Since rain doesn’t respect town boundaries, the best strategy for addressing flooding is at the Watershed scale.

Our changing climate has already impacted our rain and snow patterns, which is making storm flooding worse (and it will continue to get worse into the future).

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 underground 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.  

The Neponset River Watershed Regional Adaptation Strategy and Flood Model Phase 1 Summary Report summarizes the flood model development process. Read report.

A heavy downpour in Sharon (located upstream), might cause flooding in Dedham (located downstream).  

The flood model-based approach provides multiple benefits: 

  • a more accurate representation of surface flooding risks; 
  • a better understanding of flood extents, depth, volume, and duration, across the watershed; and
  • an easier approach to evaluate and visualize flood reduction strategies and their benefits.  

Click here to view the flood model.

Click here to for our flood model storymap.

For updates on Phase 2 of the project, visit here.

NepRWA and the rest of the project team, including our community partners, will continue to pursue funding so that we may further enhance the Watershed-wide model with additional details.

Individual communities can use the model as a starting point to inform more localized modeling for high-risk areas (either because of a high likelihood of flooding, or the presence of critical or vulnerable buildings or people). Finally, we’re looking forward to identifying regional projects that our communities can work on together through the Neponset Region Climate Resilience Collaborative.

Some municipalities have developed town-wide models to model vulnerabilities and potential solutions on a more detailed scale. Learn more about these projects: