An Extremely Undersized Infiltration Trench 10 Years Later

Infiltration trenches are a stormwater control measure (SCM) used in urban and ultra-urban areas to provide stormwater runoff volume reduction. Legacy infiltration trenches are difficult if not impossible to maintain and were often built without pretreatment. As runoff with high suspended solid loads enters an infiltration trench, continual buildup of solids clog the infiltrating surface, decreasing the hydraulic conductivity at the soil interface and the performance and longevity of these systems. The present study builds on previous work at Villanova University on an extremely undersized infiltration trench (directly connected impervious drainage area to SCM area of 160:1) to artificially accelerate annual loading to evaluate long-term performance. Ten years and 1,270 cm of rain later, infiltration through the bottom of the trench has nearly ceased and the sides have slowed as well. Recession rates have reached an equilibrium point where they no longer improve or decrease.