Flood Preparedness FAQ

The City is using a wide range of strategies to address flooding, including maintaining our stormwater management system, increasing community outreach and preparedness, implementing flood mitigation solutions, and focusing on climate action. More information, including the work of specific departments, can be found in the other sections of this page.

Yes, climate change means that flooding will happen more often and more intensely, including in places that haven‘t typically flooded in the past. This increase in flooding will happen for two different reasons. First, there will be more frequent and intense rainstorms, with a predicted 30% increase in rainfall during a 100-year, 24-hour event by 2070 (Somerville Climate Vulnerability Assessment, 2017). A 100-year storm has a 1% chance of occurring in a given year. Second, Somerville will experience sea level rise and storm surge-related flooding from the Mystic River, as sea levels in Boston Harbor are predicted to rise 4 to 8 inches by 2030 and 15 to 36 inches by 2070. For more information, please see Somerville’s Climate Change Vulnerability Assessment.

A: The Office of Sustainability and Environment and the Engineering Division recently conducted a Green Stormwater Infrastructure Feasibility Study, which concluded that green stormwater infrastructure—including rain gardens, permeable pavers, and other engineered systems designed to mimic natural systems--is most effective for managing water quality and smaller storm events, but less so for larger storm events. Green stormwater infrastructure does have many benefits, but it is likely not a solution to manage major flooding, especially without significant stormwater infrastructure projects to store and convey large volumes of water.  

By visiting the “Flooding Maps and Information” tab on this website, you can explore flooding projections for the City of Somerville for three different types of storms: a frequent, current-day storm; a moderate storm in 2030; and an extreme storm in 2070. These maps will help you to identify if your property is in an area that is more vulnerable to flooding (and at what depth), but they do not indicate every possibility of future flooding. There is uncertainty in the models, so some areas might experience more flooding than projected and other areas might experience less, depending on storm conditions and other variables.

If you need assistance or have questions, please call 311 for immediate response, as long as the issue is not an emergency (i.e., it does not pose an immediate danger to you or others). If you are caught in a flood and require emergency assistance, always call 911. Lastly, you can share flooding photos and updates with the City at flooding@somervillema.gov to inform future flood reduction efforts.

Call 311 to request City assistance in cleaning out catch basins.