Monitoring water volume variations in the Nam Ngum hydropower dam using satellite observations combined with HydroWEB and G-REALM water level data

  • Affiliations:

    1 REMOSAT, University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology, Hanoi, Vietnam
    2 Vietnam National Space Center, Vietnam Academy of Science and Technology, Hanoi, Vietnam
    3 Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
    4 Institute of Methodologies for Environmental Monitoring (IMAA), National Research Council (CNR), Tito Scalo, Italy

  • *Corresponding:
    This email address is being protected from spambots. You need JavaScript enabled to view it.
  • Received: 24th-Apr-2025
  • Revised: 14th-July-2025
  • Accepted: 14th-July-2025
  • Online: 1st-Aug-2025
Pages: 90 - 103
Views: 43
Downloads: 3
Rating: , Total rating: 0
Yours rating

Abstract:

Continuous and frequent monitoring of surface water variations in hydropower reservoirs is essential for effective energy production, flood mitigation, and water management across agricultural, industrial, and domestic sectors. This study focuses on monitoring water volume variations in the Nam Ngum hydropower reservoir, the largest water body in the Lao People's Democratic Republic (Lao PDR), from August 2022 to August 2024. The reservoir’s surface water extent was estimated using imagery acquired from optical sensors onboard Sentinel-2, Landsat-8 and Landsat-9 satellites, as well as radar sensors onboard Sentinel-1 satellite for cloud-covered conditions. The reservoir’s water level was derived from satellite altimetry data provided by the HydroWEB and G-REALM databases. In situ measurements of water level and volume, provided free of charge by the reservoir operating company, were used for validation. Results indicated that water levels derived from satellite altimetry data ranged from 200÷212 m, exhibiting an extremely high correlation with in situ measurements (R = 99.94% and RMSE = 0.1418 m). The reservoir’s water extent varied between 350 and 485 km2, with a strong correlation to water level records (R = 98.48%). Finally, the estimated water volume variations of the reservoir closely followed the in situ observations (R = 99.63%). These findings demonstrate the effectiveness of satellite data in monitoring variations in water levels at hydropower dams. Such information is crucial for water resource management, particularly in downstream regions during storm seasons. However, this study has some key limitations: (1) the reliance on optical imagery restricts its applicability during cloudy periods, which are common in tropical regions; and (2) the HydroWEB and G-REALM only provide data for a limited number of lakes with surface areas larger than 100 km2.

How to Cite
Pham, B.Duc, ., H.Manh Nguyen and Lacava, T. 2025. Monitoring water volume variations in the Nam Ngum hydropower dam using satellite observations combined with HydroWEB and G-REALM water level data. Journal of Mining and Earth Sciences. 66, 4 (Aug, 2025), 90-103. DOI:https://doi.org/10.46326/JMES.2025.66(6).07.
References

Adrian, R., O’Reilly, C. M., Zagarese, H., Baines, S. B., Hessen, D. O., Keller, W., Livingstone, D. M., Sommaruga, R., Straile, D., Van Donk, E., Weyhenmeyer, G. A., and Winder, M. (2009). Lakes as sentinels of climate change. Limnology and Oceanography, 54(6part2), 2283-2297. https://doi.org/10.4319/ lo.2009.54.6_part_2.2283.

Afifi, A. S., and Magdy, A. (2024). Flood monitoring in an Giang Province, Vietnam using global flood mapper and Sentinel-1 SAR. Remote Sensing Letters, 15(9), 883-892. https://doi.org/10.1080/2150704X.2024.2388846.

Aswathi, J., Binoj Kumar, R. B., Oommen, T., Bouali, E. H., and Sajinkumar, K. S. (2022). InSAR as a tool for monitoring hydropower projects: A review. Energy Geoscience, 3(2), 160-171. https://doi.org/10.1016/j.engeos.2021.12.007.

Avisse, N., Tilmant, A., Müller, M. F., and Zhang, H. (2017). Monitoring small reservoirs’ storage with satellite remote sensing in inaccessible areas. Hydrology and Earth System Sciences, 21(12), 6445-6459. https://doi.org/10.5194/hess-21-6445-2017.

Baup, F., Frappart, F., and Maubant, J. (2014). Combining high-resolution satellite images and altimetry to estimate the volume of small lakes. Hydrology and Earth System Sciences, 18(5), 2007-2020. https://doi.org/10.5194/hess-18-2007-2014.

Birkett, C., Reynolds, C., Beckley, B., and Doorn, B. (2011). From Research to Operations: The USDA Global Reservoir and Lake Monitor BT - Coastal Altimetry (S. Vignudelli, A. G. Kostianoy, P. Cipollini, and J. Benveniste (eds.); pp. 19-50). Springer Berlin Heidelberg. https://doi.org/10.1007/ 978-3-642-12796-0_2.

Carvalho, M., Cardoso-Fernandes, J., González, F. J., and Teodoro, A. C. (2025). Comparative Performance of Sentinel-2 and Landsat-9 Data for Raw Materials’ Exploration Onshore and in Coastal Areas. Remote Sensing, 17(2). https://doi.org/10.3390/rs17020305.

Crétaux, J.-F., Abarca-del-Río, R., Bergé-Nguyen, M., Arsen, A., Drolon, V., Clos, G., and Maisongrande, P. (2016). Lake Volume Monitoring from Space. Surveys in Geophysics, 37(2), 269-305. https://doi.org/10.1007/s10712-016-9362-6.

Crétaux, J.-F., Arsen, A., Calmant, S., Kouraev, A., Vuglinski, V., Bergé-Nguyen, M., Gennero, M.-C., Nino, F., Abarca Del Rio, R., Cazenave, A., and Maisongrande, P. (2011). SOLS: A lake database to monitor in the Near Real Time water level and storage variations from remote sensing data. Advances in Space Research, 47(9), 1497-1507. https://doi.org/10.1016/j.asr.2011.01.004.

Downing, J. A., Prairie, Y. T., Cole, J. J., Duarte, C. M., Tranvik, L. J., Striegl, R. G., McDowell, W. H., Kortelainen, P., Caraco, N. F., Melack, J. M., and Middelburg, J. J. (2006). The global abundance and size distribution of lakes, ponds, and impoundments. Limnology and Oceanography, 51(5), 2388-2397. https://doi.org/10.4319/lo.2006.51.5.2388.

Duan, Z., and Bastiaanssen, W. G. M. (2013). Estimating water volume variations in lakes and reservoirs from four operational satellite altimetry databases and satellite imagery data. Remote Sensing of Environment, 134, 403-416. https://doi. org/10.1016/j.rse.2013.03.010.

Fatchurrachman, Rudiyanto, Soh, N. C., Shah, R. M., Giap, S. G. E., Setiawan, B. I., and Minasny, B. (2022). High-Resolution Mapping of Paddy Rice Extent and Growth Stages across Peninsular Malaysia Using a Fusion of Sentinel-1 and 2 Time Series Data in Google Earth Engine. Remote Sensing, 14(8). https://doi.org/10.3390/rs14081875.

Gorelick, N., Hancher, M., Dixon, M., Ilyushchenko, S., Thau, D., and Moore, R. (2017). Google Earth Engine: Planetary-scale geospatial analysis for everyone. Remote Sensing of Environment, 202, 18-27. https://doi.org/10.1016/j.rse.2017.06.031.

Hennig, T., Harlan, T., Tilt, B., and Magee, D. (2023). Hydropower development in South Asia: Data challenges, new approaches, and implications for decision-making. WIREs Water, 10(4), e1654. https://doi.org/10.1002/wat2.1654.

Javhar, A., Chen, X., Bao, A., Jamshed, A., Yunus, M., Jovid, A., and Latipa, T. (2019). Comparison of Multi-Resolution Optical Landsat-8, Sentinel-2 and Radar Sentinel-1 Data for Automatic Lineament Extraction: A Case Study of Alichur Area, SE Pamir. Remote Sensing, 11(7). https://doi.org/10.3390/rs11070778.

Lahsaini, M., Albano, F., Albano, R., Mazzariello, A., and Lacava, T. (2024). A Synthetic Aperture Radar-Based Robust Satellite Technique (RST) for Timely Mapping of Floods. In Remote Sensing (Vol. 16, Issue 12). https://doi.org/10.3390/rs16122193.

Lehner, B., Liermann, C. R., Revenga, C., Vörösmarty, C., Fekete, B., Crouzet, P., Döll, P., Endejan, M., Frenken, K., Magome, J., Nilsson, C., Robertson, J. C., Rödel, R., Sindorf, N., and Wisser, D. (2011). High-resolution mapping of the world’s reservoirs and dams for sustainable river-flow management. Frontiers in Ecology and the Environment, 9(9), 494-502. https://doi.org/10.1890/100125.

Li, W., Ying, Q., Youqiang, S., He, H., Feng, L., Liqiao, T., and and Ding, Y. (2016). Estimating the relationship between dam water level and surface water area for the Danjiangkou Reservoir using Landsat remote sensing images. Remote Sensing Letters, 7(2), 121-130.

https://doi.org/10.1080/2150704X.2015.1117151.

Liu, C., Hu, R., Wang, Y., Lin, H., Zeng, H., Wu, D., Liu, Z., Dai, Y., Song, X., and Shao, C. (2022). Monitoring water level and volume changes of lakes and reservoirs in the Yellow River Basin using ICESat-2 laser altimetry and Google Earth Engine. Journal of Hydro-Environment Research, 44, 53-64. https://doi.org/10.1016/j.jher.2022.07.005.

Manavalan, R. (2018). Review of synthetic aperture radar frequency, polarization, and incidence angle data for mapping the inundated regions. Journal of Applied Remote Sensing, 12(2), 21501. https://doi.org/10.1117/1.JRS.12.021501.

Pham-Duc, B. (2023). Comparison of multi-source satellite remote sensing observations for monitoring the variations of small lakes: a case study of Dai Lai Lake (Vietnam). Journal of Water and Climate Change, jwc2023505. https://doi.org/10.2166/wcc.2023.505.

Pham-Duc, B., Frappart, F., Tran-Anh, Q., Si, S. T., Phan, H., Quoc, S. N., Le, A. P., and Viet, B. Do. (2022). Monitoring Lake Volume Variation from Space Using Satellite Observations: A Case Study in Thac Mo Reservoir (Vietnam). Remote Sensing, 14(16). https://doi.org/10.3390/rs14164023.

Pham-Duc, B., Papa, F., Prigent, C., Aires, F., Biancamaria, S., and Frappart, F. (2019). Variations of Surface and Subsurface Water Storage in the Lower Mekong Basin (Vietnam and Cambodia) from Multisatellite Observations. Water, 11(1), 75. https://doi.org/10.3390/w11010075.

Pham-Duc, B. (2024). Comparison of Synthetic Aperture Radar Sentinel-1 and ALOS-2 observations for lake monitoring. Vietnam Journal of Earth Sciences, 46(3 SE-Articles), 322-338. https://doi.org/10.15625/2615-9783/20639.

Pham-Duc, B., and Tong Si, S. (2021). Monitoring spatial-temporal dynamics of small lakes based on SAR Sentinel-1 observations: a case study over Nui Coc Lake (Vietnam). Vietnam Journal of Earth Sciences, 44(1), 1-17. https://doi.org/10.15625/2615-9783/16315.

Pimenta, J., Fernandes, J. N., and Azevedo, A. (2025). Remote Sensing Tool for Reservoir Volume Estimation. In Remote Sensing (Vol. 17, Issue 4). https://doi.org/10.3390/rs17040619.

Pinkeaw, S., Boonrat, P., Koedsin, W., and Huete, A. (2024). Semi-automated mangrove mapping at National-Scale using Sentinel-2, Sentinel-1, and SRTM data with Google Earth Engine: A case study in Thailand. The Egyptian Journal of Remote Sensing and Space Sciences, 27(3), 555-564. https://doi.org/10.1016/j.ejrs.2024.07.001.

Qayyum, N., Ghuffar, S., Ahmad, H. M., Yousaf, A., and Shahid, I. (2020). Glacial Lakes Mapping Using Multi Satellite PlanetScope Imagery and Deep Learning. ISPRS International Journal of Geo-Information, 9(10). https:// doi.org/10.3390/ijgi9100560.

Sanches, L. F., Guenet, B., Marinho, C. C., Barros, N., and de Assis Esteves, F. (2019). Global regulation of methane emission from natural lakes. Scientific Reports, 9(1), 255. https://doi.org/10.1038/s41598-018-36519-5.

Sarzynski, T., Giam, X., Carrasco, L., and Lee, J. S. H. (2020). Combining Radar and Optical Imagery to Map Oil Palm Plantations in Sumatra, Indonesia, Using the Google Earth Engine. Remote Sensing, 12(7). https://doi.org/10.3390/rs12071220.

Shimizu, K., Murakami, W., Furuichi, T., and Estoque, R. C. (2023). Mapping Land Use/Land Cover Changes and Forest Disturbances in Vietnam Using a Landsat Temporal Segmentation Algorithm. Remote Sensing, 15(3). https://doi.org/ 10.3390/rs15030851.

Song, X.-P., Huang, W., Hansen, M. C., and Potapov, P. (2021). An evaluation of Landsat, Sentinel-2, Sentinel-1 and MODIS data for crop type mapping. Science of Remote Sensing, 3, 100018. https://doi.org/10. 1016/j.srs.2021.100018.

Sorkhabi, O. M., Shadmanfar, B., and Kiani, E. (2022). Monitoring of dam reservoir storage with multiple satellite sensors and artificial intelligence. Results in Engineering, 16, 100542. https://doi.org/ 10.1016/j.rineng.2022.100542.

Suwanlee, S. R., Keawsomsee, S., Pengjunsang, M., Homtong, N., Prakobya, A., Borgogno-Mondino, E., Sarvia, F., and Som-ard, J. (2023). Monitoring Agricultural Land and Land Cover Change from 2001-2021 of the Chi River Basin, Thailand Using Multi-Temporal Landsat Data Based on Google Earth Engine. Remote Sensing, 15(17).https://doi.org/10.3390/rs15174339.

Tarca, G., Hoelzle, M., and Guglielmin, M. (2023). Using PlanetScope images to investigate the evolution of small glaciers in the Alps. Remote Sensing Applications: Society and Environment, 32, 101013. https://doi.org/ 10.1016/j.rsase.2023.101013.

Thu, H. N., and Wehn, U. (2016). Data sharing in international transboundary contexts: The Vietnamese perspective on data sharing in the Lower Mekong Basin. Journal of Hydrology, 536, 351-364. https://doi.org/ 10.1016/j.jhydrol.2016.02.035.

Venkatappa, M., Sasaki, N., Anantsuksomsri, S., and Smith, B. (2020). Applications of the Google Earth Engine and Phenology-Based Threshold Classification Method for Mapping Forest Cover and Carbon Stock Changes in Siem Reap Province, Cambodia. Remote Sensing, 12(18). https://doi.org/10.3390/rs12183110.

Williamson, C. E., Saros, J. E., Vincent, W. F., and Smol, J. P. (2009). Lakes and Reservoirs as Sentinels, Integrators, and Regulators of Climate Change. Limnology and Oceanography, 54(6), 2273-2282. http://www.jstor.org/stable/20622831.

Wu, S., Cai, Y., Ke, C.-Q., Xiao, Y., Li, H., He, Z., and Duan, Z. (2025). SWOT mission enables high-precision and wide-coverage lake water levels monitoring on the Tibetan Plateau. Journal of Hydrology: Regional Studies, 59, 102357. https://doi.org/10. 1016/j.ejrh.2025.102357.

Xu, H. (2006). Modification of normalised difference water index (NDWI) to enhance open water features in remotely sensed imagery. International Journal of Remote Sensing, 27(14), 3025-3033. https://doi.org/10.1080/01431160600589179.

Zhang, A. T., and Gu, V. X. (2023). Global Dam Tracker: A database of more than 35,000 dams with location, catchment, and attribute information. Scientific Data, 10(1), 111. https://doi.org/10.1038/ s41597-023-02008-2.

Other articles