Division of Water Supply Protection Climate Vulnerability: Phase 2

This is a ResilientMass action.

The Challenge

The 2022 Massachusetts Climate Change Assessment projects more frequent droughts, rising air and water temperatures, heavier precipitation, and increasingly variable weather patterns, all of which threaten the health of DWSP’s forests, wetlands, and streams that protect the drinking water supply for the MWRA system. These impacts could degrade water quality, reduce ecosystem services, and undermine the resilience of natural assets critical to maintaining the drinking water system’s unfiltered status.

Project Alignment with ResilientMass Plan Priority Actions

The DWSP Climate Change Vulnerability Assessment (CCVA) project responds to the Reduction in Clean Water Supply Statewide Priority Impact in the Infrastructure Sector of the ResilientMass Plan.

It also aligns with the following ResilientMass Plan goals:

• Supporting science-based and informed decision-making,
• Securing resilient state assets and services,
• Advancing implementation of adaptation actions for communities and ecosystems, and
• Securing resilient and equitable infrastructure, ecosystems, and communities.

Climate Resilience Project Scope

The study focuses on the Quabbin Reservoir, Ware River, and Wachusett Reservoir watersheds in central Massachusetts. It identifies and evaluates the condition and vulnerability of the critical natural assets owned and managed by the DWSP. Using sub-watershed scale analysis and future climate scenarios, the project measures sensitivity and adaptive capacity in alignment with DWSP’s mission and management goals. Results will guide opportunities to enhance resilience, implement adaptation strategies, and inform capital planning decisions. The assessment will be conducted in phases from FY2023–FY2028.

Overall Goals of the project include:

• Assess the current condition and resilience of DWSP’s forests and other natural assets, and evaluate their vulnerability to climate-related risks now and under future scenarios.
• Estimate costs and potential impacts to water quality under future conditions assuming no management of natural assets is implemented.
• Guide DWSP’s prioritization of capital planning for natural asset management and protection by addressing critical vulnerabilities and prioritizing the implementation of climate adaptation strategies to enhance long-term resilience.
• Establish a replicable model for conducting climate change vulnerability assessments (CCVA) of natural assets by developing and sharing a clear framework, methodology, and results.

Key actions completed in FY25 include:

• Finalized Vulnerability Risk Assessment (VRA): Refined and finalized the VRA methodology by incorporating Subject Matter Experts (SMEs) feedback to ensure accurate scoring of natural asset risks and vulnerabilities to six key climate stressors (increasing drought, warmer temperatures, warmer waters, increasing storminess, and high wind events) for 2030 and 2070.
• Applied Asset Condition Assessment (ACA): Evaluated the current health and performance of 29 critical natural assets by selecting appropriate indicators and spatial data, identifying existing data gaps, and calculating condition scores at the subbasin scale.
• Integrated VRA and ACA into Overall Vulnerability Assessment (OVA): Combined results from the VRA and ACA to produce an OVA for each asset at the subbasin level considering projected climate stressors for 2030 and 2070. This analysis highlights the intersection of climate risks with current asset conditions to understand potential impacts on the functionality of natural assets and the broader watershed.
• Created Vulnerability Index (VI): Aggregated OVA scores into a comprehensive Vulnerability Index (VI) for each subbasin to identify subbasins where ecosystem services or water quality are most at risk due to a combination of higher vulnerability and poorer asset conditions.
• Developed Interactive GIS Dashboard: Built an interactive GIS dashboard to geospatially compare and visualize ACA, OVA, and VI results at the subbasin scale. This user-friendly tool allows users to explore maps, tables, and charts to identify areas where vulnerabilities are most acute, with features to visualize data completeness to aid in prioritizing future data collection.

Metrics and Results

Phase II of the DWSP Climate Change Vulnerability Assessment (CCVA) project is measured through a multi-faceted approach focused on assessing and improving climate resilience of our watersheds.

Here’s how the project's contribution to climate resilience is being measured:

• Assessment of Natural Asset Resilience and Vulnerability: The CCVA measures resilience by evaluating current asset condition and projected vulnerability to climate-related risks. This is achieved by combining several key assessment components.
  • Vulnerability Risk Assessment (VRA): This component quantifies the potential future impacts of six key climate stressors (increasing drought, warmer temperatures, warmer waters, increasing storminess, and high wind events) on natural assets by 2030 and 2070. The VRA score measures how exposed and sensitive an asset is to these projected conditions. By identifying these future risks, the project gauges where resilience may be tested or diminished.
  • Asset Condition Assessment (ACA): The ACA evaluates the current health and performance of 29 critical natural assets. This assessment provides a non-climate-dependent snapshot of the functional health of various natural assets, such as forests, wetlands, and rivers. A healthy asset is inherently more resilient to stressors.
  • Overall Vulnerability Assessment (OVA): This component integrates the future climate risks (VRA) with the current asset health (ACA) to highlight assets and subbasins most likely to experience climate-driven disruption of ecosystem services or water quality. It is calculated separately for 2030 and 2070 climate scenarios, showing how resilience may change over time.
  • Vulnerability Index (VI): The VI aggregates the OVA scores at the subbasin scale to identify subbasins where disruptions to ecosystem services or water quality are most likely due to a combination of high vulnerability and poorer asset conditions. This provides a basin-scale measure of resilience, allowing DCR to prioritize areas for monitoring, restoration, or enhanced 
    management. This provides a direct measure of overall project success in maintaining resilience.
• Guiding Capital Planning and Adaptation Strategies: A primary goal is to "Guide DWSP’s prioritization of capital planning for natural asset management and protection by addressing critical vulnerabilities and prioritizing the implementation of climate adaptation strategies to enhance long-term resilience". The scores from the VRA, ACA, OVA, and VI are beginning to be incorporated into our planning and evaluation processes to directly inform these decisions, indicating where investment is most needed to build or maintain resilience.
• GIS Dashboard for Visualization and Decision-Making: An interactive GIS dashboard was developed to geospatially compare and visualize the results of the ACA, OVA, and VI. This tool enhances transparency and supports decision-making by allowing users to identify areas where vulnerabilities are most acute and where data gaps exist. It serves as a continuous tool for measuring and communicating progress towards resilience goals.

• Iterative Framework for Future Measurement: The CCVA framework is designed to be iterative and transferable, allowing for future phases to integrate additional condition factors, expand monitoring, and incorporate new data. This indicates a long-term commitment to continually measuring and improving climate resilience. Recommendations for future phases include refining assessment rubrics, improving data availability, and identifying temporal trends in asset condition to track changes over time that could impact 
  water quality and, by extension, resilience. The aspiration for the CCVA approach to serve as a " model" for integrating natural asset management and climate resilience planning also speaks to its perceived success and contribution. 
   

  CCVA Metric / Tool	Purpose / Focus	How It Aligns with ResilientMass
  Vulnerability Risk  Assessment (VRA)	Projects future climate stress on natural assets (drought, heat, storms)	Aligns with risk assessment and environmental-sector indicators measuring exposure to hazards. Supports long-term outcome tracking.
  Asset Condition  Assessment (ACA)	Assesses current health of natural assets (forests, wetlands, rivers)	Complements environmental outcomes by gauging ecosystem functionality and readiness—key to resilience benchmarks.
  Overall Vulnerability  Assessment (OVA)	Combines future stress (VRA) and current condition (ACA) to highlight vulnerability	Parallels resilience outcome metrics—pinpoints where resilience is weakest and monitoring progress over time.
  Vulnerability Index  (VI)	Aggregates OVA data across subbasins to prioritize basin-level vulnerabilities	Enables equity-informed, targeted resilience actions—supports process and outcome tracking in priority regions
  GIS Dashboard	Visualizes all resilience assessments and data gaps	Mirrors ResilientMass’s interactive dashboards—enhances transparency, communication, and supports decision-making
  Iterative Framework  Design	Built to allow repeated measurement,  integration of new data, and adaptation	Matches ResilientMass’s “living plan” approach— supports both process (adaptation actions) and outcome  (tracking resilience improvements)
  Capital Planning  Linkage	Uses all assessments (VRA, ACA, OVA, VI) to inform investment and adaptation priorities	Aligns with state goals of science-based, strategic resilience investments—as emphasized in ResilientMass governance and action tracking.

Best Practices and Lessons Learned

Phase II produced several key best practices and lessons learned, particularly in implementation and developing a transferable framework for climate resilience, including:

• Iterative and Adaptive Framework Development: The CCVA framework was designed to be iterative and transferable, allowing new data and additional condition factors to be incorporated and the expansion of the scope of monitoring. The choice to use a 
  weighted Vulnerability Index (VI) rather than a simple average prevents missing data from skewing results, ensuring the framework remains a “living” tool. This structure supports flexibility and allows for continuous evolution, improvement, and adaptation of the methodology over time. 
• Critical Role of Subject Matter Expert (SME) Involvement: Input from SMEs in forestry, hydrology, geomorphology, engineering, and environmental science refined and finalized the VRA methodology and were vital in selecting relevant condition indicators, metrics, and measures for the Asset Condition Assessment (ACA). Their involvement grounded the framework in the best available science and reflects conditions on the ground.
• Layered Assessment for Comprehensive Understanding: Integrating VRA (climate risk), ACA (current condition), OVA, and VI provided a nuanced understanding of watershed vulnerability with clear actionable next steps than any one single component alone. The OVA, for instance, which layered VRA and ACA highlights assets that are both degraded and highly exposed to climate stressors, helping target and prioritize interventions more effectively.
• Data-Driven Decision Support and Prioritization: Assessment outputs, such as VRA, ACA, OVA, and VI scores, directly inform capital planning by identifying where investments are most needed to address critical vulnerabilities and implement adaptation strategies. 
  The VI, in particular, identifies subbasins where ecosystem services or water quality are most at risk, enabling targeted monitoring, restoration, or enhanced management. The analysis highlighted subbasins with a combination of high VRA scores (elevated risk) and low ACA scores (poorer condition) as priority areas for further planning, resilience strategies, and adaptation measures.
• Value of Geospatial Visualization Tools (GIS Dashboard): The interactive GIS dashboard consolidated CCVA results into a user-friendly, web-based tool with an intuitive interface. It supports decision-making by allowing users to explore data, visualizing spatial 
  patterns, and highlighting hotspots. It also visualizes data completeness to guide and prioritize future data collection efforts.
• Identification and Addressing of Data Gaps: The project revealed the prevalence and impact of data gaps (e.g., wetland water quality, macroinvertebrate diversity, culverts, soils). This led to a key recommendation to establish a strategic, prioritized data collection plan in future phases to strengthen accuracy and completeness of the CCVA.
• Need for Continuous Monitoring and Refinement: The CCVA is not a one-time assessment but requires ongoing updates. Refining rubrics, testing scoring weights, improving data availability, and tracking temporal trends will be critical to adapt management programs and measure effectiveness over time.
• Transferability as a National Model: The project demonstrates potential as a replicable model for natural asset management and climate resilience planning. Core transferable elements include the VRA framework, adaptable ACA rubric, and integrative OVA/VI outputs. This emphasizes the importance of creating clear and accessible documentation (methodology, outcomes, conclusions) to enable others to replicate or adapt the approach.

Further Action

The Massachusetts DCR Climate Change Vulnerability Assessment (CCVA) is designed as an iterative, transferable framework that emphasizes long-term continuity, refinement, and broad applicability. Phase III, which began earlier this fiscal year with ResilientMass funding, focuses on improving accuracy by refining Asset Condition Assessment (ACA) scores through ecological thresholds, weighting factors, and additional indicators. Efforts also include automating data processing and conducting detailed subbasin analyses. A major priority, for Phase III and beyond, is closing data gaps through a strategic collection plan, improved accuracy reviews, and monitoring temporal trends to track long-term ecosystem changes. 

The CCVA is built to scale and be adapted by others. Transferable components include the Vulnerability Risk Assessment (VRA), ACA rubric development, Overall Vulnerability Assessment (OVA), and Vulnerability Index (VI). To support replication, DCR plans to produce public-facing documentation and enhance the interactive GIS dashboard.

Overall, the CCVA is structured around continuous assessment, adaptation, and knowledge sharing, with the goal of informing resilience planning both within DWSP and beyond.