Willamette Valley Wetland Priority Sites [Oregon]
Oregon GEOHub · 2023 Full Details
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Full Details
- Title
- Willamette Valley Wetland Priority Sites [Oregon]
- Description
- Wetland Priority Sites for the Willamette Valley Basin, Version 20090812 (Aug 12, 2009) Oregon Natural Heritage Information Center and The Wetlands Conservancy (TWC) have created a GIS layer for the Willamette Valley that identifies areas with concentrations of important wetland habitats and opportunities for successful wetland restoration. The map is intended to assist conservationists, private landowners, and policymakers in choosing where to site projects for wetland conservation, restoration, mitigation, and enhancement. It will help focus wetland work in the most important places, support no net less of wetland values or acres, and build on past or ongoing project locations. The data is a component of the Oregon Wetlands Explorer website, a collaborative project funded by EPA. Rev 20090812. Synchronization with near-finalized Willamette Valley Synthesis coverage by The Nature Conservancy (TNC). Modified Site Names, attempting to be consistent with TNC's Willamette Valley Synthesis naming. Rev 20090715. Incorporated feedback from provisional version sent out for review in March 2009. The map is based on The Nature Conservancy (TNC) Willamette Synthesis project, with subsequent adjustments and additions made by OSU and The Wetlands Conservancy. The Willamette Synthesis represents a two-year effort that integrates (1) TNC's portfolio sites identified by ecoregional planning (2), ODFW's Conservation Opportunity Areas from their Oregon Conservation Strategy, (3) NRCS hydric soils mapping, (4) FEMA floodplain mapping, (5) Army Corps of Engineers historical floodway maps, and (6) Oregon's Greatest Wetlands as identified by The Wetlands Conservancy and OSU, discussed further below; and a number of other sources detailed in http://oregonstate.edu/ornhic/transfer/wv_synthesis_draft_methods.zip. The Wetlands Conservancy (TWC) and Oregon Natural Heritage Information Center (ORNHIC) developed an "Oregon's Greatest Wetlands" layer, identifying areas in the state having wetlands of significant conservation interest. The "Oregon's Greatest Wetlands" areas were included in the initial Synthesis Site layer. In 2008, TWC and ORNHIC analyzed historic (pre-settlement) vegetation reconstructions, hydric soil densities, and current wetland densities (using National Wetland Inventory and Local Wetland Inventory data where available) that were within the Willamette Valley Ecoregion synthesis sites identified by The Nature Conservancy. The sites were further filtered with information obtained from various Agency and NGO conservation plans. We then reduced in size, or eliminated, WVER synthesis sites based on this analysis. Brief reasoning for the site selection is provided in the Motiv attribute. To improve the focus on wetlands, OSU and TWC then removed the larger upland portions (e.g., oak savanna and woodland, upland prairie) from the Synthesis map, and included additional wetland information based on conservation data, restoration opportunities, and cluster analysis of USFWS National Wetlands Inventory mapping. The lower portion of the Sandy River watershed is located in the Level III Willamette Valley Ecoregion. As such, it was included in the TNC Willamette Synthesis project, even though it is not strictly part of the Willamette Basin. We thus include wetland priority sites for the Sandy River watershed in this dataset.
- Creator
- State of Oregon
- Publisher
- Oregon GEOHub
- Temporal Coverage
- Last Modified: 2023-06-27
- Date Issued
- 2023-06-20
- Rights
- Distributed with the understanding that the dataset is not a delineation of wetlands; that large areas within the borders may not be suitable for wetland restoration. Credit to authors is required. NOTE: the Oregon Wetlands cover is for planning purposes only. It is an estimation of the occurrence and extent of wetlands in Oregon, and does not necessarily map all wetlands or represent wetlands that are subject to Federal or State jurisdiction. It should not be used as a substitute for a wetland determination or delineation performed by a qualified wetland specialist. Many polygons in the base NWI dataset and supplementary data added to the Oregon Wetlands Cover were derived only from aerial photo interpretation and may or may not meet wetland criteria in the field. Per current Federal and Oregon Wetland Mapping Standards, the Oregon Wetlands cover is "neither designed, nor intended, to support legal, regulatory, or jurisdictional analyses of wetland mapping products, nor does it attempt to differentiate between regulatory and non-regulatory wetlands."
- Access Rights
- Public
- Format
- ArcGIS FeatureLayer
- Language
- English
- Date Added
- August 10, 2025
- Provenance Statement
- The metadata for this resource was last retrieved from Oregon GEOHub on 2026-01-08.
Cite and Reference
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Citation
State of Oregon (2023). Willamette Valley Wetland Priority Sites [Oregon]. Oregon GEOHub. https://geohub.oregon.gov/datasets/oregon-geo::willamette-valley-wetland-priority-sites (web service) -
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