Projected Streamflow in the Kurau River Basin of Western Malaysia under Future Climate Scenarios

Abstract

Climate change-induced spatial and temporal variability of stremflow has significant implications for hydrological processes and water supplies at basin scale. This study investigated the impacts of climate change on streamflow of the Kurau River Basin in Malaysia using a Climate-Smart Decision Support System (CSDSS) to predict future climate sequences. For this, we used 25 reliazations consisting from 10 Global Climate Models (GCMs) and three IPCC Representative Concentration Pathways (RCP4.5, RCP6.0 and RCP8.5). The generated climate sequences were used as input to Soil and Water Assessment Tool (SWAT) to simulate projected changes in hydrological processes in the basin over the period 2021-2080. The model performed fairly well for the Kurau River Basin, with coefficient of determination (R 2), Nash-Sutcliffe Efficiency (NSE) and Percent Bias (PBIAS) of 0.65, 0.65 and-3.0, respectively for calibration period (1981-1998) and 0.60, 0.59 and −4.6, respectively for validation period (1996-2005). Future projections over 2021-2080 period show an increase in rainfall during August to January (relatively wet season, called the main irrigation season) but a decrease in rainfall during February to July (relatively dry season, called the off season). Temperature projections show increase in both the maximum and minimum temperatures under the three RCP scenarios, with a maximum increase of 2.5 °C by 2021-2080 relative to baseline period of 1976-2005 under RCP8.5 scenario. The model predicted reduced streamflow under all RCP scenarios compared to the baseline period. Compared to 2021-2050 period, the projected streamflow will be higher during 2051-2080 period by 1.5 m 3 /s except in February for RCP8.5. The highest streamflow is predicted during August to December for both future periods under RCP8.5. The seasonal changes in streamflow range between-2.8% and-4.3% during the off season, and between 0% (nil) and-3.8% during the main season. The assessment of the impacts of climatic variabilities on the available water resources is necessary to identify adaptation strategies. It is supposed that such assessment on the Kurau River Basin under changing climate would improve operation policy for the Bukit Merah reservoir located at downstream of the basin. Thus, the predicted streamflow of the basin would be of importance to quantify potential impacts of climate change on the Bukit Merah reservoir and to determine the best possible operational strategies for irrigation release. The variability in water resources is projected to increase with climate change and raise the risk of disasters; it will affect water and food security and economic growth. So, actions for managing water should be focused on climate change with an emphasis on basin-scale hydrological management techniques 1. Human-induced climate change is continuously altering the hydrological systems and, consequently, affecting water resources with implications for many sectors, such as agriculture, forestry, fisheries and inland navigation 2. Asia is the largest rice p...

Long-term rainfall projection based on CMIP6 scenarios for Kurau River Basin of rice-growing irrigation scheme, Malaysia

“…Several studies have implemented the CMIP models, especially CMIP5, in projecting future rainfall in different parts of Malaysia. Dlamini et al [8] and Adib et al [25] examine 10 CMIP5 models for future rainfall projection in the Northwest and North part of Peninsular Malaysia, respectively. Their results indicated a similar pattern, in which most GCMs predicted a decreasing trend in future rainfall from January to February and an increase from July to December.…”

Hydrological Models and Artificial Neural Networks (ANNs) to Simulate Streamflow in a Tropical Catchment of Sri Lanka

“…Among many other available computer models used for simulating rainfall-runoff processes, the Soil and Water Assessment Tool [4], the Hydrologic Engineering Centre-Hydrologic Modelling System (HEC-HMS) [5], the Variable Infiltration Capacity Model [6], the HBV-light model [7], and the J2000 model [8] are frequently used by hydrological modellers around the world [9][10][11]. However, time-series hydrological models inherit uncertainties in streamflow estimations due to unavailability of long-term data including meteorological and streamflow data [12].…”