Tidal Wetland Restoration in San Francisco Bay: History and Current Issues

John C Callaway,Michael C Vasey,V Thomas Parker,Lisa M Schile,Ellen R Herbert

doi:10.15447/sfews.2011v9iss3art2

John C Callaway, Michael C Vasey + Show 3 more

Open Access

https://doi.org/10.15447/sfews.2011v9iss3art2

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Abstract

Early restoration efforts in San Francisco Bay focused primarily on establishing appropriate elevations for plant recruitment, based on plant distributions in natural wetlands. Sites were graded and planted, and tidal connections were re-established with the expectation that restored wetlands would quickly resemble natural ecosystems. Over time, restoration efforts have evolved, with the realization that natural development of restoration sites is preferable, including a dense channel network and the accumulation of soils of appropriate texture. Bay restoration efforts also have grown substantially in size and scope. Whereas projects of 50 hectares were considered large in the 1980s, now many projects are 100s of hectares. Larger projects are on the scale of 1000s of hectares, with the largest approximately 6000 hectares (the South Bay Salt Pond Restoration Project). This massive increase in scale has brought enormous restoration opportunities, but it also has increased the complexity of restoration projects and highlighted the necessity of largescale public involvement. Awareness of non-native plants at restoration sites is just one example of factors that have increased restoration complexity. Potential impacts of climate change also have moved to the forefront of restoration design, as sea-level rise and potential shifts in salinity are critical factors for long-term restoration planning.

Highlights

Wetland losses to date have been enormous throughout San Francisco Bay, ranging from 70% to 93% loss of historic area across regions (Table 1)
Loss rates for tidal wetlands have been reduced in recent decades (Goals Project 1999), and the Clean Water Act (CWA), along with a growing understanding of the value of wetland ecosystems, has led to large-scale interest in wetland restoration around the bay
We review the evolution of tidal wetland restoration in the bay, including an evaluation of current and future challenges for bay restoration

Summary

Introduction

Wetland losses to date have been enormous throughout San Francisco Bay (hereafter, the bay), ranging from 70% to 93% loss of historic area across regions (Table 1). Salt pond construction, along with urban development, affected large areas of tidal wetlands in the south and central San Francisco Bay. After the Clean Water Act (CWA) was amended in the early 1970s, wetlands became protected from further filling, diking, and dredging.

Results

Conclusion