Presenter/Author Information

E. Wang
L. Zhang
H. Cresswell
K. Hickel

Keywords

catchment water balance, empirical modelling, biophysically-based modelling, land use

Start Date

1-7-2006 12:00 AM

Description

This paper presents a simulation study to compare a top-down and bottom-up approach for water balance modelling as affected by rainfall seasonality, vegetation types and spatially variable land use patterns. It shows that point-based water balance calculations from the two approaches are broadly comparable. When applied at catchment scale water balance predictions were consistent in some years but different in particular years that warrant further investigation. The bottom-up model integrates the impact of different vegetation types, soil types, and management practices, whereas the top-down approach has the advantage of simplicity and associated decrease in error propagation. There is sufficient consistency in the prediction to suggest value in using a detailed bottom-up model to generate data needed for development and parameterisation of top-down catchment water balance models. The bridging of these two approaches may provide a way forward to increase model simplicity without losing the explanatory capacity necessary to analyse the impact of local management changes on catchment water balance.

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Jul 1st, 12:00 AM

Comparison of Top-Down and Bottom-Up Models for Simulation of Water Balance as affected by Seasonality, Vegetation Type and Spatial Land Use

This paper presents a simulation study to compare a top-down and bottom-up approach for water balance modelling as affected by rainfall seasonality, vegetation types and spatially variable land use patterns. It shows that point-based water balance calculations from the two approaches are broadly comparable. When applied at catchment scale water balance predictions were consistent in some years but different in particular years that warrant further investigation. The bottom-up model integrates the impact of different vegetation types, soil types, and management practices, whereas the top-down approach has the advantage of simplicity and associated decrease in error propagation. There is sufficient consistency in the prediction to suggest value in using a detailed bottom-up model to generate data needed for development and parameterisation of top-down catchment water balance models. The bridging of these two approaches may provide a way forward to increase model simplicity without losing the explanatory capacity necessary to analyse the impact of local management changes on catchment water balance.