Morphological changes in the lower Lancang River due to extensive human activities

Peijia Wang; Kaidao Fu; Jiangcheng Huang; Xingwu Duan; Zaizhi Yang

doi:10.7717/peerj.9471

Morphological changes in the lower Lancang River due to extensive human activities

PeerJ. 2020 Jul 23:8:e9471. doi: 10.7717/peerj.9471. eCollection 2020.

Authors

Peijia Wang^{1

2}, Kaidao Fu^{1

2}, Jiangcheng Huang^{1

2}, Xingwu Duan^{1

2}, Zaizhi Yang^{1

2}

Affiliations

¹ Institute of International Rivers and Eco-Security, Yunnan University, Kunming, Yunnan, China.
² Yunnan Key Laboratory for International Rivers and Transboundary Eco-Security, Yunnan University, Kunming, Yunnan, China.

Abstract

Background: Morphological changes in river beds determine the risk for soil erosion within floodplain areas. At present, little is known about river morphological changes in high-altitude mountainous area influenced by extensive human activities. The study has important reference value for clarifying the morphological changes of mountainous rivers due to extensive human activities.

Methods: Based on the long-term multi-source remote sensing image data, we analyzed morphological changes in the lower Lancang River (LCR) in Southwest China at regional and local scales, and determined their influencing factors. Visual interpretation is used to extract the information and unify the interpretation standards of various localities, mainly including water bodies, sandbars, shorelines and beaches. Based on high-resolution remote sensing images, we analyzed the planforms, erosion and accretion conditions in Jinghongba (JHB) reach and Ganlanba (GLB) reach.

Results: Our results showed that: (1) during 1993-2016, the planforms of Jinghongba and Ganlanba in the wide valley of the lower LCR changed significantly, (2) In the interval 1993 to 2016, the JHB reach exhibited extensive erosion, with the right bank more eroded seriously than the left bank, and an erosion area of 0.36 km². The erosion area of the GLB reach was 0.33 km², with accretion area of 0.61 km². The right bank was dominated by erosion, while the left bank by sedimentation; (3) Morphological changes in JHB and GLB reches were the result of the combined effects of cascade hydropower development, river regulation, and sand-mining in the river. The results improved the understanding of riverbed evolution, and could help guide sediment management in mountainous areas influenced by extensive human activities.

Keywords: Lancang-Mekong; Multi-source remote sensing image; River morphological changes; Influencing factors; Mountain river.

Grants and funding

This work was supported by the National Natural Science Foundation of China (No.41571032, No.41561144012). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.