by Jane Pangilinan, Digital Engagement Technician

Erosion is a major problem for shorelines, agriculture, and freshwater areas. Erosion is a natural process that removes soil and also reduces specific aspects of the soil like its ability to retain water (Duran Zuazo & Rodriguez Pleguezuelo, 2008). Erosion affects the soil’s ability to grow food and can cause eroded land cover that can lead to severe land loss. Human impacts are known to accelerate erosion (Aziz & Islam, 2023) and erosion has increased in intensity and occurrence in recent decades (Maximiliano-Cordova et al., 2019). Erosion can come from a variety of sources, such as wind and water, so it is important to look at different types of erosion control.

Why is erosion a major issue for soil? Soil is more than just dirt. Soil is composed of many parts and functions and is better understood with science and expertise. When erosion happens, soil becomes unable to function as best as it can because erosion takes away soil biota and organic matter. Without these aspects, soil loses its ability to grow plants let alone food. This makes erosion control incredibly important in conserving our soil and shorelands.

When exploring the different methods of erosion control, there is now more intensive research on the prospect of using plants to reduce the impacts of erosion. Current research shows that plants are a great way to reduce erosion, while also provide resiliency against climate change, and valuable wildlife habitat. Plant roots reinforce soil (Chok et al., 2015), increasing soil cohesion and creating a closely spaced root system for the soil to stay in (Chok et al., 2015).

When selecting plants for erosion control, it is important to think about whether they are native to the environment, and will thrive in the area where they are planted. Important factors to consider are soil type, moisture level, sunlight availability, and height (to protect any desired views). Native plants are better because they have healthy linkages to the wildlife and other plants around them. Invasive plants lack predation and can over- and out-compete with the other plants for space, food, and sunlight. Some native plants species that are well suited for erosion control because of the complex and deep root systems include Sweet Gale, Fragrant Sumac, and Silver Maple. You can find suitable native species for your region by using the free, Canada-wide Native Plant Database from Watersheds Canada’s Natural Edge Program.

Another method of erosion control is using hard structures. These structures can look like retaining walls or groins (Ciarmiello & Di Natale, 2016). However, human-made structures are not perfect. Using hard structures can actually create erosion in adjacent locations and negatively impact the littoral zone (Maximiliano-Cordova et al., 2019), and impedes the land-water interface for aquatic and terrestrial wildlife to use. In all cases of erosion control, here are some best practices (from the 2010 Shoreline Stabilization Techniques guide):

1. Imitate nature: Nature knows best. Native vegetation helps keep the shoreline intact by holding it together with its roots and foliage. Try to imitate nature wherever possible.

2. Keep slopes gentle: Steeper slopes mean more erosion impacts. Steeper slopes are more susceptible to erosion from waves and water currents, whereas gentle slopes break waves and can lead in less soil loss.

3. Mix it up: The more diverse it is, the better. Diversity through different plant types adds to biodiversity in the ecosystem. With variety, there is better resilience to impacts like plant disease and herbivory.

4. Plant as much as possible: Native species are adaptable to changing environmental conditions (ex: floods or droughts) and can grow and multiply to provide even more security for erosion control. 

This blog is part of a five-part series generously funded under the Great Lakes Protection Initiative – Areas of Concern (AOC) Program by Environment and Climate Change Canada. This three-year project will support important shoreline restoration in the St. Lawrence River AOC through the Natural Edge Program, and is being delivered by Watersheds Canada, Mohawk Council of Akwesasne, River Institute, Great River Network, and Raisin Region Conservation Authority. There are many trained community organizations across Canada who deliver The Natural Edge; find the closest one to you here.

References

Aziz, S., & Islam, M. S. (2023). Erosion and runoff reduction potential of vetiver grass for hill slopes: A physical model study. International Journal of Sediment Research, 38(1), 49-65. doi:https://doi-org.proxy.lib.uwaterloo.ca/10.1016/j.ijsrc.2022.08.005

Chok, Y.H., Jaksa, M.B., Kaggwa, W.S. et al. Assessing the influence of root reinforcement on slope stability by finite elements. Geo-Engineering 6, 12 (2015). https://doi.org/10.1186/s40703-015-0012-5

Ciarmiello, M., Di Natale, M. (2016). Coastal Erosion Control. In: Kennish, M.J. (eds) Encyclopedia of Estuaries. Encyclopedia of Earth Sciences Series. Springer, Dordrecht. https://doi.org/10.1007/978-94-017-8801-4_386

Durán Zuazo, V.H., Rodríguez Pleguezuelo, C.R. Soil-erosion and runoff prevention by plant covers. A review. Agron. Sustain. Dev. 28, 65–86 (2008). https://doi-org.proxy.lib.uwaterloo.ca/10.1051/agro:2007062

Maximiliano-Cordova, C., Salgado, K., Martínez, M.L. et al. Does the Functional Richness of Plants Reduce Wave Erosion on Embryo Coastal Dunes?. Estuaries and Coasts 42, 1730–1741 (2019). https://doi-org.proxy.lib.uwaterloo.ca/10.1007/s12237-019-00537-x

Shoreline Stabilization Techniques. (2010). Department of Environmental Conservation. New York State. https://www.dec.ny.gov/docs/permits_ej_operations_pdf/stabiltechguid.pdf