From: Creeks Are Coming Back Into the Light
Why Daylighting?
To make way for new development, urban planners in the 1950s and '60s often "culverted" natural streams and creeks by routing them through channels or pipes and paving over them. Beginning in the 1970s the trend changed, and today many such streams are being partially or completely uncovered, or "daylighted." When it's possible to do so, daylighting projects might re-establish a waterway in its original channel. If existing development doesn't allow that, a new open channel might be routed between buildings, streets, and other structures.
Why would a community go to the trouble and expense of daylighting a buried stream? There are several reasons. One of the most urgent is that increased runoff resulting from new development becomes too great for the pipes or underground channel to accommodate, leading to overflows and flooding; an open channel generally has greater hydraulic capacity. Sometimes it's simply a matter of saving money: if a culvert collapses it might be cheaper to open up the waterway than to rebuild.
The main benefits, however, have to do with water quality and the aesthetic value to the community. As Richard Pinkham points out in his article "Daylighting: New Life for Buried Streams" (Stormwater, November/December 2001,) an open waterway that accommodates aquatic and riparian vegetation can improve water quality through the plants' uptake of pollutants. A channel with an earthen bottom, not encased in a pipe or culvert, might slow runoff and allow infiltration. And communities generally value water and the habitat it supports; property values tend to increase around lakes, creeks, and streams.
January-February 2005
From: Creeks Are Coming Back Into the Light
Why Daylighting?
To make way for new development, urban planners in the 1950s and '60s often "culverted" natural streams and creeks by routing them through channels or pipes and paving over them. Beginning in the 1970s the trend changed, and today many such streams are being partially or completely uncovered, or "daylighted." When it's possible to do so, daylighting projects might re-establish a waterway in its original channel. If existing development doesn't allow that, a new open channel might be routed between buildings, streets, and other structures. Why would a community go to the trouble and expense of daylighting a buried stream? There are several reasons. One of the most urgent is that increased runoff resulting from new development becomes too great for the pipes or underground channel to accommodate, leading to overflows and flooding; an open channel generally has greater hydraulic capacity. Sometimes it's simply a matter of saving money: if a culvert collapses it might be cheaper to open up the waterway than to rebuild.
The main benefits, however, have to do with water quality and the aesthetic value to the community. As Richard Pinkham points out in his article "Daylighting: New Life for Buried Streams" (Stormwater, November/December 2001,) an open waterway that accommodates aquatic and riparian vegetation can improve water quality through the plants' uptake of pollutants. A channel with an earthen bottom, not encased in a pipe or culvert, might slow runoff and allow infiltration. And communities generally value water and the habitat it supports; property values tend to increase around lakes, creeks, and streams.