Numerical simulation of baseflow modification due to effects of sediment yield

Abstract

Alluvial rivers re-shape their own geometry by depositing sediments or eroding the channel when their dynamic equilibrium is disturbed. Such adjustments may induce river-bed and water-level profiles that have significant effects on the interaction of streams and aquifers that are connected hydraulically. Physically-based mathematical modelling affords the opportunity to look at this kind of interaction, which should be simulated by deterministic responses of both water and fluvial processes. In addition to simulating the streamflow and groundwater dynamics, the model should also be capable of tracking down the level of the coupling interface boundary.



A procedure for modelling alluvial stream-aquifer interaction - MASAI - has been developed to enable the coupling of unstable alluvial stream-aquifer interacting systems. Application of MASAI to hypothetical alluvial stream-aquifer systems reveals the complex relationships between individual elements of the systems, and highlights the influence of sediment yield on baseflow.


WaterSA Vol.27(2) 2001: 205-212