Erosion is a process where natural forces like water, wind, ice, and gravity wear away rocks and soil. It is a geological process, and is apart of the rock cycle. Erosion occurs at the Earth's surface, and has no effect on the Earth's mantle and core. Most of the energy that makes erosion happen is provided by the Sun. The Canyon itself was carved by the Colorado River and the wind that caused the surface of the sedimentary rocks to become exposed and erode over a long period of time.
For the most part, soil will stay in place. However, on steep slopes and embankments, there is the elevated risk of erosion. It is essential to put as much effort as possible into actions that will stop the soil from being washing away. This is because not only could this make the area that has been eroded barren, but it could also adversely affect water supply and introduce pollutants into the area. Additionally, it could take decades to rebuild even the initial layer of topsoil, so it essential to have some insight on how to keep and control topsoil in place.
Plant Grass & Shrubs
Grass and shrubs are very effective at stopping soil erosion. This is primarily because plant roots tend to hold soil together, making it harder to erode. The leaves of the plants also help to reduce the velocity of raindrops falling on the ground, making it harder for them to displace the soil and erode it. Ornamental grass and low, spreading shrubs work best as they leave no areas of bare soil exposed to the elements. The lid planted with grass prevented erosion of soil even more because the fibrous roots, rhizomes, and stolon helped hold the soil in place while the water traveled over and through it. The grass plants themselves also provide an alternative surface for the water to travel over. Cover crops; such as vetch, rye and clover, are excellent plants for erosion control. These hardy easy to grow plants send out nets of roots that help hold topsoil in place while also reducing competitive weeds. When tilled back into the soil, they increase the nutrient density as they start to compost.
Sturdy ground covers and shrubs are a great way to dissuade foot traffic through an area (another contributor to soil erosion). Juniper, rosemary, and buttonbush are great plants for the job. Juniper and rosemary are both evergreen and easy to care for. They do best in full sun and need little water once established, and juniper comes in so many varieties that you're bound to find a version that thrives in the zone you reside in. Rosemary makes an excellent edible addition to any garden. The deciduous buttonbush shrub, or button willow, is a water absorber that needs moist soil, making it a smart option for damp climates.
Trees
For trees that will flourish in a hillside garden, look for species with extensive root systems capable of keeping the tree steady on a slope and penetrating several layers of earth. Cascara, fir, pine, and willow all fit the requirements. The cascara and willow (especially weeping willows) thrive in full sun and require moist to wet soil. They do best in milder climates without harsh winters. Firs and pines, both members of the conifer family, need abundant sunlight too, but they do well in dry soil and are hardy enough to withstand below-zero temperatures
Use Erosion Control Blankets to Add Vegetation to Slopes
There are many varieties of fiber, biodegradable, and compost blankets/mats on the market today, and they have all been designed with one aim; to minimize the effects of water erosion on steep slopes and embankments. Rolled mats are usually made from mulch that is held together by a thick fiber mesh. They degrade slowly, allowing vegetation that may have been grown in the area to grow and take over the job of protecting the soil from erosion when the mats have finally degraded completely. Compost erosion control blankets act similarly to mulch products but provide organic nutrients that promote vegetation growth, even in areas where germination, moisture management and irrigation could be challenging.
Build Terraces
If you are planning on trying to control the erosion on very erosion control steep slopes or embankments, sometimes planting vegetation may just not cut it as the slope may be too steep to support anything other than the hardiest grass due to the speedy rate of erosion. If this is the case, you should consider building terraces to help slow down erosion as the vegetation takes hold. Terraces can be made out of anything, from wood to concrete blocks to bio-mechanical solutions like the Cascadia Green Wall that uses Filter Soxx with natural mulch/seed filling and geogrid for structural stability. The beds that are created by the terraces can then be used to plant vegetation such as ornamental plants or grass.When most people think of terraces as a method of erosion control, some may think of the Incas in Peru. There the natives implemented the early methods of erosion control on the Andes Mountains for many centuries. Terrace walls help to hold soil in place while providing a convenient surface to plant a variety of plants. Building terraces can be as simple as using a couple of wooden blocks to create a terrace wall, or it could be more sophisticated and involve the use of engineered stones, concrete retaining wall blocks or a living green wall solution
Create Diversions to Help Drainage
Depending on the incline of the slope or embankment, one of the most effective ways to help prevent erosion is to create diversions which will channel excess water down the slope along a predetermined path. One of the simplest ways to do this is to create open ditches or drains by simply digging along the slope at regular intervals. Use of pipes and gutters is also very effective, and work just as well as natural drains when designed and installed properly.
