Impacts of Climate Alteration on the Hydrology of the Yarra River Catchment, Australia Using GCMs and SWAT Model

Sushil K Das,Muhammad Atiq Ur Rehman Tariq,Amimul Ahsan,Nitin Muttil,Anne W M Ng,Md Habibur Rahman Bejoy Khan

doi:10.3390/w14030445

Abstract

A rigorous evaluation of future hydro-climatic changes is necessary for developing climate adaptation strategies for a catchment. The integration of future climate projections from general circulation models (GCMs) in the simulations of a hydrologic model, such as the Soil and Water Assessment Tool (SWAT), is widely considered as one of the most dependable approaches to assess the impacts of climate alteration on hydrology. The main objective of this study was to assess the potential impacts of climate alteration on the hydrology of the Yarra River catchment in Victoria, Australia, using the SWAT model. The climate projections from five GCMs under two Representative Concentration Pathway (RCP) scenarios—RCP 4.5 and 8.5 for 2030 and 2050, respectively—were incorporated into the calibrated SWAT model for the analysis of future hydrologic behaviour against a baseline period of 1990–2008. The SWAT model performed well in its simulation of total streamflow, baseflow, and runoff, with Nash–Sutcliffe efficiency values of more than 0.75 for monthly calibration and validation. Based on the projections from the GCMs, the future rainfall and temperature are expected to decrease and increase, respectively, with the highest changes projected by the GFDL-ESM2M model under the RCP 8.5 scenario in 2050. These changes correspond to significant increases in annual evapotranspiration (8% to 46%) and decreases in other annual water cycle components, especially surface runoff (79% to 93%). Overall, the future climate projections indicate that the study area will become hotter, with less winter–spring (June to November) rainfall and with more water shortages within the catchment.

Highlights

The manual tuning of the Soil and Water Assessment Tool (SWAT) model’s runoff and baseflow-related parameters was performed for runoff and baseflow calibration
As a result, assessing future water resources in the context of climate alterations is critical for developing improved water management techniques and climate adaptation strategies for catchments
Future climate alterations in the agricultural middle Yarra division (MYD) of the Yarra River catchment was evaluated using five CMIP5 general circulation models (GCMs) under the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios for 2030 and 2050. These climatic scenarios were incorporated into a calibrated SWAT model, and the alteration of future water cycle elements were described against the baseline circumstances (1990–2008)

Summary

Introduction

The alteration of climate has occurred since industrialization due to greenhouse gas pollution and rapid advancements in technology [1]. According to the recent Intergovernmental Panel on Climate Change (IPCC) report, the global average surface temperature rose by 0.85 ◦ C between 1880 and 2012 [2]. Since 1910, the average temperature of Australia has increased by 1.4 ◦ C, resulting in extreme heat events and a decline in rainfall in the southern and eastern regions of the continent [3]. Climate alteration likely impacts catchment hydrology due to changes in rainfall, temperature, and atmospheric CO2 levels

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Conclusion