Benefits of Tidal and Estuary Restoration

Introduction to Summer 2015 Ecesis, Volume 25, Issue 2

California has nearly 850 miles of coastline where land meets the Pacific Ocean; but when shorelines along bays, inlets and river mouths are accounted for, California has approximately 3,400 miles of tidally influenced shoreline. Since European colonization of the United States, extensive simplification and degradation of estuaries and tidally influenced shoreline has occurred. For example, in the San Francisco Bay more than 90% of the tidal wetlands and salt marshes were diked, drained and filled.

Estuaries and the lands surrounding them are places of transition from land to sea and from fresh to salt water. Although influenced by tides, estuaries are often protected from the full force of ocean waves, winds, and storms by such land forms as barrier islands or peninsulas. Estuarine environments are among the most productive on earth —supporting unique communities of plants and animals especially adapted for life at the margin of the sea. Estuaries are also important habitats for juvenile salmon and steelhead as they transition from freshwater into the marine environment. In some larger watersheds, a single species of salmonid may express varying strategies of estuarine use, from relatively quick movement through the system to spending several months foraging and putting-on additional growth before entering the ocean. Conversely, many marine organisms — including many commercially important species of fish — depend on estuaries at some point during early life-stage development. Because they are biologically productive, estuaries also provide ideal areas for migratory birds to rest and re-fuel during their long journeys. 

Estuaries provide humans with a suite of resources, benefits, and services. They provide places for recreational activities, scientific study, and aesthetic enjoyment. Estuaries have important commercial value and their resources provide economic benefits for tourism, fisheries, and recreational activities. The protected coastal waters of estuaries also support important public infrastructure, serving as harbors and ports vital for shipping and transportation.

Estuaries also perform other valuable services. Water draining from uplands carries sediments, nutrients, and other pollutants to estuaries. As the water flows through wetlands such as swamps and salt marshes, much of the sediments and pollutants are filtered out. This filtration process creates cleaner and clearer water, which benefits both people and marine life. Wetland plants and soils also act as natural buffers between the land and ocean, absorbing flood waters and dissipating storm surges. This protects upland habitat as well as valuable real estate from storm and flood damage. Salt marsh grasses and other estuarine plants also help prevent erosion and stabilize shorelines.

Although tidal and estuary restoration projects are occurring throughout California, this issue of Ecesis is focused on several restoration efforts located in Humboldt County. Two projects are located in the Humboldt Bay watershed, on Salmon Creek (South Bay) and McDaniel Slough (North Bay). The third project is an ongoing, multiphase program to restore the tidal function of the Salt River located in the lower Eel River watershed near Ferndale. — Ross Taylor, Ross Taylor & Associates