{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,17]],"date-time":"2026-01-17T21:03:05Z","timestamp":1768683785732,"version":"3.49.0"},"reference-count":35,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2022,9,19]],"date-time":"2022-09-19T00:00:00Z","timestamp":1663545600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>With the increasing number of reservoirs on the Nile River Basin, it has become important to understand the reservoir operations in the basin for coordinated water management among the various countries. With the lack of a proper framework for data sharing amongst the Nile basin countries, satellite remote sensing provides a simple transparent way to continuously monitor the changes taking place in reservoirs in all regions of the Nile River Basin. This paper presents a comparison between Sentinel-1- and Sentinel-2-derived reservoir water levels and the altimetry-based water level from G-REALM (Global Reservoirs and Lakes Monitor) for three major reservoirs downstream of the Millennium Reservoir impounded by the Grand Ethiopian Renaissance Dam (GERD) on the Nile River for the period of 2014\u20132021. Water surface extents were derived from Sentinel-1 using dynamic thresholds and from Sentinel-2 with the use of the NDWI (Normalized Difference Water Index). The water levels were estimated using a DEM-based contour matching technique. For Roseires Reservoir, the water levels from Sentinel agreed well with those from G-REALM (RMSE = 0.92 m; R2 = 0.82). For Lake Nasser, the water levels also agreed well (RMSE = 0.72 m; R2 = 0.85). For Lake Merowe, there was a significant mismatch in the derived water levels, mostly due to a lack of sufficient data from both sources. Overall, satellite imagery from Sentinel provides a very good alternative to altimetry-based water levels for the Nile River Basin.<\/jats:p>","DOI":"10.3390\/rs14184667","type":"journal-article","created":{"date-parts":[[2022,9,20]],"date-time":"2022-09-20T04:28:55Z","timestamp":1663648135000},"page":"4667","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Water Levels in the Major Reservoirs of the Nile River Basin\u2014A Comparison of SENTINEL with Satellite Altimetry Data"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6824-1770","authenticated-orcid":false,"given":"Prakrut","family":"Kansara","sequence":"first","affiliation":[{"name":"Engineering Systems and Environment, University of Virginia, Charlottesville, VA 22904, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7431-9004","authenticated-orcid":false,"given":"Venkataraman","family":"Lakshmi","sequence":"additional","affiliation":[{"name":"Engineering Systems and Environment, University of Virginia, Charlottesville, VA 22904, USA"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1029\/2006RG000197","article-title":"Measuring Surface Water from Space","volume":"45","author":"Alsdorf","year":"2007","journal-title":"Rev. Geophys."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"933","DOI":"10.1080\/02508060.2015.981783","article-title":"Data-Sharing Bottlenecks in Transboundary Integrated Water Resources Management: A Case Study of the Mekong River Commission\u2019s Procedures for Data Sharing in the Thai Context","volume":"39","author":"Plengsaeng","year":"2014","journal-title":"Water Int."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1007\/s10784-010-9144-4","article-title":"Water Resources Data and Information Exchange in Transboundary Water Treaties","volume":"11","author":"Gerlak","year":"2011","journal-title":"Int. Environ. Agreem."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.ejar.2020.03.001","article-title":"Water Resources in Egypt and Their Challenges, Lake Nasser Case Study","volume":"46","year":"2020","journal-title":"Egypt. J. Aquat. Res."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1353\/sais.2002.0044","article-title":"The Nile River Basin Initiative: Too Many Cooks, Too Little Broth","volume":"22","author":"Swain","year":"2002","journal-title":"SAIS Rev."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Taburet, N., Zawadzki, L., Vayre, M., Blumstein, D., le Gac, S., Boy, F., Raynal, M., Labroue, S., Cr\u00e9taux, J.F., and Femenias, P. (2020). S3MPC: Improvement on Inland Water Tracking and Water Level Monitoring from the Oltc Onboard Sentinel-3 Altimeters. Remote Sens, 12.","DOI":"10.3390\/rs12183055"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"111287","DOI":"10.1016\/j.rse.2019.111287","article-title":"Estimating Water Levels and Volumes of Lakes Dated Back to the 1980s Using Landsat Imagery and Photon-Counting Lidar Datasets","volume":"232","author":"Ma","year":"2019","journal-title":"Remote Sens. Environ."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"670","DOI":"10.1080\/01431161.2018.1516316","article-title":"Water-Volume Variations of Lake Hulun Estimated from Serial Jason Altimeters and Landsat TM\/ETM+ Images from 2002 to 2017","volume":"40","author":"Yuan","year":"2019","journal-title":"Int. J. Remote Sens."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"111643","DOI":"10.1016\/j.rse.2020.111643","article-title":"Analysis of Sentinel-3 SAR Altimetry Waveform Retracking Algorithms for Deriving Temporally Consistent Water Levels over Ice-Covered Lakes","volume":"239","author":"Shu","year":"2020","journal-title":"Remote Sens. Environ."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1007\/s10712-008-9051-1","article-title":"Monitoring Continental Surface Waters by Satellite Altimetry","volume":"29","author":"Calmant","year":"2008","journal-title":"Surv. Geophys."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"531","DOI":"10.1080\/02626668909491360","article-title":"R\u00f4le de La T\u00e9l\u00e9detection Par Satellite Dans La Surveillance Des Ressources En Eau de Surface Dans Un Milieu Aride","volume":"34","author":"Sharma","year":"1989","journal-title":"Hydrol. Sci. J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"9724","DOI":"10.1029\/2017WR022437","article-title":"Satellite Remote Sensing for Water Resources Management: Potential for Supporting Sustainable Development in Data-Poor Regions","volume":"54","author":"Sheffield","year":"2018","journal-title":"Water Resour. Res."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1098","DOI":"10.1016\/j.crte.2006.08.002","article-title":"Lake Studies from Satellite Radar Altimetry","volume":"338","author":"Birkett","year":"2006","journal-title":"Comptes Rendus Geosci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1007\/s10661-006-5233-9","article-title":"Measuring Water Storage Fluctuations in Lake Dongting, China, by Topex\/Poseidon Satellite Altimetry","volume":"115","author":"Zhang","year":"2006","journal-title":"Environ. Monit. Assess."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Kansara, P., Li, W., El-Askary, H., Lakshmi, V., Piechota, T., Struppa, D., and Sayed, M.A. (2021). An Assessment of the Filling Process of the Grand Ethiopian Renaissance Dam and Its Impact on the Downstream Countries. Remote Sens., 13.","DOI":"10.3390\/rs13040711"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"341","DOI":"10.5194\/hess-19-341-2015","article-title":"Satellite Radar Altimetry for Monitoring Small Rivers and Lakes in Indonesia","volume":"19","author":"Sulistioadi","year":"2015","journal-title":"Hydrol. Earth Syst. Sci."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Schwatke, C., Dettmering, D., and Seitz, F. (2020). Volume Variations of Small Inland Water Bodies from a Combination of Satellite Altimetry and Optical Imagery. Remote Sens., 12.","DOI":"10.3390\/rs12101606"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1134\/S009780781202008X","article-title":"Satellite Altimetry of Inland Water Bodies","volume":"39","author":"Troitskaya","year":"2012","journal-title":"Water Resour."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Dettmering, D., Ellenbeck, L., Scherer, D., Schwatke, C., and Niemann, C. (2020). Potential and Limitations of Satellite Altimetry Constellations for Monitoring Surface Water Storage Changes\u2014A Case Study in the Mississippi Basin. Remote Sens., 12.","DOI":"10.3390\/rs12203320"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"306","DOI":"10.1016\/j.isprsjprs.2022.03.013","article-title":"Water Body Classification from High-Resolution Optical Remote Sensing Imagery: Achievements and Perspectives","volume":"187","author":"Li","year":"2022","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"333","DOI":"10.1029\/2018RG000598","article-title":"Detecting, Extracting, and Monitoring Surface Water From Space Using Optical Sensors: A Review","volume":"56","author":"Huang","year":"2018","journal-title":"Rev. Geophys."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Bioresita, F., Puissant, A., Stumpf, A., and Malet, J.P. (2018). A Method for Automatic and Rapid Mapping of Water Surfaces from Sentinel-1 Imagery. Remote Sens., 10.","DOI":"10.3390\/rs10020217"},{"key":"ref_23","first-page":"271","article-title":"Potential of Large-Scale Inland Water Body Mapping from Sentinel-1\/2 Data on the Example of Bavaria\u2019s Lakes and Rivers","volume":"88","author":"Schmitt","year":"2020","journal-title":"PFG J. Photogramm. Remote Sens. Geoinf. Sci."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Biancamaria, S., Lettenmaier, D.P., and Pavelsky, T.M. (2016). The SWOT Mission and Its Capabilities for Land Hydrology, Springer.","DOI":"10.1007\/978-3-319-32449-4_6"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1016\/j.jare.2010.09.002","article-title":"Lake Nasser Evaporation Reduction Study","volume":"1","author":"Ebaid","year":"2010","journal-title":"J. Adv. Res."},{"key":"ref_26","unstructured":"Mobasher, A.M.A. (2010). Adaptive Reservoir Operation Strategies under Changing Boundary Conditions\u2014The Case of Aswan High Dam Reservoir. [Ph.D. Thesis, Darmstadt University of Technology]."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1179\/175355211X13179154166231","article-title":"The Loss of Innocence: Political and Ethical Dimensions of the Merowe Dam Archaeological Salvage Project at the Fourth Nile Cataract (Sudan)","volume":"13","author":"Kleinitz","year":"2011","journal-title":"Conserv. Manag. Archaeol. Sites"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.ejrh.2018.02.006","article-title":"Evaluation of Multi-Storage Hydropower Development in the Upper Blue Nile River (Ethiopia): Regional Perspective","volume":"16","author":"Mulat","year":"2018","journal-title":"J. Hydrol. Reg. Stud."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"938","DOI":"10.1016\/j.scitotenv.2016.05.029","article-title":"Hydrological, Socio-Economic and Reservoir Alterations of Er Roseires Dam in Sudan","volume":"566\u2013567","author":"Alrajoula","year":"2016","journal-title":"Sci. Total Environ."},{"key":"ref_30","unstructured":"Huffman, G.J., Bolvin, D.T., Nelkin, E.J., and Tan, J. (2020, January 25). IMERG Technical Documentation, Available online: https:\/\/gpm.nasa.gov\/sites\/default\/files\/document_files\/IMERG_doc_190909.pdf."},{"key":"ref_31","unstructured":"(2022, April 17). Copernicus Sentinel Data Accessed from ESA Open Hub. Available online: https:\/\/scihub.copernicus.eu\/dhus\/."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"RG2004","DOI":"10.1029\/2005RG000183","article-title":"The Shuttle Radar Topography Mission","volume":"45","author":"Farr","year":"2007","journal-title":"Rev. Geophys."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1141","DOI":"10.5194\/essd-12-1141-2020","article-title":"Satellite-Based Remote Sensing Data Set of Global Surface Water Storage Change from 1992 to 2018","volume":"12","author":"Tortini","year":"2020","journal-title":"Earth Syst. Sci. Data"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Gourgouletis, N., Bariamis, G., Anagnostou, M.N., and Baltas, E. (2022). Estimating Reservoir Storage Variations by Combining Sentinel-2 and 3 Measurements in the Yliki Reservoir, Greece. Remote Sens., 14.","DOI":"10.3390\/rs14081860"},{"key":"ref_35","first-page":"11","article-title":"Sentinel-1 GRD Preprocessing Workflow","volume":"18","author":"Filipponi","year":"2019","journal-title":"Proceedings"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/18\/4667\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:34:32Z","timestamp":1760142872000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/18\/4667"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,9,19]]},"references-count":35,"journal-issue":{"issue":"18","published-online":{"date-parts":[[2022,9]]}},"alternative-id":["rs14184667"],"URL":"https:\/\/doi.org\/10.3390\/rs14184667","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,9,19]]}}}