Turf Design Build Magazine - October, 2012
Meeting the erosion control challenge
Whether you are a landscape designer in coastal Florida or an installation specialist in Iowa, the worldwide problem of soil erosion impacts your work on a daily basis. While ordinary decomposition in certain areas is not a concern, keeping soil healthy and in place is essential for sustainable landscapes.
The homeowners envisioned an outdoor kitchen, entertainment area and pool in their sloped backyard.
Scientists estimate that U.S. soil erodes at 17 times the rate at which it is formed. The ramifications are seen socially and economically in such problems as declining water quality.
Challenges in landscaping arise as well. Without consideration for erosion issues, a spectacular design on paper can be a disaster on a client's property. Fortunately, landscapers have learned to overcome this obstacle.
Borst Landscape & Design was able to transform the space by using a combination of techniques, including terracing, retaining walls and drainage.
PHOTOS COURTESY OF BORST LANDSCAPE & DESIGN.
A combination of methods is often required to manage slopes, low-lying areas and shady spots. Terrain modification may be paired with drainage or retention devices. Common solutions professionals advocate include the use of ground cover plantings, establishing dryscapes and installing retaining walls.
Ground cover plantings and soil covers
Properly selected plantings help stabilize soil, while aesthetically improving properties. Whether turf, naturalizing plants or trees are right for a particular site, vegetation's protective cover mitigates rainfall's spread over the land and eases each drop's landing. Hardy root systems help hold the soil in place. Thus, plantings are especially key in moist terrain, such as wetlands and along waterway shores.
Mark C. Borst, president of Borst Landscape & Design (www.borstlandscape.com) in Allendale, N.J., adds that issues such as sun exposure must be considered. Areas that can support trees aid the landscaper in creating wooded zones that work hard in terms of both beauty and runoff management.
The extent and grade of the slope involved guides plant choices. In addition, striking a balance of growth patterns results in a landscape that is more easily maintained throughout its lifetime. A well-planned mix of soil covers, whether plantings, mulch, rocks, mats or blankets, goes a long way in preventing the harmful effects of erosion on a landscape.
Strategic plantings and rock installations help mitigate erosion issues near residential streets.
Working with dryscapes
In some areas, a dryscape "can be a very satisfying approach," says Borst. Where plants are not sustainable options, a bed of attractive river stones is an effective, appealing substitute. This technique also works well in border areas that do not support vegetation, while helping to prevent lawn damage resulting from pooling water.
Again, the site's slope is a key consideration. Maximum effectiveness on steeper slopes is achieved with the installation of larger stones. Water redirection is a vital factor as well. In some locations, grading, drainage systems and catch basins may be required.
Wall it in
Another solution is the use of retaining walls, which are highly effective in managing slope-based erosion. Through terracing, the problem can be mitigated in a visually pleasing way that forms the foundation for functional outdoor spaces. A wide range of materials is available, so you can help your clients choose a finish that complements their home and fits their budget.
Materials include natural fieldstone, manufactured concrete block, dry-stacked manufactured concrete walls and masonry walls veneered with stone.
Borst Landscape crews install stairs and retaining walls to manage a sloping backyard.
In many communities, the technique is subject to local ordinances and zoning regulations.
Working with clients
As with any project, erosion control solutions require landscape professionals to be educators. Clients' understanding of the problems and potential fixes helps guide their expectations and ultimate satisfaction with the outcome.
Those concepts, paired with best practices, facilitated a Borst residential project. The client presented the company with a challenging backyard that sloped significantly. The homeowners' vision of a recreational and entertainment paradise was not a natural fit for the terrain.
Retaining walls are a popular way to manage problem terrain.
"Solving the erosion issue was extremely important to the survival of the landscape and the combination of [several techniques] was essential," Borst says.
To fulfill the client's dream of an outdoor kitchen, patio, entertainment area and pool, the team put the yard through heavy excavation to remedy the lay of the land. The slope was further managed with several terraced stone walls and concrete stairways. Seepage tanks and drains prevent water from escaping the walls.
What erosion control measures will be favored in years to come? No doubt prevention will remain a priority and new techniques will surface. As the landscape industry's stewardship of the planet becomes more mainstream, greener solutions may be more prevalent in battling erosion issues.
Based in Greensboro, N.C., the author writes about horticulture, landscaping, agriculture and travel. She is a frequent contributor to Moose River Media publications.