Hydraulic behavior of multi-processed manufactured best management practices

Exfiltration apparatus (ExA) is a promising (low footprint) manufactured best management practice (MBMP) for treating urban stormwater runoff. A scaled-down acrylic prototype of the ExA was designed and built to evaluate its hydraulic behavior (prototype W, L, H = 0.15, 0.91, 0.84 in meters). Flow through setup and head losses along the layers were monitored under set incoming flows. Maximum filtration capacity in pristine condition was measured to be 2.37 to 2.55 dm3/s (37.5 – 40.5 gpm). Changing infiltration capacity and head loss overtime was observed for during test runs. When considering typical rainfall durations, the time taken to achieve steady flow and steady head losses cannot be ignored and warrants exploring unsteady porous flow theory for modelling. Pore Reynolds numbers above unity were observed and analysis of the eventual steady state data showed inertial, nonlinear porous flow behavior.