Reseeding Not a Futile Move Despite Slides, Expert Says

The destructive mudslides Thursday are unlikely to hamper reseeding of the hillsides and open areas denuded by the recent fires, a soil erosion expert said.

“The mudslides are definitely not a setback,” said Michael Harding, an expert in erosion and sediment control at Woodward-Clyde, the company hired by the city.

But he said “aggressive measures” must be taken to protect the reseeding effort from being wiped out later in the rainy season.

Harding said his company has a proposed plan for reseeding burned-out areas in the city that will be presented to the City Council on Saturday. If the city quickly approves the proposal, he said, the reseeding can begin as early as next week.

State officials also plan to reseed portions of the burned areas, but have not released details of their plan. State offices were closed for Veterans Day on Thursday and officials could not be reached for comment about the mudslides.

Once reseeding begins, Harding said, his company will use one of the following methods to hold the new seed in place in the face of future rains:

* Apply the seed, then blow wheat-free straw on top before shooting a chemical binder onto the surface to act as a glue holding the seed and straw in place.

* Use recycled paper fiber or wood fiber mixed with an acrylic material to form a viscous mixture that, when sprayed on the ground, will soak in and act as a mulch to bind the soil and seed in place.

* Create a bonded fiber matrix out of wood fiber and a special kind of adhesive that, together, act as a “blanket” on the soil.

* Use actual erosion control blankets made of straw, coconut or wood fiber to be laid on the hillsides after seeding.

These methods, Harding said, were successfully used by his company after the Oakland fire.

“Until that seed gets established or native vegetation returns,” he said, “you’re still going to have a lot of erosion. The idea is to stabilize the soil up there” long enough for the new seeds to grow.

Some opposed to reseeding pointed to the mudslides Thursday as new evidence that reseeding is a futile gesture.

“You can’t prevent mudslides,” said Michael Eaton, supervising ranger at Crystal Cove State Park, who opposes reseeding on ecological grounds. “The reality is that if they had reseeded, the seeds would have been washed away.”

Harding concedes that some seeds would have been washed away by the mudslides before having a chance to germinate, and that more could be lost in future slides. But the mudslides did not occur everywhere, he said. And where they did not occur, the mulching procedures would have retained the seeds.

“The fact that we have moisture in the soil now will help the vegetation later,” he said, adding that vegetation should appear about two months after reseeding. Until then, he said, mulching techniques can “provide really good erosion protection.”

Harding said that he and other employees of his company had spent much of the last two weeks preparing for the expected rains by placing hundreds of straw bales and gravel bags at strategic points in drainage ditches to reduce the flow of sediment.

“We anticipated that we would have problems like this,” he said, referring to the rain.