An Ensemble of Methods for Determining the Efficiency of Curb Inlets for Green Stormwater Infrastructure

Abstract

This paper presents an ensemble of methods for determining the variations in the efficiency of a common small curb inlet that directs runoff to green stormwater infrastructure due to changes in longitudinal and crossroad slopes and runoff rate. A physical model of a curb inlet with a lateral curb inlet opening size of 0.46 m was built and its efficiencies were measured. Two computational models, HEC-RAS 6.3 and Ansys Fluent 18.1, were developed and compared with measured data. The measurements showed that an increase in longitudinal slope and runoff rate reduced the curb inlet efficiency, whereas an increase in crossroad slope increased the efficiency. Both computational models captured the variations and trends in curb inlet efficiencies. The HEC-RAS error varied from −21% to 12% with a mean absolute error of 8.8%, whereas for the Ansys Fluent, the error varied from −37% to 7% with a mean absolute error of 32%.