Creek jumps at Chicken Ranch, shows need for work

03/13/2019

The years-long restoration plans for Chicken Ranch Beach were put to the test last month when storms led Third Valley Creek to jump its banks and take a new route across the beach into the bay. 

To assess the changes, Tom Gaman, chair of the Tomales Bay Watershed Council, met on Tuesday with Craig Richardson, open space planner for Marin County Parks, and Greg Kamman, the hydrologist both parties have commissioned for water-quality testing to inform a restoration project. 

The group largely agreed that the storm primarily showed a greater need for the plans already drafted by both parties. 

Typically, Third Valley Creek drains from Mount Vision through a series of culverts below Sir Francis Drake Boulevard, across several properties, and out to the bay under the bridge at the beach entrance. But during the last storm, the creek jumped over the culverts—one of which had become blocked—and took another route, funneling into Channel B, one of two channels that cuts across the northwest end of the beach during high tides. 

Channel B has historically been the area of particular concern for restoration: it routinely exceeds state fecal coliform standards for human contact, and it lies in an area where children and families congregate to play, swim and picnic throughout the year. 

It is unclear where the coliform is originating; there are no hits higher up in the watershed or obvious culprits in the immediate area. The watershed’s foundation and Marin County Parks each contributed around $5,000 last year to Mr. Kamman’s San Rafael-based hydrology company to undertake new testing to gather more data. This week, Mr. Kamman said the source of the high coliform levels remains unknown. 

Mr. Gaman said the creek had not in recent memory jumped into Channel B, which in the late ‘90s a past property owner dug by hand—on county land—in order to drain water off his adjacent property. 

The storm, Mr. Gaman said, only affirmed his assurance that the wetland area needed to be restored. “We hope to enlarge and restore the continuity of the wetlands on the west side of the beach so we have more natural opportunity to cleanse the water it collects and create more habitat for wildlife,” he explained. “I’m hoping there are now some expanded opportunities.” 

Back in 2013, the council released a suite of restoration alternatives, which considered redirecting creek flows, improving marsh habitat, removing invasive plants and filling Channel B. 

In 2015, however, after the county paid for DNA testing that ruled out the presence of coliform from human waste, representatives said they would not pursue work at Chicken Ranch, particularly given the ongoing and expensive efforts to restore the Bolinas Lagoon. 

Yet When Supervisor Dennis Rodoni came into office, he breathed new life into the project. Conversations turned to a tentative idea for a project focused specifically on filling in Channel B and creating new wetlands on a parcel at the back of the beach, which is fenced off and owned by the State Lands Commission. 

Mr. Kamman said the biggest question he has for the design project is how to restore the wetland and eliminate the risk that the creek jump its banks—and form a new Channel B—in another large storm.

This spring, the watershed council and the parks department will bring their plans to an interagency review group called Marin Project Coordination before proceeding with a design.