Dynamic Separation of Catchment Water Balance


Principal Investigator

Anthony Jakeman

Centre for Resource and Environmental Studies

This project aims to develop a conceptually simple approach to dynamically separate a catchment
water balance into its key hydrological components; soil moisture, streamflow and evaporation. The modification and utilization of the surface hydrology model IHACRES allows investigation of evaporative feedbacks to the atmosphere which is a key interaction for atmospheric models, as well as long term investigations into changes in the water balance due to land use changes or climatic changes.



Jason Evans

Li Zhang

Centre for Resource and Environmental Studies




s31 - PC


What are the results to date and the future of this work?

A parametrically efficient way of dynamically calculating the evaporative losses has been developed and tested on several catchments. The model has subsequently been used in a long term water balance study of the Peel River upstream of Chaffey Dam. In this study the changes in land use was of primary importance in particular the massive increase in the number of farm dams in the catchment and its long term effect on the streamflow. Further development of the evaporative loss module is being undertaken using data from intensive field experiments carried out in the US, as well as an extended study into the long term changes in the water balance due to the effects of land use change throughout the Namoi basin.

What computational techniques are used?

The hydrological model uses a transfer function or discrete difference equation at each grid cell. The evaporative module uses a system of simultaneous equations to dynamically process time series data.


J. P. Evans, A. J. Jakeman, Development of a simple, catchment-scale, rainfall-evapotranspiration-runoff model, Environmental Modeling and Software, (in press) (1997)

- Appendix A