A child riding her bike through Alewife sewage flood water on 9/19/2023. Photo by Ann McDonald.
There is a long history1 of Alewife Brook flooding during rain storms. Alewife Brook flooding occurs because of its topography and because of urbanization. The area is relatively flat and has been heavily developed with impervious surfaces like pavement and buildings. This results in a reduction of natural flood storage.
The urban stormwater drainage system is designed to handle limited, small-size storms2. When we get larger or more intense storms, there is flooding. When Alewife Brook floods, there is likely untreated sewage in the floodwater. 3. Flooding is bad enough. Sewage flooding is many times worse and a serious health hazard.
2023 Flood Events
We have documented that Alewife Brook flooded at least 5 times in 2023. It is possible that more flooding occurred. But based on photographic evidence,4 and confirmed with USGS water gage data5, we know of at least 5 times.
In these 2023 storms, sewage-contaminated flood water covered parts of the Alewife Greenway. The Greenway is a popular multi-use path on State Parkland for walkers, joggers, students, and cyclists. The Alewife Greenway connects residents from Somerville, Medford, Cambridge, and Arlington to the Alewife MBTA Station and the Minuteman Bikeway.
August 8th, 2023: Area residents jogged and pushed baby strollers through sewage floodwater on the Alewife Greenway. Photo by David Stoff.
USGS Water Gage Data & Rainfall in 2023
The table below shows the 5 flooding events in 2023 that were documented with photos and gage data. There were also documented CSO sewage discharges on each of these flood dates. According to the MWRA, total Alewife CSO sewage discharges in 2023 were over 29 million gallons6.
| Flooding | Max Water | Max Water | Daily Rainfall |
|---|---|---|---|
| Date | Height (feet) | Flow (cfs) | (in) ↟ |
| Mar 13-14 | 3.54 | 94.80 | 2.54 |
| Aug 8 | 4.10 | 149.25 | 1.33 |
| Sep 18-19 | 3.81 | 103.83 | 1.52 |
| Dec 11 | 3.26 | 93.83 | 1.75 |
| Dec 18 | 3.60 | 108.75 | 1.68 |
↟ Daily values do not fully capture rainfall intensity.
2023 Broadway Bridge USGS Gage Data
Thanks to the Tri-Community Flood Group, we have a USGS water gage at the Broadway Bridge: Alewife Brook Near Arlington, MA – 01103025
References
- Tri-Community Flood Group Progress Report, Appendix F: Alewife Rainfall and Flooding Summary by Stephen Kaiser, March 2010 Flood Video & Will Brownsberger’s Collected Observations ↩︎
- Cambridge DPW Stormwater Guidelines 2006 ↩︎
- Alewife Brook and Charles River System Optimization Evaluations, Table 1-2 ↩︎
- https://savethealewifebrook.org/2024/01/31/2023-alewife-sewage-pollution/ ↩︎
- Broadway Bridge Gage Data, thanks to the Tri-Community Flood Group: Alewife Brook Near Arlington, MA – 01103025 ↩︎
- MWRA CSO Annual Report 2023, Table 2-3 ↩︎
LEt’s not play into municipal divisions between Belmont, Cambridge, Arlington and Somerville, but bring the caring environmental communities together to advocate to protect the watershed. Municipalities altogether, by nature, consider their own border lines first and foremost, so it would be up to you and us to come together politically for citizen’s recreational and ecological climate safety in the future. Watershed leadership is needed very much. Thanks to Save the Alewife Brook for showing us the way now. Good time to do it, despite gloomy political climate everywhere.
Ellen Mass
Former President and Founder of Friends of Alewife Reservation