Feb 15th 2014

An introduction to Erosion

An introduction to Erosion
Erosion is when a layer of soil is loosened, swept away and deposited elsewhere. Erosion is a natural process, however, there are two major factors in causing erosion. One, from a geological standpoint, it just happens naturally from Wind and Water... the Grand Canyon being a major example. Two, it happens from man-made alterations of the land, as in with construction or agriculture. What happens when we don't protect the soil from eroding away? Levees and slopes fail and collapse, we end up with drainage problems, vegetation fails to grow, topsoil is lost - reducing or removing the most fertile and organic layer of the soil, soil acidity increases, water pollution, shoreline degradation, gullies and let's not forget loss of structure and stability. Have you ever been stuck in the mud? Imagine if you could lay something down that would prevent that.

How can we manage erosion?
Solutions vary by location. Landscapes are different throughout the world, so you should definitely be aware of the soil composition in your area as well as what types of weather events are common in your geographical location. Here are some of the main erosion control measures and their functions.

Mulch, Seed and Fertilizer - The root systems from vegetation provide a strong defense against erosion control. Therefore, establishing vegetative cover through the use of a mulch with a tackifier, seed and fertilizer are a great option. Mulches are available as straw, paper and wood. A tackifier (or glue, so to speak) is an additive which helps keep the mulch from blowing away. Mulch can be loosely applied or applied as HydroSeeding with the use of a hydraulic machine.

Erosion Control Blankets - ideal for slopes, ditches and swales, Erosion Control Blankets are made up of either straw, wood or coconut held together by either a single net on top or a net on both top and bottom of the blanket. Which material to use depends on the longevity you would like to achieve.These blankets are then secured to the ground with sod staples.The key with using Erosion Control Blankets is preparing the slope, which at times includes the application of lime, fertilizer and seed. The Erosion Control Blanket must have good contact with the soil surface. When using Erosion Control Blankets, keep in mind, you may want to remove them once they've served their purpose. The nets can cause issues with mowers or other equipment and perhaps wildlife. However, blankets are available with biodegradable netting.

Geosynthetics: Geotextiles, Geogrids, GeoCells

Geotextiles - Geotextile Fabric, also known as filter fabric, is a geosynthetic primarily used in the construction of roads to improve poor soil conditions. Geotextiles are ideal for establishing/enhancing infrastructure in roads, embankments, pipelines and other "earth retaining" structures. They provide reinforcement through separation as well as allowing water to flow in and out and offering a level of sealing and protection. Fabric keeps soils from mixing and by doing so, keeps drainage in tact, preventing soil contamination and maintaining the structure and stability of the road. Geotextiles come in many different variations, such as Woven or NonWoven, with various stress ratios and weights. Which fabric is needed, depends on the soil conditions of the location.

Geogrids - Another type of geosynthetic, geogrids provide high tensile reinforcement of roads, retaining walls, foundations, steep slopes and more. Geogrid is in the pattern of a grid, hence the name Geogrid.