A catchment framework for one‐dimensional models: introducing FLUSH and its application

Abstract

AbstractA new modelling framework capable of incorporating detailed one‐dimensional models in a catchment context is presented which can be used to asses the hydrological implications (recharge, discharge, salt movement) of different land uses on different parts of the catchment. The modelling framework incorporates farming systems models and, thus, simulates crop and pasture production, whilst also accounting for lateral fluxes of water (surface and subsurface) and groundwater recharge and discharge.The framework was applied to Simmons Creek catchment, a subcatchment of the Billabong Creek in southern New South Wales, comprising gentle uplands and substantial low‐relief areas containing swamps. An integrated approach incorporating soil, hydrology, hydrogeology, and terrain analysis resulted in interpretation of landscape function and the necessary parameterization of the modelling framework. Current land use (crop rotation and pasture) and an alternative land use (10% trees on uphill units and pasture in the lower lying lands) were simulated to compare the relative contribution of parts of the catchment with total recharge. Comparison between current and alternative land use over 44 years of simulations indicated a decrease of mean annual drainage from 39 to 29 mm year−1 and an average reduction of the groundwater level of about 0·4 m. A more substantial decrease in water‐table depth would require targeted tree planting over larger areas. This can be investigated further with the spatial framework. Copyright © 2007 John Wiley & Sons, Ltd.