Daylighting; Bringing a New Light to Streams in Urban Areas
August 5th, 2010 by Sarah Taylor
In urban areas most people can’t imagine, that there was once, or still is a stream underneath them. Many municipal urban planners are bringing these streams “to light,” by a process called daylighting. This includes bringing a stream to light, from underground, often by integrating storm water management and ecosystems. Daylighting can have many benefits, including ecological, economic, and social. We wrote about a daylighting project in Seoul, South Korea about a year ago. Since then daylighting has gotten exposure from cities like Seattle, Berkeley, Portland, and our very own San Francisco. Most of these streams and creeks, which have not been visible since the 1800’s are now viewable as sewers and pipes transformed underground in order to make room for urban development. With global warming on the rise, many cities cannot handle the pressure of rising stormwater runoff, often backing up water treatment plants, which directly affects the entire city. Urban planners are turning to daylighting as a resource to relieve pressure from stormwater runoff as well as connecting people with their water resources.
Seoul’s landmark daylighting project involved tearing down a major divisive freeway through the heart of the city and replacing in, instead of with another vehicular transportation network, with an enhancement of the natural environment, a community amenity, and a stormwater management improvement.
Thornton Creek in North Seattle has just recently been daylighted in collaboration with a mixed-use, residential, commercial, and office, development adjacent to the Northgate Mall.
While daylighting seems like an extremely attractive option for urban water system improvements, there are also many issues related to daylighting. One of our engineer’s Adam writes, “While it’s easy to tout the benefits of daylighting from an academic or professional perspective, American municipalities often get caught up on fiscal constraints, searching for exaggerated untruths to defend inaction. Benefits vary depending on the location and scale of the drainage network, what habitats are associated with the stream, the local climate conditions, existing stormwater management conditions and infrastructure, and the scope of the daylighting project.”
Recently San Francisco has pondered upon the thought of using daylighting throughout the city, which would relive stormwater runoff pressures and would expose watersheds to the public. Show your support for the use of daylighting in San Francisco by attending the next community meeting here.









