Climate-driven floods, heat waves, and drought don’t respect town boundaries, so the best strategy for building climate resilience is at the watershed scale.
Introducing the Neponset River Watershed Climate Resilience Model!
Our changing climate has already impacted our weather patterns, bringing heavier rains, more frequent heat waves, and more severe drought.
This computer-based tool analyzes several climate impacts and existing conditions in Neponset communities to help us understand current and future risks to our communities.
- To help communities prepare for increased flooding, the model analyzes rainfall, surface runoff, and water movement through stormwater systems.
- To help communities prepare for increased heat waves, the model analyzes temperature and humidity data to predict heat intensity across the Watershed and identify hotspot areas.
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NepRWA and community partners, along with other project partners, will continue seeking funding to further enhance the watershed-wide model with added detail.
Individual communities can use the model as a starting point for more localized modeling in high-risk areas (due to flooding risk or the presence of critical or vulnerable buildings and populations).
We also look forward to identifying regional projects communities can work on together through the Resilient Neponset Climate Collaborative.
Some municipalities have developed town-wide models to assess vulnerabilities and potential solutions at a more detailed scale.
Neponset Watershed Flood Modeling
The flood model-based approach provides multiple benefits:
- A more accurate representation of surface flooding risks;
- A better understanding of flood extents, depths, volume, and duration across the watershed; and
- An easier approach to evaluate and visualize flood reduction strategies and their benefits
A computer-based flood model that incorporates hydrologic analysis (examining rainfall and estimating surface runoff) and hydraulic analysis (studying the movement of water as it runs off, including through stormwater pipes) serves as a valuable tool for understanding current and future flooding within a watershed.
The process of creating the model includes collecting and combining the drainage information from each town into one map. Then the details of existing culverts, dams, and underground pipes are added to the model.
Finally, future climate projections are added, and the future risk of flooding is estimated in terms of the total flooded area and other model outputs.
- View updated StoryMap to explore where flooding could occur—and where green infrastructure solutions may help (June 2025)
- View the updated flood model with a summary view of the Neponset Watershed and potential sites for green infrastructure (June 2025)
- Learn what the flood model says about future risks and solutions (June 2024)
- Version 1 of the previous flood model (June 2023)
Neponset Watershed Heat Modeling
The heat model will:
- Identify areas that experience the highest heat exposure;
- Improve understanding of temperature variations across neighborhoods and different types of landscapes (streets, commercial areas, school playgrounds, parks, and natural areas);
- Inform heat mitigation strategies and their benefits
The computer-based model helps communities assess the urban heat island (UHI) effect across the Watershed under present and future scenarios.
The first iteration of the model uses weather station data from one of the hottest days of summer in 2022. It combines this with land surface temperature data (gathered from satellites), as well as other environmental factors like impervious surfaces (pavement), tree cover, elevation, and proximity to water bodies.
Together, these inputs are used to estimate ambient air temperatures and heat index values across the Watershed.
These initial maps highlight patterns of heat exposure across the Watershed, showing how temperature varies by land use and landscape features.
Sensor Installation and Data Collection
While weather stations and satellite data provide broad regional coverage, on-the-ground sensors can capture air temperature and humidity at specific locations.
These measurements are critical for refining the heat model, improving its accuracy, and helping to identify localized hot spots that may not be visible from satellite data alone.
During Summer 2026, a network of 25 sensors was installed across the Watershed.
Sensors were mounted on trees, light posts, signs, and similar structures to measure ambient air temperature and relative humidity in a range of settings, including urban streets, parks, and residential areas.
This approach will allow the model to better reflect real conditions experienced by residents of the Watershed.
