Journal article

Towards more realistic runoff projections by removing limits on simulated soil moisture deficit

Keirnan JA Fowler, Gemma Coxon, Jim E Freer, Wouter JM Knoben, Murray C Peel, Thorsten Wagener, Andrew W Western, Ross A Woods, Lu Zhang

JOURNAL OF HYDROLOGY | ELSEVIER | Published : 2021

Abstract

Rainfall-runoff models based on conceptual “buckets” are frequently used in climate change impact studies to provide runoff projections. When these buckets approach empty, the simulated evapotranspiration approaches zero, which places an implicit limit on the soil moisture deficit that can accrue within the model. Such models may cease to properly track the moisture deficit accumulating in reality as dry conditions continue, leading to overestimation of subsequent runoff and possible long-term bias under drying climate. Here, we suggest that model realism may be improved through alternatives which remove the upper limit on simulated soil moisture deficit, such as “bottomless” buckets or defi..

View full abstract

Grants

Awarded by Government of Victoria


Awarded by UK's Natural Environment Research Council grant MaRIUS: Managing the Risks, Impacts and Uncertainties of droughts and water Scarcity


Awarded by Engineering and Physical Sciences Research Council


Funding Acknowledgements

This study was conducted with the support of the Australian Research Council and the Government of Victoria via Linkage Projects LP170100598 and LP180100796. Authors from the University of Bristol acknowledge the support of the UK's Natural Environment Research Council grant MaRIUS: Managing the Risks, Impacts and Uncertainties of droughts and water Scarcity (NE/L010399/1) and the Engineering and Physical Sciences Research Council grant EP/L016214/1 (WISE CDT). Streamflow, precipitation, and potential evapotranspiration data used in this study are publicly available as part of the CAMELS-AUS project (Fowler et al., 2021) at https://doi.pangaea.de/10.1594/PAN-GAEA.921850.Groundwater data were from www.vvg.org.au.The authors thankfully acknowledge the two anonymous reviewers whose feedback greatly improved the article.