Section 3.4 Biological Resources 3.4- Biological Resources
SECTION 3.4 BIOLOGICAL RESOURCES 3.4- BIOLOGICAL RESOURCES 3.4 BIOLOGICAL RESOURCES This section discusses the existing sensitive biological resources of the San Francisco Bay Estuary (the Estuary) that could be affected by project-related construction and locally increased levels of boating use, identifies potential impacts to those resources, and recommends mitigation strategies to reduce or eliminate those impacts. The Initial Study for this project identified potentially significant impacts on shorebirds and rafting waterbirds, marine mammals (harbor seals), and wetlands habitats and species. The potential for spread of invasive species also was identified as a possible impact. 3.4.1 BIOLOGICAL RESOURCES SETTING HABITATS WITHIN AND AROUND SAN FRANCISCO ESTUARY The vegetation and wildlife of bayland environments varies among geographic subregions in the bay (Figure 3.4-1), and also with the predominant land uses: urban (commercial, residential, industrial/port), urban/wildland interface, rural, and agricultural. For the purposes of discussion of biological resources, the Estuary is divided into Suisun Bay, San Pablo Bay, Central San Francisco Bay, and South San Francisco Bay (See Figure 3.4-2). The general landscape structure of the Estuary’s vegetation and habitats within the geographic scope of the WT is described below. URBAN SHORELINES Urban shorelines in the San Francisco Estuary are generally formed by artificial fill and structures armored with revetments, seawalls, rip-rap, pilings, and other structures. Waterways and embayments adjacent to urban shores are often dredged. With some important exceptions, tidal wetland vegetation and habitats adjacent to urban shores are often formed on steep slopes, and are relatively recently formed (historic infilled sediment) in narrow strips.
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