ECTC Offers a Website Tool to Help Landscape Architects with Erosion Problems

By Laurie L. Honnigford

The World Wide Web offers us a way to access information instantly and find solutions to many problems with just the click of a mouse. The Erosion Control Technology Council (ECTC) has developed a website tool designed to assist Landscape Architects and designers in solving erosion control problems. A tremendous amount of information is available at ectc.org that will make the Landscape Architect’s job easier. The ECTC is a group of rolled erosion control product professionals that have come up with nifty ways for Landscape Architects to handle soil erosion. More State, County and local municipalities are requiring a plan for dealing with erosion prior to allowing soil on site to be moved. The ECTC website gives the Landscape Architect numerous solutions to wide and varied erosion problems.

Rolled erosion control products have made steady inroads into the many ways soil and sediment can be controlled. This acceptance has come more easily as the success stories continue to reinforce what ECTC has been saying for a long time — rolled erosion control systems products great solutions for some of Mother Nature’s most vexing problems.

Landscape Architects have been putting erosion control products to the test in a variety of demanding ways. Many of your clients are looking for unique and different landscapes. Some of these designs involve slopes and channels prone to soil erosion. The challenge of moving soil and holding it in place until the desired vegetation takes root can be easily solved with rolled erosion control products. You will be able to design steep slopes and more varied and natural landscapes if you employ the advantages of these products.

Before the grasses and vegetation are established, there is great potential for erosion if proper steps are not taken to prevent it from occurring. This is true even if the slope is very gentle or channel is mild in design. All it takes is one heavy downpour prior to vegetation and repairs will be needed. The time and money needed to repair and re-grade the topography when this happens adds to the overall cost of construction and can erode money off of your bottom line.

Rolled erosion control products are typically used in slope and channel applications. The design elements needed for both applications are provided in detail on the ectc.org website. Log onto ectc.org and click to the section entitled "Product Information." Once there you can choose between slope or channel design. Click on your desired application.

If you choose slopes, the first design parameter you will selection is the degree of slope. The charts will provide information on slopes as gentle as a 5:1 slope or as severe as 0.5:1. Then you will need to choose how long the product will need to work (functional longevity) before the desired vegetation is established on the slope. Again, rolled erosion control products will give the designer maximum choices designed to suit the demands of the site. The rolled erosion control products you select can function less than three months, or be a permanent part of the finished structure. The website is designed so that you can easily click through the specific information to find what you are looking for. Once you have located the chart with the materials listed, there is a convenient website link provided that will take you to the manufacturer’s website where you can get additional product information.

The channel website charts work in a similar manner, except your first selection will be the maximum shear stresses the channels will be exposed to. If you need assistance in calculating the shear stresses, a guide is provided for you on the website. Your second choice will be the length of time the product will need to perform (functional longevity) prior to vegetation establishment. Once you have made your selections, the site will then direct you to the products appropriate for your project design.

A panel of industry experts with a broad spectrum of industry experience has carefully reviewed these website charts. The products selected for each chart represent those products most likely to be recommended. Please bear in mind that soil conditions, topography, climatic conditions and other variables can influence the products needed. Some applications work best when combinations of products are used on the project. Feel free to contact any of the Directing Members listed on the website for additional information or to answer any questions you may have. The manufacturers of rolled erosion control products have a wide breadth of experience and they can recommend those products that will work best based on your particular circumstances.

Some of the benefits of using rolled erosion control materials:

Rolled erosion control products bring an element of predictability into the outdoor variations in terrain. Because they are manufactured products, erosion control products can be produced according to stringent material quality control standards. They are subjected to rigorous quality assurance processes and the variation in material quality can be controlled.

The Landscape Architect can specify products according to the needs of the project. For example, if the requirements of the project demand that vegetation is quickly established and mowers and other maintenance equipment will need to be used on the site soon, the rolled erosion control products can be purchased with a photodegradable netting. Photodegradable netting breaks down quickly and prevents mower blades from getting wrapped up in the netting.

Erosion control blankets can be easily obtained and shipped as needed for construction. Generally, rolled erosion control products are less costly to purchase, transport and install than soil and aggregates or sod. This accessibility provides the Landscape Architect with the ultimate in flexibility.

One excellent feature of rolled erosion control products is the ability of the landscape designer to choose the exact type of seed and plant life needed in the design. This gives the designer the maximum control over the seed mixtures. Many golf courses find this advantage particularly attractive. The mixture of seed types can be specifically formulated to give the course certain playing characteristics. This feature is also great when the type of grass desired cannot be readily found in sod.

Also, the use of seed rather than sod often gives the grass stand a deeper, more horizontal root system. This gives the soil stronger erosion resistance. It also makes for a healthier plant. The use of an erosion control blanket for example, can reduce the amount of watering needed and speed seed germination time. In addition, the blanket holds the soil in place while vegetation is being established.

Another important benefit to using rolled erosion control products is the cost efficiency. The cost of installing sod can be two times as expensive as an erosion-control blanket, seed and fertilizer. In Minnesota for example, sod can cost approximately $2.00 per square yard. While, the cost of blanket, seed and fertilizer can be approximately $1.00 per square yard.

Water features can be an important element of a landscape design. But whether your design contains a stream or a pond, erosion can occur. Runoff generally flows to the nearest body of water or low spot and collects. The aesthetic appeal is degraded when sediment runoff ends up in an undesirable location. Erosion control products can be used in and around bodies of water to prevent shoreline erosion. Shorelines can be then be seeded with a mixture of wetland plants rather than using hard armor or rip rap. This will give your water feature a more natural appearance.

Finally, the use of an erosion control blanket can help retain moisture in the soil. When sod is laid, it is imperative that it be watered immediately. With an erosion control blanket, if it is not immediately watered, the seed will still germinate. Additionally, the erosion control blanket will prevent evaporation. When sod is laid in a new golf course for example, the contractor or superintendent is dependent on the irrigation system being up and running. If the system is not running, then water must be trucked in or run the risk of the sod dying before it can get established. This material also proves beneficial when there are dry conditions due to drought during construction. The erosion control blanket keeps the ground more consistently moist.

Product Selection

Erosion control blanket manufacturers have been very innovative in providing a wide range of products that the Landscape Architect can select from. The ectc.org website describes these products in more detail. The following is a brief summary of some of the most common products:

• Turf reinforcement mats (TRM) are flexible, synthetics, 3-dimensional mats designed to be used in conjunction with topsoil and seed or turf to create strong, durable and continuous soil-root-mat matrices which can provide nearly twice the erosion protection of plain grass alone.

• Erosion Control Blanket (ECB) is a temporary degradable rolled erosion control product composed of processed natural or polymer fibers mechanically, structurally or chemically bound together to form a continuous matrix that covers the surface and promotes/enhances the growth of vegetation.

• Open weave geotextile (OWT) is a temporary degradable rolled erosion control product composed of processed natural or polymer fibers woven into a matrix, used to provide erosion control and facilitate vegetation establishment.

Conclusion

There are many industry groups working to advance the science behind the use of these materials. The ectc.org website will give the Landscape Architect one more tool in his or her arsenal to get the job done efficiently. The rolled erosion control products industry has been very active in promoting standards, developing index testing, and educating end-users on the proper installation and maintenance of these products. Individuals seeking assistance or additional resources on erosion control products are encouraged to contact the following organizations.

• The Erosion Control Technology Council (ECTC), a non-profit organization whose mission is to develop performance standards, uniform testing procedures, and guidance on the application and installation of rolled erosion control products. www.ectc.org.

• The International Erosion Control Association (IECA) provides education, resource information and business opportunities for professionals in the erosion and sediment control industry. www.ieca.org.

About the author

Laurie L. Honnigford, is the Marketing Manager for the Erosion Control Technology Council, St. Paul, MN.