It's no secret that aircraft and birds don't play well together. Dayton International (DAY), Ohio's third-largest airport and the historic birthplace of aviation, strives to keep the peace on its airfield by separating the two populations from one another.
Working with a local nature center, DAY recently revamped its landscaping to make active airfield areas unattractive to migratory waterfowl, large birds and flocking species. Changes are also expected to reduce the airport's carbon footprint and help manage stormwater runoff.
Last spring, DAY joined forces with the Aullwood Audubon Center and Farm to plant nearly 300 acres of native warm-season prairie grass on non-aeronautical property at the airport. By mowing the new prairie just once per season, DAY is trying to create an environment birds will avoid because they fear natural predators are lurking in the tall grass and dense undergrowth. Ultimately, airport officials hope the new prairie will reduce bird strikes on the airfield.
Project: Establishing a Tallgrass Prairie
Location: Dayton (OH) Int'l Airport
Primary Goals: Deter birds from active airfield areas; reduce carbon dioxide emissions; help manage stormwater during heavy rainfall
Consultant: Vanasse Hangen Brustlin
Informal Partner: Aullwood Audubon Center & Farm
Area Planted: 270 acres
Cost: $392/acre (includes prepping, seed & planting expenses)
Seed: Ohio Prairie Mix #27, from Ohio Pheasants Forever
Seed Supplier/Wildlife Habitat Planning Support: The Conservationist
Timeline: Seed planted in spring 2015; prairie should be fully established 2017-2018
Projected Carbon Dioxide Reduction: 25%
In the last five years, DAY has logged nearly 150 reported bird strikes, though none were categorized as serious.
"Historically, we've been very poor stewards of our property," says Terrence G. Slaybaugh, who has served as airport director at DAY since 2011. "We wanted to know what we could do with our land that would reduce the airport's footprint, make us better stewards of the property and be better partners with communities around the airport. The theory is that the prairie will reduce bird conflict with aviation."
Slaybaugh brings out-of-the-ordinary credentials to the airport's top post: an undergraduate degree in urban and environmental studies with a concentration in fish and wildlife management. "I had a real interest in how we could utilize the land we control around the airport and ensure its impact on wildlife is positive," he says.
FAA-Funded Sustainability Plan
Planting native warm-season grasses was one of the key land management strategies recommended to the airport last year in a sustainability master plan created by the consulting firm Vanasse Hangen Brustlin. DAY was one of 44 U.S. airports selected to receive FAA funds to help pay for such studies.
"The airport wanted to find opportunities to establish more sustainable land management practices, and we thought one option was to take some land out of agricultural use and re-establish a prairie that has minimal maintenance," explains Kari Hewitt, the firm's director of sustainability. "We worked closely with Aullwood to make sure we were doing it in the most effective way to provide appropriate habitat for wildlife but not a habitat that would endanger aeronautical operations."
Slaybaugh notes that DAY sits on a large expanse of property for a small hub airport - 5,200 acres. Fully half is undeveloped or is being used for commercial and agricultural purposes, he adds. Much of the land was purchased 15 to 20 years ago, as part of a noise mitigation initiative undertaken when DAY's traffic regularly included 60 cargo aircraft movements per night. "As a result of that, we acquired a lot of property outside the fence around the airport," Slaybaugh explains.
Since then, a local farm has been raising corn and soybeans on roughly 1,180 of the acres of that land, with DAY sharing costs and revenues from the crops. Converting about 270 acres of the cropland into a tallgrass prairie presented a new idea for deterring birds away from active airfield areas. "Knowing geese and large waterfowl don't like that type of habitat, we went with it," explains Slaybaugh.
The same farm that leases airport land for crops also maintains the prairie grass.
Planners from Vanasse Hangen Brustlin emphasize how helpful Aullwood personnel were during the project. "They offered a wealth of information on how the prairie grass areas could be set up and the value of them," notes Ben Siwinski, senior airport planner with the sustainability consulting firm.
DAY's recent landscaping changes are also helping the airport reduce its operational carbon footprint. According to projections, the new prairie may decrease carbon dioxide emissions by up to 25%. While many agricultural processes produce carbon dioxide, prairie grass absorbs it, Slaybaugh explains.
Vanasse Hangen Brustlin created a special emissions calculator tool to help plan DAY's land conversion. According to the consultant's projections, landscaping changes will help the airport reduce its greenhouse gas emissions by 428 metric tons per year. "That's the equivalent of taking the emissions produced by 90 cars off the road every year," notes Siwinski.
"Not only do you avoid the greenhouse gas emissions associated with soil tillage, fertilizer and pesticide application, and equipment use; but the native warm-season grasses also capture CO2 once they are thriving," Siwinski explains.
Planted from seed supplied by Ohio Pheasants Forever, DAY's new prairie should be fully established in two to three years. The special mix of prairie grasses and wildflowers got off to a good start this year due to heavy rains in late spring and summer. Mike Cross, environmental scientist at DAY, reports that the tallgrass prairie cost about $392 per acre, including expenses for ground preparation, seed and planting.
Once developed, DAY's prairie will need to be cut just once per year, compared to three times a month for airfield turf, Slaybaugh notes. Alternately, the airport could opt to burn off the grass and wildflower area every few years, which would provide additional benefits to the soil via nutrient-rich ash.
In addition to addressing wildlife concerns and lowering certain emissions, DAY's new prairie will also help manage stormwater runoff. Vanasse Hangen Brustlin personnel explain that the area's soil, grasses and wildflowers absorb water better than typical turf or agricultural land. "Studies have shown that prairies can absorb up to 9 inches of rainfall before any runoff occurs," says Hewitt.
The added efficiency provides benefits beyond airport property lines. In converting to this type of grass, DAY enhances the surrounding community's stormwater capacity minimizing the airport's impact to the local watershed. The benefits are especially pronounced during high precipitation, notes Hewitt.
"The airport understands the significance of its role to lead by example with regard to enhancing resiliency within the region," she adds. "There are a number of factors that are likely to impact agriculture in the near future, including climate change impacts, fuel price increases, pollution regulations, fertilizer and pesticide price variability. Prairie grasses are much more resilient to such changes. They manage stormwater well, but are also tolerant to periods of drought. The diversity of plant species in prairie grass systems also makes them more resilient in the face of disease or pest invasion."
History of Cooperation
The spring planting project wasn't the first time DAY has collaborated with Aullwood. The two organizations, which are located next to one other, have enjoyed an informal, but enduring, partnership.
About 15 years ago, DAY officials teamed with the Audubon Center to create a 150-acre prairie grass habitat on airport property. "The thought was that by creating a tallgrass prairie, we would be attracting some of the most threatened grassland songbirds and provide a suitable habitat for them in the summer and when they are nesting," explains Charity Krueger, who recently retired as executive director of Aullwood after 33 years with the center. "And coincidently enough, it is low maintenance and it attracts birds that don't impact airplane flight."
Personnel at Vanasse Hangen Brustlin describe the cooperation between Aullwood and DAY as remarkable. "Birds and airports don't mix. There are typically competing interests," says Siwinski, cutting to the chase. "But this collaboration was really exciting; and it was brought on by the airport leadership."
The local Audubon Center has certainly held up its end of the relationship. John Aull, one of Aullwood's founders, apparently appreciated both nature and aviation. Krueger relates that Aull was friends with the Wright brothers and even pulled their flying machines behind his car to help get them started. Today, the Aullwood Center includes an interpretive trail that highlights the Wright brothers and describes how they created their airplanes after observing bird behavior.
Krueger hopes that Aullwood's recent collaboration at DAY will have an even larger impact. "If this prairie grass project works, it would be a win-win for the National Audubon Society as well as the airport," she explains. "It could be a viable land use technique to use across the country. It's exciting to see how conservation organizations can collaborate with airports to make it work for both airplanes and for the little birds we care about that are threatened."
Because of its proactive work with the prairie grasses, DAY has been selected to participate in a U.S. Department of Defense study about using switch grass as airport land cover. Led by the U.S. Department of Agriculture and Mississippi State University, the study will address elements such as wildlife strikes, financial cost and environmental impact. Researchers will observe four switchgrass test beds at DAY for the next three to five years. Like prairie grasses, switchgrasses don't require frequent cutting.
"We kind of have a laboratory here at DAY for ground treatment," Slaybaugh reflects. "We're looking at prairie grass, different types of switchgrass, and then we have the airfield, where we continue to mow grass. For the next several years, we're going to be observing the wildlife impact around the airport with the different types of groundcover."