Being proactive helps maintain heavy-traffic turf at public parks

Portland’s Waterfront Park, located in the downtown core along the Willamette River, is the largest non-sports field grassy park and features major pedestrian traffic.
Photo courtesy of Portland Parks & Recreation.

Vigilance and proactive care are the two catchphrases that pop up when maintaining high-traffic areas in public parks. With traffic spiking at predictable times of the year within parks, staying ahead of the trampling feet is the only way to protect the turf.

In the Pacific Northwest, both Seattle and Portland have high-use, often waterfront property, public parks that draw crowds throughout and host large events in the summer months. It is that constant high usage topped off by regular events that worry the groundskeepers.

Portland’s Waterfront Park, located in the downtown core along the Willamette River, is the largest non-sports field grassy park with major traffic. Portland’s famous rose gardens and unique downtown block parks (entire city blocks in the downtown core were retained and made into grassy areas) also require some differing downtown care. Other high-use areas that necessitate careful watch are picnic areas near playgrounds and sports fields.

Seattle’s Gas Works Park on the shores of Lake Union, overlooking downtown Seattle and the Space Needle, is its highest use grassy park. Green Lake Park near downtown is also a busy pedestrian draw, according to Donald Allen, crew chief for Seattle Parks and Recreation.

While turf renovation is common for sports fields, Mike Carr, turf and irrigation supervisor for Portland Parks and Recreation, says that renovation tactics are important on busy pedestrian areas, too. Waterfront Park gets several renovations each year, generally immediately following a large event. The final renovation occurs in late September, after the last event of the season.

Because Waterfront Park is sand-based, and slightly different than the soil-based turf of the rest of Carr’s parks, total renovations are needed often, especially after Portland’s massive Rose Festival in June. During these renovations Carr applies a full overseed of perennial ryegrass.

Placing new sod in parks is nonexistent in Portland and quite rare in Seattle, so it is all about topdressing and reseeding. It takes the seed a week to germinate, and it is ready for use within two weeks at Waterfront Park. There, the roots will run 2 to 4 feet deep. Carr says that with a total overseed, a topdress and then plenty of water and fertilizer, the turf will be back to as good as new for another event.

Since it takes weeks to overhaul sections of the park, Carr moves events around within the park as much as possible, renovating sections in stages to allow smaller events to use different spaces. While the entire park gets renovated multiple times each spring and summer, it only happens all at one time at the end of the year. As required by the city, the event organizers pay for the extra care for the turf.

While Seattle doesn’t have Waterfront Park to deal with, the city’s Gas Works Park is plenty busy. Allen says that being on top of things prior to big events is the key, especially before the Fourth of July, when the park is absolutely overrun with people. In the weeks leading up to any large event, crews aerate, topdress and more heavily fertilize. They also step up the irrigation and let the grass get longer than the normal nearly 3-inch length so it is better equipped to handle the extra traffic. Keeping fertility levels up in the days leading to the event is important in the health of the grass during the event.

After the event, Allen goes back in with more aeration, topdressing and heavy irrigation. He says it gets tougher to monitor the turf when events last multiple days and irrigation becomes impossible. “You can lose it right away and the recovery is longer,” he says. All the more reason to have the turf as healthy as possible before the tents go up and the people roll in.

Because of the unique wind issues and hills at Gas Works, hydroseeding is sometimes used in areas where the seed simply won’t take. Event planners occasionally donate sod, so that gets used from time to time, but Allen isn’t a fan of sod placements because they can look like a patch for months.

There are also plenty of areas in and around Portland and Seattle where special events aren’t the root of the wear on the grass. Carr says that based on the amount of traffic, areas can get worn out in patches, forcing him to come in and renovate smaller areas. At times, he will even grade down and reseed sections that are in major disrepair. “We are constantly trying to keep areas up and not let them go,” Carr notes.

“If you can take care of it before it’s gone, that is ideal,” he says. “When it starts to turn, rotate people off it so you don’t end up with bare soil that is trashed. Thin and bare areas-stay ahead of those.”

Also, as areas get bare and new seed is needed, weeds start to compete with the grass, so getting overseeding done quickly and early is imperative. Carr likes to take advantage of dry spells in February or March to get a jump on growing seed.

Keeping the Portland downtown park blocks up is entirely different than large grassy areas like Waterfront Park. Because of the high volume of shade in the heavily treed city, Carr uses a 50-50 mix of hard fescue and perennial rye. “We are constantly working these areas,” he says. “They are always a challenge. There are some areas we are not able to keep people off, and the shade is an issue.”

While Portland tapes off the areas under renovation, it is hard to keep everybody out, so he says that getting into an area before it is totally gone is really the only safe practice.

While watering techniques can help out in the battle against wear, many of Portland’s outlying parks aren’t irrigated, at least corner to corner. Instead, Portland focuses its irrigation efforts just on high-use areas. “We have different levels of green,” Carr says about watering. Sports fields are kept up to safe, usable levels, picnic areas are kept splendidly green and the rest of the irrigation-capable areas fall somewhere in the middle.

Seattle’s Green Lake Park has plenty of athletic fields, but also heavily used turf near the lake. Allen says that topdressing those areas three or four times per year helps keep them looking stellar.

New parks require much of the same work as established ones. Nick Borer, crew chief with Seattle Parks and Recreation, says that getting turf established is the first step. “Really keeping on top of parks when they are first built is really important,” he notes.

Much of the traffic in high-use parks is predictable, but some isn’t. A common problem within large parks is when users decide to form their own path across turf. Carr says that anytime you have one of these paths, if you are able, it makes more sense to turn it into an official path instead of constantly fighting the problem.

One of the aspects that gets looked into when the city does park reviews are these paths. “Are people going to cut across the grass?” Carr says is the common question. “If so, maybe we put a direct path in there as part of the design. Sometimes we find out later and turn it into a path.”

Because of the heavy compaction, these “goat paths,” as Allen calls them, require as much aeration as possible to open up the rootzone to let water soak in instead of sitting on the top of the damaged turf.

Waterfront Park is sand-based, so total renovations are often needed, especially after major events that attract a lot of people.
Photo courtesy of Portland Parks & Recreation.

To fix the path problem, the Seattle Parks staff tries to turn the paths into official non-grass paths whenever possible. If that doesn’t happen, Allen goes in with a Harley Rake or a rototiller to clean it out and start over with new seed. Allen says, “You can’t topdress a compacted path, you have to regrade it.”

With restoration and repair techniques effectively taking people off high-use areas, staying on top of turf and getting it prepped for heavy traffic in order to minimize adverse impact becomes the best strategy in maintaining green public parks ready to host the public. That vigilant care keeps the public happy and the turf healthy.

Tim Newcomb is a freelance magazine writer and newspaper editor in western Washington.