Articles | Volume 19, issue 6
Hydrol. Earth Syst. Sci., 19, 2837–2857, 2015
Hydrol. Earth Syst. Sci., 19, 2837–2857, 2015

Research article 19 Jun 2015

Research article | 19 Jun 2015

A 2-D process-based model for suspended sediment dynamics: a first step towards ecological modeling

F. M. Achete1, M. van der Wegen1,2, D. Roelvink1,2,3, and B. Jaffe4 F. M. Achete et al.
  • 1UNESCO-IHE, Delft, the Netherlands
  • 2Deltares, Delft, the Netherlands
  • 3Delft University of Technology, Delft, the Netherlands
  • 4US Geological Survey Pacific Science Center, Santa Cruz, California, USA

Abstract. In estuaries suspended sediment concentration (SSC) is one of the most important contributors to turbidity, which influences habitat conditions and ecological functions of the system. Sediment dynamics differs depending on sediment supply and hydrodynamic forcing conditions that vary over space and over time. A robust sediment transport model is a first step in developing a chain of models enabling simulations of contaminants, phytoplankton and habitat conditions.

This works aims to determine turbidity levels in the complex-geometry delta of the San Francisco estuary using a process-based approach (Delft3D Flexible Mesh software). Our approach includes a detailed calibration against measured SSC levels, a sensitivity analysis on model parameters and the determination of a yearly sediment budget as well as an assessment of model results in terms of turbidity levels for a single year, water year (WY) 2011.

Model results show that our process-based approach is a valuable tool in assessing sediment dynamics and their related ecological parameters over a range of spatial and temporal scales. The model may act as the base model for a chain of ecological models assessing the impact of climate change and management scenarios. Here we present a modeling approach that, with limited data, produces reliable predictions and can be useful for estuaries without a large amount of processes data.

Short summary
Suspended sediment concentration (SSC) levels are important indicator for the ecology of estuaries. Observations of SSC are difficult to make, therefore we revert to coupled 2-D hydrodynamic-sediment process-based transport models to make predictions in time (seasonal and yearly) and space (meters to kilometers). This paper presents calibration/validation of SSC for the Sacramento-San Joaquin Delta and translates SSC to turbidity in order to couple with ecology models.