From Bluebelts to Greenbelts: Converting Wetlands and Stormwater Storage Ponds to Parkland
An eleventh excerpt from the recently released book published by Island Press called Urban Green: Innovative Parks for Resurgent Cities. In this post, we look at some cities who have created parkland from wetlands and stormwater storage ponds.
For environmental, financial, and legal reasons, urban stormwater management is getting much more attention – and the result is helping to build the urban parks movement. Gone are the days when flood-control engineers would prescribe the construction of straight, deep concrete channels, and one stream after the next would be converted into sterile spillways. (The poster channelized waterway, the Los Angeles River, was used for a spine-tingling truck chase scene in the movie Terminator 2 and was once also proposed–seriously–for use as a highway.) Cities that still have extensive natural wetland areas are now carefully protecting them to contain and filter stormwater; many others are now also creating artificial swales and other storage areas to slow down and capture the sheets of water running off streets and asphalt surfaces.
When it comes to water management and recreation, parks-as-ponds and ponds-as-parks are two sides of the same coin. Although the former doesn't technically add parkland, it makes existing parks more environmentally productive; the latter can add to a city's de facto parkland inventory and, of course, adds a second bin of funding opportunities–all the state and federal water protection programs–to the fundraising arsenal. There is no question that the marriage of stormwater retention and parks will become more common in the coming decades, for both ecological and economic reasons.
New York City, in addition to the thousands of acres under Department of Parks and Recreation control, has another 480 acres of so-called Blue Belt land under the jurisdiction of the Department of Environmental Protection (DEP). The Blue Belt, located largely but not entirely in Staten Island (the least built-up of the city's five boroughs), consists of mapped wetlands that DEP acquires for stormwater management. The Blue Belts are zoned as open space and are protected from development, although the protection is not as stringent as for mapped parkland. Parkland can only be de-mapped and "alienated" from the park system through a vote of the state legislature; DEP lands can be sold to a private party if the buyer agrees to protect the official drainage corridors that traverse it–no property owner is allowed to modify a watercourse. Although the Blue Belt lands are partially fenced (to help focus the points of ingress and egress), they are fully open to the public. "Since we're spending Water Board money and aren't supposed to be spending it on recreation uses," said Dana Gumb, director of the Staten Island Bluebelt, "we don't specifically build any walking trails or other features. But we do have lightly used maintenance access pathways which we're happy to let people utilize, if they do so appropriately."
The converse occurs when DEP utilizes official park property for water management and water purification. "We'll install a storm sewer system under a street to catch rainwater from a neighborhood, and then we'll daylight it–bring it up to the surface–in a park," said Gumb. "We've done that in Conference House Park, Lemon Creek Park, Wolf's Pond, Bloomingdale Park, and others." The department constructs a pond-like water detention and treatment facility that holds the rainwater for about twenty-four hours, absorbs much of the destructive energy of the rushing torrent, allows sediment to settle out, and then permits the cleaned water to seep gradually into Raritan Bay and the Atlantic Ocean. "We're usually able to locate the holding ponds in areas that had previously been degraded," Gumb explained. "Places that had been disturbed with fill or were overrun with invasive vines. We use the opportunity to fix them up. When we're done the community ends up with something beautiful that also cleans the water."
Although many other municipalities regulate how individuals and commercial entities impact stormwater, almost none currently uses a municipal agency to construct and operate control facilities, and no other city has an agency as sensitive to public recreational use as New York's DEP. Of course, it's not always smooth sailing. There are times when DEP's ecological requirements conflict with the community's desires and the aesthetics of a park. In neighborhoods with combined sewers that mix household wastewater with street stormwater for joint processing, huge underground holding tanks with pumps and smokestacks are required to cope with the influx from large storms. In the worst of those cases the facility can be a blight on a corner of a park. Even in the best cases with successful restoration, a park may be closed for several years during construction.
"There've been instances where DEP has had to pay dearly for the use of parkland," said Gumb. Perhaps most famous was a multiyear battle over the installation of a mammoth underground drinking water storage tank in Van Cortlandt Park in the Bronx. Although the tank was to be completely buried and invisible to park users, the construction project was so large and was slated to take so long that the courts ruled that it was effectively an "alienation" of parkland and would need to be approved by the state legislature. After protracted negotiations, DEP agreed to pay the Parks Department $200 million for the temporary loss of parkland; the money was used to buy and improve dozens of other parks in the Bronx.
As public awareness grows, potentially even more could be done with water detention facilities. In some cases boardwalks, benches and interpretive signage could be added to these natural and manmade marshy areas to put them to double use for walking, running and cycling. Some stormwater storage areas could conceivably also be used as dry-weather playing fields, or skateboard parks if they are fitted with proper warning signage, fencing, and a commitment to hosing down residue following each high-water incident.
When the Seattle Housing Authority planned the demolition of the distressed High Point public housing site and its transformation into a new mixed-income community, the authority was required to capture all stormwater to keep it from running off the property. The water was required to be released gradually rather than being funneled destructively into a nearby salmon-bearing stream. But when it considered the aesthetics of the standard, unadorned, chain-link-surrounded holding pit, the authority balked. Instead, it created an extensive 130-acre drainage system culminating in one-and-a-quarter-acre Viewpoint Park with benches, a boulder-filled stream, a pond, a trail, a grass lawn, stairs, a playground, and gardens. "We turned what could've been a huge liability into an incredible asset for the community–in a place with a direct view of downtown Seattle," says Tom Phillips, project manager. Constructed by the Housing Authority, the park has been turned over to the Parks and Recreation Department for management and maintenance.