The Challenge
Coastal and Inland Wetland Resource Areas including Bordering Vegetated Wetlands, Land Subject to Flooding, Riverfront, and Salt Marshes provide important public interests and are subject to protection under the Massachusetts Wetland Protection Act (310 CMR 10.00). Functioning Wetland Resource Areas provide protection of public and private water supply, protection of groundwater supply, flood control, storm damage prevention, prevention of pollution, protection of land containing shellfish, protection of fisheries, and protection of wildlife habitat.
These valuable Resource Areas are vulnerable to the impacts of climate change including the predicted increase in temperatures, rainfall, coastal storms, and sea level rise. Impacts may result in shifting Resource Area Boundaries (e.g., expansion of Bordering Land Subject to Flooding due to increased size and frequency of storms, etc.). Our goal was to evaluate potential future changes in Wetland Resource Areas and important habitats to provide better guidance on future wetland protection, wetland restoration, and regulatory jurisdiction.
Project Scope
The Feasibility Analysis was a one-year assessment completed in June 2024. The goal of the project was to determine the level of effort that would be required to create and scale a mapping tool to depict and analyze the vulnerability corridor surrounding wetland resource areas, i.e. potential future boundaries of Wetland Resource Areas. The feasibility assessment incorporated existing tools, maps and layers and analyzed broad patterns in the overlay results, highlighting data needs and shortfalls. Predictors of change including MA Coastal Flood Risk Model (MC-FRM), groundwater change models (UMass) and sea level rise impacting marshes (SLAMM) were sought to analyze the potential wetland vulnerabilities under future climate change scenarios. Many models are still in development and could not be fully assessed. A result of the analysis was an understanding of the level of complexity of mapping areas of potential change based on existing models and data.
Metrics
The project, a feasibility assessment, successfully identified important data layers and models needed to predict change. The project deliverable was a feasibility report including a summary of the status of data and models needed to assess future projected resource areas. The final report includes recommendations and a level of effort for a potential tool development as well as next steps and recommendations to fill data gaps. One recommendation is to update the 2005 wetland map layer to improve our delineation of existing wetland resource areas as a first step in predicting where future boundaries will be.
Results
MassDEP and CEI concluded that while it is feasible to overlay existing, publicly available models (such as MC-FRM and SLAMM) and data layers (such as the 2005 DEP wetland layer) in a new data viewer, on its own it is not helpful. A deeper analysis of the associated shifts resulting from climate driven changes (ground water levels, for example) is needed and would be valuable. Changes to inland wetland extent and vulnerability are more difficult to predict than coastal change with existing modeling tools and data. Further analysis will be dependent on finalizing several models currently in development, including the UMass groundwater model. Final project recommendations included revising existing mapping layers (e.g., the 2005 Bordering Vegetated Wetlands) to better reflect current Wetland Resource Area extents while allowing ongoing future assessments (e.g., EEA HydroRisk Future Flows, UMass-Amherst Future Groundwater Elevation, etc.) to further progress.
Best Practices and Lessons Learned
By determining timelines for ongoing efforts of various predictive tools and data layers (e.g., EEA HydroRisk Future Flows, UMass-Amherst Future Groundwater Elevation, etc.), the project was able to better assess the most valuable next step. The timeline for developing new data layers and a web viewer will be better implemented in the future after ongoing data sets can be considered, reviewed, and incorporated and baseline conditions can be more effectively mapped.
Project Alignment with ResilientMass Plan Priority Actions
The project advances several specific actions from the ResilientMass Plan 1) Cross-government ACTION 7: Floodplain Regulatory and Coordination Framework, and 2) ACTION topic 4, To improve coastal wetland mapping, resilience planning and resource efforts and 4a: Develop a GIS mapping tool for climate coastal and inland wetlands to identify resource area vulnerability corridors.
The project incorporated numerous priority actions including the assessment of existing and future-based (if available) Wetland Resource Area data layers that are related to the Priority Impacts of:
- Coastal / soil erosion
- Loss of biodiversity
- Degradation of wetland resource areas.
Further Action
Next steps include revising existing map layers (e.g., 2005 DEP Wetland Maps). With improved existing conditions maps we will have a more reliable baseline to anchor predictive vulnerability mapping.