Assessment of climate change impacts on water balance and hydrological extremes in Bang Pakong-Prachin Buri river basin, Thailand

Thundorn Okwala; Sangam Shrestha; Suwas Ghimire; S Mohanasundaram; Avishek Datta

doi:10.1016/j.envres.2020.109544

Assessment of climate change impacts on water balance and hydrological extremes in Bang Pakong-Prachin Buri river basin, Thailand

Environ Res. 2020 Jul:186:109544. doi: 10.1016/j.envres.2020.109544. Epub 2020 Apr 25.

Authors

Thundorn Okwala¹, Sangam Shrestha², Suwas Ghimire¹, S Mohanasundaram¹, Avishek Datta³

Affiliations

¹ Water Engineering and Management, School of Engineering and Technology, Asian Institute of Technology, P.O. Box 4 Klong Luang, Pathum Thani, 12120, Thailand.
² Water Engineering and Management, School of Engineering and Technology, Asian Institute of Technology, P.O. Box 4 Klong Luang, Pathum Thani, 12120, Thailand. Electronic address: sangam@ait.ac.th.
³ Agricultural Systems and Engineering, Department of Food, Agriculture and Bioresources, School of Environment, Resources and Development, Asian Institute of Technology, P.O. Box 4 Klong Luang, Pathum Thani, 12120, Thailand.

PMID: 32361258
DOI: 10.1016/j.envres.2020.109544

Abstract

Among many factors the hydrology of a watershed is mainly influenced by climate and land use change. This study examined the impacts of climate change on water resources and extreme events in the Bang Pakong-Prachin Buri River Basin, Thailand using three different Regional Climate Models (RCMs) ACCESS1-CSIRO-CCAM, CNRM-CM5-CSIRO-CCAM, and MPI-ESM-LR-CSIRO-CCAM under RCP4.5 and RCP8.5 emission scenarios. Soil and Water Assessment Tool (SWAT) was used to simulate the future streamflow and Extreme Value Type I distribution (EVI) was used to analyze the extreme events under projected climate conditions. The result of this study showed an increase in maximum (1.9 °C/3.6 °C) and minimum (1.6 °C/3.3 °C) temperatures under RCP4.5/8.5 at the end of the 21st century. In addition, projected rainfall is expected to decrease up to 6.8% (8.5%) in 2050s and then increase slowly such that the decrement remains 4.2% (11.0%) under RCP4.5 (RCP8.5) at the end of the century. The rainfall pattern is projected to considerably fluctuate, in particular, a shift in long term average annual peak event from September to August is predicted in 2080s under emission scenario RCP4.5 (RCP8.5). On the other hand, the average annual discharge is expected to increase up to 13.5% (2020s) and 7.6% (2050s) under RCP4.5 and RCP8.5 respectively with decreasing trend in low flows and increasing trend in high flows. Further analysis on extreme events; strengthened the results from hydrological modeling with an increase in flow volume for the same return period under changed climate conditions. This raises water resources management issues in the Bang Pakong-Prachin Buri River Basin regarding the frequency of flood and drought events in the future calling for proper policy formulation and implementation.

Keywords: Bang Pakong-Prachin Buri; Climate change; Extreme value type I distribution; Hydrology; SWAT.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Climate Change
Floods
Hydrology*
Rivers*
Thailand