H2bid Blog

The Benefits Of Rediscovering Buried Waterways

If you live in an urban area, chances are that you pass over hidden waterways every day on your commute to work. Of course, we may barely notice the streams and rivers that are visible but what most city dwellers don’t realize is that there is likely a hidden watershed buried under miles of concrete and pavement. In many cases, cities are “resurfacing” or “daylighting” these streams and creeks, allowing the sun to shine upon these waters once more.

Historically, as cities expanded, they often buried or diverted streams that were “in the way” of progress. This is far from a modern trend; there are examples that stretch back to the Roman Empire. In many cases, these waterways were incorporated into the sewer system; in others they were diverted or buried to prevent flooding in the heavily populated areas. As modern sewer systems were built, city streams and creeks often found their way into the storm sewer system.

Specific examples of this type of urban planning can be found all across North America from Los Angeles’ Arroyo de la Brea to Philadelphia’s Mill Creek. Virtually every major city has a hidden waterway to be found. Urban explorers are drawn to these hidden waterways partly because of the challenge in finding them and partly to reveal these streams that once ran free to the greater public. Exploring the deep underside of the city isn’t for everyone, though, so the stories tied to these waters are not well known. There are new trends emerging, however, that may allow everyone to see and experience some of these waterways once more.

In San Francisco, the city’s Public Utilities Commission is studying plans to expose or “daylight” several creeks and streams that have been buried for decades. Top contenders for daylighting include: Islais Creek, originating in Glen Canyon Park and flowing through Bernal Heights to Islais Creek Channel, passing under Third Street just north of Bayview; Yosemite Creek, flowing from McLaren Park in Visitacion Valley through Portola to Bayview and entering the bay near Candlestick Park; and the little-known Stanley Creek, flowing along Brotherhood Way into Lake Merced near the border with Daly City.

The city is considering bringing these waterways to the surface and allowing them to flow in open-air channels that parallel the streets and sidewalks. Though this won’t return the waterways to their original, natural states, the city’s compromise approach will offer considerable benefits to the city. A study funded by the Public Utilities Commission found that bringing Yosemite Creek to the surface would reduce strains on the water system by taking the natural flow of the creek out of the sewer system. In addition, it would reduce the annual runoff volume by 36 million gallons per year. In another study involving Islais Creek, it was shown that there would be a reduction in a peak flow through the sewer system of three to nine percent – a significant factor.

Nearby, the city of Berkeley has a history of bringing forgotten waterways to the surface. Strawberry Creek was one of Berkeley’s earliest daylighting or resurfacing experiments. Completed in 1984 at a cost of about $50,000, a 200-foot section of the creek was removed from a culvert beneath an empty lot and transformed into the centerpiece of a city park. The impact of that transformation has been significant. Property values in the area around Strawberry Creek Park have increased, crime has decreased, and an empty warehouse has been converted to offices and a bakery.

Strawberry Creek’s success was followed in 1993 with the daylighting of Codornices Creek. The city daylighted 400 feet of the creek; nearly four hundred volunteers helped to restore the original crooks and bends stream, which was an important factor in regulating speed and controlling floods. After the completion, the area saw a gradual increase in the population of species like crayfish, damselflies, garter snakes, mallards, egrets, and gophers.

The success in Berkeley shows what can happen when buried waterways are rediscovered and utilized. Now, with a major city like San Francisco following suit, the practice could be more widely adopted. It seems clear that there are significant benefits to restoring the natural flow of water through a city both in terms of urban ambiance and the more practical matter of enhancing the capacity of the storm sewer systems. It appears that “daylighting” should be considered as part of any urban area’s comprehensive water management approach.