Potential Impacts of Climate Change on Water Resources in the Kunhar River Basin, Pakistan

Rashid Mahmood,Shaofeng Jia,Mukand Babel

doi:10.3390/w8010023

Abstract

Pakistan is one of the most highly water-stressed countries in the world and its water resources are greatly vulnerable to changing climatic conditions. The present study investigates the possible impacts of climate change on the water resources of the Kunhar River basin, Pakistan, under A2 and B2 scenarios of HadCM3, a global climate model. After successful development of the hydrological modeling system (HEC-HMS) for the basin, streamflow was simulated for three future periods (2011–2040, 2041–2070, and 2071–2099) and compared with the baseline period (1961–1990) to explore the changes in different flow indicators such as mean flow, low flow, median flow, high flow, flow duration curves, temporal shift in peaks, and temporal shifts in center-of-volume dates. From the results obtained, an overall increase in mean annual flow was projected in the basin under both A2 and B2 scenarios. However, while summer and autumn showed a noticeable increase in streamflow, spring and winter showed decreased streamflow. High and median flows were predicted to increase, but low flow was projected to decrease in the future under both scenarios. Flow duration curves showed that the probability of occurrence of flow is likely to be more in the future. It was also noted that peaks were predicted to shift from June to July in the future, and the center-of-volume date—the date at which half of the annual flow passes—will be delayed by about 9–17 days in the basin, under both A2 and B2 scenarios. On the whole, the Kunhar basin will face more floods and droughts in the future due to the projected increase in high flow and decrease in low flow and greater temporal and magnitudinal variations in peak flows. These results highlight how important it is to take cognizance of the impact of climate change on water resources in the basin and to formulate suitable policies for the proper utilization and management of these resources.

Highlights

The concentration of greenhouse gases (GHGs) has dramatically increased during the last few decades because of anthropogenic forces such as burning of fossil fuels and biomass, land use changes, rapid industrialization, and deforestation
The main objectives of the present study were: (1) the development of Hydrologic Engineering Center (HEC)-HMS, a hydrological model, in the mountainous Kunhar River basin which is greatly influenced by winter snowfall; and (2) to assess the possible impacts of climate change on the water resources of the Kunhar
The values of E and R2 were improved to 0.63–0.88. These results are quite satisfactory and complement well some previous studies such as Meenu et al [22] in India, Verma et al [23] in India, Yimer et al [24] in Ethiopia, and Garcia et al [25] in Spain. All these studies used HEC-HMS to simulate streamflow for climate change studies, with E ranging from 0.48–0.83 and R2 from 0.63–0.84

Summary

Introduction

The concentration of greenhouse gases (GHGs) has dramatically increased during the last few decades because of anthropogenic forces such as burning of fossil fuels and biomass, land use changes, rapid industrialization, and deforestation. This increased GHGs concentration has resulted in global warming and a global energy imbalance [1,2]. The average annual precipitation is likely to increase in the high latitudes and the equatorial Pacific Ocean by the end of the 21st century under RCP8.5. In several mid-latitude areas and subtropical dry regions, mean precipitation is likely to decrease

Objectives

Methods

Results

Conclusion