Bolinas Beach, a popular surf spot, has been closed indefinitely because of wastewater contamination believed to be emanating from the gridded Big Mesa area of the town. Sarah Jones, director of the Marin County Community Development Agency, said members of her staff spotted effluent coming out of Big Mesa’s eroding cliff face above the beach when visiting the town to inspect a site for a permit application on Sept. 5. Jones said the staff members identified wastewater coming off the bluffs at a couple of dozen spots. “In some areas the water was seeping and in others it was flowing,” she said. “Our staff observed some high volume flows of up to 10 gallons a minute or more, so that is a lot of liquid coming out and going into the ocean,” Jones said. “This would not be what we would expect to see from one person’s septic system failing. There seems to be something bigger going on.”