In previous blogs, we’ve discussed the differences between structural and non-structural Best Management Practices (BMPs). Another important distinction in stormwater compliance is temporary versus permanent BMPs. While both help manage stormwater runoff and protect water quality, they serve different purposes at different stages of a project.
What Are Temporary BMPs?
Temporary BMPs are designed to control erosion, sediment, and stormwater runoff during active construction activities. Since construction sites frequently have exposed soil and changing grades, temporary controls help reduce the amount of sediment and pollutants leaving the site before permanent stabilization is established.
These BMPs are installed early in the project and are adjusted, repaired, or relocated as site conditions change throughout construction.
Common Examples of Temporary BMPs
- Silt fence
- Inlet protection
- Straw or wood chip wattles
- Vehicle tracking controls
- Check dams
- Temporary seeding and mulch
- Concrete washout areas
- Sediment traps and basins
Temporary BMPs require regular inspections and maintenance to remain effective. Weather events, equipment traffic, and ongoing grading can all impact their performance over time.
Why Temporary BMPs Matter
During active construction, disturbed soil is highly vulnerable to erosion. Without temporary controls in place, sediment can easily leave the site and enter nearby storm drains, waterways, and neighboring properties.
Properly installed temporary BMPs help slow stormwater runoff, reduce erosion, and protect water quality. Maintaining the BMPs helps projects remain in compliance with stormwater permits and SWMP requirements
Routine inspections are critical because temporary BMPs often experience wear and tear throughout a project.
What Are Permanent BMPs?
Permanent BMPs are long-term stormwater management features that remain after construction is complete. Unlike temporary controls, permanent BMPs are designed to manage stormwater runoff for the life of the development.
These systems help control both the quantity and quality of stormwater leaving a site by slowing runoff, promoting infiltration, and capturing pollutants before water enters downstream drainage systems.
Common Examples of Permanent BMPs
- Detention ponds
- Retention ponds
- Water quality ponds
- Bioswales
- Underground detention systems
- Riprap outlets
- Permanent stabilization and vegetation
- Sand filters and hydrodynamic separators
Permanent BMPs are typically installed during later phases of construction as final site grades and drainage patterns are established.
Permanent BMP Maintenance and Inspections
Although permanent BMPs are designed for long-term use, they still require ongoing maintenance and inspections to function properly. Sediment buildup, erosion, damaged structures, clogged outlets, and vegetation issues can all reduce performance over time.
Many jurisdictions throughout Colorado require annual inspections and maintenance documentation for permanent stormwater facilities. Property owners, HOAs, commercial developments, and facility managers are often responsible for ensuring these systems remain functional and compliant.
How Temporary and Permanent BMPs Work Together
Stormwater compliance extends far beyond installing a few controls on a site. Both temporary and permanent BMPs play important roles in protecting water quality, reducing erosion, and helping projects remain compliant throughout construction and beyond.
Temporary BMPs protect the site during construction when soil disturbance is at its highest. Permanent BMPs then take over once the project is complete, helping manage stormwater runoff for years to come.
A successful stormwater compliance program depends on understanding when each type of BMP is needed, how they should function, and how they should be maintained throughout the life of a project. Understanding the differences between these BMPs can help project teams better plan for inspections, maintenance, and long-term stormwater management needs.
If your project needs support with stormwater inspections, SWMP compliance, or BMP evaluations, Summit Services Group can help.