Data summary
Use the Coastal Atlas Map to access the following Wetland Data map layers (select "Add/Remove Map Data" and select the Wetlands Data tab):
- Modeled Wetlands Inventory for Western Washington: This medium-resolution scale map can be used to look for wetlands in your area. It was developed by us and NOAA modeled from NOAA's Coastal Change Analysis Program. Modeled wetland inventory data are available for the years 1992, 1996, 2001, 2006, 2011, and 2016.
- Wetland Mitigation Areas: Locations of wetland compensatory mitigation sites required under Ecology's authority from Section 401 of the federal Clean Water Act and/or the state Water Pollution Control Act (Chapter 90.48 RCW). The polygons have been hand digitized by wetland mitigation staff and are based on permit figures, drawings, as-built reports, parcel layers, and site visits. This layer is a work in progress.
- Mitigation Banks: Locations of approved and proposed wetland mitigation banks in Washington.
- Simplified National Wetland Inventory (NWI): This layer is derived from the National Wetland Inventory (NWI) and updated periodically for display in the Coastal Atlas. This map displays simplified Cowardin classes from NWI and does not display deep water and other non-wetland habitats that may be included in NWI. The data displayed may not reflect the most current version. Please consult the U.S. Fish and Wildlife Service Wetlands Mapper for the most current data.
- Hydrologic Landscape Class: This layer displays hydrologic landscape classes developed by the U.S. Environmental Protection Agency to characterize stream flow vulnerability from climate change. For more information see Hydrologic Landscape Characterization for the Pacific Northwest, USA.
- Soils (Clay, Organic, Hydric): With guidance from the Natural Resource Conservation Service (NRCS), Ecology derived three soil layers from the Gridded Soil Survey Geographic Database (gSSURGO). The layers identify areas where organic or clay soils represent major or minor components of a soil polygon. The hydric soil layer shows polygons that are not identified as clay or organic where the soil polygon is classified as hydric by NRCS. For more information on the soil map layers, see the NRCS map unit description web page.
Data limitations
- Wetland data layers provided in the Coastal Atlas map have statewide coverage, except for the Modeled Wetland Inventory that only covers western Washington.
- Wetland data layers provided in the Coastal Atlas map are for reference, only. The datasets are not meant to be used for regulatory purposes. They are for planning purposes and only indicate the potential for wetland presence. As with all map data, presence or absence of wetland features at any location will always need to be verified.
Data summary
We worked in partnership with NOAA's Coastal Change Analysis Program (C-CAP) to carry out the Wetland Change Analysis project, which was partially funding by an EPA Wetland Program Development grant. To more accurately map Washington wetlands, C-CAP was used to develop a method to create a Modeled Wetlands Inventory. The inventory is based on a land cover classification using Landsat scenes analyzed according to C-CAP protocol to determine land cover. This involved extracting the wetlands land cover classifications from the overall land cover layer.
NOAA applied the improved wetland layer to previous C-CAP analyses that occurred between 1992 and 2016. C-CAP will use the improved wetland layer for land cover mapping and analyses every five years.
The Modeled Wetlands Inventory:
- Is more accurate than the National Wetlands Inventory for wetlands larger than one acre, especially in agricultural/pasture, forests, and stream corridors.
- Includes a "Potentially Disturbed Wetlands" category for areas that have a high potential to be wetland, but have an observed land cover of "pasture/hay" or "cultivated."
- Can be used for planning purposes and for initial permit review.
Map data
Data limitations
- Most wetlands one acre or less in size are not mapped.
- The data are less accurate detecting forested and slope wetlands.
- The inventory identifies areas that have a high potential to be wetlands. Locations of mapped wetlands are approximate due to the medium resolution scale. The absence or presence of a wetland on the map does not mean that the wetland is actually absent or present.
Data summary
We conducted a statewide survey to inventory wetland maps and mapping efforts. We were interested in the general areas and regions where wetland-mapping work is completed or underway to gain a better understanding of the status of wetland mapping in Washington. From the completed surveys and resulting discussions, a statewide list of available mapping projects and resources was produced. This list is paired with a web map visualizing broad geographic regions and extents where wetland mapping is occurring.
Data limitations
- Data represented in this study was produced on a voluntary basis from project participants.
- Data were accurate at the time of collection, contacts and generated data specifics may have changed since this study was conducted.
- Wetland information collected during this study were often derived from a variety of resources and should be reviewed for completeness and levels of accuracy before use. We recommend that you verify the data with the associated contacts before use.
Data summary
As part of an effort to improve wetland mapping statewide and with funding from EPA, Ecology collaborated with the University of Washington Remote Sensing and Geospatial Analysis Laboratory (UW-RSGAL) on a pilot project to test semi-automated remote sensing of wetlands, with a focus on improving mapping of forested wetlands.
From this initial effort and with additional funding from the Wetland Science Advisory Group (WetSAG) for Forest Practices, UW-RSGAL developed a novel method to map the probability of wetland presence called the Wetland Intrinsic Potential tool (WIP) using several data inputs. The WIP is now available in the ArcGIS watershed toolbox and has been used to map several areas across Washington and elsewhere for planning and research projects.
Ecology recently received funding from EPA to generate medium-scale WIP coverage statewide, while UW-RSGAL is working to generate coarse-scale WIP coverage nationwide.
More information on the development of this tool can be found in the paper published in Hydrology and Earth System Sciences, The Wetland Intrinsic Potential tool: mapping wetland intrinsic potential through machine learning of multi-scale remote sensing proxies of wetland indicators.
Data summary
The Washington Natural Heritage Program (WNHP) Data Explorer includes two map pages:
- Rare Plant and Ecosystem Locations displays all publicly available rare plant and rare/high-quality ecosystem locations in the WNHP database. It also includes the WNHP Reference Standard Wetlands layer, which displays wetlands considered to be among the best examples of specific wetland types based on their ecological integrity. This map application replaces the previous WA Wetlands of High Conservation Value map viewer.
- Ecological Integrity Assessment Data presents Level 1 and Level 2 Ecological Integrity Assessment (EIA) data. EIAs measure the ecological condition of upland and wetland ecosystems using WNHP’s standardized metrics to categorize sites into condition classes. Level 1 EIAs are entirely remote sensing/GIS-based, while Level 2 EIAs are based on rapid, mostly qualitative field data.
For more information please review the WNHP Data Explorer User Guide.
Data summary
PHS on the Web is a Washington Department of Fish and Wildlife (WDFW) web-based, interactive map where you can find basic information about the known location of Priority Habitats and Species (PHS) in Washington State. PHS is a source of best available science that can inform local planning and conservation. Wetlands are included as Priority Habitat polygons. Some wetlands may include observations or data collected by WDFW biologists in the field. Use the Priority Habitats and Species (PHS) on the Web to find information about known locations of Priority Habitats and Species in Washington. Users can navigate to an area of interest and use one of the selection tools to generate a PHS report showing the Priority Habitats and Species mapped in that area.
Data limitations
- The species and habitats that appear on the map are informed by WDFWs PHS List. The map displays known locations of Priority Habitats and Species that have been provided to WDFW by agency biologists and other sources of scientific data about species and habitat locations. Data are updated as new information is gathered and verified in the field. This map should not be considered an exhaustive survey of all fish and wildlife presence.
- The data displayed on PHS on the Web are for informational purposes only. WDFW strongly recommends a field visit by a fish and wildlife biologist or habitat expert to make determinations about species presence, absence, or locations. Species locations change over time, not every parcel has been surveyed, and biologists add new field observations on a regular basis.
- PHS maps do not provide an official agency determination of the potential impacts to fish and wildlife of a specific project.
- PHS map data are meant to serve as a starting point to identify priority habitats and species. They are not meant to replace or preempt more detailed field-based, site-level mapping.
Data summary
The National Oceanic and Atmospheric Administration (NOAA) Coastal Change Analysis Program (C-CAP) produces standardized high resolution land cover and change products for the coastal regions of the U.S. and its Territories. C-CAP products inventory coastal intertidal areas, wetlands, and adjacent uplands with the goal of monitoring changes in these habitats.
Data limitations
C-CAP data sets are not jurisdictional or intended for use in litigation. While efforts have been made to ensure that these data are accurate and reliable within the limits of current technology, NOAA cannot assume liability for any damages or misrepresentations caused by inaccuracies in the data, or as a result of the data to be used on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty. This is a national and regional data set that should be used only as a screening tool for very local or site-specific management decisions. Small features and changes should be verified with a higher-resolution data source.
Data summary
The US Fish and Wildlife Service produces and distributes maps and other geospatial data on American wetland and deepwater habitats, as well as monitors changes in these habitats through time. This information is available to the public through two primary datasets: the wetlands mapper and wetlands status and trends reports. These provide complementary information on wetland and deepwater habitat type, location, and trends to support research, land management planning and analyses, policy development, and modeling activities.
Data limitations
Please review the NWI data limitations page hosted by USFWS. Here you will find important information regarding the data limitations, exclusions, and precautions regarding NWI data.
