Stormwater Awareness Week 2024: Stormwater System Management Practices
Stormwater Awareness Week 2024
Stormwater Awareness Week 2024 is celebrated September 23-27. Stormwater management plays a crucial role in our communities, and effective stormwater management protects our waterways and enhances public health and safety. Civil engineers play a crucial role in the design process, ensuring stormwater management is effective and complies within city codes and regulations.
Why Does Stormwater Management Matter?
Protects water quality: Stormwater that isn't managed correctly can carry harmful pollutants into rivers, lakes, and oceans which can negatively affect aquatic life and drinking water resources.
Prevents flooding: Effective stormwater management reduces the risk of flooding by controlling the volume and flow of stormwater runoff.
Enhances our communities: Well-designed stormwater systems contribute to the overall longevity of our communities so they can withstand extreme weather events or climate change impacts.
Common Stormwater Systems
Detention Vault: A detention vault is a storage facility constructed with reinforced concrete. It’s used to manage stormwater quantity flowing to nearby surface waters and helps prevent flooding and erosion in rivers and streams.
- Generally used for sites that lack adequate greenspace for above-ground storage
- Is a water-tight system, therefore it’s used on sites with high groundwater
- Is typically is used when infiltration is infeasible
Detention Pond: A pond used to temporarily hold the stormwater runoff and release it slowly over time. The primary goal is to control the peak flow rates of stormwater, reducing the risk of downstream flooding and erosion.
- Typically used on large residential and industrial projects
- Often not feasible for small commercial projects
- Cannot be used on sites with high groundwater
- Has a high maintenance cost due to landscaping and vegetative growth
Retention Pond: A stormwater management facility designed to hold a permanent pool of water. It captures and stores stormwater runoff, allowing sediments and pollutants to settle before the water is slowly released or infiltrated.
- Often landscaped with vegetation to enhance aesthetics and provide habitat
- Requires a large area for construction
- Provides water quality treatment by allowing sediments and pollutants to settle
Detention Chamber: An underground structure designed to temporarily store stormwater runoff, reducing peak flow rates and controlling flooding. It allows water to slowly drain or infiltrate into the ground, minimizing the risk of downstream flooding and erosion.
- Sized based on the volume of stormwater runoff expected from the drainage area
- Can be designed to handle various storm events, from frequent small storms to rare large storms
- Must be designed to handle the load from the surrounding soil and any surface traffic
Retention Chamber: An artificial structure that is designed to temporarily hold stormwater runoff. These chambers collect water from storm drains and release it at a controlled rate into nearby water bodies once peak inflow volumes subside.
- This system cannot be combined with stormwater treatment
- The system is not water-tight and cannot be used on sites with high groundwater
- Combines chambers and gravel volume to customize the depth of the section
Proprietary Treatment Solutions: Devices that use various processes to remove pollutants from stormwater runoff before it is discharged to another BMP or the receiving water. There are many types of proprietary systems available in the market, each with different designs, technologies, and pollutant removal efficiencies.
- Allows stormwater to drain directly into the system
- The system can accommodate landscape or hardscape placement
- It can be placed before or after volume retention systems
Dry Well: An underground storage facility that temporarily stores stormwater runoff from roofs or other surfaces. The runoff drains into a gravel-filled pit or a plastic or concrete tank, and then slowly infiltrates into the surrounding soil.
- Typically, 30-70 feet deep and 3 feet wide at the surface
- Reduces stormwater runoff volume by allowing water to infiltrate into the soil
- Prevents stormwater from entering streams and lakes, reducing pollution and erosion
Infiltration Trench: A shallow, excavated trench filled with gravel or crushed stone that captures and infiltrates stormwater runoff. It allows water to percolate into the ground, reducing surface runoff and recharging groundwater.
- Requires pretreatment to remove contaminants from runoff
- Ideal for small drainage areas (less than 5 acres)
- Reduces peak discharge rates and total runoff volume
Stormwater System Management Practices
The chart below provides a comparison of various stormwater management practices. It highlights key factors to consider when deciding the best stormwater management system for development. These include type of treatment, construction costs, maintenance costs, routine maintenance, operations and maintenance complexity, and soil type. These systems are evaluated based on each site, and the stormwater management goals that are required for development. This visual guide will serve as a great resource to offer a basic understanding of what each stormwater system accomplishes in site development.
*Disclaimer: This chart should serve as a reference point to understand the general factors of consideration when implementing stormwater system design in development. The suitability of different stormwater management options are dependent on specific project needs, site features, and soil conditions.*
If you have any questions about stormwater design, please reach out through our Contact Us page.
