Research papersA fully coupled depth-integrated model for surface water and groundwater flows

- Fully coupled numerical model for surface water and groundwater flows are set up.
- Surface water and groundwater flows can be simulated simultaneously with the same scheme.
- The model is suitable for groundwater flow in both fine and coarse porous media.
- The model has been verified using experimental data and empirical formulae.

This paper presents the development of a fully coupled surface water and groundwater flow model. The governing equations of the model are derived based on a control volume approach, with the velocity profiles of the two types of flows being both taken into consideration. The surface water and groundwater flows are both modelled based on the unified equations and the water exchange and interaction between the two types of flows can be taken into account. The model can be used to simulate the surface water and groundwater flows simultaneously with the same numerical scheme without other effort being needed to link them. The model is not only suitable for the porous medium consisting of fine sediments, but also for coarse sediments and crushed rocks by adding a quadratic friction term. Benchmark tests are conducted to validate the model. The model predictions agree well with the data.