Version 20091030 (October 30, 2009). The Oregon Wetlands Cover is a compilation of polygon data from numerous sources, and represents the most comprehensive dataset available for the location and composition of the state's wetlands. It uses as a base all available digital data from the National Wetland Inventory (NWI; U.S. Fish and Wildlife Service, USFWS), to which has been added draft NWI mapping (Oregon Natural Heritage Information Center and The Wetlands Conservancy, ORNHIC and TWC), mapping from Local Wetland Inventories (LWIs; Department of State Lands, DSL), wetlands along state highways (Oregon Department of Transportation, ODOT), and mapping of individual sites by a variety of federal, state, academic, and nonprofit sources. Because the Oregon Wetlands Cover is based on the NWI framework, it represents all wetland categories in the Cowardin classification (Cowardin, L.M., V. Carter, F.C. Golet & E.T. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. USDI Fish & Wildlfe Service, Biological Services Program. FWS/OBS-79/31. 103 pp. <http://www.npwrc.usgs.gov/resource/wetlands/classwet/index.htm>; <http://el.erdc.usace.army.mil/emrrp/emris/emrishelp2/cowardin_report.htm>) that are known to be present and mappable in Oregon. It includes perennially inundated "open water" aquatic habitats such as lacustrine limnetic, riverine (all subsystems), and marine and estuarine intertidal and subtidal. Man-made water features such as industrial detention ponds, log ponds, municipal sewage treatment lagoons, and flooded gravel pits are also included because they are often habitat for wetland biota. Portions of upland riparian areas may also be included where they are intermixed with riverine or palustrine wetlands and cannot be separated at the scale used in original mapping. Despite the inclusion of wetland spatial data from many different sources, a multitude of wetlands in Oregon have yet to be identified and mapped, and are not present in this coverage. This is especially true for seasonal, small, farmed, and forested wetlands that are difficult to detect with aerial photography.
The Oregon Wetlands Cover is a key component of the Oregon Wetland Explorer data portal (http://oregonexplorer.info/wetlands), and is intended to (1) serve as a framework for storing and disseminating information on the state's wetlands, and (2) promote comprehensive monitoring, assessment, conservation, and restoration of Oregon's wetlands.
The Oregon Wetlands dataset was developed from several primary data sources and multiple secondary supplementary sources, which are described in more detail under the "Process Step" header in the "Data Quality Information" section of the metadata. Wetland data are limited to the legal border of Oregon, which includes a 3 mile offshore buffer. Abbreviations for data sources occasionally appear attribute fields. They include: NRI (Natural Resources Inventory), ODOT (Oregon Department of Transportation), ODSL (Oregon Department of State Lands), ORNHIC (Oregon Natural Heritage Information Center), PHF (Pacific Northwest Hydrography Framework), PW (Potential Wetland), TNC (The Nature Conservancy), TWC (The Wetlands Conservancy), USFWS (US Fish and Wildlife Service), USACE (US Army Corps of Engineers). The Oregon Wetlands dataset will be updated as additional wetland information is obtained and processed. NWI data in this release include recently completed NWI linework for southeastern Oregon. Some portions of western Oregon are represented by preliminary NWI linework that has not been approved by USFWS.
1980-Current
Credit to authors is required.
Oregon Natural Heritage Information Center & The Wetlands Conservancy. 2009. Oregon Wetland Cover, Dated 20091030. ESRI file geodatabase. Oregon Natural Heritage Information Center, Oregon State University.
Attribute accuracy varies, depending on source and attribute. For NWI-derived polygons, the Cowardin classification was determined by the photointerpreter, who may not have had on-the-ground information to assign Class, Water Regime, or Special Modifier codes. Some percentage of NWI polygons will have incorrect Cowardin codes because of subsequent development, disturbance, or hydrological changes from the time of the initial classification. Incorrect Cowardin codes from all data sources were auto-corrected by TWC using a lookup table that identified, among other things, capitalization errors and obsolete terminology. For polygons obtained from a Local Wetland Inventory, SITENAME is the same as the city name of the LWI, even if the polygon is identifying a specific feature with a commonly accepted name. When electronically available, attributes for LWIs (or equivalent) were imported directly, or used a look-up table to convert the consultant's attributes to an OWMS attribute. In such cases, the accuracy of the attributes are the responsibility of the consultant. Older LWI reports frequently were not available electronically, and were entered into spreadsheets, then joined to the polygons. Based on quality control checks, we estimate that the attributes were correctly entered 95-98% of the time. Wetland polygons obtained from a Local Wetland Inventory are attributed as "Local Wetland Inventory" (DATA_S_TYP = 2) only if the original digital geodata of the LWI has been reviewed and approved by Oregon Dept. of State Lands. Wetland polygons for LWIs that have been obtained from other sources, including digitization from paper copies of LWI maps, should be regarded as preliminary. Such preliminary LWI polygons are attributed as "Local or Regional Government" (DATA_S_TYP = 5). SAC attributes for non-springs wetlands are estimated to be 95-98% accurate. LSW is defined only for areas within an inventory boundary. This includes LWIs and areas where a jurisdiction performed a Locally Significant Wetland designation for planning purposes. The use of "U" for several attributes indicates that we currently do not have information for the given polygon or that we have not yet processed the information. Vernal pool complexes are often represented as a single polygon, even though the wetland portion of a complex occupies only a portion of the polygon area. This is due in part to the difficulty in digitizing individual vernal pools which may be small or difficult to see in imagery. The Agate Desert area (Medford/White City) contains large areas of vernal pool and upland mosaics. Polygons for vernal pool complexes are typically given a "PEM" Cowardin classification, but the entire polygon should not be interpreted to be a wetland. Future revisions may better delineate individual vernal pools, or give vernal pool complexes a unique designation or classification. Per NWI convention, linear features are represented as polygons of 5.0 meter fixed with total. Most often, such linear features are R3: Riverine Upper Perennial and R4: Riverine Intermittent) Because most of these linear features are usually less than 5 meters in width, summaries of areas dominated by these features are likely to overestimate the actual area. Future revisions may attempt to tag such polygons, but will maintain the 5.0 meter fixed with geometry.
The OWMS specifies that wetland polygons must not overlap. In this release (20091030), polygons with small overlaps of less than 400 square feet occur infrequently throughout the state, mostly due to the incorporation and processing of older NWI linear feature datasets.
In this release, four 7.5 minute quads have missing NWI linework. The quads are: Sixteen Butte (43120e8), Spring Butte (43120e3), Esau Canyou (45120d4), and Corn Lake (42119g7). The percentage of missing quads is relatively low; Oregon is covered by 1931 USGS 7.5-minute quads. Several attributes are minimally populated in this release: SITENAME, VEG_SPEC, WET_MGT, COV_TYP, HGM, HYD_xxx, VEG_COND, DEVELOP. The GOAL_5_17 is not populated in the 20091030 release. Preliminary linework for four approved Local Wetland Inventories are not included in this release: Lakeside, Clatskanie, Rockaway Beach, Port Orford. In 2002, USGS began an update of NWI data for the Oregon coast, creating new mapping up to the 100 foot (above sea level) elevation contour. The updated NWI data for the northern and southern portions of the coast are incorporated in this release. However, the updated NWI data for the central coast between Lincoln City and Bandon were not available in time for this release. Mapping for the central coast therefore reflects older NWI work dating to the 1980s. It will be replaced with the updated NWI data in the next release.
Horizontal accuracy varies, depending on source data. For NWI data, the scale of the original linework is embedded within the DATA_S_YR attribute. The NWI scales ranged from 1:24000 (40.0 feet HA) to 1:80000 (133.3 feet HA). LWI linework was typically drawn at 1:9600 scale (26.6 feet HA). ODOT SRSAM linework was digitized at a 1:5000 scale. Recent linework that is digitized to imagery conforms to the FGDC Wetland Mapping Standard (FGDC-STD-015-2009, July 2009), with a minimum horizontal accuracy of 5 meters HA (16.6 feet) relative to the imagery. Note that wetland delineations derived solely from imagery may vary significantly with on-ground conditions, depending on season, year of imagery, and interpreter experience. While image-derived polygons may meet the 5 meter HA specification, actual wetland conditions may differ by distances much larger than the 5 meters. Wetland delineations derived solely from imagery may vary significantly with on-ground conditions, depending on season, year of imagery, and interpreter experience. Discontinuities due to digitization errors or deliberate breaks made by photointerpreters can be anticipated. Due to the varied history of wetland datasets included in the Oregon Wetlands coverage, wetland polygons may or may not overlap with networked hydrography datasets such as NHD (National Hydrography Dataset).
Per Federal (FGDC) and Oregon Wetland Mapping Standards (OWMS), vertical accuracy is not specified.
The NWI is the base wetland polygon data layer for the Oregon Wetlands dataset, to which other wetland data are being added in order to build a comprehensive dataset from numerous sources. NWI geodata were obtained from the USFWS Master Wetlands Geodatabase. This included the linear (polyline) feature class and NWI metadata.
Starting in 1999, ODOT created a dataset representing wetlands within 500 feet of all State Highways. This work was done as part of ODOT's Salmon Resource and Sensitive Area Mapping project. Wetlands were first identified from digital orthophotography and existing NWI datasets, then field-verified. Polygons were not attributed and simply indicate the presence of a wetland. ORNHIC and TWC integrated the ODOT wetland data with the Oregon Wetlands Cover to provide additional information about wetlands, because many polygons in the ODOT layer were not represented in the original base layer from NWI.
ORNHIC and TWC maintain a database of wetlands of conservation concern, including reference sites, high-quality examples of specific wetland types, and the only known remaining examples of certain wetland types. Data on these wetlands originated from field work, publications, and conservation plans made by individuals, public agencies, and private organizations over the last 50 years. These polygons may contain detailed information on plant associations not available from other sources. ORNHIC and TWC periodically integrate the ORNHIC and TWC wetland data with the Oregon Wetlands Cover to provide additional information about wetlands, as many polygons and/ or attributes were not represented in the original base layer from NWI.
Springs data provide locations for sites of groundwater discharge that is critical for many wetlands, including many rare wetland types. ORNHIC and TWC integrated springs data with the Oregon Wetlands Cover to provide additional information about wetlands, as springs were not represented in the original base layer from NWI. Springs geodata were obtained from Oregon DOGAMI, USGS GNIS (Geographic Names Information System), NOAA Thermal Springs, and Pacific Hydrography Framework (PHF).
ORNHIC and TWC integrated Local Wetland Inventory (LWI) data with the Oregon Wetlands Cover to provide additional information about wetlands, because many polygons in LWIs were not represented in the original base layer from NWI. Most wetlands within the boundaries of LWIs were field-verified either through visual confirmation or by sampling hydrology, vegetation, and soils per the standard 1987 US Army Corps of Engineers wetland determination method. LWI polygons consequently have a greater mapping accuracy than NWI polygons. LWIs have been compiled since 1992 by wetland consultants under contract with local jurisdictions. About 70 cities currently have LWIs approved by ODSL. Inventories conducted without ODSL oversight are treated as Natural Resource Inventories (NRIs) in Source 6 (following). Polygon attributes may vary among different LWIs, or polygons may simply indicate the presence of a wetland and have no additional attributes. Hydrogeomorphic (HGM) codes or information on hydrological alterations may not be available in earlier LWIs. Variation among LWIs is attributable to differences in jurisdiction, changes in inventory rules over time, and the discretionary practices or technical resources available to wetland consultants over time. Wetland polygons obtained from a Local Wetland Inventory are attributed as "Local Wetland Inventory" (DATA_S_TYP = 2) only if the original digital geodata of the LWI has been reviewed and approved by Oregon Dept. of State Lands. Wetland polygons for LWIs that have been obtained from other sources, including digitization from paper copies of LWI maps, should be regarded as preliminary. Such preliminary LWI polygons are attributed as "Local or Regional Government" (DATA_S_TYP = 5).
Natural Resource Inventories (NRIs) or equivalent types of local wetland mapping identify many wetlands that have previously not been documented. They differ from Local Wetland Inventories (LWIs) because they have not been reviewed or approved by ODSL for consistency with standards and guidelines in Oregon Administrative Rules. However, they are usually more recent and of better quality than NWI data. Polygon attributes may vary among different NRIs, or polygons may simply indicate the presence of a wetland and have no additional attributes. Variation among NRIs is attributable to differences in jurisdiction, changes in inventory rules over time, and the discretionary practices or technical resources available to wetland consultants over time.
Hydrogeomorphic (HGM) data for selected polygons from the Willamette Valley.
Create base layer for Oregon Wetland Cover from NWI wetland mapping. Most NWI mapping for Oregon was created in the 1980s and 1990s, using true color and infrared imagery with limited ground truthing. Mapping included both polygons for wetlands and polylines for streams or other linear features. The current NWI standard recommends converting all linear features to 5-meter-wide polygons centered on the linear feature, and all linear NWI data in the Oregon Wetlands dataset have been converted to polygons (both sides buffered to 2.5 meters, edges rounded, then burned on top of existing NWI polygons and erasing portions of underlying NWI polygons). We then dissolved contiguous NWI polygons that shared a common Cowardin attribute. This automated process may inadvertently create 'sliver' polygons of very small (< 2 meter) widths. NWI datasets, originally mapped as 7.5-minute quad maps (1:24,000), exhibit a variety of stream densities. This variation does not represent hydrological reality but only the stream density chosen when various NWI maps were created. Coverage for 96 quad maps was created by ORNHIC and TWC in 2008 and is pending approval by NWI. These maps will replace obsolete 15-minute (1:62,500) NWI mapping created in the 1970s. All non-linear wetlands of 0.5 acres and greater are represented. Stream networks were mapped for about 1/3 of the quads and the remaining 2/3 are in progress. Stream networks were digitized first as linear features, then buffered to 5.0 meter total width. Steam density was mapped at 1:1000,000 using the National Hydrography Dataset (NHD), Region 17. Using the NHD dataset for reference only, final linework for streams was created by interpreting (1) 0.5 meter color aerial imagery from the National Agriculture Imagery Program (NAIP), (2) data derived from 10-meter DEMs, (3) 1:24,000 USGS stream cover, and (4) the Coastal Landscape Analysis and Modeling Study (CLAMS; www.fsl.orst.edu/clams). The NAIP imagery was taken in summer 2005. Color infrared photography was not available for the quads mapped by ORNHIC and TWC.
1322 SE Morrison St.
Integrate ODOT Highway wetland layer with Oregon Wetland Cover. ORNHIC and TWC integrated the ODOT wetland data with the Oregon Wetlands Cover to provide additional information about wetlands, because many polygons were not represented in the original base layer from NWI. ORNHIC and TWC are assigning Cowardin codes to the polygons based on intersection with or proximity to existing NWI datasets, and structure evident in 2005 NAIP imagery.
Integrate data on wetlands of conservation concern with Oregon Wetland Cover. ORNHIC and TWC periodically integrate the ORNHIC and TWC wetland data with the Oregon Wetlands Cover to provide additional information about wetlands, because many polygons and/ or attributes were not represented in the original base layer from NWI. Many of these polygons are Special Areas of Concern (SACs).
Integrate data on springs with Oregon Wetland Cover. Data on springs was obtained from GNIS point data (carto_code = "Spring or seep") available from the Pacific Northwest Hydrography Framework Clearinghouse (http://nhd.usgs.gov). Point data for springs were buffered to a 2.5-meter-radius and burned on top of all other existing wetland polygons, to indicate sources of groundwater.
Integrate data from ODSL-approved Local Wetland Inventories (LWIs) with Oregon Wetlands Cover. ORNHIC and TWC integrated LWI wetland data with the Oregon Wetlands Cover to provide additional information about wetlands, because many polygons were not represented in the original base layer from NWI. LWI data included in the Oregon Wetlands cover supersede NWI data, and all NWI polygons within boundaries of LWIs were erased. Discontinuities along boundaries between NWI data LWI wetland polygons may be expected. LWI boundaries are available in a separate shapefile. Most wetlands within the boundaries of LWIs were field-verified using hydrology, vegetation, and hydric soils, and LWI polygons consequently have a greater mapping accuracy than NWI polygons. Because LWIs are legal documents that are reviewed and approved by ODSL for consistency with Oregon Administrative Rules, all LWI polygons are retained in the Oregon Wetlands Cover. Where land development has occurred since completion of an LWI and change is evident on current aerial photography, the original LWI polygon remains but the 'DEVELOP' attribute will indicate if a wetland is still present on site. Documentation on the sources of individual LWI spatial data, attribute availability, and limitations for each LWI are forthcoming.
1322 SE Morrison St.
Integrate data from local Natural Resource Inventories (NRIs) or equivalent with Oregon Wetlands Cover. ORNHIC and TWC integrated NRI wetland data with the Oregon Wetlands Cover to provide additional information about wetlands, because many NRI polygons were not represented in the original NWI base layer or in other wetland mapping products. NRI data included in the Oregon Wetlands Cover supersede NWI data, and NWI polygons within boundaries of NRIs were modified or erased to prevent redundant representation. Discontinuities along boundaries between NWI and NRI polygons may be expected. Documentation on the sources of individual NRI spatial data, attribute availability, and limitations for each NRI are forthcoming.
Integrate hydrogeomorphic (HGM) data from the Willamette Valley with the Oregon Wetland cover. ORNHIC and TWC assigned HGM codes to selected wetland polygons per Adamus & Field 2001 (See Source Information for HGM for full citation).
Internal feature number.
ESRI
Feature geometry.
ESRI
Perimeter of the polygon (in feet)
Name of closest mapped locality.
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Source and year of original data
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Creator and year of polygon if different than DATA_S_YR
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Method of data creation
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Accuracy of data, indicating the level of precision of a mapped feature
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Cowardin system, subsystem, class, subclass, water regime, and special modifiers where applicable, per FGDCWMS.
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Source and year of Cowardin data if different than DATA_S_YR
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Hydrogeomorphic (HGM) class and subclass code.
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Source and year of HGM if different than DATA_S_YR
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Wetland polygon ID in original data
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Field verified, onsite or offsite
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Data source type
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Known or reported artificial hydrological barrier
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Known or reported artificial drainage
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Known or reported unnatural inflow
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Wetland management type, if known
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Dominant vegetation per original data source, in 6-letter acronym format
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
General condition of vegetation
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Source and year of original vegetation data if different than DATA_S_YR
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Locally significant wetland, identified in a LWI. Not applicable outside the boundary of a LWI. Defined only for wetlands within the bounds of an LWI survey.
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Wetland cover type (Oregon name) and map code
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Polygon is within a Goal 5 or Goal 16 area defined by a local jurisdiction
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Special Area of Concern (wetland of conservation concern)
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Development status of wetland
Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009
Attributes for the Oregon Wetlands dataset conform to the Oregon Wetland Mapping Standard (OWMS), Version 2.0 Draft, March 2009. If the dataset is downloaded as a file geodatabase, many of the lookup tables in the OWMS are built-in as a "Domain." If the data are obtained as a shapefile, the lookup tables will not be available but the attributes are coded as specified in the OWMS.
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." The Oregon Wetlands cover also is not intended to be a hydrography dataset, and it should not be used to infer hydrologic connectivity, or lack thereof, between wetland polygons.
Downloadable Data at Oregon Geospatial Enterprise Office (GEO), Oregon Dept. of Adminstrative Services. Web site: http://www.oregon.gov/DAS/EISPD/GEO/alphalist.shtml
1322 SE Morrison St.