An infiltration trench is a gravel-filled excavated trench designed to collect stormwater runoff and allow it to gradually infiltrate into the surrounding soil, functioning similarly to a dry well but typically covering a longer, linear area rather than a single concentrated point.
This technique is often used for managing runoff from larger paved areas, like driveways or parking areas, where a linear trench along the edge of the impervious surface can capture and disperse runoff more effectively across a broader footprint than a single point-source dry well.
Because infiltration trenches, like dry wells, depend on adequate soil percolation for effective function, site evaluation for soil drainage characteristics matters before committing to this approach for stormwater management.
What Does an Infiltration Trench Involve?
- A gravel-filled linear excavated trench
- Collection of runoff along its length
- Gradual infiltration into surrounding soil
- Common application for larger paved area drainage
Why Are Infiltration Trenches Important?
By providing a linear, broader footprint for stormwater collection and infiltration, this technique offers effective drainage management for larger impervious surfaces, addressing runoff volumes that a single point-source dry well might not handle as effectively given its more limited collection footprint. This scalability has made infiltration trenches a common solution for managing driveway and parking area runoff on larger properties.
As with any infiltration-based drainage technique, verifying adequate soil percolation before installation helps ensure the trench will genuinely function as intended rather than becoming a source of standing water if the surrounding soil can’t absorb collected runoff at an adequate rate. This upfront evaluation helps ensure the chosen drainage solution genuinely fits the site’s conditions.
Infiltration Trench vs. Dry Well
An infiltration trench covers a longer, linear area suited to larger runoff volumes. A dry well is a more concentrated, point-source structure, typically serving a single downspout or smaller drainage need.