One of the research goals for the Infiltration Trench was to see how site performance changed over time. Using the instrumentation installed at the Infiltration Trench, performance of the site was monitored during rain events. The following example shows how the performance of the Infiltration Trench changed over the course of a year by comparing two storms, one year apart.
When comparing the storms a year later, major differences in trench performance can be seen. Most notably, the overall performance and infiltration rates within the trench changed drastically over the course of one year (2004-2005). In Figure 1 (2004), all of the water within the infiltration trench percolates into the ground within 4 hours for the 0.43 inch rainfall event. In comparison, Figure 2 shows that for the 2005 storm event, it takes approximately 50 hours for the 2.2 inch rainfall event to percolate into the ground.