When heavy rain hits Alewife Brook, sewage-contaminated floodwaters spill onto walking trails, into neighborhoods, and across wildlife habitat. In August 2023, just 2.6 inches of rain caused severe flooding along the Alewife Brook Greenway, sending millions of gallons of combined sewage overflow into the brook.
The Ocean River Institute has a nature-based solution.
We propose creating a dense native “Cool Forest” where Tannery Brook meets Alewife Brook — one of the most flood-prone and polluted locations in the watershed. Instead of relying solely on expensive underground infrastructure, this project works with nature to absorb, filter, and cool stormwater before it reaches the river.
The system combines engineered water treatment with ecological restoration. During storms, combined sewer overflow (CSO) water would be captured and filtered through mycelium, wood chips, and biochar that help remove pollutants and improve water quality. The treated water would then flow into underground leach fields beneath a dense Miyawaki-style native forest designed for rapid growth, deep root systems, and maximum water absorption.
The result is a living sponge — a forested leach field that becomes more effective every year.
Healthy forests naturally cool the air, stabilize soil, retain moisture, and absorb stormwater. Diverse native plant communities also create underground fungal and microbial networks that help trees grow faster and become more resilient to climate stress.
Our Cool Forest would include native understory trees and shrubs such as witch hazel, sassafras, viburnums, spicebush, elderberry, winterberry, lowbush blueberry, sweet fern, and many other native species. Together, these plants would create habitat for wildlife while helping protect nearby communities from polluted flooding.
As the forest grows, more sewage overflow is absorbed naturally. Water quality in Alewife Brook improves. Urban heat radiating from pavement decreases. Trees and shrubs help clean the air and buffer traffic noise from Alewife Brook Parkway. Diverse native flowering plants attract pollinators and strengthen local biodiversity.
The Alewife Brook Greenway becomes healthier, cooler, more beautiful, and more meaningful for everyone who walks its trails.
This is climate resilience powered by nature.
The Ocean River Institute is advancing innovative ecological solutions that protect people, rivers, and biodiversity together.
Your support can help us:
- Complete ecological and engineering design
- Advance public outreach and partnerships
- Restore native habitat
- Build long-term community stewardship
Donate today to help transform Alewife Brook from a sewage flood zone into a thriving living forest.
Together, we can restore the Alewife and build climate resilience for generations of fish, wildlife, and people to come.
