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Renovating Existing Parks With Stormwater in Mind

The following is an excerpt from City Parks, Clean Water, a report by the Trust for Public Land’s Center for City Park Excellence that examines the role of urban parks in managing stormwater. This is the ninth installment in a series of 20 posts.

Existing parks can offer all of the same benefits as brand new parks designed with stormwater in mind, but may need to be upgraded or modified slightly in order to be most effective. Certainly it makes sense to first approach parks that are severely affected by flooding, washouts, or erosion, but even parks without significant water issues can benefit.

Mill Creek Canyon credit City of Kent

Mill Creek Canyon Earthworks Park was renovated to manage flooding, and has remained a popular attraction for both residents and visitors. (City of Kent)

Modifying a current park to handle stormwater has advantages and disadvantages. On the upside, the land is available at no cost. On the downside, the park’s existing features and uses may be sacrosanct to current users who then resist any design or management changes. The process, therefore, requires a strong administrative hand, a good public information process, and top-notch scientific analysis and explication. Chances are that there is a strong legal or financial justification to take remedial steps since stormwater from the park is negatively affecting downstream resources.

A typical passive stormwater management features modifications that keep rainwater within the park for a longer period of time. Doing more than that – filtering and absorbing water from beyond the park’s boundary – generally requires more space or more complex systems, as at Echo Park in Los Angeles.

Echo Park Lake collects stormwater from a large surrounding uphill neighborhood – a swath of about 770 acres. The 125-year-old facility, which began as a reservoir of drinking water from the Los Angeles River but is now a discharging pond to that same waterway, was renovated in 2014 to handle more runoff and improve water quality through sediment traps, constructed floating wetlands, and better circulation. The upgrade improved the look and smell of the park and also allowed more boating. However, the lake can only manage rainfall from smaller storms; in a major deluge it can hold only about 25 percent of the neighborhood’s water, with the rest shunted straight to the river.

OLYMPUS DIGITAL CAMERA

The new design of Echo Park Lake has improved the water quality, helping to bring back the beloved but dwindling lotuses, among other benefits. (KCET)

In Milford, Connecticut, Eisenhower Park along the Wepewaug River was vastly improved when Connecticut Light & Power Corp. agreed to invest $800,000 as mitigation for installing a new overhead transmission line. The company paid to convert an unattractive and unusable abandoned gravel pit in the park into an ecologically active artificial wetland. The wetland served as such successful water storage that the old river levee could be partially punctured, reconnecting the Wepewaug to its historic floodplain. Kent, Washington, did something similar, though with more artistic flair, at Mill Creek Canyon Earthworks Park (pictured above). In the early 1980s, faced with the need to protect its downtown from flooding by Mill Creek, the city rejected the idea of building a traditional engineered dam and opted for a park that could do the same thing. The 2.5-acre, sculptural earthwork park contains enough detention basins and berms to accommodate a 10,000-year storm, and grassy lawns and hillocks provide an attraction to residents and visitors alike during the majority of times without flooding.

The renovation of Discovery Park in Seattle started with a minor departmental work order to repave a parking area. But when environmental engineer Andy Sheffer discovered that culverts under the park were washing out, the repair was completely re-conceived. The city tore out the culverts, brought the water back to the surface, stabilized the slope, and transformed the creek into a cascade of pools. “This began as a maintenance project but it resulted in an accessible water feature,” explained Sheffer. “It’s been highly acclaimed. People love hearing that good environmental deeds are being done, but above all, they really love watching moving water. As soon as we daylight a stream, people want to see more of the riparian corridor exposed. These projects catalyze park projects further downstream.”

When faced with problems such as flooding, runoff, washouts, or poor quality water features (to list only a few), an existing park may be renovated for water management and greatly improved. It can be challenging to work with already established places, but often has benefits for everyone involved.

Designing New Water-Smart Parks: Two Stories From California

The following is an excerpt from City Parks, Clean Water, a report by the Trust for Public Land’s Center for City Park Excellence that examines the role of urban parks in managing stormwater. This is the eighth installment in a series of 20 posts.

When it comes to green infrastructure, the easiest parks to work with are new ones — facilities that don’t yet exist and can be specifically designed with stormwater management in mind. Every park is different, from size to geography to the surrounding culture and politics, but when it comes to water-smart parks there are three main issues to be considered:

  • Is the physical relationship of the park to the surrounding community such that a redesign could reduce neighborhood flooding or the pollution of downstream waterways?
  • Does the park have any available space for water flow and storage?
  • Is the composition of the existing soils, water table and underlying rock such that the park can absorb a significant amount of water in the necessary amount of time?

    Tujunga pathway and stream - credit Water Education Foundation

    A recreated streambed at Tujunga Wash in Los Angeles helps revive depleted aquifers. (Water Education Foundation)

Continue reading

The Goals of Combining Parks and Stormwater

The following is an excerpt from City Parks, Clean Water, a report by the Trust for Public Land’s Center for City Park Excellence that examines the role of urban parks in managing stormwater. This is the seventh installment in a series of 20 posts.

City parks departments and water agencies both stand to benefit from designing parks for stormwater management. However, it isn’t always easy to meet the needs of both parties, as well as those of the citizen users of a park. For one thing, stormwater has a complex range of impacts, and the techniques for dealing with those impacts are not easy to carry out, or even to explain to the public. There are also many different kinds of park users who have vastly different opinions about what makes a park great and what degrades it. Continue reading

Public School 261, Brooklyn

The following is an excerpt from City Parks, Clean Water, a report by The Trust for Public Land’s Center for City Park Excellence that examines the role of urban parks in managing stormwater. This is the sixth installment in a series of 20 posts.

A schoolyard in New York is easing the burden on an overtaxed waterway while also providing additional community play space in a park-poor neighborhood.

Brooklyn’s P.S. 261, whose schoolyard had been paved over decades earlier, leaving a half-acre of asphalt and a deteriorated jungle gym for recess, was one of the few locations in its neighborhood that had a bit of open space. Fortunately, the site was a priority for two different city agencies — the city’s Department of Education (for playground renovation) and the Department of Environmental Protection (for water quality improvements from reduced sewer overflows) — as well as a private conservation group, The Trust for Public Land.

TPL has been working with New York City since 1996 to convert school playgrounds into after-school-hours community parks. In the early days of the partnership, the goal was merely to work with students, parents, teachers and community residents to create great play spaces with such amenities as fields, running tracks, gazebos, basketball and game courts, and even hair-braiding areas. Beginning in 2012, the mission was expanded to also include stormwater management.

P.S. 261 was the first of what became 40 schoolyard renovations carried out through the three-way partnership. Although the construction could have become a source of strife in the community, the public process and the many ancillary benefits to the neighborhood were so compelling that the reworked park was accepted enthusiastically. Permeable pavers reduce runoff from the hardtop, rain gardens and the artificial turf field absorb runoff, and the gazebo features a green roof and rain barrels to store runoff for irrigation during dry spells. The field itself consists of permeable artificial turf underlain with broken stone to store stormwater and perforated pipes for drainage. All told, the half-acre park can capture about 500,000 gallons of stormwater annually.

Girls play jump rope at P.S. 261 Playground

Student drawings inspired the art on the schoolyard’s new, permeable blacktop. The outdoor classroom space and gardens are visible in the background.(Pedro Diez)

Fortunately, even in the cramped quarters of an inner-city schoolyard, it’s not either/or — play or store. “Stormwater management features always rank high on kids’ priority
lists. They like green spaces,” explained Mary Alice Lee, New York playground program
director for TPL. “It’s not a tradeoff between basketball courts and rain gardens since we
can squeeze both into even a small space.”

Each renovated schoolyard costs about $1 million (including $650,000 for construction) and is funded primarily by the two agencies with supplemental donations raised by TPL. As with other schoolyards renovated through the initiative, P.S. 261 must be open to the general public outside of the school day from dawn to dusk and on weekends, vacations, and holidays; the school’s custodian receives extra compensation from the city for taking on added responsibilities in the schoolyard.

“There are always growing pains in taking a successful program to scale,” explained
DEP assistant commissioner Angela Licata, “but our only challenge has been managing
construction delays against our strict consent decree deadlines. This was such a
clear win-win situation for us and the school that we’d like to see participatory design
and stormwater management become standard practice in every schoolyard capital
improvement in New York.”

Students perform hand stands at P.S. 261 Playground

(Pedro Diez)

 

Cromwell Park, Shoreline, Wash.

Cromwell Park

(City of Shoreline)

The following is an excerpt from City Parks, Clean Water, a report by The Trust for Public Land’s Center for City Park Excellence that examines the role of urban parks in managing stormwater. This is the fifth installment in a series of 20 posts.

After the Seattle suburb of Shoreline passed a parks and open space levy in 2006, the city sought renovation projects that could meet multiple city goals. One opportunity arose at 9-acre Cromwell Park, a flat field on the site of a former school in a neighborhood with frequent floods. The surrounding Meridian Park community had already been targeted for a major stormwater upgrade by the city’s public works department.

CromwellDrainageProblem before

Before renovations. (City of Shoreline)

“It was filled with a lot of dead grass and not much else,” laughed Kirk Peterson, who oversaw the project for the parks and recreation department. The two agencies partnered on Cromwell Park’s redesign, radically restoring the site’s natural topography and redirecting runoff to a wetland for treatment. They built new inlets from adjacent residential streets and a nearby county building, where most of the runoff percolates into the ground. (In a deluge an overflow outlet releases excess water to the sewer system.) The 1.33-acre wetland can hold an acre-foot of water (almost 435,000 gallons), enough to eliminate the neighborhood flooding problem.

Most noticeable to residents are the recreational improvements. The renovation added a new playground, a full-size basketball court, and a new baseball field. Walking trails encircle the wetland, even crossing it on a bridge. Neighbors were adamant that the wetlands not be fenced off, Peterson noted, although the city eventually had to install safety cables by a particularly steep-sided section. One of the best investments, Peterson added, was the selection of diverse, native wetland vegetation that makes the park look good even in dry spells.

Changes in the park sacrificed some recreational space, but Peterson said the wetlands have become one of its most popular features. “In the design process, neighbors were skeptical. They were worried about mosquitoes and bad smells. But now people love the space. There is often interesting wildlife, and people are fascinated to see the basins fill up with water after a rainstorm.”

Design and construction, which lasted from 2007 to 2010, cost $1.6 million, with about
two-thirds coming from the park bond and one-third from the Surface Water Utility Fund. The two agencies share maintenance responsibilities, with the park costing about $60,000 a year and the stormwater features about $11,000.

Cromwell Park credit City of Shoreline

This sculpture helps show the wetlands’ work, disappearing and reappearing with fluctuations in water levels. (City of Shoreline)

 

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