Drilling Slurry Believed Source of White Plume in Redwood Creek; Agencies Investigating

Water from Redwood Creek enters the South Fork Eel River basin before converging just south of the entry point.

The mysterious white plume that turned Redwood Creek milky and reached the South Fork Eel River this week is believed to have come from nearby drilling activity, according to information provided to Redheaded Blackbelt by the California Department of Fish & Wildlife. Lab results that could confirm the substance are not yet in.

A Cal OES Hazardous Materials Spill Report filed Tuesday evening, June 2, first documented the opaque, bluish-white substance in Redwood Creek between Seely Creek and the Eel River along Briceland Thorn Road west of Redway. The substance covered the water shore to shore. Community members reported it had appeared the previous Saturday before clearing, then returned.

The material is now believed to be a mixture of bentonite, water, rock, sand, and clay — byproducts of drilling activity in the area, which has since stopped, according to CDFW spokesperson, Peter Tira. The situation remains under investigation. CDFW’s Law Enforcement Division and the North Coast Regional Water Quality Control Board both responded to the initial spill report. The water board collected a water sample and sent it to a lab for analysis; results are pending and may be available later today. CDFW’s environmental science staff is now checking for impacts to fish and other species.

Josh Curtis, Assistant Executive Officer for the North Coast Regional Water Quality Control Board, said Wednesday the board, at that point, had no current evidence of significant harm to aquatic life and no fish kill has been observed. He said there is no official directive to stop pumping water from the river or to halt recreational activities but urged people to “hold off if possible” on using the water until results are available.

What bentonite does to a river

In an interview with KMUD News, Patrick Higgins, a consulting fisheries biologist and managing director of the Eel River Recovery Project, said the white cloudy water moving down Redwood Creek and into the South Fork is consistent with a bentonite spill. He said people do not need to worry about it as a toxic substance — bentonite is inert — but said it is injurious to the aquatic ecosystem.

Higgins said the suspended clay particles can prevent steelhead and coho salmon migrating downstream right now from feeding. When bentonite settles, it coats the stream bottom like toothpaste, filling the cracks between rocks where aquatic insects live — the primary food source for fish. He said the damage can persist until winter flows flush the gravel clean.

Higgins said he studied bentonite impacts firsthand in the Garcia River watershed in 1992, after AT&T used bentonite clay during cable drilling and it surfaced in a tributary. The aquatic invertebrate population downstream was nearly wiped out, and AT&T paid damages.

Is this legal?

Discharging drilling slurry into waterways without a permit is not allowed. Under the federal Clean Water Act’s NPDES program, discharging pollutants into waters of the United States requires a permit. California drilling waste regulations require that drilling mud and cuttings be discharged only to on-site sumps with appropriate containment.

Higgins said the discharge appears to violate both the Clean Water Act and the North Coast Regional Board’s Basin Plan, which protects fish and cold-water beneficial uses. “When things like this substance enter public waters like Redwood Creek and the South Fork, it’s definitely not consistent with the basin plan,” he said.

Redheaded Blackbelt will update this story as more information becomes available.

Earlier: [Update] Unknown Substance Turns Redwood Creek White, Reaches South Fork Eel River