Urbanization typically results in increased imperviousness which alters suspended sediment yield and impacts geomorphic and ecological processes within urban streams. Therefore, there is an increasing interest in the ability to predict suspended sediment yield. This study assesses the combined impact of urban development and increased precipitation on suspended sediment yield in the Cuyahoga River using statistical modeling. Historical satellite-based land-cover data was combined with precipitation and suspended sediment yield data to create a Multiple Linear Regression (MLR) model for the Cuyahoga watershed. An R² value of 0.71 was obtained for the comparison between the observed and predicted results based on limited land-use and land-cover data. The model also shows that every 1 mm increase in the mean annual precipitation has the potential to increase the mean annual suspended sediment yield by 860 tons/day. Further, a 1 km² increase in developed land area has the potential to increase mean annual suspended sediment yield by 0.9 tons/day. The framework proposed in this study provides decision makers with a measure for assessing the potential impacts of future development and climate alteration on water quality in the watershed and implications for stream stability, dam and flood management, and in-stream and near-stream infrastructure life.

The current equations for curb inlet opening sizing often inaccurately estimate the capture efficiency of small urban green stormwater infrastructure (GSI) curb inlets. Most of these equations are based on studies with openings much larger than typical urban GSI curb inlets (i.e., less than 0.6 m). This study introduces a new, three-dimensional (3D) numerical approach for evaluating curb efficiency using the ANSYS Fluent computational fluid dynamics (CFD) model that can be applied to a wide range of curb inlet conditions. Simulated curb efficiency results for typical urban curb inlet openings are verified by laboratory experiments of field-scale conditions. A high prediction accuracy is obtained (Nash-Sutcliffe efficiency $\mathrm{coefficient}=0.97$ ) between the observed and the CFD model results. The CFD model also performs better than three commonly used methods for estimating curb inlet efficiency; the Hydraulic Engineering Circular No. 22, and the 2009 and 2012 Comport and Thornton equations. The high level of accuracy observed in this study makes 3D CFD modeling a more effective alternative to existing equations for evaluating GSI curb inlet efficiency. The quick simulation times realized in this study also demonstrate that CFD modeling of GSI inlets has an added benefit of quickly evaluating several design alternatives without a need for costly full-scale or on-site testing often performed to assess such inlets.

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%.

Green stormwater infrastructure (GSI) mitigates runoff in urbanized environments. In bioinfiltration GSI, stormwater is infiltrated through the s |