Abstract
The Vietnamese Mekong Delta (VMD) is frequently affected by seasonal floods, especially with An Giang Province being one of the most vulnerable regions. In the context of climate change and human activities, such as dam construction and dyke development, the flood regime in this area is rapidly and unpredictably changing. These alterations have exacerbated challenges in agriculture, water management, and local livelihoods, yet reliable long-term flood maps and early-warning tools remain limited. This study used Sentinel-1 satellite imagery on the Google Earth Engine (GEE) platform to monitor and evaluate flood dynamics in An Giang from 2015 to 2024. The results show that flooding still occurred in low-lying areas without closed-dike protection, though the overall flooded extent slightly decreased during 2015–2024. However, the annual patterns showed considerable variability: while 2017–2018 recorded extensive flooding with peak inundation exceeding 30,000 ha, 2019–2020 experienced minimal flood extent. This sharp contrast highlights the increasing irregularity of the flood regime in An Giang. This study created a long-term remote sensing dataset for An Giang by using Sentinel-1 and GEE, providing a scientific basis for flood monitoring, agricultural adaptation, and advancing remote sensing applications in deltaic flood monitoring.
References
- Tran DD, Van Halsema G, Hellegers PJ, Ludwig F, Wyatt A. Questioning triple rice intensification on the Vietnamese Mekong Delta floodplains: An environmental and economic analysis of current land-use trends and alternatives. J Environ Manag. 2018;217:429-441.
- General Statistics Office of Vietnam. Statistical Yearbook of Vietnam 2021. Hanoi: Statistical Publishing House; 2021.
- Ministry of Agriculture and Rural Development. Annual Report on Agricultural Production 2022. Hanoi: Agricultural Publishing House; 2022.
- Tran DD, Van Halsema G, Hellegers PJGJ, Hoang LP, Tran TQ, Kummu M, et al. Assessing impacts of dike construction on the flood dynamics of the Mekong Delta. Hydrol Earth Syst Sci. 2018;22(3):1875-1896.
- Cochrane TA, Arias ME, Piman T. Historical impact of water infrastructure on water levels of the Mekong River and the Tonle Sap system. Hydrol Earth Syst Sci. 2014;18(11):4529-4541.
- Dinh TT, Long TX, Nguyen H. Long-Term Assessment of Flood and Drought Phenomena In The Long Xuyen Quadrangle, Vietnamese Mekong Delta. Nativa, 13(1):80-92.
- Räsänen TA, Lindgren V, Guillaume JHA, Buckley BM, Kummu M. On the spatial and temporal variability of ENSO precipitation and drought teleconnection in mainland Southeast Asia. Clim Past. 2016;12(9):1889-1905.
- Piman T, Cochrane TA, Arias ME, Green A, Dat ND. Assessment of Flow Changes from Hydropower Development and Operations in Sekong, Sesan, and Srepok Rivers of the Mekong Basin. J Water Resour Plann Manage. 2012;139(6):723-732.
- Dung NV, Merz B, Bárdossy A, Thang TD, Apel H. Multiobjective automatic calibration of hydrodynamic models utilizing inundation maps and gauge data. Hydrol Earth Syst Sci. 2011;15(4):1339-1354.
- Nguyen D, Renwick J, McGregor J. Variations of surface temperature and rainfall in Vietnam from 1971 to 2010. Int J Climatol. 2013;34(1):249-264.
- Chen Y, Huang C, Ticehurst C, Merrin L, Thew P. An evaluation of MODIS daily and 8-day composite products for floodplain and wetland inundation mapping. Wetlands. 2013;33(5):823-835.
- Torres R, Snoeij P, Geudtner D, Bibby D, Davidson M, Attema E, et al. GMES Sentinel-1 mission. Remote Sens Environ. 2012;120:9-24.
- Tran KH, Menenti M, Jia L. Surface water mapping and flood monitoring in the Mekong Delta using Sentinel-1 SAR time series and OTSU threshold. Remote Sens. 2022;14(22):5721.
- Sakamoto T, Van Nguyen N, Kotera A, Ohno H, Ishitsuka N, Yokozawa M. Detecting temporal changes in the extent of annual flooding within the Cambodia and the Vietnamese Mekong Delta from MODIS time-series imagery. Remote Sens Environ. 2007;109(3):295-313.
- Dang TD, Cochrane TA, Arias ME, Van PDT, De Vries TT. Hydrological alterations from water infrastructure development in the Mekong floodplains. Hydrol Process. 2016; 30(21):3824–3838.
- Tsyganskaya V, Martinis S, Marzahn P, Ludwig R. Detection of temporary flooded vegetation using Sentinel-1 time series data. Remote Sens. 2018;10(8):1286.
- Tiwari V, Kumar V, Matin MA, Thapa A, Ellenburg WL, Gupta N, et al. Flood inundation mapping–Kerala 2018; harnessing the power of SAR, automatic threshold detection method and Google Earth Engine. PLoS One. 2020;15(8):e0237324.
- Misra A, White K, Nsutezo SF, Straka W, Lavista J. Mapping global floods with 10 years of satellite radar data. Nat Commun. 2025;16(1):60973.
- Uddin K, Matin MA, Meyer FJ. Operational flood mapping using multi-temporal Sentinel-1 SAR images: a case study from Bangladesh. Remote Sens. 2019;11(13):1581.
- Lam C, Niculescu S, Bengoufa S. Monitoring and mapping floods and floodable areas in the Mekong Delta (Vietnam) using time-series Sentinel-1 images, convolutional neural network, multi-layer perceptron, and random forest. Remote Sens. 2023;15(8):2001.
- Hanh LN, Son NH, Lang LPC, Van An N, An TT. Flood mapping and impact assessment in agricultural land in Hoa Vang, Da Nang using remote sensing and Google Earth Engine. VNU J Sci Earth Environ Sci. 2024;40(1):5068.
- Thao NTP, Linh TT, Ha NTT, Vinh PQ, Linh NT. Mapping flood inundation areas over the lower part of the Con River Basin using Sentinel-1A imagery. Vietnam J Earth Sci. 2020;42(3):15453.
- Sy HM, Luu C, Bui QD, Ha H, Nguyen DQ. Urban flood risk assessment using Sentinel-1 on the Google Earth Engine: a case study in Thai Nguyen city, Vietnam. Remote Sens Appl Soc Environ. 2023;31:100987.
- Van Rutten P, Lazaro IB, Muis S, Teklesadik A, Van Den Homberg M. Flood and rice damage mapping for tropical storm Talas in Vietnam using Sentinel-1 SAR data. Remote Sens. 2025;17(13):2171.
- Nguyen THD, Nguyen TC, Nguyen TNT, Doan TN. Flood inundation mapping using Sentinel-1A in An Giang Province in 2019. Vietnam J Sci Technol. 2020;62(4):36-42.
- Afifi AS, Magdy A. Flood monitoring in An Giang Province, Vietnam using global flood mapper and Sentinel-1 SAR. Remote Sens Lett. 2024;15(9):883-92.
- Vanderhoof MK, Alexander L, Christensen J, Solvik K, Nieuwlandt P, Sagehorn M. High-frequency time series comparison of Sentinel-1 and Sentinel-2 satellites for mapping open and vegetated water across the United States (2017–2021). Remote Sens Environ. 2023;288:113498.
- Van CT, Thuy HTT, Viet C, Anh LN, Van Anh VT, Tran DD. Unveiling flood vulnerability in the Vietnamese Mekong Delta: a case study of An Giang Province. Int J Disaster Risk Reduct. 2024;106:104429.
- Vu HTD, Tran DD, Schenk A, Nguyen CP, Vu HL, Oberle P, et al. Land use change in the Vietnamese Mekong Delta: new evidence from remote sensing. Sci Total Environ. 2021;813:151918.
- General Statistics Office of Vietnam. Population and housing census 2019. HanoiL Statistical Publishing House; 2019.
- Van Khanh Triet N, Dung NV, Fujii H, Kummu M, Merz B, Apel H. Has dyke development in the Vietnamese Mekong Delta shifted flood hazard downstream? Hydrol Earth Syst Sci. 2017;21(8):3991-4010.
- Ле Т, Нгуен Т, Ку Д, Цветков А, Чыонг Х, Зыонг Ч, Нгуен Д. Meteorological characteristics of the Mekong Delta in the period of 2014–2020. Ecosyst Transform. 2024;7(1):52-69.
- An Giang Provincial People’s Committee. Natural condition [Internet]. 2025 [cited 2025 Jun 1].
- Minh HVT, Lien BTB, Ngoc DTH, Van Ty T, Ngan NVC, Cong NP, et al. Understanding rainfall distribution characteristics over the Vietnamese Mekong Delta: a comparison between coastal and inland localities. Atmosphere. 2024;15(2):217.
- Thanh VQ, Roelvink D, Van Der Wegen M, Reyns J, Kernkamp H, Van Vinh G, et al. Flooding in the Mekong Delta: the impact of dyke systems on downstream hydrodynamics. Hydrol Earth Syst Sci. 2020; 24(1):189–212.
- Dang TD, Cochrane TA, Arias ME, Tri VPD. Future hydrological alterations in the Mekong Delta under the impact of water resources development, land subsidence and sea level rise. J Hydrol Reg Stud. 2018;15:119-33.
- Mondal A, Le M, Lakshmi V. Land use, climate, and water change in the Vietnamese Mekong Delta (VMD) using earth observation and hydrological modeling. J Hydrol Reg Stud. 2022;42:101132.
- Vu HTD, Trinh VC, Tran DD, Oberle P, Hinz S, Nestmann F. Evaluating the impacts of rice-based protection dykes on floodwater dynamics in the Vietnamese Mekong Delta using Geographical Impact Factor (GIF). Water. 2021;13(9):1144.
- Google for Developers. Sentinel-1 SAR GRD: C-band synthetic aperture radar ground range detected, log scaling [Internet]. [cited 2025 Jun 1].
- Choi H, Jeong J. Speckle noise reduction technique for SAR images using statistical characteristics of speckle noise and discrete wavelet transform. Remote Sens. 2019;11(10):1184.
- Yommy AS, Liu R, Wu AS. SAR image despeckling using refined Lee filter. In: 2015 7th Int Conf on Intelligent Human–Machine Systems and Cybernetics. Hangzhou, China: IEEE; 2015. p. 260–5.
- Chapman AD, Darby SE, Hong HM, Tompkins EL, Van TPD. Adaptation and development trade-offs: fluvial sediment deposition and the sustainability of rice-cropping in An Giang Province, Mekong Delta. Clim Change. 2016;137(3–4):593-608.
- Livsey J, Da CT, Scaini A, Lan THP, Long TX, Berg H, et al. Floods, soil and food – interactions between water management and rice production within An Giang Province, Vietnam. Agric Ecosyst Environ. 2021;320:107589.
- Wang C, Jiang Z, Zhou L, Dai B, Song Z. A functional group approach reveals important fish recruitments driven by flood pulses in floodplain ecosystem. Ecol Indic. 2018;99:130-9.
- Kontgis C, Schneider A, Ozdogan M, Kucharik C, Tri VPD, Duc NH, et al. Climate change impacts on rice productivity in the Mekong River Delta. Appl Geogr. 2018;102:71-83.
- Van Binh D, Kantoush SA, Saber M, Mai NP, Maskey S, Phong DT, et al. Long-term alterations of flow regimes of the Mekong River and adaptation strategies for the Vietnamese Mekong Delta. J Hydrol Reg Stud. 2020;32:100742.
- Normandin C, Frappart F, Bourrel L, Blarel F, Biancamaria S, Wigneron J, et al. Sharp decline in surface water resources for agriculture and fisheries in the Lower Mekong Basin over 2000–2020. Sci Total Environ. 2024;950:175259.
- Van Binh D, Kantoush S, Sumi T. Changes to long-term discharge and sediment loads in the Vietnamese Mekong Delta caused by upstream dams. Geomorphology. 2019;353:107011.
- Yoshida Y, Lee HS, Trung BH, Tran H, Lall MK, Kakar K, et al. Impacts of mainstream hydropower dams on fisheries and agriculture in Lower Mekong Basin. Sustainability. 2020;12(6):2408.
- Dang H, Pokhrel Y. Evolution of river regimes in the Mekong River Basin over 8 decades and the role of dams in recent hydrological extremes. Hydrol Earth Syst Sci. 2024;28(14):3347-65.
- Thanh VQ, Roelvink D, Van Der Wegen M, Reyns J, Kernkamp H, Van Vinh G, et al. Flooding in the Mekong Delta: the impact of dyke systems on downstream hydrodynamics. Hydrol Earth Syst Sci. 2020;24(1):189-212.
- Vu HTD, Trinh VC, Tran DD, Oberle P, Hinz S, Nestmann F. Evaluating the impacts of rice-based protection dykes on floodwater dynamics in the Vietnamese Mekong Delta using Geographical Impact Factor (GIF). Water. 2021;13(9):1144.
- Dang NA, Benavidez R, Tomscha SA, Nguyen H, Tran DD, Nguyen DTH, et al. Ecosystem service modeling to support nature-based flood water management in the Vietnamese Mekong River Delta. Sustainability. 2021;13(24):13549.
- Mekong River Commission. State of the Basin Report 2018. Vientiane: MRC Secretariat; 2018.
- Dinh T, Long TX, Nguyen H. Long-term assessment of flood and drought phenomena in the Long Xuyen Quadrangle, Vietnamese Mekong Delta. Nativa. 2025;13(1):80-92.

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Copyright (c) 2025 Array