Effect of Urban Debris on Hydraulic Efficiency of an Elliptical Sharp-Crested Weir

An elliptical sharp-crested weir design was developed for detention pond outlets to address discharge, pollution, and maintenance concerns. The weir was designed in an effort to efficiently pass debris through an outlet as well as having the ability to easily remove any debris attached to the weir plate. Interactions between various types of debris materials were investigated using a 1:2 Froude-scale physical model. Stage discharge data were collected to quantify reduced hydraulic efficiencies with the presence of debris in the weir plate. Nine debris tests were conducted using plastic bags, newspapers, and turf reinforcement mat material. Reductions in hydraulic efficiencies were quantified from the resulting data. Plastic bags and newspapers produced the greatest reduction in hydraulic capacity, whereas turf reinforcement mat material generated the smallest reduction. Observations regarding the ability of debris material to pass through the weir at increased flows were also made using the physical model.