The Peninsula Watershed has been integral to the story of San Francisco's growth ever since the Gold Rush. The rapid influx of settlers to San Francisco during the Gold Rush spurred a sudden demand for a reliable water source, which led to the formation of the Spring Valley Water Works (later purchased by the Spring Valley Water Company [SVWC]) in 1858 (Hanson 2005 ). Over the subsequent 70 years, SVWC bought up large swaths of land on the Peninsula, and constructed a complex system of dams, tunnels, and pipes to capture and transport water to San Francisco. Within the Peninsula Watershed, this system includes the Crystal Springs and San Andreas reservoirs, located in the San Andreas Creek, Laguna Creek, and Upper San Mateo Creek basins along the San Andreas Fau The City of San Francisco purchased SVWC in 1930, and today the Peninsula Watershed, managed by the San Francisco Public Utilities Commission (SFPUC), continues to be a key source of water for San Francisco and for other communities in the South and East Bay. Despite the past 150 years of reservoir construction and other hydrologic modifications, the construction of transportation and utility corridors, and the large-scale suburban development that has occurred to the east, the Peninsula Watershed has remained largely undeveloped and is managed to protect water quality, water supply, wildlife habitat, and a range of other natural and cultural resources. The watershed supports some of the largest intact remnants of contiguous habitat in the region, including extensive oak woodlands, old-growth Douglas-fir forests, serpentine grasslands, chaparral, and coastal scrub. Over the past 250 years since Spanish explorers first set foot on the watershed, however, changes in disturbance regimes and other large-scale anthropogenic modifications, including fire suppression, homesteading, livestock grazing, agriculture, tree planting, introduction of plant pathogens, spread of invasive species, and climate change, have altered vegetation dynamics and changed the distribution and structure of vegetation communities throughout the watershed. The changes have raised many questions about the historical ecology of the watershed: What was the extent, distribution, and composition of terrestrial, riparian, and wetland habitats prior to Euro-American modification? How have vegetation distributions changed over the past two centuries, and what are the implications of those changes for species support? Are there remnant patches of relatively unmodified habitat present in the watershed, or areas that are currently in a state of recovery? Where are current habitat characteristics most similar to or different from historically documented conditions? How have key natural and anthropogenic disturbance regimes and processes changed over time? The Peninsula Watershed Historical Ecology Study aims to advance understanding of landscape conditions of the Peninsula Watershed prior to major Euro-American modification, and to provide insights into the nature and drivers of vegetation change since the first Spanish explorers set foot in the watershed 250 years ago. The primary goal of the research was to examine the historical extent, distribution, and composition of terrestrial vegetation types and their trajectories of change within the watershed. To the extent possible, research also addressed historical riparian, wetland, and estuarine habitats; hydrology and sediment dynamics; wildlife support; land use history; and a range of other topics.

The Clean Water Act (CWA) requires that wetlands be protected from degradation because of their important ecological functions including maintenance of high water quality and provision of fish and wildlife habitat. However, this protection generally does not encompass riparian areasâ€"the lands bordering rivers and lakesâ€"even though they often provide the same functions as wetlands. Growing recognition of the similarities in wetland and riparian area functioning and the differences in their legal protection led the NRC in 1999 to undertake a study of riparian areas, which has culminated in Riparian Areas: Functioning and Strategies for Management. The report is intended to heighten awareness of riparian areas commensurate with their ecological and societal values. The primary conclusion is that, because riparian areas perform a disproportionate number of biological and physical functions on a unit area basis, restoration of riparian functions along America's waterbodies should be a national goal.

Using the framework developed in this report, urban designers and local residents can work together to link local parks, greenways, green roofs, street trees, stormwater basins, commercial landscaping, and backyards to support biodiversity while making cities better places to live.

The Tijuana River Valley Historical Ecology Investigation synthesizes hundreds of historical maps, photographs, and texts to reconstruct the ecological, hydrological, and geomorphic conditions of the Tijuana River valley prior to major European-American landscape modification. How did the valley look and function before there was the state of California, the city of Tijuana, or an international border? What habitat types and wildlife were found there? How have these habitat types and the physical processes that shaped them changed over time? And finally, what can the valley's ecological past tell us about its present and future? In answering these fundamental questions, this richly-illustrated study provides scientists, managers, and residents in the valley with information designed to support and inspire ongoing management and restoration activities.

The original report From the Sierra to the Sea: Ecological History of the San Francisco Bay-Delta Watershed was a product of a three-year effort to develop a landscape level overview of the natural ecological structure, function and organization of the watershed, and the way it had changed over the course of the 19th and 20th centuries. Technical review and contributions from government and water agencies helped produce a collaborative document that provided information on the historical ecological baseline in order to assist in what was envisioned at the time as the most ambitious restoration effort ever undertaken in the United States. We are proud of the fact that the original document is still used as an objective reference, and has provided a foundation and inspiration for similar but more intensively researched localized efforts by others in the Bay-Delta watershed. This 20th anniversary edition contains a new Afterword describing changes to the estuary and its watershed since the report was originally published in 1998.