,
Md. Atiqur Rahman,
Nafia Muntakim,
Tomalika Biswas,
Md. Mujibor Rahman,
Md. Redwanur Rahman
Hakaluki Haor is a major freshwater wetland in north-eastern Bangladesh, but the spatial concentration of persistent water and the consistency of recent winter open-water change remain poorly resolved. We combined JRC Global Surface Water v1.4 with Landsat Collection 2 surface reflectance in Google Earth Engine. A reproducible 164.410 km2 analysis domain was defined from pixels with long-term water occurrence above 15%. At the 80% threshold, persistent permanent-water cores, mapped as candidate dry-season refugia, occupied 20.316 km2 (12.357% of the domain). JRC monthly recurrence gave a mean of 7.378 recurrence-weighted water-month equivalents over ever-water pixels; 68.569% of that area fell in the 6–12-month-equivalent classes. Lost-water classes exceeded new-water classes in the original domain, two buffered domains and the full bounding box, although the ratio was strongly boundary-dependent (36.7–985.9). Of 32 Landsat winters from 1995 to 2026, 23 passed scene and clear-area requirements. The full Landsat record had no significant monotonic trend (Sen’s slope +0.296 km2 yr-1; p=0.342), whereas 2016–2026 declined significantly (Sen’s slope −1.939 km2 yr-1; p=0.008) at all three tested MNDWI thresholds. Sentinel-1 and Sentinel-2 winter areas covaried strongly during 2018–2026 (Pearson r=0.972), but their absolute extents differed. Published waterbird counts were available for nine matched winters; their moderate association with water area (r=0.413) became weak after adjustment for the number of beels surveyed (r=0.085). Published field studies support the ecological plausibility of retained-water refugia, but the mapped locations remain candidates for field verification.
| Published in | International Journal of Environmental Monitoring and Analysis (Volume 14, Issue 5) |
| DOI | 10.11648/j.ijema.20261405.14 |
| Page(s) | 178-189 |
| Creative Commons |
This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited. |
| Copyright |
Copyright © The Author(s), 2026. Published by Science Publishing Group |
Wetland Monitoring, Dry-season Refugia, Surface Water Persistence, Google Earth Engine, Landsat, Sentinel-1, MNDWI, Waterbird Habitat
| [1] | Steinbach, S., Hentschel, E., Hentze, K., Rienow, A., Umulisa, V., Zwart, S. J., Nelson, A. Automatization and evaluation of a remote sensing-based indicator for wetland health assessment in East Africa on national and local scales. Ecological Informatics. 2023, 75, 102032. |
| [2] | Pekel, J.-F., Cottam, A., Gorelick, N., Belward, A. S. High-resolution mapping of global surface water and its long-term changes. Nature. 2016, 540, 418–422. |
| [3] | Aziz, M. S. B., Hasan, N. A., Mondol, M. M. R., Alam, M. M., Haque, M. M. Decline in fish species diversity due to climatic and anthropogenic factors in Hakaluki Haor, an ecologically critical wetland in northeast Bangladesh. Heliyon. 2021, 7, e05861. |
| [4] | Aziz, M. S. B., Mondol, M. M. R., Alam, M. M., Haque, M. M., Islam, S. R. Underpinning the criteria for the sustainability assessment of Hakaluki Haor using the RAPFISH tool. Fisheries Research. 2024, 278, 107080. |
| [5] | Uddin, M. J., Mohiuddin, A. S. M., Hossain, S. T., Hakim, A. Eco-environmental changes of wetland resources of Hakaluki Haor in Bangladesh using GIS technology. Journal of Biodiversity & Endangered Species. 2013, 1, 103. |
| [6] | Islam, M. N., Rakib, M. R., Sufian, M. A., Raihan Sharif, A. H. M. Detection of climate change impacts on the Hakaluki Haor wetland in Bangladesh by use of remote sensing and GIS. In Bangladesh I: Climate Change Impacts, Mitigation and Adaptation in Developing Countries; Islam, M. N., van Amstel, A., Eds.; Springer: Cham, Switzerland; 2018, pp. 195–214. |
| [7] | Waleed, M., Sajjad, M., Shazil, M. S., Tariq, M., Alam, M. T. Machine learning-based spatial-temporal assessment and change transition analysis of wetlands: An application of Google Earth Engine in Sylhet, Bangladesh (1985–2022). Ecological Informatics. 2023, 75, 102075. |
| [8] | Siddique, A. B., Rayhan, E., Sobhan, F., Das, N., Fazal, M. A., Riya, S. C., Sarker, S. Spatio-temporal analysis of land use and land cover changes in a wetland ecosystem of Bangladesh using a machine-learning approach. Frontiers in Water. 2024, 6, 1394863. |
| [9] | Gorelick, N., Hancher, M., Dixon, M., Ilyushchenko, S., Thau, D., Moore, R. Google Earth Engine: Planetary-scale geospatial analysis for everyone. Remote Sensing of Environment. 2017, 202, 18–27. |
| [10] | Masek, J. G., Vermote, E. F., Saleous, N. E., Wolfe, R., Hall, F. G., Huemmrich, K. F., et al. A Landsat surface reflectance dataset for North America, 1990–2000. IEEE Geoscience and Remote Sensing Letters. 2006, 3(1), 68–72. |
| [11] | Vermote, E., Justice, C., Claverie, M., Franch, B. Preliminary analysis of the performance of the Landsat 8/OLI land surface reflectance product. Remote Sensing of Environment. 2016, 185, 46–56. |
| [12] | Xu, H. Modification of normalised difference water index (NDWI) to enhance open water features in remotely sensed imagery. International Journal of Remote Sensing. 2006, 27(14), 3025–3033. |
| [13] | Mann, H. B. Nonparametric tests against trend. Econometrica. 1945, 13(3), 245–259. |
| [14] | Sen, P. K. Estimates of the regression coefficient based on Kendall’s tau. Journal of the American Statistical Association. 1968, 63(324), 1379–1389. |
| [15] | Hamed, K. H., Rao, A. R. A modified Mann–Kendall trend test for autocorrelated data. Journal of Hydrology. 1998, 204, 182–196. |
| [16] | Olofsson, P., Foody, G. M., Herold, M., Stehman, S. V., Woodcock, C. E., Wulder, M. A. Good practices for estimating area and assessing accuracy of land change. Remote Sensing of Environment. 2014, 148, 42–57. |
| [17] | Roy, D. P., Kovalskyy, V., Zhang, H. K., Vermote, E. F., Yan, L., Kumar, S. S., Egorov, A. Characterization of Landsat-7 to Landsat-8 reflective wavelength and normalized difference vegetation index continuity. Remote Sensing of Environment. 2016, 185, 57–70. |
| [18] | Torres, R., Snoeij, P., Geudtner, D., Bibby, D., Davidson, M., Attema, E., et al. GMES Sentinel-1 mission. Remote Sensing of Environment. 2012, 120, 9–24. |
| [19] | Drusch, M., Del Bello, U., Carlier, S., Colin, O., Fernandez, V., Gascon, F., et al. Sentinel-2: ESA’s optical high-resolution mission for GMES operational services. Remote Sensing of Environment. 2012, 120, 25–36. |
| [20] |
Google Earth Engine. Cloud Score+ S2_HARMONIZED V1. Earth Engine Data Catalog. Available from:
https://developers.google.com/earth-engine/datasets/catalog/GOOGLE_CLOUD_SCORE_PLUS_V1_S2_HARMONIZED (accessed 15 August 2026). |
| [21] |
Thompson, P., Haque, E. U., Chowdhury, S. U., Mohsanin, S. Waterbird trends and impacts of conservation and co-management in four wetlands. CREL Technical Report No. 2. Dhaka: Climate-Resilient Ecosystems and Livelihoods Project; 2018. Available from:
https://bfis.bforest.gov.bd/library/wp-content/uploads/2018/10/CREL-Technical-Report2-waterbirds.pdf (accessed 15 August 2026). |
| [22] | DeAngelis, D. L., Trexler, J. C., Cosner, C., Obaza, A., Jopp, F. Fish population dynamics in a seasonally varying wetland. Ecological Modelling. 2010, 221(8), 1131–1137. |
| [23] | Imran, M. F., Habib, A. H. M. S., Hossain, M. N. Seasonal variation and fish assemblage at Hakaluki Haor, Moulvibazar, Bangladesh. International Journal of Fisheries and Aquatic Studies. 2023, 11(3), 17–27. |
| [24] | Aziz, M. S. B., Islam, S. R., Alam, M. M., Haque, M. M., Mondol, M. M. R., Ghosh, M. K., Rahman, M. A. Changes in water areas and capture fisheries production in Hakaluki Haor, Bangladesh: Understanding the socio-economic impacts through time-series analysis. Air, Soil and Water Research. 2026, 19, 11786221261429780. |
APA Style
Hossain, M. I., Rahman, M. A., Muntakim, N., Biswas, T., Rahman, M. M., et al. (2026). Candidate Dry-season Refugia and Recent Winter Open-water Decline in Hakaluki Haor, Bangladesh (1995–2026). International Journal of Environmental Monitoring and Analysis, 14(5), 178-189. https://doi.org/10.11648/j.ijema.20261405.14
ACS Style
Hossain, M. I.; Rahman, M. A.; Muntakim, N.; Biswas, T.; Rahman, M. M., et al. Candidate Dry-season Refugia and Recent Winter Open-water Decline in Hakaluki Haor, Bangladesh (1995–2026). Int. J. Environ. Monit. Anal. 2026, 14(5), 178-189. doi: 10.11648/j.ijema.20261405.14
AMA Style
Hossain MI, Rahman MA, Muntakim N, Biswas T, Rahman MM, et al. Candidate Dry-season Refugia and Recent Winter Open-water Decline in Hakaluki Haor, Bangladesh (1995–2026). Int J Environ Monit Anal. 2026;14(5):178-189. doi: 10.11648/j.ijema.20261405.14
Share This Article
Twitter
Linked In
Facebook
Copy
Download@article{10.11648/j.ijema.20261405.14,
author = {Md. Imran Hossain and Md. Atiqur Rahman and Nafia Muntakim and Tomalika Biswas and Md. Mujibor Rahman and Md. Redwanur Rahman},
title = {Candidate Dry-season Refugia and Recent Winter
Open-water Decline in Hakaluki Haor, Bangladesh (1995–2026)},
journal = {International Journal of Environmental Monitoring and Analysis},
volume = {14},
number = {5},
pages = {178-189},
doi = {10.11648/j.ijema.20261405.14},
url = {https://doi.org/10.11648/j.ijema.20261405.14},
eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijema.20261405.14},
abstract = {Hakaluki Haor is a major freshwater wetland in north-eastern Bangladesh, but the spatial concentration of persistent water and the consistency of recent winter open-water change remain poorly resolved. We combined JRC Global Surface Water v1.4 with Landsat Collection 2 surface reflectance in Google Earth Engine. A reproducible 164.410 km2 analysis domain was defined from pixels with long-term water occurrence above 15%. At the 80% threshold, persistent permanent-water cores, mapped as candidate dry-season refugia, occupied 20.316 km2 (12.357% of the domain). JRC monthly recurrence gave a mean of 7.378 recurrence-weighted water-month equivalents over ever-water pixels; 68.569% of that area fell in the 6–12-month-equivalent classes. Lost-water classes exceeded new-water classes in the original domain, two buffered domains and the full bounding box, although the ratio was strongly boundary-dependent (36.7–985.9). Of 32 Landsat winters from 1995 to 2026, 23 passed scene and clear-area requirements. The full Landsat record had no significant monotonic trend (Sen’s slope +0.296 km2 yr-1; p=0.342), whereas 2016–2026 declined significantly (Sen’s slope −1.939 km2 yr-1; p=0.008) at all three tested MNDWI thresholds. Sentinel-1 and Sentinel-2 winter areas covaried strongly during 2018–2026 (Pearson r=0.972), but their absolute extents differed. Published waterbird counts were available for nine matched winters; their moderate association with water area (r=0.413) became weak after adjustment for the number of beels surveyed (r=0.085). Published field studies support the ecological plausibility of retained-water refugia, but the mapped locations remain candidates for field verification.},
year = {2026}
}
TY - JOUR T1 - Candidate Dry-season Refugia and Recent Winter Open-water Decline in Hakaluki Haor, Bangladesh (1995–2026) AU - Md. Imran Hossain AU - Md. Atiqur Rahman AU - Nafia Muntakim AU - Tomalika Biswas AU - Md. Mujibor Rahman AU - Md. Redwanur Rahman Y1 - 2026/10/29 PY - 2026 N1 - https://doi.org/10.11648/j.ijema.20261405.14 DO - 10.11648/j.ijema.20261405.14 T2 - International Journal of Environmental Monitoring and Analysis JF - International Journal of Environmental Monitoring and Analysis JO - International Journal of Environmental Monitoring and Analysis SP - 178 EP - 189 PB - Science Publishing Group SN - 2328-7667 UR - https://doi.org/10.11648/j.ijema.20261405.14 AB - Hakaluki Haor is a major freshwater wetland in north-eastern Bangladesh, but the spatial concentration of persistent water and the consistency of recent winter open-water change remain poorly resolved. We combined JRC Global Surface Water v1.4 with Landsat Collection 2 surface reflectance in Google Earth Engine. A reproducible 164.410 km2 analysis domain was defined from pixels with long-term water occurrence above 15%. At the 80% threshold, persistent permanent-water cores, mapped as candidate dry-season refugia, occupied 20.316 km2 (12.357% of the domain). JRC monthly recurrence gave a mean of 7.378 recurrence-weighted water-month equivalents over ever-water pixels; 68.569% of that area fell in the 6–12-month-equivalent classes. Lost-water classes exceeded new-water classes in the original domain, two buffered domains and the full bounding box, although the ratio was strongly boundary-dependent (36.7–985.9). Of 32 Landsat winters from 1995 to 2026, 23 passed scene and clear-area requirements. The full Landsat record had no significant monotonic trend (Sen’s slope +0.296 km2 yr-1; p=0.342), whereas 2016–2026 declined significantly (Sen’s slope −1.939 km2 yr-1; p=0.008) at all three tested MNDWI thresholds. Sentinel-1 and Sentinel-2 winter areas covaried strongly during 2018–2026 (Pearson r=0.972), but their absolute extents differed. Published waterbird counts were available for nine matched winters; their moderate association with water area (r=0.413) became weak after adjustment for the number of beels surveyed (r=0.085). Published field studies support the ecological plausibility of retained-water refugia, but the mapped locations remain candidates for field verification. VL - 14 IS - 5 ER -
Institute of Environmental Science, University of Rajshahi, Rajshahi, Bangladesh;Department of Geospatial Research, GRID Bangladesh (Geospatial Research & Insight for Development), Rajshahi, Bangladesh
Institute of Environmental Science, University of Rajshahi, Rajshahi, Bangladesh
Institute of Environmental Science, University of Rajshahi, Rajshahi, Bangladesh
Department of Geosciences, Colorado State University, Fort Collins, United States
Environmental Science Discipline, Khulna University, Khulna, Bangladesh
Institute of Environmental Science, University of Rajshahi, Rajshahi, Bangladesh
Information