Environmentalists have filed another lawsuit aimed at stalling work on the Willits bypass.

They will be asking a Mendocino County judge on Wednesday for an injunction to stop soil from being moved from timber company property to wetlands Caltrans is filling as part of the $210 million, 5.9-mile Highway 101 bypass around Willits.

The bypass, conceived more than five decades ago, has increasingly sparked opposition as it verges on reality. It generated another lawsuit last year and a multitude of protests since construction began early this year.

Proponents say the bypass will alleviate traffic jams through Willits, where Highway 101 is the main through street; reduce vehicle exhaust; and make the streets safer.

Opponents say it's unnecessary, will destroy wetlands, harm fish and irrevocably change the rural nature of the Little Lake Valley.

The most recent lawsuit, filed Friday against the county of Mendocino, claims county planners wrongly issued a permit allowing 883,950 cubic yards of fill dirt to be moved from Mendocino Forest Products land to the bypass property without adequate environmental and regulatory review.

"It's a lot of dirt," said Ellen Drell, of the Willits Environmental Center.

But county planning staff issued a simple grading permit, apparently agreeing with Mendocino Forest Products' engineering consultants who contended that the project didn't need more intensive review because it is on industrial land and that flattening it will make the property more usable.

"It's pretty outrageous really," Drell said.

The permit did not require Mendocino Forest Products — an affiliate of Mendocino Redwood Company — to test the soil for contaminants, she said. The soil will be placed adjacent to streams and sensitive wetlands, she said. It also didn't adequately evaluate the impacts on the forest property. The grading includes removal of fir trees, Drell said.

The lawsuit contends that the county violated the California Environmental Quality Act and the Surface Mining and Reclamation Act when it issued the permit.

County Counsel Tom Parker said the county is evaluating its options.

"We are looking at the lawsuit and we are considering what the response will be," he said Tuesday.

Caltrans spokesman Phil Frisbie said the permit was sought by, and issued to, Mendocino Forest Products and did not involve Caltrans.

However, Caltrans does test soil samples for contaminants before it is utilized for fill, Frisbie said.

The samples have tested within an acceptable range for contaminants, he said.

The lawsuit is the second filed against the project in a little over a year.

Four environmental groups in 2012 filed a lawsuit in federal court that contends the bypass will harm wetlands, salmon-bearing streams and endangered plants.

The project is expected to result in the loss of nearly 100 acres of wetlands but Caltrans plans to create new ones and enhance others.

A ruling on that case is expected by Sept. 21.

The bypass project also has been the subject of protests. They've included people sitting in trees and chaining themselves to heavy equipment used to drive huge wick drains into the wetlands to speed earth compaction.

The drains and environmental mitigations also are the subject of a warning letter to Caltrans from the U.S. Army Corps of Engineers.

In an Aug. 16 "notice of non-compliance," the Corps said Caltrans was behind in plans for mitigating the impacts of the project, including removing cattle from the land. It also requested further studies on the impacts of using wick drains on wetlands and set deadlines for Caltrans' response to the notice.

"Failure to comply with this order may result in suspension of your permit or administrative penalties," the notice states.

Frisbie said Caltrans is in the process of complying with the notice. He said such notices are fairly common with large projects.

They are "like fix-it tickets," Frisbie said.

You can reach Staff Writer Glenda Anderson at 462-6473 or glenda.anderson@pressdemocrat.com.