Birders, bogs, and bathwater

The effluent running through the man-made marshes didn't bother Jean Starkweather, past president of the Marin Audubon Society. She was bird watching at the Las Gallinas Sanitary District's ponds in San Rafael, where birders have identified 175 species. A short-eared owl flew overhead. Starkweather focused her binoculars on a Eurasian widgeon. ``It's wonderful how the engineers [who monitor the marshes] become hooked on birds,'' she said.

Each day, the Las Gallinas marshes handle 2.9 million gallons of effluent from a population of about 27,000.

This project, a 385-acre complex of ponds, freshwater marshes, saltwater marshes, and irrigated pasture, was built in 1983 as an alternative to a six-mile, $12 million deepwater outfall. The San Francisco Bay is shallow offshore from the district's sewage treatment plant. Mudflats extend for miles at low tide.

The Regional Water Quality Control Board's mitigation requirement includes maintaining the freshwater and brackish marshes as well as refraining from discharging any effluent at all during June, July, and August.

``Those are the months,'' said James Emanuel, the engineer who manages the Las Gallinas complex, ``that apparently are the worst as far as shellfish absorbing pollutants.''

The project includes 40 acres of retaining ponds for the no-discharge months, and 200 acres of pasture irrigated in the dry summer months with reclaimed water.

Ed Nute, the civil engineer who built the marsh, said evaporation from the storage ponds also helps the district meet the no-discharge requirement.