Buried Stream Sees the Light of Day
Nov. 25, 2014 - Nearly a hundred years ago a stream was covered over and diverted into an underground culvert in Northwest Washington, D.C. Now environmentalists are taking steps to restore the stream to a more natural flow and revive the native flora and fauna. The idea isn't unique to Washington: Around the world, people are working to give similar streams a second life, a process known as daylighting. National Geographic followed the year-long project.
Click here to read more about daylighting
Transcript
Steve Saari
Project Manager
District of Columbia Department of the Environment
[00:07] What we're trying to do is take a stream that really never needed to be piped, where no construction occurred, and bring that stream back to the surface.
We are in Northwest Washington D.C., we're about 3 miles from the White House, we're about a mile from the border of Maryland.
Steve Dryden
Environmental Advocate
[00:29] The idea back in the distant, not-so-distant past actually, was that you had to get rid of storm water, and you had to get rid of the potential of flooding, and people didn't really understand about stream ecology or they didn't really consider that to be that important. So in our urban areas and in our suburbs a lot of streams were just put into pipes, they just buried them and put them into pipes. And this fundamentally altered the way the stream workes, and made it not work very well.
Keith Underwood
Project Designer
Underwood and Associates
[01:06] When we build these projects we start by filling the channel with that clean sand, we use that as the working platform, as the construction haul road.
Steve Saari
[01:20] And that haul road itself doubles as the area where the stream bed will eventually be. So we start at the downstream end where the water flows to, and build structures moving upstream to the end of the project. And once we get to the end of the project we break open the pipe and the water will begin to flow through the whole project area.
Keith Underwood
[01:45] A conventional approach to this kind of restoration would be to cut the banks back and disturb a lot of the riparian zone. This approach is called regenerative stream channels. And they're quite different from that old approach in that they are bent on spreading the water out to slow it down and filter it through sands and gravel.
Steve Saari
[02:10] It's not going to be exactly like it was 90 - 100 years ago, so what we're trying to do is make it natural a system as we can. So we're doing adaptive management, we'll be doing here and there for about three to five years after the project is completed to make changes to either take a little less storm water in or change the structures a little bit to make sure everything is flowing smoothly and that we don't have any erosion problems, we don't have any flooding problems.
[02:40] Piping of streams is something that happens across the world and it's not DC specific, we do have a lot of streams that have been piped. Unfortunately only a few streams have been day lighted, once they're buried, oftentimes they're gone forever.
