Combatting Stormwater Erosion with Detention and Retention Tanks

Posted by Graham Wilson on May 16, 2024 3:24:50 PM
Graham Wilson
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Erosion occurs when winds or water interact with soil and rock, causing the affected earth to wear away. The most common example of erosion is at the beach, where tide patterns cause water to move up onto the shore and away from the shore, dragging the sand out to sea and changing the landscape. 

To remedy this, communities have built retaining walls that follow parallel to the shoreline to help stop surface and subsurface erosion. While the beach may be the most thought of place where erosion occurs, it also happens onshore. Torrential downpours can wreak havoc by causing flooding and extreme soil erosion. Like beach erosion, there are ways to mitigate this issue.  

Stormwater management systems are the most popular way to prevent erosion from torrential downpours and other water-related events. 


What are Detention & Retention Tanks?

Stormwater detention and retention are both components of stormwater management systems, but they serve different purposes. Traditional stormwater management techniques like ponds or wetlands take up a large area. Tanks have a smaller footprint, and many communities are able to utilize them in areas where ponds are not feasible. 

  • Detention Tanks: Detention tanks are designed to temporarily hold stormwater runoff and release it at a controlled rate to prevent flooding and erosion downstream. They are typically used in areas with limited space for traditional stormwater management techniques like ponds or wetlands. Detention tanks are often underground structures that collect excess stormwater during heavy rainfall events and slowly release it into the local drainage system or watercourse. 
  • Retention Tanks: Retention tanks are designed to capture and store stormwater runoff for later use or infiltration into the ground. Unlike detention tanks, which only temporarily hold stormwater, retention tanks retain the water for extended periods. Retention tanks can be used for purposes such as irrigation, groundwater recharge, or reusing stormwater for non-potable purposes like flushing toilets or watering landscaping.  

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Protecting Utilities with Stormwater Tanks

In urban areas, space is at a premium as land is developed for commercial and residential use. Due to this lack of space, a traditional retention pond isn't a feasible mitigation solution. A stormwater detention tank is utilized in cases where ponds are not suitable. 

These stormwater retention tanks serve the same function as a detention pond or basin but are built below grade, typically attached to a building. They prevent flooding caused by an overloaded sewer or stormwater runoff system by collecting the water and then allowing it to drain at a rate the surrounding systems and landscape can tolerate. 

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A stormwater detention tank may also be utilized in rural areas with hilly terrain, where building a basin or pond is impossible. Here, tanks are typically used at utility outposts such as electricity substations. These systems help prevent the quick erosion of the soil both on the surface and below ground to ensure the utility equipment will not shift, collapse, or slide away. 

Stormwater detention tanks are important and necessary for cities and towns worldwide. They protect water and sewer systems from overload, help mitigate the risk of flooding, and combat extreme sudden erosion. Proper protection is essential for these systems to perform optimally. 



Waterproofing Stormwater Tanks

Stormwater detention tanks can be made of many materials, but concrete is one of the most common types. Their longevity and efficiency depend significantly on their resistance to water, chemicals, and harsh weather conditions. These water containment structures are constantly exposed to various elements and pressure changes. The consistent presence of water, coupled with the chemical composition of stormwater, can degrade materials, threatening the tank's structural integrity. 

Waterproofing these systems is not just about preventing water ingress but also about safeguarding the concrete tank against potential damage. Thus, these critical infrastructures continue to serve communities effectively, mitigate flood risks, and promote sustainable water management. 

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In summary, stormwater detention tanks are primarily used to manage stormwater flow and prevent flooding, while retention tanks capture and store stormwater for later use or infiltration. Whether you are designing and protecting a tank within a stormwater management system or rehabilitating one already in use, the proper waterproofing selection is of the utmost importance for your system's longevity and proper function.   

Reach out to CIM Industries today to find out how our line of CIM products can provide you with a tough, durable waterproofing system designed to withstand the most rigorous demands stormwater can make! 

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Topics: Concrete Waterproofing, Water Tank

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