Particle-laden flows occur in many ways in natural and technological situations. Jain et al. [4] presented four DNS studies of sediment transport with varying particle shapes. However, in industrial applications, the RANS equations are commonly used for simulations of turbulent flows. Chauchat et al. [2] developed a closure model in their two-phase CFD solver for sediment transport applications, SedFoam-2.0. The mean flow quantities are represented well. However, SedFoam-2.0 relies on modelling assumptions for the fluid-particle interactions which are often not satisfied, in particular for the cases simulated with DNS considered. Among others, sediment does not always act as purely dissipative, but can also enhance turbulence by its roughness. The aim of the present work, therefore, is to improve the turbulence modelling in RANS simulations utilising the DNS data.