Everybody wants that perfectly manicured swath of green lawn from sidewalk to doorstep, but how does that pristine grass impact our water?
The American dream lawn that closely resembles a golf course may not be the best choice to cover your property. “It just doesn’t need to be the default vegetation in a landscape,” said Susan Barton, a University of Delaware professor. Barton studies how to best manage landscapes to reduce the impact our yards have on the environment, especially on water.
“The best way to cleanse the water is to let it flow through the soil and down through the rocks,” Barton said. “By the time it gets to the ground water, it is as pure as it could be.”
And the best way to let that water stay on site to get cleansed? Variety.
Adding the variety of a small meadow or forest area to your lawn greatly increases the ability of your yard to allow water to filter down through the soil, Barton said.
“Alternatives to lawn give you more bio-diversity. They also clean water much better than a lawn will, they cause the water to stay in one place and seep in through the soil which is a lot more effective.”
Barton points to the massive meadow on display at Longwood Gardens as a prime example of that variety. “It’s probably the best thing that’s happened to landscapes in this area in a long time because if people see that Longwood Gardens can do it, and it’s a popular landscape form at a place like Longwood, it’s very likely that people will start accepting it as a landscape form that they can use in their own home landscape.”
Barton has written a series of pamphlets on the topic and is also part of Delaware’s Livable Lawns program, which certifies lawn professionals, training them on proper techniques. The biggest area of emphasis is not over-fertilizing.
“The new word is ‘less is better,'” said Bob Finochiaro who heads up Finochiaro Landscape Company. His company was one of the first to be certified under the Livable Lawns program. “There’s a lot of old ideas out there about fertilizers, everybody wants a green lawn, but it isn’t just putting a lot of fertilizer down.”
The Livable Lawn program also offers tips to the do-it-yourselfers, especially when it comes to fertilizing.
“What’s going to happen if you over-apply it to the street, a hard surface, it’s going to run down and make it into the streams,” Finochiaro said. “If you over-apply it to the land, it’s going to go down and go into the water underneath.”
Finochiaro said while his company can purchase the appropriate mix of fertilizers with low nitrogen and phosphorous, it’s much harder for a home owner to get the same mix.
“Retailers will stock and sell what you buy,” Finochiaro said. “The trouble is, right now, we’ve got high nitrogen fertilizers, we’ve got phosphorous that they’re selling because they always did it.”
To change that paradigm, customers need to ask their stores to stock low nitrogen, low phosphorous products. Finochiaro said if enough people demand it, stores will be more inclined to stock it on their shelves.
It all adds up
There’s another culprit when it comes to lawn runoff: man’s best friend.
“So you figure, 80 million dogs times half a pound a day, that can really build up in time,” said Lisa Wool of the Partnership for the Delaware Estuary.
That “half a pound” she’s referring to? Yup. Dog poop.
“Basically every time it rains, any dog waste that’s left on the ground gets slowly dissolved and broken down, and it actually mixes in with that rain water,” Wool said. “It gets washed into either storm drains or into streams that are nearby. As it gets carried there, it takes with it any parasites, any bacteria.”
A state study found that about 12 percent of the coliform bacteria in the Pike Creek Watershed is due to dog waste. “The dog waste, what it does, the nitrogen in it actually makes the algae bloom,” Wool said.
Animal waste accounts for 20 to 30 percent of water pollution in America, according to the U.S. Geological Survey.
The Partnership for the Delaware Estuary has been part of an effort to get more dog owners to clean up after their pets. They’ve placed 46 bag dispensers at parks and neighborhoods in the Pike Creek area, potentially removing more than 18,000 piles of dog waste from being washed down stream.
“This is such an easy, cheap and simple fix,” Wool said. “Just grab a bag, pick up your dog waste, put it in a garbage can or empty it into your toilet without the bag, and flush it. Either way it will go somewhere it gets handled properly.”