Discretization approach for large-scale sediment modeling: calibration strategies based on hydro-sediment variability at a range of spatial scales

Abstract

ABSTRACT The lack of observed data and calibration strategies, scale variability, and difficulties in representing heterogeneity of sediment-processes contribute to the usual challenges in achieving satisfactory results in hydro-sedimentological modeling, particularly when using the MUSLE equation for large-scale applications. As a consequence, we investigated five major topics: (1) a sediment-process-based parameterization technique (Hydro-sedimentological Response Unit map - HRUSed); (2) the quality of hydrological modeling with different process-focused parameterizations; (3) a calibration strategy based on the sediment discretization approach for hydro-sedimentological modeling; (4) the use of suspended sediment concentration (SSC) versus suspended sediment discharge (SSD) data for calibration; and (5) trade-offs between increasing the spatial resolution of a large-scale model and using the proposed HRUSed discretization. The current study demonstrated (1) the HRUSed map for South America and (2) a similar performance of large-scale hydrological modeling using a hydrological or hydro-sedimentological discretization approach. (3) The HRUSed discretization approach produced better hydro-sedimentological modeling results. (4) We improved the model’s performance for HRUSed (SSC and SSD results) and for HRU (Hydrological Response Unit map) only for SSD results. (5) Only more detailed spatial discretization has failed to improve process representation. However, increased spatial discretization with a process-parameterization approach focused on hydro-sedimentological dynamics improved model performance.