Posted on May 14, 2026 in ASRC News, Environmental Sciences Initiative
Why saving our streams is a wicked problem.
Coastal communities across the globe are facing a silent, invisible threat: nitrogen. While it’s a vital nutrient for plants, too much nitrogen, often from fertilizers and urban runoff, pollutes in our oceans and creates dead zones where aquatic life cannot survive. Scientists have been investigating targeting “sweet spots”—areas where stream restoration could simultaneously provide major environmental, economic, and social benefits—as an approach to tackling nitrogen pollution. But, a new study published in Nature Sustainability and led by Peter Groffman, a professor with the ASRC’s Environmental Science Initiative and Brooklyn College’s Department of Earth & Environmental Science, reveals that finding the perfect locations to restore waterways is much harder than it looks.
Groffman’s research team recently explored the Baltimore, Maryland region to locate sweet spots. Their findings suggest that these ideal locations are incredibly rare, highlighting a classic “wicked problem” where solving one issue often means neglecting another.
The study examined three main goals for restoration: reducing nitrogen pollution; investing where residents show a high willingness to pay for local improvements; and providing green space to underserved, densely populated urban neighborhoods. The problem is that these goals rarely overlap. High nitrogen concentrations are typically found in suburban and exurban areas. However, the greatest social need and the highest total economic benefit are concentrated in urban centers.
“The results suggest that if we are going to address nitrogen removal objectives with stream restoration, we will be directing funds to areas where both the social need and the “willingness to pay” for environmental restoration is low relative to more dense and generally less wealthy urban areas that already have low green space due to a long history of systematic disinvestment,” Groffman said.
Mediocrity Instead of Excellence
When the team combined environmental, economic and social factors into a single sweet-spot index, they didn’t find many bitter spots (areas totally unsuitable for work), but they did find a sea of mediocrity. Most locations produced only average results across the three categories.
“This happens because we often try to bundle too many goals into a single project,” Groffman said. “For instance, a project designed to stabilize a collapsing streambank might also try to claim “nitrogen credits” to save money. While this sounds efficient, it can lead to sub-optimal choices that don’t effectively solve any of the original problems.”
Unbundling the Solution
To move forward, the researchers suggest unbundling these benefits. Instead of looking for one-size-fits-all projects, cities might need separate strategies: one specifically targeted at nitrogen removal in the suburbs, and another focused purely on greening and social equity in the city.
By recognizing that we can’t always have it all in one spot, planners can make more transparent, effective decisions that ensure both the environment and the community get the specific help they need.