Wetlands Mitigation

AggMan Staff | Published on June 7, 2012

Martin Stone Quarries leverages long-term benefits from wetlands creation.

Nearly 15 years ago, a few cattails found in a portion of one of its quarries led Bechtelsville, Pa.-based Martin Stone Quarries, Inc. to create wetlands that have not only extended the lifespan of its operation, but also yielded a long-term benefit for the company’s education and outreach programs.

When creating a wetland, evaluate the functions and values of the land it will replace, then consider how to improve on each.

“There was a partially manmade swale that was in an old orchard on the property, and it had the three criteria that met the definition of a wetland,” recalls Eric Gehman, who serves as senior sales representative for the company and oversees the created wetlands. Those three criteria include the presence of hydrology, hydric soils, and hydrophytic vegetation.

Through federal and state permitting, Martin has been able to do a wetland mitigation project to replace those wetlands. They found a proposed site for the new wetlands and performed hydrologic studies to determine that it had the hydrology needed to sustain a wetland. Once that was established, Martin was able to move forward with the design and construction of the site.

“In my experience, proper planning of a wetland is going to pay dividends in the long run because it is such a long process,” Gehman says of the design phase. “It’s a long permitting process. It’s a long process to monitor. If you don’t look at it over the long term, a project could easily fail.”

He explains that construction projects are often short-term commitments where an operator builds the project and walks away. With a wetland, however, the operator has long-term regulatory ties to the project. “The keys to success,” he says, “are due diligence, proper design, and long-term planning.

“The other thing I like to do is look at the functions and values,” Gehman adds. “You’re assessing what the function of the existing wetland was and what kind of value it had, not only to plants and animals, but to the community. A lot of times, wetlands exist, but they aren’t accessible. Try to find a way to bring people to the wetlands to make it accessible and get the educational benefit out of it. People just don’t understand about these ecosystems and how fragile they can be.”

A top-notch wetlands project not only mitigates the functions and values of the existing wetlands, but also improves upon them. In the case of this created wetlands area, Martin Stone succeeded in making it accessible to the public. “One of the issues before was that the wetland was in the middle of a quarry,” he says. “Now, we’ve constructed wetlands that have an educational component, where we can bring the school kids out and talk to them and educate them about wetlands. They can touch and feel and understand how the ecosystem works. It has added some additional functions and values.” Other examples of functions and values may include aesthetics, nutrient retention, water purification, and pollution prevention, among others.

The tangibles of the physical engineering properties also factor into the design and construction. An operator must consider if there is enough water to sustain a constructed wetland and select plants that would thrive in that environment. The soil mixture must be nutrient rich, and location and long-term maintenance are also important considerations.

Once the design was completed, construction began. “The construction was done almost like a typical construction project. It had large equipment — excavators and articulated haul trucks. It needed surveyors to lay it out and stake it,” Gehman says. “The physical construction of the wetland was very much like building a Walmart or another construction project.”

The difference, he says, is the additional forethought that is performed with regard to soil and plant selection. In this case, the top soil was amended with a mushroom compost. Plant selection was based on plants that were native to the area and would thrive. “There are successional plants that do very well early, but die off. Then there are plants, like willows or cattails, that are very hardy,” he explains. “They can grow very rapidly and actually out-compete the invasive species. With the plant selection, you’re looking for plants that will do well in a local environment and are fast-growing and very hardy to compete against the other plants. You’re pitting plant against plant.”

Careful attention to details regarding soil and plantings are important because of the long-term commitment to the created wetlands’ success. “The U.S. Army Corps of Engineers requires long-term maintenance to ensure the success of the project because they don’t want people to go out, dig a hole, and call it a constructed wetland and walk away,” Gehman notes. “They want to make sure that each project is successful.”

As part of the Corps’ five-year monitoring plan, the operator must catalog and document the plants, soils, and animals using the site. Any invasive species found on the site must also be documented. “Early on, there were some (invasive plants) that needed to be sprayed with an herbicide or manually pulled just to make sure that they never took root,” he says. “There’s a passive approach in the design and an active approach during the maintenance period.”

Even though Martin Stone Quarries’ regulatory requirements have long been fulfilled, it continues to use the wetlands in its school and community outreach efforts. “Now that we know the vegetation has flourished and a plethora of wildlife use the site, we see the educational benefit to it. We were able to parlay the site into wetlands education and environmental sustainability as part of the mining program here,” he explains. “The kids respond to it really well. They are as excited about the big trucks and the equipment as they are about the plants and the wetlands and the water. It’s very hands-on, which kids respond to.”

Adults are also impressed, he says, by the property: “People are very surprised to see that a wetland can be involved with an aggregates operation. It’s a great educational tool, from our standpoint, to show sustainability with our operation.”

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