Future climate and cryosphere impacts on the hydrology of a scarcely gauged catchment on the Jhelum river basin, Northern Pakistan

Muhammad Azmat; Muhammad Uzair Qamar; Christian Huggel; Ejaz Hussain

doi:10.1016/j.scitotenv.2018.05.206

Future climate and cryosphere impacts on the hydrology of a scarcely gauged catchment on the Jhelum river basin, Northern Pakistan

Sci Total Environ. 2018 Oct 15:639:961-976. doi: 10.1016/j.scitotenv.2018.05.206. Epub 2018 May 26.

Authors

Muhammad Azmat¹, Muhammad Uzair Qamar², Christian Huggel³, Ejaz Hussain⁴

Affiliations

¹ Department of Geography, University of Zurich, 8057 Zurich, Switzerland; Institute of Geographical Information Systems (IGIS), National University of Sciences and Technology (NUST), Islamabad, Pakistan. Electronic address: muhammad.azmat@geo.uzh.ch.
² Department of Irrigation and Drainage, University of Agriculture, Faisalabad, Pakistan. Electronic address: muhammad.uzair@uaf.edu.pk.
³ Department of Geography, University of Zurich, 8057 Zurich, Switzerland. Electronic address: christian.huggel@geo.uzh.ch.
⁴ Institute of Geographical Information Systems (IGIS), National University of Sciences and Technology (NUST), Islamabad, Pakistan. Electronic address: ejaz@igis.nust.edu.pk.

PMID: 29929335
DOI: 10.1016/j.scitotenv.2018.05.206

Abstract

Streamflow projections are fundamental sources for future water resources strategic planning and management, particularly in high-altitude scarcely-gauged basins located in high mountain Asia. Therefore, quantification of the climate change impacts on major hydrological components (evapotranspiration, soil water storage, snowmelt-runoff, rainfall-runoff and streamflow) is of high importance and remains a challenge. For this purpose, we analysed general circulation models (GCMs) using a multiple bias correction approach and two different hydrological models i.e. the Hydrological Modelling System (HEC-HMS) and the Snowmelt Runoff Model (SRM), to examine the impact of climate change on the hydrological behaviour of the Jhelum River basin. Based on scrutiny, climate projections using four best fit CMIP5 GCMs (i.e. BCC-CSM1.1, INMCM4, IPSL-CM5A-LR and CMCC-CMS) were chosen by evaluating linear scaling, local intensity scaling (LOCI) and distribution mapping (DM) approaches at twenty climate stations. Subsequently, after calibration and validation of HEC-HMS and SRM at five streamflow gauging stations, the bias corrected projected climate data was integrated with HEC-HMS and SRM to simulate projected streamflow. Results demonstrate that the DM approach fitted the projections best. The climate projections exhibited maximum intra-annual rises in precipitation by 183.2 mm (12.74%) during the monsoon for RCP4.5 and a rise in T_min (T_max) by 4.77 °C (4.42 °C) during pre-monsoon, for RCP8.5 during 2090s. The precipitation and temperature rise is expected to expedite and increase snowmelt-runoff up to 48% and evapotranspiration and soil water storage up to 45%. The projections exhibited significant increases in streamflows by 330 m³/s (22.6%) for HEC-HMS and 449 m³/s (30.7%) for SRM during the pre-monfaf0000soon season by the 2090s under RCP8.5. Overall, our results reveal that the pre-monsoon season is potentially utmost affected under scenario-periods, and consequently, which has the potential to alter the precipitation and flow regime of the Jhelum River basin due to significant early snow- and glacier-melt.

Keywords: Bias corrections; Climate change; Climate models; Hydrological modelling; Precipitation- and snowmelt-runoff.