A unified discharge capacity formula of clogged grate inlets

To investigate the influence of different clogging degrees of a street inlet on its discharge capacity, an experimental campaign with the clogging degree of inlet grate and connection tube varying from 0.0 to 0.75 were conducted in a double-layer flume platform with a horizontal bottom. A total of 608 experimental runs were conducted in a subcritical state, with the inflow discharge and surface water depth varying from 24 L/s to 45 L/s and from 0.022 m to 0.38 m, respectively. To facilitate the application of the unified formula under different clogging scenarios, a parameter termed the clogging decay coefficient was introduced. The relationship between clogging decay coefficient and clogging degree was proposed respectively for the clogging of grate and connection tube. The proposed unified formula has several advantages, including a simple structure, a better accuracy, and without the necessity to select different discharge coefficients.