Geospatial Analysis of Wetland Dynamics on Lake Abaya-Chamo, The Main Rift Valley of Ethiopia.

Wetlands worldwide and in Ethiopia have long been subject to severe degradation due to anthropogenic factors. This study was aimed at analyzing the impact of land use/land cover dynamics on Lake Abaya-Chamo wetland from 1990-2019. Data were acquired via Landsat TM of 1990, ETM+ of 2000, and OLI of 2010 and 2019 images plus using interview. Supervised classifications (via ERDAS14 and ArcGIS10.5) were applied to detect land use/land cover classes. Change matrix model and Kappa coefficients were used for analysis of the land use/land cover dynamics in the lake-wetland. It was found that forest; water body, shrub land, agricultural land, settlement and swamp area were the main land use/land cover classes. Wetland/swamp area has continuously declined throughout 1990-2000, 2000-2010 and 2010-2019 where its magnitude of shrinkage in the respective periods was 11.4 % (700 ha), 16 % (867 ha) and 31.3 % (1,424 ha). While 'settlement' and 'water body' of the lake-wetland increased at progressively increasing magnitudes of changes in three periods within 1990-2019, 'shrub land' and wetland/'swamp' declined at progressively increasing magnitudes of loss in the same periods. Siltation, rapid population growth-led expansion of settlement and irrigation-based farming were the main drivers of the land use/land cover dynamics and degradation of the lake-wetland. Thus, consistent mapping and integrated actions should be taken to curb the threats on the sustainability of the lake-wetland in Southern Ethiopia. To reduce the impact of LULC dynamics on wetlands, the regime should: advance a clear political, institutional and legal framework for wetland management.