Catch basins are designed to convey surface runoff into sewer systems. They are also found to be effective in retaining sediments. A number of factors can influence catch basin sediment capture efficiency, such as sediment size distribution, flow hydraulics and catch basin design. To better understand the influence of these factors, numerical simulations using the Eulerian-Lagrangian method were conducted to provide insights into flow fields and to predict sediment capture rates. The numerical model was validated using previous experimental measurements of flow field and sediment capture rates for sediment sizes larger than 0.25 mm. The influence of catch basin designs, including the bottom sump and inflow arrangements, was also studied, and an equation was developed for predicting the capture rate.