Nobody wants an airport in their backyard because of the noise. As existing airports get busier and busier due to increased demand for air travel and people get more sensitive to noise pollution, air transportation faces major problems in developed countries.
But a simple solution developed accidentally by Dutch farmers can be easily used to cut down the amount of noise generated by planes taking off and landing.
If you fly into Amsterdam’s Schiphol Airport you’ll notice that just past the edge of the runway, there’s an odd assortment of hedges and ditches laid out in a diamond-like pattern. At first you may think its just one of the Netherlands world-famous gardens.
But this garden has a very specific purpose: cancel out airplane noise.
Covering just over 80 acres the green space is the Buitenschot Land Art Park. It’s not just an agricultural solution to noise pollution but also serves as a recreation area, containing numerous bike paths and sports fields.
Schiphol is one of the busiest airports in the world and the main hub of KLM Royal Dutch Airlines. In addition to passenger traffic its also a major shipping point for cargo going to Asia. It sees 1,600 daily flights meaning its busy and loud.
The location was originally chosen because of it is flat, wide and open. But those qualities also make it a giant megaphone, effectively amplifying the noise of the planes across a wide area. This problem is common to most airports of the world and becoming more acute as once rural sites are increasingly surrounded by houses.
Ground noise is difficult to control due to the way it travels. The low frequency, long wavelength sound skips over single barriers, like concrete walls.
In 2008, responding to increased resident complaints, Schiphol called upon the Netherlands Organization for Applied Scientific Research [TNO] to study the problem.
The researchers made the fascinating discovery that in the fall, after the nearby fields had been plowed, noise levels decreased markedly. The furrows in the fields, because they had multiple ridges to absorbed the low frequency sound waves, deflected the sound and thereby muted the noise.
But Dutch officials, knowing for clever uses of land for centuries, didn’t just want to cut the noise. Instead they reimagined the land surrounding the airport to drown out as much of the ground noise as possible while also designing a maze-like park that could be used for something other than just cancelling sound.
By October 2013, the Buitenschot park had cut the decibel level of the noise in half. The airport thinks it can cut that down even further by changing when certain planes take off and by limited the type of aircraft allowed to land based on their specific noise profile.
NASA studied the impact of just controlling noise by conventional means, such as limited the number of flights or time of day aircraft can take off and land and found that “noise management plans have the potential to severely disrupt interstate, or international, commerce and exert strong negative pressure on the aviation industry,” the study said.
By using the Dutch method noise can be cut by over half without causing the negative economic consequences created by just cutting down the number of flights. It also helps beautify the surrounding area and improves the social lives of local residents.
The development should also pay big dividends in the future, as planemakers increasingly design jets around low noise profiles. Canadian company Bombardier is doing just that with its new C Series jet that is specifically designed to dramatically reduce engine noise. Such planes may become mandatory in the future in order to cut the noise pollution around airports.
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