Using the online mapping tool to investigate targets for wetlands across the region
by the Center for Coastal Resources Management at the Virginia Institute of Marine Science
About WetCAT
The Wetland Condition Assessment Tool, or WetCAT, has been recognized by the Environmental Council of States as an outstanding state initiative that can serve as a model for other states, and received the Virginia Governor’s Technology Award in 2019.
WetCAT is an online tool providing many geospatial layers that local planners, regulators, and the public can use to investigate how land use changes may affect wetlands and the critical services they provide.
The key data layer in WetCAT is National Wetland Inventory
(NWI) wetlands that have been scored from Slightly Stressed to Severely Stressed using a field-checked approach for two ecosystem services: the ability to provide habitat and to improve water quality.
Users can explore wetland locations, stress levels, and links to impaired waters; run geoprocessing tools to visualize impacts upstream and downstream; and create print reports summarizing the information.
Wetlands provide valuable ecosystem services
WetCAT focuses primarily on two ecosystem services that healthy wetlands provide: providing habitat for fish and other wildlife and improving water quality. Other positive benefits of wetlands include reducing erosion of shorelines and riverbanks, recharging groundwater supplies, mitigating flooding, and providing recreation opportunities including fishing and tourism, to name only a few.
Picture of streamside wetlands in Virginia
Picture of streamside wetlands in Shenandoah area.
Picture of living shoreline with marsh and a low rock sill
Picture of a blue heron in a tidal marsh
Picture of an extensive tidal marsh
From upstream wetlands along creeks to tidal salt marshes along rivers flowing directly into the Chesapeake Bay or the Albemarle-Pamlico Sound, tidal and nontidal wetlands provide numerous valuable ecosystem services including providing critical habitat and filtering out nutrient pollution and excess sediments. Opportunities to restore impacted wetlands and create new wetlands will improve the ecosystem services they can provide, resulting in less pollution and a healthier ecosystem.
Photos from left to right capture wetlands across the watershed: nontidal wetlands along creeks and rivers to tidal marshes and living shorelines across Virginia. (Photo credits: CCRM)
However, as human disturbance on the landscape increases, the capacity for wetlands to provide these benefits decreases. Improved ecosystems services (like improved water quality) can be achieved by restoring degraded marshes and/or creating new wetlands in suitable locations.
Using WetCAT to find target areas for restoration and creation of wetlands
The wide array of spatial layers and geoprocessing tools available in WetCAT can be used to identify restoration targets for wetlands across the region - from nontidal freshwater wetlands along headwater streams to tidal salt marshes lining the Bay.
Restoration opportunities for NWI wetlands (freshwater and brackish wetlands)
Highlighted wetland with water quality condition scores displayed.
A non-tidal forested wetland near Charlottesville has a high potential for improvement in both habitat (+57%) and water quality (+300%) services, if buffers surrounding the wetland can be restored.
The NWI Conditions layer provides detailed scores for habitat and water quality, based on the level of stress from human activities. Using available information for the area immediately surrounding a wetland, like land use and number of roads, stress levels are calculated and scored on a scale from less to more disturbed.
Restoration Potential scores are also calculated for each wetland. This score captures a relative improvement in wetland function can be achieved if disturbances were decreased around the wetland.
Wetlands with higher restoration potential are excellent opportunities for restoration actions with the biggest gains for ecosystem services.
Restoration opportunities for tidal salt marshes
Shoreline along the Ware River in Gloucester County showing the Preferred Best Management Practice, including areas where creating or restoring new marshes along the shoreline is recommended.
It is possible to identify restoration opportunities for tidal salt marshes by looking at the Shoreline Management Model (SMM) layer.
The SMM identifies suitable shoreline erosion control practices for tidal shorelines across Virginia. Using a variety of shoreline conditions (e.g., exposure to wind and waves, offshore water depth, bank height, and many other metrics), the model generates a suitable Best Management Practice (BMP) for that shoreline stretch.
Shorelines where the SMM recommends non-structural living shorelines (i.e., planting marsh) and plant marsh BMPs are ideal areas for creating new wetlands.
More than 77% of the tidal shorelines in Virginia have the recommendation to protect or restore existing marsh, or are considered suitable for creating new marsh. This suggests that there is a lot of opportunity to improve ecosystem services across these tidal shorelines.
Finding restoration opportunities using geoprocessing tools and layers
Using geoprocessing tools available in WetCAT can allow users to evaluate upstream and downstream impacts of restoration projects on nearby waters (including impaired waters), and to assess restoration actions on a particular wetland. See the below examples of these tools:
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Downstream Path tool
The Downstream Path displays where water will flow downstream from a chosen point or wetland within a buffer area (see the purple line within the red dashed buffer area).
This can be used to evaluate impacts of a potential restoration project including: are there any impaired waters that may benefit?
Turning on the SMM layer while the downstream path is displayed can help identify areas downstream from a location suitable for creating new wetlands.
Contributing Watershed tool
Using land elevation, this tool identifies the area (outlined in purple) from which water flows into or near the point or wetland chosen.
This tool can be used to identify waterways or wetlands that flow into the chosen point and summary scores are provided for the chosen wetland.
Resource managers summary tool
This summary combines information within a kilometer buffer around any map point and provides useful information about wetlands, restoration potential, and nearby impaired waters, all in a printable document.
Rescore a wetland
Using the Rescore Wetland tool located at the bottom of the NWI wetland summary, it is possible to assess potential restoration actions or the impacts of proposed projects on the health of a wetland.
Summary
Restoring and creating new wetlands will increase the overall capacity to provide beneficial ecosystem services across the region. WetCAT provides multiple layers and tools that enable users to search for restoration opportunities, and to estimate the impacts of restoration projects on individual wetlands.
More information about the Shoreline Management Model (SMM), can be found on CCRM's SMM page.
A non-tidal forested wetland near Charlottesville has a high potential for improvement in both habitat (+57%) and water quality (+300%) services, if buffers surrounding the wetland can be restored.
Shoreline along the Ware River in Gloucester County showing the Preferred Best Management Practice, including areas where creating or restoring new marshes along the shoreline is recommended.
