Fremont area, DUST Marsh

Trails from Ardenwood Blvd. at Alameda Creek or Patterson Ranch Rd. at entrance to Coyote Hills Regional Park EBRPD Map

White pelicans flock to the wildlife-rich DUST Marsh
White pelicans flock to the wildlife-rich DUST Marsh

The 55-acre Demonstration Urban Stormwater Treatment (DUST) Marsh was  created in 1983 by the Association of Bay Area Governments (ABAG), East Bay Regional Park District, and Alameda County Flood Control.

Like much of its surroundings, the area had been dried out for farming and development by cutting channels and diking. The marsh is fed by Crandall Creek, a former Alameda Creek side channel that drains a large part of north Fremont, which was then and still is rapidly urbanizing.

From the creek, the urban runoff flows into a small basin where log baffles encourage mixing and pollutant settling, and also trap large debris. The marsh leads runoff through conditions ranging from pond to mudflat to shallow flow over land. Culverts then channel the water to the main marsh of adjacent Coyote Creek Regional Park, which drains to San Francisco Bay. Tides bring Bay influence to the DUST Marsh, so its water is sometimes fresh, sometimes brackish or even saline.

Monitoring shows that the runoff does lose many of its heavy metals, nutrients, and other pollutants by the time it reaches the main marsh. Wildlife thrives in the DUST Marsh, and there has been no evidence of build-up of toxins.

But much of the pollution removal takes place upstream, in the cattails and tules of the creek channel. And in this and many other sloughs and drainage channels of the low-lying South Bay, flood-control authorities continually remove this vegetation to keep it from slowing flood waters and trapping sediment. Such conflicts in goals are common.