Changes

==Overview==

==Overview==

Erosion is the movement of earthen materials from one area to another due to forces such as wind, water, and ice. This process occurs slowly under natural conditions. However, erosion is often accelerated by anthropogenic activities, such as [[Erosion and Sediment Control|construction]], agriculture, and deforestation (AAFC, 2025)<ref>Agriculture and Agri-Food Canada. 2025. Soil erosion. https://agriculture.canada.ca/en/environment/resource-management/indicators/soil-erosion.</ref>. This accelerated rate of erosion can compromise the effectiveness of LID systems and impact watershed health.

Erosion is the movement of earthen materials from one area to another due to forces such as wind, water, and ice. This process occurs slowly under natural conditions. However, erosion is often accelerated by anthropogenic activities, such as [[Erosion and Sediment Control|construction]], agriculture, and deforestation (AAFC, 2025)<ref>Agriculture and Agri-Food Canada. 2025. Soil erosion. https://agriculture.canada.ca/en/environment/resource-management/indicators/soil-erosion.</ref>. This accelerated rate of erosion can compromise the effectiveness of LID systems and impact watershed health.

Managing the risk associated with erosion is one of the primary roles of Conservation Authorities under the Conservation Authorities Act (TRCA, 2025)<ref>Toronto and Region Conservation Authority. 2025. Erosion Risk Management. https://trca.ca/conservation/erosion-risk-management/</ref>. This Act allows Conservation Authorities to establish and undertake initiatives on private and public land to help achieve its objectives and can include :

Managing the risk associated with erosion is one of the primary roles of Conservation Authorities under the Conservation Authorities Act (TRCA, 2025b)<ref>Toronto and Region Conservation Authority. 2025. Erosion Risk Management. https://trca.ca/conservation/erosion-risk-management/</ref>. This Act allows Conservation Authorities to establish and undertake initiatives on private and public land to help achieve its objectives and can include :

*monitoring of areas affected by flooding, erosion, and or slope instability;

*monitoring of areas affected by flooding, erosion, and or slope instability;

*study and investigation of the watershed; and

*study and investigation of the watershed; and

*remediation of erosion and/or slope stability hazards

*remediation of erosion and/or slope stability hazards

One way conservation authorities manage the risk of erosion is by recommending the use of [[Erosion and Sediment Control|Erosion and Sediment Controls (ESC)]] during construction projects.

One way Conservation Authorities manage the risk of erosion is by recommending the use of [[Erosion and Sediment Control|Erosion and Sediment Controls (ESC)]] during construction projects. An ESC plan may be required for projects within a Regulated Area. For more information, contact [https://trca.ca/conservation/erosion-risk-management/ TRCA's Erosion Risk Management department].

 

==Impacts of erosion==

==Impacts of erosion==

[[Image:Screenshot 2025-07-30 102735.png|250px|thumb|right|Clay sediment accumulated on top of the mulch layer of a bioretention facility

[[Image:Screenshot 2025-07-30 102735.png|250px|thumb|right|Clay sediment accumulated on top of the mulch layer of a bioretention facility

resulting from improper erosion and sediment controls]]

resulting from improper erosion and sediment controls (MECP, 2021).<ref name = "MECP2021">Ministry of the Environment, Conservation and Parks. 2022. Low Impact Development Stormwater

Management Guidance Manual. Chapter 7. https://prod-environmental-registry.s3.amazonaws.com/2022-01/Draft%20LID%20Stormwater%20Management%20Guidance%20Manual%202022.pdf</ref>]]

{{textbox|Erosion releases sediment-laden runoff and airborne dust, which can have a range of environmental and infrastructure-related impacts. These include:  

{{textbox|Erosion releases sediment-laden runoff and airborne dust, which can have a range of environmental and infrastructure-related impacts. These include:  

*'''Impairing air quality''', especially through wind-blown dust (Tian et al., 2021)<ref>Tian, M., Gao, J., Zhang, L., Zhang, H., Feng, C., Jia, X. 2021. Effects of dust emissions from wind erosion of soil on ambient air quality. https://doi.org/10.1016/j.apr.2021.101108.</ref>.}}

*'''Impairing air quality''', especially through wind-blown dust (Tian et al., 2021)<ref>Tian, M., Gao, J., Zhang, L., Zhang, H., Feng, C., Jia, X. 2021. Effects of dust emissions from wind erosion of soil on ambient air quality. https://doi.org/10.1016/j.apr.2021.101108.</ref>.}}

==Types of erosion==

==Types of erosion==

*'''Gravitational erosion''': Mass movement of soil down slope due to gravity.}}

*'''Gravitational erosion''': Mass movement of soil down slope due to gravity.}}

Managing the different types of erosion requires a 2-step [[Erosion and Sediment Control|ESC]] approach during construction:

Managing the different types of erosion requires a 2-step [[Erosion and Sediment Control|ESC]] approach during construction (MECP, 2021)<ref name = "MECP2021">Ministry of the Environment, Conservation and Parks. 2022. Low Impact Development Stormwater

Management Guidance Manual. Chapter 7. https://prod-environmental-registry.s3.amazonaws.com/2022-01/Draft%20LID%20Stormwater%20Management%20Guidance%20Manual%202022.pdf</ref>:

# Eliminate or reduce erosion

# Eliminate or reduce erosion

# Control sediment releases

# Control sediment releases

===Erosion potential===

===Erosion potential===

[[Image:Bluestemcombined.png|500px|thumb|right|Big Bluestem (left) and Little Bluestem (right) are native ground cover ideal for erosion control and have [[Graminoids: List|demonstrated good performance]] in projects designed, installed and monitored by STEP.<ref>https://www.ontarioinvasiveplants.ca/wp-content/uploads/2020/04/Southern-Grow-Me-Instead-1.pdf</ref>]]

[[File:Screenshot 2025-07-30 115525.png|400px|thumb|right|Established groundcover helps to decrease erosion potential (TRCA, 2020)<ref name = "TRCA2020"></ref>.]]

The potential for soil erosion is influenced by several factors, including:

{{textbox|The potential for soil erosion is influenced by several factors, including (STEP, 2019)<ref name = "STEPESC">STEP. 2019. The Erosion and Sediment Control Guide for Urban Construction. https://sustainabletechnologies.ca/app/uploads/2020/01/ESC-Guide-for-Urban-Construction_FINAL.pdf</ref>:

*'''[[Understanding rainfall statistics|Rainfall]] characteristics''': Droplet size, intensity, frequency, duration

*'''[[Understanding rainfall statistics|Rainfall]] characteristics''': Droplet size, intensity, frequency, duration

*'''Topography''': Slope length and steepness

*'''Topography''': Slope length and steepness

*'''[[Soil groups|Soil type]]''': Soil texture, structure, permeability, organic matter content

*'''[[Soil groups|Soil type]]''': Soil texture, structure, permeability, organic matter content

*'''Ground cover''': Type and quality/areal density of cover

*'''Ground cover''': Type and quality/areal density of cover}}

{| class="wikitable" style="border-collapse:collapse;width: 650px;"

{| class="wikitable" style="border-collapse:collapse;width: 590px;"

|+ Erosion potential of soil types and ground covers<ref name ="STEPESC"></ref>

|+ Erosion potential of soil types and ground covers<ref name ="STEPESC"></ref>

! style="border:1px solid black;" | Soil Type

! style="border:1px solid black;" | Soil Type

Sandy clay<br>

Sandy clay<br>

Silty clay<br>

Silty clay<br>

Sandy clay Loam<br>

Sandy clay loam<br>

Silty clay Loam<br>

Silty clay loam<br>

Sandy loam<br>

Sandy loam<br>

Silty sand<br>

Silty sand<br>

Least<br>[[Image:Arrow.png|40px]]<br>Most

Least<br>[[Image:Arrow.png|40px]]<br>Most

|}

|}

==Erosion and LID==

==Erosion and LID==

[[File:Stepped cells.png|550px|thumb|Stepped [[Swales|bioswales]] that incorporate strategic rock and vegetation placement can help decrease the volume and speed of runoff, providing erosion control.]]

[[File:Stepped cells.png|500px|thumb|Stepped [[Swales|bioswales]] that incorporate strategic rock and vegetation placement can help decrease the volume and speed of runoff, providing erosion control.]]

[[Image:Bluestemcombined.png|500px|thumb|right|Big Bluestem (left) and Little Bluestem (right) are native ground cover ideal for stabilizing soils and have [[Graminoids: List|demonstrated good performance]] in projects designed, installed and monitored by STEP (Grow Me Instead, 2020).<ref>Grow Me In stead. 2020. A Guide for Southern Ontario: Beautiful Non-Invasive Plants for your Garden. https://www.ontarioinvasiveplants.ca/wp-content/uploads/2020/04/Southern-Grow-Me-Instead-1.pdf</ref>]]

{{textbox|LID can help to minimize conditions that lead to erosion by:  

{{textbox|LID can help to minimize conditions that lead to erosion by:  

*'''Reducing runoff speed''': LID features like [[Swales| vegetated swales]] help slow the speed of water by increasing [[Flow in a swale|surface roughness]]. This reduces the velocity of runoff that would otherwise erode soil surfaces.  

*'''Reducing runoff speed''': LID features like [[Swales| vegetated swales]] help slow the speed of water by increasing [[Flow in a swale|surface roughness]]. This reduces the velocity of runoff that would otherwise erode soil surfaces.  

*'''Stabilizing soils''': [[Plant lists|Vegetated]] components (e.g., [[Vegetated filter strips|filter strips]]) anchor the soil with plant roots, protecting surfaces from erosion.  

*'''Stabilizing soils''': [[Plant lists|Vegetated]] components (e.g., [[Vegetated filter strips|filter strips]]) anchor the soil with plant roots, protecting surfaces from erosion.  

*'''Applying [[Erosion and Sediment Control]] during construction''': Slowing runoff, trapping sediment, and protecting exposed soils reduces the amount of sediment released during construction. It is especially important to apply erosion and sediment controls during LID construction, since sediment build-up in infiltration-based LID BMPs can result in malfunction or failure (MECP, 2021)<ref>Ministry of the Environment, Conservation and Parks. 2022. Low Impact Development Stormwater

*'''Applying [[Erosion and Sediment Control]] during construction''': Slowing runoff, trapping sediment, and protecting exposed soils reduces the amount of sediment released during construction. It is especially important to apply erosion and sediment controls during LID construction, since sediment build-up in infiltration-based LID BMPs can result in malfunction or failure (MECP, 2021)<ref name = "MECP2021">Ministry of the Environment, Conservation and Parks. 2022. Low Impact Development Stormwater

Management Guidance Manual. Chapter 7. https://prod-environmental-registry.s3.amazonaws.com/2022-01/Draft%20LID%20Stormwater%20Management%20Guidance%20Manual%202022.pdf</ref>.

Management Guidance Manual. Chapter 7. https://prod-environmental-registry.s3.amazonaws.com/2022-01/Draft%20LID%20Stormwater%20Management%20Guidance%20Manual%202022.pdf</ref>.

*'''Controlling flow paths''': Controlling the path of water helps to prevent the formation of concentrated flow paths that can intensify erosion, such as rills or gullies.}} <br>

*'''Controlling flow paths''': Controlling the path of water helps to prevent the formation of concentrated flow paths that can intensify erosion, such as rills or gullies.}} <br>