21 Apr 2023
 | 21 Apr 2023
Status: this preprint is open for discussion.

Historical and projected future runoffs over the Mekong River Basin

Chao Wang, Stephen Leisz, Li Li, Xiaoying Shi, Jiafu Mao, Yi Zheng, and Anping Chen

Abstract. The Mekong River (MR) crosses the borders and connects six countries including China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. It provides critical water resources and supports natural and agricultural ecosystems, socio-economic development, and livelihoods of the people living in this region. Understanding changes in runoff of this important international river under projected climate change is critical for water resource management and climate change adaptation planning. However, research on long-term runoff dynamics for the MR and the underlying drivers of runoff variability remains scarce. Here, we analyse historical runoff variations from 1971 to 2020 based on runoff gauge data collected from eight hydrological stations along the MR.With these runoff data, we then evaluate the runoff simulation performance of four global climate models (GCMs) and five global hydrological models (GHMs) under the ISI-MIP project. Furthermore, based on the best simulation combination, we quantify the impact of future climate change on river runoff changes in the MR. The result shows that the an nual runoff in the MR has not changed significantly in the past five decades, while the establishment of dams and reservoirs in the basin significantly affected the annual runoff distribution.WaterGap2 forced by GCMs ensemble-averaged climates has the best runoff simulation performance. Under representative concentration pathways (RCPs, i.e., RCP2.6, RCP6.0 and RCP8.5), runoff of the MR is projected to increase significantly (from 3.81 m3 s−1 a−1 to 16.36 m3 s−1 a−1). In particular, under the RCP6.0 scenario, the annual runoff increases most significantly in the middle and lower basin due to increased precipitation and snowmelt. Under the RCP8.5 scenario, the runoff distribution in different seasons varies significantly, increasing the risk of flooding in the wet season and drought in the dry season.

Chao Wang et al.

Status: open (until 22 Jun 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Chao Wang et al.

Chao Wang et al.


Total article views: 106 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
81 20 5 106 2 1
  • HTML: 81
  • PDF: 20
  • XML: 5
  • Total: 106
  • BibTeX: 2
  • EndNote: 1
Views and downloads (calculated since 21 Apr 2023)
Cumulative views and downloads (calculated since 21 Apr 2023)

Viewed (geographical distribution)

Total article views: 117 (including HTML, PDF, and XML) Thereof 117 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 07 Jun 2023
Short summary
Climate change can significantly impact river runoff; however, predicting future runoff is challenging. Using historical runoff gauge data to evaluate model performances in runoff simulations for the Mekong River (MR), we quantify future runoff changes in the MR with the best simulation combination. Results suggest significant increases in the annual runoff, along with varied seasonal distributions, heightening the need for adapted water resource management measures.