Stream “Restoration” Projects Being Washed Away by Climate Change
Twelve years ago, Baltimore spent $2.2 million on an erosion control project in a stream called the Stony Run that flows through a beautiful wooded park in North Baltimore. The city brought in bulldozers, cut down about 150 trees, and built rock walls and dams in an effort to slow the water’s flow.
The project succeeded in creating a series of pools in which minnows now live. But there is no evidence that it achieved its main objective: catching and reducing sediment, nitrogen, and phosphorus pollution being washed downstream into the Chesapeake Bay.
Then, about two years after it was built, rain storms overwhelmed the system. The storms knocked the streamside boulders down into the waterway and required the construction crews and backhoes to return to the park again to fix it, temporarily.
A few years later, this fix was undone by another set of rain storms that again bashed the rocks out of place -- requiring a new round of repairs, this time costing $500,000.
It is a common scene being played out across the Chesapeake Bay region. Local governments are spending hundreds of millions of dollars on what are called stream ‘restoration’ projects, many of which have questionable value and are not engineered to withstand the increased intensity of rain storms being caused by climate change.
“We absolutely have to think about climate change when we design these projects,” said Jana Davis, Executive Director of the Chesapeake Bay Trust, which funds many of the projects. “Changing weather patterns, changing rainfall patterns, changing rainfall amounts – it is to me, at this point, a no-brainer. A 100-year storm isn’t a 100-year storm anymore. And we’re all recognizing that.”
Baltimore is far from alone in having restoration projects to restore. Thomas Jordan, a senior scientist at the Smithsonian Environmental Research Center, witnessed a similar washout of a stream erosion control project in Anne Arundel County.
“Right after they built it, they started to have the rocks tumbling off,” Jordan said. “And temporarily, they were sending people out to put the rocks back up after the storm. I was thinking of it as the Sisyphus strategy for stream restoration.”
Baltimore is somewhat different, however, because of its extreme poverty. It’s a city so short on money that children literally shiver in coats and gloves in their unheated classrooms. This year, however, the city is spending about a million dollars to temporarily shore up four poorly-designed stream restoration projects that were built last decade but not engineered to cope with the growing rainfall from climate change.
Prakash Mistry, an engineer for the Baltimore Department of Public Works, led neighbors on a recent tour of the one of the four repair projects, along the Stony Run.
“These projects are not designed to handle large, large storms,” Mistry said. “They are basically, in terms of engineering, designed for what we call ‘two year storms.’ Which is about three inches or so (of rain) – no more than that.”
Tempers flared as local residents complained that the city would spend $500,000 of taxpayer money, cut down as many as 50 trees, and tear up the park yet again just to pile up rocks that will inevitably tumble back into the stream in a few years. Some were angererd by what they saw as poor planning and communication by the city and inaccurate project maps.
“You can imagine, as a community, our lack of confidence in all of you to have this kind of a mistake,” said James Piper Bond, a resident of East Lane. “God knows if we hadn’t got come out here, they would have come out here and mowed all that (forest) down, and that would have been a mistake.”
Do stream “restoration” projects like this even work? (The term is in quotes, because they do not actually restore streams to the way they ever were in the past – but instead add new man-made features like rows of boulders armoring their banks and v-shaped rock weirs to create ponds).
Scientists say there is evidence that some newer stream reconstruction projects in rural areas that allow streams to spread out and form wetlands can be successful in filtering out pollutants. But that’s not true for older designs – like the one in Baltimore’s Stony Run – that rely on stone walls and short dams.
“For a while, people were hoping that restoring streams was going to solve all these problems,” said Solange Filoso, Associate Research Professor at the University of Maryland Center for Environmental Science. “It’s not going to be that simple. We need to look at where the problem is coming from.”
That means replacing parking lots and blacktop that surround streams with more green spaces, trees and gardens that absorb pollution, instead of simply dumping more rocks and dams into our waterways.