SAUVIE ISLAND & MULTNOMAH CHANNEL BOTTOMLANDS CONSERVATION OPPORTUNITIES: A Resource for Landowners & Land Managers Sauvie Island & Multnomah Channel Bottomlands Conservation Opportunities 1 SAUVIE ISLAND & MULTNOMAH CHANNEL BOTTOMLANDS CONSERVATION OPPORTUNITIES: A Resource for Landowners & Land Managers of Acknowledgements Table Contents FUNDING PHOTOS INTRODUCTION AND PURPOSE 4 CONSERVATION OPPORTUNITIES 30 West Multnomah Soil & Water Conservation District Jane Hartline, Sauvie Island Habitat Partnership Native Vegetation 31 The Wetlands Conservancy Pat Welle, Scappoose Bay Watershed Council SAUVIE ISLAND AND MULTNOMAH Invasive Species 32 CHANNEL BOTTOMLANDS 5 US Fish and Wildlife National Digital Library Oak Savannah and Woodland 35 West Multnomah Soil & Water Conservation District AUTHORS SAUVIE ISLAND’S PAST – HOW IT Riparian Buffers and Canals 36 Jane Hartline, Sauvie Island Habitat Partnership SHAPES THE PRESENT 5 Hedgerows 38 Pat Welle, Scappoose Bay Watershed Council GRAPHIC DESIGN Island Formation and Historic Flooding 5 Grasslands 39 Elena Cronin, Elena Cronin Design Native-American and Early Pollinator Habitat 40 EDITORS Euro-American Settlers 8 Wetland and Aquatic Habitat 41 Kammy Kern-Korot, West Multnomah Soil & Water Conservation District Carolyn Lindberg, West Multnomah Soil & Water Conservation District RECOMMENDED CITATION HISTORIC AND CURRENT CONDITIONS; Water Quality 43 WMSWCD, 2018. Sauvie Island & Multnomah Channel SIGNIFICANT CHANGES 10 Soil Health and Diversity 44 Bottomlands Conservation Opportunities: A Resource MAPS/GIS WORK Ownership and Land Use Patterns 10 Community Science 46 for Landowners and Land Managers Jane Rombouts, The Wetlands Conservancy Private Land Ownership 11 Sauvie Island Habitat Partnership Land Use Planning 47 Pat Welle, Scappoose Bay Watershed Council Sauvie Island Wildlife Area 11 Scappoose Bay Watershed Council Sturgeon Lake Restoration 50 Other Public Lands 11 West Multnomah Soil & Water Conservation District CONTRIBUTORS The Wetlands Conservancy Soils and Geology 13 APPENDIX 1: WILDLIFE 53 Susan Barnes, Oregon Department of Fish and Wildlife Soil Types Within the Plan Area 13 APPENDIX 2: PLANT SPECIES 59 John Christy, Wetlands Ecologist COPYRIGHT Hydrology and Water Quality 14 Michelle Delepine, West Multnomah Soil & Water Conservation District Hydrology on Sauvie Island 14 This open source publication may be reproduced and used APPENDIX 3: SPECIES OF CONCERN 76 Scott Gall, West Multnomah Soil & Water Conservation District with attribution and permission by contacting Jane Hartline, Sauvie Island Drainage and Irrigation District Mark Greenfield, Audubon Society of Portland sauviehabitats (at) gmail.com. (SIDIC) 17 APPENDIX 4: INVASIVE SPECIES 90 Chris Hein, Bat Conservation International Hydrology on the Western Lowlands 17 Tom Josephson, Columbia River Estuary Study Taskforce COVER PHOTO Water Quality on Sauvie Island 18 APPENDIX 5: PLANT COMMUNITIES 97 Esther Lev, The Wetlands Conservancy Camas, the Western meadowlark – our state bird, and Water Quality in Scappoose Bay, the APPENDIX 6: CONSERVATION Mark Nebeker, Oregon Department of Fish and Wildlife Oregon white oaks are all iconic species for Sauvie Island Bottomlands and along Multnomah Channel 18 and the Multnomah Channel Bottomlands. PROJECTS 103 Jennifer Ringo, Oregon Department of Fish and Wildlife Plant Communities (Land Cover) 20 Liz Ruther, formerly of Oregon Department of Fish and Wildlife Plant Community Descriptions 21 REFERENCES 108 Wildlife 24 Conservation Projects 25 RESOURCES 108 Sauvie Island Rural Area Plan ACRONYMS USED IN THIS and Zoning 29 DOCUMENT 109 First printing, September 2018 INTRODUCTION AND PURPOSE Goals of this document are to: auvie Island and the surrounding bottomlands are home Inform to a vibrant farming and residential community, plus S Provide detailed information on the unique ecological features large public wildlife and recreation areas, that all benefit of the area, its landscape history, current land uses, ongoing from rich natural resources. The area was once a vast conservation efforts and those involved in them; catalog its complex of wetlands and prairies with pockets of mostly natural assets and assemble information useful to agencies, deciduous forests and savannahs. Although the hydrology and organizations and landowners involved in conservation efforts; geographical features have been greatly altered by dams, dikes, identify potential threats and promote understanding of the agriculture and invasive species, the area still provides habitat ecological importance of conservation efforts. to an amazing diversity of waterfowl, songbirds and other wildlife. These wild lands provide beauty and a place of respite for residents as well as urban visitors. Identify Opportunity Wetlands cover a large part of Sauvie Island. Describe and prioritize conservation opportunities in terms Recognizing this area as the treasure it is, and realizing the of ecological importance, landscape location (including resource conditions but has not been well represented in importance of maintaining and improving its natural assets, proximity to related habitats), likelihood for success and SAUVIE ISLAND AND other watershed plans. The adjoining sub-watersheds of multiple agencies as well as many private landowners have other relevant conservation actions. Scappoose Creek and Milton Creek are addressed in the engaged in conservation and restoration practices. MULTNOMAH CHANNEL Scappoose Bay Watershed Strategic Action Plan, which was BOTTOMLANDS completed in June, 2018. This Conservation Opportunities document shares Inspire information pulled together from the combined knowledge Outline conservation opportunities to enlist landowners, of many scientists and ecology professionals as well as the agency land managers, conservation organizations and The conservation opportunities laid out in this document knowledge of residents working the land. It catalogs the others to continue to provide stewardship and enhance the encompass all of Sauvie Island, plus the low-lying mainland SAUVIE ISLAND’S natural assets of the area and most importantly, intends to conservation values of the area; promote cooperation on areas that run the length of Sauvie Island, between Highway 30 PAST – HOW IT inform and inspire future conservation and restoration efforts. these efforts and sharing of information. and Multnomah Channel. For the purposes of this document, this area will be called the Plan Area. The Plan Area includes SHAPES THE PRESENT The document was authored by Sauvie Island Habitat portions of land west of Scappoose Bay, north to St. Helens Implement Partnership, Scappoose Bay Watershed Council, West and south to Miller Creek near Harborton Road (Figure 1 – Lay out a blueprint for conservation projects to be Multnomah Soil & Water Conservation District and The Plan Area Map), the base of the Tualatin Mountains on the east accomplished by multiple agencies, organizations and Island Formation and Historic Wetlands Conservancy. Other partners include Oregon side, and the Scappoose Bay Bottomlands. landowners, along with monitoring actions to objectively Department of Fish and Wildlife, Sauvie Island Drainage Flooding measure environmental changes. Improvement Company, Natural Resources Conservation The Plan Area was selected due to the unique qualities of Service and Metro. Sauvie Island and the physical, biological and hydrologic Sauvie Island is located northwest of Portland and is similarity of the included lowlands on the mainland. The approximately 21,000 acres – running 17 miles long and Plan Area boundary nearly follows the Oregon side of the almost 5 miles wide. Multnomah Channel borders the island floodplain area of Hydrogeomorphic Reach F, as defined in on the west, the Columbia River on the north and east, and Columbia River Ecosystem Classification – Concept and the Willamette River on the south (Figure 1). Application (Simenstad, 2011). This “Middle Tidal Floodplain The island was formed in the Pleistocene era through Basin” of the Columbia River Estuary (CRE) is the widest sediment accumulation behind a ledge of large rocks, now floodplain reach of the upper CRE and is characterized by known as Warrior Rock, on the island’s north end (Sauvie wetlands, circuitous sloughs and seasonal ponds within bar- Island Community Association). Historically, the island was and-swale deposits, terraces and rocky outcroppings. influenced by seasonal flooding events from Columbia and Sauvie Island takes up the largest portion of the Plan Area. Willamette River freshets as well as daily tidal patterns. It holds significance in terms of history, culture, and natural Construction of dams along the rivers and flow regulation 4 Sauvie Island & Multnomah Channel Bottomlands Conservation Opportunities Sauvie Island & Multnomah Channel Bottomlands Conservation Opportunities 5 have significantly reduced spring flooding and altered Hudson Bay Company established dairies on the island to hydrologic patterns (greater detail on geology and hydrology support its Fort Vancouver property just across the river. is provided in the following sections). These were managed by Laurent Sauvé, for whom the island was renamed. Additional settlers of European descent arrived in the late-1840s via the Oregon Trail. Native-American and Early European-American settlers had staked out most of Sauvie Euro-American Settlers Island by the mid-1850s and farmed the island’s fertile soil. The following information is compiled from several sources,