March 18, 2013 03:46

Business Talk

Simple Techniques to Control Soil Erosion

Two easily implemented, though sometimes expensive, techniques being employed to control soil erosion in Missouri are riprap and the strategic placement of woody vegetation. These techniques have proven effective in preventing soil erosion in Mozingo Lake in Nodaway County.

“One of the best ways to control the erosion is to use riprap, which is just broken stone that is placed there and holds the soil; it will withstand wind erosion, and especially, the water pounding on it,” said Grant Evans, Mozingo Lake manager. “However, Riprap is very expensive to buy and especially to truck in.”

A less expensive solution, though just as effective, is to use woody vegetation cleared from grasslands. Consisting mainly of locus and hedge trees, the woody vegetation will then be placed along the edge of the lake, serving the same purpose as a wind break, Evans said.

But whichever route is chosen, placement strategies are always an underlying consideration. “It is important to address the strategic locations for soil erosion in parks. It helps with water quality and keeps costs down, in terms of processing the water and just really the overall health and sustainability of the lake,” the assistant city manager said.

Shoreline Threatened

Shoreline erosion at the Colonial National Historical Park in Virginia is an imminent threat, if major repairs aren’t done soon. The bluff’s edge could be within five or six feet of the Colonial Parkway in only a few years.

Dorothy Geyer, natural resource specialist, said that the park is seeking $3.9 million from the National Park Service to repair the four-mile stretch of its york River shoreline. The Indian Field Creek project will cost between $500,000 and $750,000, and will be funded through revenue from the park’s entrance fee.

The bluff is “especially at risk because of riverbank slumping and the formation of gully erosion in close proximity to the road surface,” the report said. The edge of the bluff has already eroded 20 feet over the last 30 years, or just over half a foot a year.

Repairs will focus on building up existing revetments with a mix of armor stone, splash apron and bluff stone. Additional soil will help fill in the area behind the revetment. Geyer said that the improvements will make the revetment about four feet taller. Much of the work will be done from the river where the stones will be hauled in by boat.

The Army Corps of Engineers designed the Indian Field Creek project and will supervise construction. Work on the project will likely start in a few months.

Projects Tackle Erosion and Water Storage Control

Two projects are underway in Detroit, Michigan, neighborhoods aimed at tackling erosion and pollution. The work is financed by a combination of county grant money and city funds.

In the first project, more than 600 lineal feet of Bell Creek’s streambank will be stabilized by Erie Construction, which received a contract of $249,403 to perform the work. “They built up the embankment, cleaned out culverts of sediment and are reshaping the banks,” said City Engineer Todd Zilincik. A 20-foot wide vegetated buffer of native grass/sedge mix and woody plantings will be added to the disturbed floodplain area.

Work also continues on a stormwater detention basin upstream at a local golf course. The city approved a contract for $281,563 with Stante Excavating of Wixom and $80,000 for OHM for consulting and design work. Zilincik said the new water storage area will reduce new water volumes and velocities and protect existing habitat from destruction or pollution.

“The projects will help keep the soil from eroding, and keep the banks stabilized,” Zilincik said. “They will help improve the water quality and habitat.”

Farmer Fined

The State of Washington Department of Ecology fined B&G Farms and owner Mike Brown $20,000 for violating Washington’s water quality laws by not preventing extreme erosion on his farm land in Grant County.

A heavy storm on July 20, 2012, sent a large amount of soil down the hill and into Lower Crab Creek, covering the road, smothering fish habitat, and polluting the creek with mud.

Lower Crab Creek is a body of water identified by the Washington Department of Fish and Wildlife as habitat for Chinook and steelhead trout.

Oyster Shells Used to Control Erosion

Oyster shells are being used to fight erosion around the archeological site of Wright’s Landing, located in Florida. The site boasts an ancient burial mound and a 17th Century Spanish mission.

The plan is to eventually use 78,000 pounds of oyster shells that would have otherwise ended up in a landfill. The shells are collected from local restaurants.

The discarded oyster shells are also helping to create the next generation of young bivalves. By using the shells to control erosion, oyster larvae have begun to colonize. More oyster beds are good news for the local economy.

Forty other species of aquatic life also have been observed making their homes among the old shells.

Soil Erosion Emerges as Key Green Issue

According to the United Nations yearbook, the UN Environmental Programme (UNEP), soil depletion is one of the most pressing environmental issues today.

The UNEP cites, “The globe’s soil erosion is at rates one hundred times greater than the rates at which nature can form soil.” Twenty-four percent of global land has declined in productivity over the past 25 years. This decline is due to unsustainable land-use.

The yearbook warns that without changes in the way land is managed, there will be grave losses in forests, peatlands and grasslands, as well as in biodiversity.

UNEP Executive Director Achim Steiner says, “The thin skin of soil on the Earth’s surface is often one of those forgotten ecosystems, but it is among the most important to the future survival of humanity.”

In addition, if huge amounts of carbon stored in the soil are released in the atmosphere, land erosion will affect climate change and aggravate global warming.

Steiner urges each nation to improve the management of the world’s soils.

State Says No to Motel’s Erosion Control Efforts

State environmental officials have warned an oceanfront motel in Montauk, Long Island, New york, that its attempts at controlling erosion are not permitted under state law. The owners of the Royal Atlantic Beach Resort Hotel installed large concrete rings to reinforce its beach after Superstorm Sandy and the November nor’easter eroded the dunes.

They first paid for sand to replace the dunes lost in Sandy, but the November storm blew that away, too. So, the motel owners installed about a dozen concrete rings, to form new dunes on the beach behind the hotel on South Emerson Avenue.

Reversing Erosion Could Cost $10 Million

The underwater system designed to reverse erosion specifically in Flagler Beach, Florida, has an estimated price tag of $10 million. This includes $1 million toward engineering, technical and other costs.

City and county commissioners agreed in 2012 to spend $50,000 in tax dollars to pay for a preliminary study. The forty-four page report produced by Dick Holmberg, president of Holmberg Technologies Inc., was recently released. In the report, Holmberg estimates the project to result in two million cubic yards of sand gain per mile and would increase the beach vertically by at least two feet.

The proposal recommends installing eight tubes split between two sites on the north and south sides of the city. These tubes, made out of fabric, would be filled with concrete slurry and placed hundreds of feet perpendicular to the beach. As currents and waves pass over the tubes, sand is pushed toward the shore, controlling beach expansion. With time, sand buries the system.

The report states, “The system will eliminate the need for future dredging and stop the need for erosion-related expenditures.”

A Million Dump Trucks Needed for Hurricane Sandy

The Army Corps of Engineers reported that more than 15 million cubic yards of sand were blown away during Hurricane Sandy. That’s just the estimate on beaches that the Corps counts among its projects, so the total is likely even higher.

In New Jersey, about 12 million cubic yards of sand were lost on project beaches, which include Long Beach Island, all of Monmouth along the ocean and most of south Jersey.

In New york, about 3.5 million cubic yards were washed away on Army Corps beaches; that land includes Gilgo Beach, the Rockaways, Coney Island, Westhampton and the area west of Shinnecock Inlet.

The Corps recently agreed to expedite a $30 million dredging project that would restore sections of beaches damaged during Sandy.

Also in Soil Erosion News

In many ways, we are fortunate that, in our chosen profession, we are able to help people when certain disasters occur: the tornadoes in Missouri, Oklahoma, Louisiana and Georgia, the flooding in Louisiana, the snows in the northeastern part of the country, the rain in California, and the snow in Colorado....

Do not miss another issue.
Read the new issue of Soil Erosion Magazine online