(The following article by Charles Levin was posted on the Ventura County Star website on May 17.)
OXNARD, Calif. — As sinkholes go, the one on a dirt road in south Oxnard doesn’t seem threatening. It’s about 5 feet across and a few feet deep.
But peek through the orange plastic fence that wards off passers-by, and you’ll notice two large corrugated pipes in the dirt. One of them has at least a half-dozen holes.
Ventura County Watershed Protection District officials said the punctures are causing the sinkhole, and they worry that more holes will follow and the sinkhole could spread, threatening a nearby railroad track.
Citing a “threat to public health and safety,” district officials today will ask the county Board of Supervisors for authority to negotiate a $300,000 emergency repair contract.
“Our biggest concern is we get it repaired before the sinkhole happens under the railroad tracks,” Tom Lagier, a district operations and maintenance manager, said Monday. “That would be a bad thing, because we don’t want a train falling in the hole.”
The sinkhole is located on a dirt road that crosses over a culvert consisting of five 60-inch, galvanized-iron pipes. The crossing, just west of Perkins Road in south Oxnard, offers a path for some trucks and the rail spur.
The 48-year-old pipes carry stormwater under the crossing and down a county flood control channel to the ocean. The pipes are coated with a polyvinyl material inside, but brackish tidal water has eroded the coating and weakened the pipes, Lagier said.
“It’s amazing they’ve lasted this long,” Lagier said.
A company called Ventura County Railroad leases the rail spur, which connects with the main Union Pacific tracks. The company transports fertilizer-related materials from a business in the area, General Manager Doug Verity said Monday. A couple of trains visit the business each week along the six-mile spur, he said.
A railroad worker spotted the sinkhole May 4 and notified the county. The sinkhole sits in the southwest corner of the culvert crossing. The rail tracks are roughly 40 feet away, in the northwest corner.
Last week, county officials inspected all the pipes and found at least two in bad shape. Three others will soon follow suit without some attention soon, Lagier said.
Officials have tested the ground with rail cars moving over them and found it is safe for now, Lagier said. The cars, however, must move slowly, he said.
The two-week repair job would involve inserting slightly smaller, high-density, polyethylene pipes inside the existing ones. Workers will then inject cement grout between the two pipes and existing holes in the dirt, Lagier said.
Under emergency contract rules, the county is exempt from state environmental laws. But construction work must proceed without harming several endangered fish, including the tidewater goby, according to a staff report. The county will direct channel water around the area during the repair job, Lagier said, giving crews a dry surface to work on while posing no threats to fish.
Even if the board approves the request today, it’s unclear when the work would start. County officials are seeking quotes from companies now, Lagier said, but culvert materials are in short supply because of all the storm damage this year.
“We’re having trouble finding material,” Lagier said. “It will probably have to be made, so that delays things a little bit.”