Coupling Remote Sensing and Hydrological Model for Evaluating the Impacts of Climate Change on Streamflow in Data-Scarce Environment

Fazlullah Akhtar,Usman Khalid Awan,Christian Borgemeister,Bernhard Tischbein

doi:10.3390/su132414025

Abstract

The Kabul River Basin (KRB) in Afghanistan is densely inhabited and heterogenic. The basin’s water resources are limited, and climate change is anticipated to worsen this problem. Unfortunately, there is a scarcity of data to measure the impacts of climate change on the KRB’s current water resources. The objective of the current study is to introduce a methodology that couples remote sensing and the Soil and Water Assessment Tool (SWAT) for simulating the impact of climate change on the existing water resources of the KRB. Most of the biophysical parameters required for the SWAT model were derived from remote sensing-based algorithms. The SUFI-2 technique was used for calibrating and validating the SWAT model with streamflow data. The stream-gauge stations for monitoring the streamflow are not only sparse, but the streamflow data are also scarce and limited. Therefore, we selected only the stations that are properly being monitored. During the calibration period, the coefficient of determination (R2) and Nash–Sutcliffe Efficiency (NSE) were 0.75–0.86 and 0.62–0.81, respectively. During the validation period (2011–2013), the NSE and R2 values were 0.52–0.73 and 0.65–0.86, respectively. The validated SWAT model was then used to evaluate the potential impacts of climate change on streamflow. Regional Climate Model (RegCM4-4) was used to extract the data for the climate change scenarios (RCP 4.5 and 8.5) from the CORDEX domain. The results show that streamflow in most tributaries of the KRB would decrease by a maximum of 5% and 8.5% under the RCP 4.5 and 8.5 scenarios, respectively. However, streamflow for the Nawabad tributary would increase by 2.4% and 3.3% under the RCP 4.5 and 8.5 scenarios, respectively. To mitigate the impact of climate change on reduced/increased surface water availability, the SWAT model, when combined with remote sensing data, can be an effective tool to support the sustainable management and strategic planning of water resources. Furthermore, the methodological approach used in this study can be applied in any of the data-scarce regions around the world.

Highlights

Climate change is a global concern given its impacts on human and animal lives, water resources, and their inter-relationship [1]
The impacts of climate change on streamflow under RCPs 4.5 and 8.5 simulated in this study provide additional information to relevant agencies and policymakers to critically construct coping strategies and sustainably reduce the future negative impacts of climate change on water resources in a basin known for its data scarcity, given its inefficient hydraulic infrastructure and the deficient scientific studies on water resources and climate change
The calibration outcomes of the Soil and Water Assessment Tool (SWAT) simulations indicate that the Nash–Sutcliffe Efficiency (NSE) for Nawabad and Pul-e-Qarghayi streamflow gauging stations during the calibration period (2008–2010)

Summary

Introduction

Climate change is a global concern given its impacts on human and animal lives, water resources, and their inter-relationship [1]. Current research shows that climate change will reduce terrestrial water storage in several regions, in the Global South [2]. Another study [4] in the Nile Delta shows an increase and decrease in the mean annual temperature and precipitation, respectively. It shows that by the end of the century, the Upper Nile might experience around a 27% increase in the potential evapotranspiration, and surface runoff is expected to increase by 14%.

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Conclusion