County banking on grass to remedy erosion issues
A special grass that curbs erosion and absorbs substances such as lead and arsenic from the soil and water through its roots is part of a Maui County pilot project that begins today.
Maui County’s Department of Environmental Management is working with Vetiver Farms Hawai’i LLC in planting an estimated 1,200 vetiver grass starters at Lanai Landfill that county officials hope will be a remedy for soil erosion, said Deputy Director Michael Miyamoto on Monday.
“We want to take a look at it first,” he said of the vetiver grass test project.
Miyamoto added that if the grass is able to alleviate storm water runoff and erosion, the county might use it at other landfills.
Proponents tout the grass’s ability to control erosion, with its 12-foot-deep roots, and to absorb chemicals from the water table way below the surface with microbial activity in its root system.
While there are environmental benefits for soil and water from the grass, Miyamoto said that the primary purpose for the planting project is to prevent erosion.
Whenever there is rain, there is erosion at landfills that exposes trash that already has been covered with dirt or regular grass, Miyamoto said. Heavy equipment is deployed to scoop dirt over the exposed trash. Grass at times also may have to be replanted because of erosion.
Miyamoto hopes by planting vetiver grass that is similar to a bushy plant, it could remedy the erosion issue and reduce expense to the county.
Vetiver grass will be installed at a closed portion of Lanai Landfill, he said. The Lanai site was chosen because of its steep slope and the water runoff the site gets from nearby roads.
Miyamoto did not immediately have the cost of the planting project Monday but did say it will cost more than planting regular grass. He added that if vetiver grass reduces erosion it will be worth the investment.
As for vetiver’s other environmental benefits, Miyamoto said that’s an added bonus.
Jason B. Fox, owner and certified vetiver systems technician for Vetiver Farms Hawai’i LLC of Papaikou on the Big Island, said the Lanai Landfill will be the first site in Hawaii and second site in the nation to have installed vetiver grass at a landfill. The other is in Biloxi, Miss.
An electric fence to keep deer and other predators from munching on the new grass will be installed today, Fox said. It will take around four days to plant the vetiver grass variety “Sunshine,” which has been approved for use in Hawaii.
The grass, which will be planted as sprigs, is noninvasive and doesn’t spread. The grass that comes from India grows to a maximum of 2 feet in diameter, has no “runners” and its seeds are not viable, Fox said.
The grass is similar to lemon grass and has a spiny feel to it, Fox added. Its full 12-foot extensive root system will develop in about a year or a year and a half. The grass can grow to 6 feet tall, although most people like to keep it around 18 inches high, Fox added.
It’s a durable plant that is even fireproof; the leafy parts will burn, but the grass will re-generate itself, Fox said.
The grass can be removed if needed. Roundup will kill it, as will cutting off the crown, which is just under the soil.
According to Fox’s company website, certified vetiver systems offer a soil-stabilization equivalent to having 12-foot steel plates in the ground while allowing soil and water to be filtered. It also is scientifically proven to reduce nitrate and phosphate levels by up to 90 percent. It absorbs heavy metals such as mercury, arsenic and lead, and other metals as well.
He added that the grass has an oil in its system that repels ground termites.
Fox’s company, which has been in business since 2010, has done erosion control work at places including Tahiti and at private properties across the state.
Back on Lanai, Fox said that the grass initially will need to be watered regularly for the first couple of months, but then the grass will thrive on its own.
The grass might turn brown and look dead during dry periods, but the roots are still working and the grass will turn green when the rain falls again, he added.
Miyamoto said Fox will monitor the grass for about a year so that it can be stabilized before the county takes over its maintenance.
* Melissa Tanji can be reached at email@example.com.