table was to require developers to create stormwater retention basins within the project site.

The idea sounded good, so these basins soon became part of every new project that was built, including government projects such as roads, parks, and public buildings.

Another reason is to help mitigate the flood threat to downstream communities.

There are several of these basins in Lompoc, and during the recent storms none of them failed. Perhaps it was the way they were constructed, maybe it was soil type used for the barriers, and maybe it was just luck.

Tens of thousands of these basins exist today all over California; many are owned by county, or municipal governments.

These basins are bodies of water confined by a barrier, which is the Merriam-Webster definition of a dam. Some basins contain a large amount of water during heavy rainstorms. Rarely is much attention paid to the barriers that form the pond.

Flood control districts were organized to control storm flows, and the Santa Barbara County website says:

“The primary purpose of the Flood Control is to provide flood protection and to conserve storm, flood, and surface waters for beneficial public use.”

Gov. Gavin Newsom recently announced he was cutting $40 million in funding for flood control improvements. Where? In the Central Valley, which is largely conservative.

The county website continues: “Throughout the County, natural and man-made flood control facilities in the County are subject to damage and loss of capacity through sedimentation, vegetation growth, bank erosion, and other obstructions by debris.

“The District uses heavy equipment to remove sediment, clear obstructive vegetation, and correct erosion problems.”

Both preceding and following storms, we’ve seen local media reports that show caravans of dump trucks carrying away hundreds of tons of storm residue away.

In Lompoc, the county clears basins and stores the residue next to Highway 246 west of town.

Recently, two of the county owned retention basins failed to contain runoff in Orcutt; and another privately maintained levy failed in Guadalupe — for the fourth time in 30 years.

In each instance, homes were damaged, and some destroyed, along with all the home occupant’s property.

While the county was quick to react, first with emergency services and then with cleanup and road repair, it still left the victims homeless.

There are federal and state programs available to help those families recover their losses, but if history is an indicator, it will take several months — maybe years — before funding arrives to replace their lost property.

Could these failures have been prevented? Perhaps. Those barriers were constructed using sandy soil, and this may not be the best material to use to impound water.

We don’t know the maintenance history for these sites, but I am almost sure they didn’t get the same attention as those of the South Coast.

Stormwater retention basins are small dams; they should be managed the same way larger dams are because they can cause the same type of problem, just on a lesser scale unless the property that’s flooded is yours. 

The California Division of Safety of Dams defines a “downstream hazard” as potential downstream impacts to life and property should a dam fail.

This definition should be applied when planning and operating all stormwater retention basins in the county, whether they are government or privately owned.

I think it’s time for the Board of Supervisors and local governments to take a hard look at how all these small dams that were required due to state mandates are built and maintained.

Then, take the lessons learned during this and previous storms and apply them to regulatory and/or design fixes.

Why? Because the California Division of Safety of Dams isn’t going to add these small dams to its inspection list, but someone in government needs to.

If action isn’t taken to mitigate the hazards created by the retention basins, then we’ll see the same kind of reports following the next serious rain event.