Design

A possible answer for preventing sewage from flowing into waterways in extreme weather

During Hurricane Sandy, 10 billion gallons of raw sewage were released into the rivers, canals and bays of New York and New Jersey — and into homes and buildings that were flooded in the storm. This shocking number comes from a report by Climate Central. As reported in The New York Times earlier this week, the sludge would have been enough to cover Central Park in a 41-foot tall blanket of muck.

“Our sewage infrastructure isn’t designed to handle this type of storm surge,” explained Dr. Alyson Kenward, the principal author of the report.

Right before Hurricane Sandy, architect Ate Atema gave a talk in the TED office (part of our then-new TED@250 series) with an idea for something that might alleviate this very problem in cities like New York: street creeks.

In this talk, Atema explained that “CSO” does not stand for Chicago Symphony Orchestra — it stands for Combined Sewage Overflow, which happens when storm surge overwhelms sewage pipes and causes them to overflow into waterways. Surprisingly, CSOs happen by design. In the 1900s, underground sewer systems were built on a one-pipe model that flows storm runoff and sewage through the same pipes. The pipes were angled so that, when overwhelmed, sewage-tainted water would flow into local waterways, rather than back into homes. Many cities like New York have simply not been able to upgrade these systems.

Atema’s idea is to create separate channels for storm runoff, keeping it separate from sewage by building creeks alongside streets that capture rainwater and flow it into waterways. The creeks are designed with catch basins that weed out street trash and cisterns able to catch the “first flush” of rainwater — which picks up 80% of street pollution contamination. The creeks can be planted with trees and grass, making them into a amenity for a block while treating contamination.

To hear more about how street creeks would work, watch this talk. Want to hear more about New York’s Gowanus Canal? Watch the talk “Reviving New York’s rivers – with oysters.”