By Zach Henderson | Woodard & Curran
Communities across the nation experience issues with water quality, deteriorating infrastructure, and concerns about flooding, and though there are many ways to address issues like this as they crop up, stream daylighting enables communities to deal with these challenges all at once. In the right situation, using a technique like this that restores waterways to their natural state can have a significant positive impact on all three of these major concerns.
What is stream daylighting?
As property development increased nationwide, many streams were buried or directed into culverts and pipes to accommodate communities’ needs. What we’ve since realized is stream burial can have significant impacts on streams by eliminating habitats, changing stormwater runoff patterns, and altering a landscape’s hydrology. When these structures begin to break down, communities essentially have two choices: replace the aging pipe or culvert with a new one or restore the stream to its natural state.
The latter option here is what is called stream daylighting, which is the process of uncovering previously buried rivers or streams. Just recently, we worked with the Town of Lexington, MA on a stream daylighting project that involved restoring a stream in a conservation area to its natural state, as part of a town-wide initiative to enhance drainage and ecology. This involved uncovering 260 feet of previously buried stream channel and implementing natural stream channel design principles. The town could have chosen to simply replace the deteriorating culvert, but chose to daylight it instead for the good of the ecosystem, reduced long-term life cycle cost, and community benefit.
Three major benefits to stream daylighting
Some project owners looking to rehabilitate a buried stream may initially be hesitant—simply replacing a pipe or culvert often seems like the simplest, cheapest option—but consider these three major benefits, and you might think twice.
Restoring water quality and aquatic habitats
When streams and rivers are buried, the streams obviously lose their ecological value. Restoring aquatic habitats in the right locations can have all the benefits of recreating natural habitat. Additionally, a restored stream channel can have a positive educational benefit for the community.
Reducing flood risks
One of the larger problems that comes with burying streams is that piped systems, unless significantly oversized, can create “bottlenecks” for adequate drainage. These bottlenecks increase the chance for upstream flooding, and the higher velocity in piped systems can negatively affect downstream stream reaches. Restoring streams and rivers to their natural states, though, both improves floodplain storage reduces upstream flooding, and slows down the water’s flow, which reduces the risk of erosion downstream. Many communities have notably decreased the incidence and severity of flooding and erosion through daylighting streams.
Saving money in the long run
The prospect of restoring a stream to its natural state might seem expensive in comparison to replacing a pipe, and in the short-term, it might be. But once you consider that you’ll be repairing aging culverts or replacing pipes again and again over the years, as opposed to daylighting a stream once, the life-cycle costs may be comparable or reduced.
Along with these benefits comes the simple aesthetic boost any area gets when a stream is restored to its natural state. Daylighting a stream or river can increase property values and revitalize urban areas by offering a natural destination for members of a community. All told, the benefits of stream daylighting much outweigh the costs, making this method a component well worth considering in any city’s stormwater and drainage management strategy.