Spatio-Temporal Dynamics of Surface Water Extent in Lake Haramaya, Ethiopia Using Multi-Sensor Satellite Data (1990–2024)

Abstract

Lake Haramaya, one of the most important freshwater lakes in eastern Ethiopia, has been severely degraded in recent decades due to a combination of climate variability, recurrent drought, increasing water abstraction, rapid population growth and unsustainable land-use practices. This study examines the significant fluctuations in the surface area of Lake Haramaya in eastern Ethiopia from 1990 to 2024, utilizing time series analysis of Multi-Spectral (MS, Landsat) and Synthetic Aperture Radar (SAR, Sentinel-1) satellite imagery. Annual water extent was mapped using the Modified Normalized Difference Water Index (MNDWI) applied to MS data and complementary SAR-based water detection. The analysis reveals a clear trajectory of severe decline, with the lake’s surface area shrinking by 87.5% from 3.77 km² in 1990 to a critical low of 0.47 km² by 2020, culminating in near-complete desiccation around 2005 and again in 2017. A weak statistical correlation between lake extent and rainfall (r ≈ − 0.27) indicates that climatic variability was not the primary driver of this collapse. Instead, the shrinkage is strongly attributed to anthropogenic pressures, including unregulated water extraction for irrigation, particularly for khat cultivation, urban water supply, domestic use, and watershed erosion. Remarkably, a significant resurgence was observed after 2020, with the lake recovering to 2.73 km² by 2024, primarily due to concerted catchment rehabilitation and soil and water conservation efforts. In particular, the Participatory Integrated Watershed of Haramaya Lake Development (PILHWSD) program, led by local institutions and communities, has played a central role in improving watershed conditions that reduce runoff, and enhance recharge. The findings underscore the critical impact of human activity on fragile aquatic ecosystems and highlight the potential for recovery through integrated watershed management and sustainable water resource policies. This study analysed the spatiotemporal dynamics of Lake Haramaya, eastern Ethiopia, from 1990 to 2024 using multi-temporal Landsat and Sentinel-1and 2 satellite imagery, processed on the Digital Earth Africa Open Data Cube platform using the Water Observations from Space (WOfS) model. The analysis employed the Modified Normalized Difference Water Index (MNDWI) to map changes in lake extent, supported by rainfall and temperature data from NASA and PERSIANN-CDR. Results revealed a drastic 87.5% decline in surface area from 3.77 km² in 1990 to 0.47 km² by 2020, showing a weak correlation with rainfall (r ≈ = -0.27) and indicating that unregulated water extraction, khat cultivation, and erosion were the primary drivers. Remarkably, the lake recovered to 2.73 km² by 2024 following integrated watershed management and conservation interventions, demonstrating that while human activities caused the lake’s collapse, targeted restoration and sustainable water resource governance can reverse ecosystem degradation and foster recovery This study analysed the spatiotemporal dynamics of Lake Haramaya, eastern Ethiopia, from 1990 to 2024 using multi-temporal Landsat and Sentinel-1and 2 satellite imagery, processed on the Digital Earth Africa Open Data Cube platform using the Water Observations from Space (WOfS) model. The analysis employed the Modified Normalized Difference Water Index (MNDWI) to map changes in lake extent, supported by rainfall and temperature data from NASA and PERSIANN-CDR. Results revealed a drastic 87.5% decline in surface area from 3.77 km² in 1990 to 0.47 km² by 2020, showing a weak correlation with rainfall (r ≈ = -0.27) and indicating that unregulated water extraction, khat cultivation, and erosion were the primary drivers. Remarkably, the lake recovered to 2.73 km² by 2024 following integrated watershed management and conservation interventions, demonstrating that while human activities caused the lake’s collapse, targeted restoration and sustainable water resource governance can reverse ecosystem degradation and foster recovery A 34-year (1990–2024) spatiotemporal analysis was conducted on Lake Haramaya using Multi-Spectral (Landsat and Sentinel-2) and SAR (Sentinel-1) imagery. Satellite Data were processed through the Digital Earth Africa Open Data Cube (ODC) and Water Observations from Space (WOfS) algorithm. The lake’s surface area declined by 87.5%, from 3.77 km² (1990) to 0.47 km² (2020), with near-total desiccation in 2005 and 2017. The correlation between lake extent and rainfall was weak (r ≈ = -0.27). Major drivers included unregulated water extraction, khat cultivation, urban and domestic water use, and catchment erosion. Post-2020, the lake recovered to 2.73 km² (2024) following integrated watershed rehabilitation-a forestation, and conservation programs. Present the potential for ecological recovery through community-based restoration and sustainable water resource management.