Reversing land degradation through effective sustainable land management practices in the Abaya-Chamo Lake basins

PROJECT DESCRIPTION

Land degradation including soil acidification and salinization, erosion by runoff, gullying and landslides, and sediment transport to the lakes Abaya and Chamo s sub-basins, is a major threat for agricultural productivity, land and lake biodiversity, and economic growth. These challenges highly impact the livelihood of the subsistence farmers in the lake's basin. In phase-I of the AMU-IUC P4 sub-project, key land degradation problems were identified; their process and controlling factors were better understood. In phase-II, these land degradation problems will be addressed or reversed in selected sub catchments by identifying, testing and demonstrating the added value of effective Sustainable land Management (SLM) practices, and linking land degradation processes to the evolution of the lakes. Although SLM practices have been studied for many years and some are implemented in the study region, their effectiveness and the conditions favoring their implementation by small-holder farmers have not yet been studied, leading to haphazard and limited level of implementation. Among the Sustainable Development Goals (SDG), our project will contribute to 7 SDG goals: SDG1 No Poverty, SDG2 Zero Hunger (3), SDG4 Quality Education, SDG5 Gender Equality (fair woman representation in RSP4 and engaging women in SLM practices), SDG13 (2) Climate Action, SDG14 Life below Water and SDG15 Life on Land (1).

Soil degradation is a common challenge in the Abaya-Chamo catchment. In phase-I, the major problems were identified in three elevation zones along the mountain transect: upland, midland, and lowland (land and lake) regions. In the upland, the major problems are soil acidity and soil nutrient deterioration. In the upland, the major causes identified for these are sheet/rill soil erosion, poor agricultural land management practices, crop harvest loss (poor soil nutrient input) and geological processes (e.g., parent materials). In the midland, the identified challenges are soil fertility decline manifested by biodiversity loss and decrease in agricultural productivity. In this zone, the key causes for these problems are gully erosion and landslides. In the lowland, the identified problems are soil salinity and poor agricultural productivity. The major causes for these are poor irrigation practices (poor irrigation water management) and using lake water for irrigation. SLM practices mitigating negative impacts on agriculture neither have been systematically documented and their effectiveness verified, nor are they applied widely across the affected catchments. In the lakes, challenges include sediment load, abrupt changes in lake levels and surface area, poor water quality, and decline in fish (aquatic) productivity. Intense erosion in upland and sediment transport by rivers into the lake are considered as major causes. The perceived changes in rainfall patterns associated with global warming can also be considered as causative factor. However, the water and sediment budget at the level of individual river catchment, contributing to the lakes Abaya and Chamo evolution, have not yet been estimated for the current and future climate scenarios, raising the challenge to identify best management strategies to preserve the Lake ecosystems.

PROJECT RELATED PUBLICATIONS
Articles
1. Belayneh, L., Dewitte, O., Gulie, G., Poesen, J., O’Hara, D., Kassaye, A., ... & Kervyn, M. (2022). Landslides and Gullies Interact as Sources of Lake Sediments in a Rifting Context: Insights from a Highly Degraded Mountain Environment. Geosciences, 12(7), 274.
2. Tilahun, A. K., Verstraeten, G., Chen, M., Gulie, G., Belayneh, L., & Endale, T. (2022). Temporal and spatial variability of suspended sediment rating curves for rivers draining to the Ethiopian Rift Valley. Land Degradation & Development. https://doi.org/10.1002/LDR.4473
3. Shano, L., Raghuvanshi, T. K., & Meten, M. (2022). Fuzzy set theory and pixel-based landslide risk assessment: the case of Shafe and Baso catchments, Gamo highland, Ethiopia. Earth Science Informatics, 1-14.
4. Shano, L., Raghuvanshi, T. K., & Meten, M. (2021). Landslide susceptibility mapping using frequency ratio model: the case of Gamo highland, South Ethiopia. Arabian Journal of Geosciences, 14(7), 1-18.
5. Shano, L., Raghuvanshi, T. K., & Meten, M. (2022). Landslide Hazard Zonation using Logistic Regression Model: The Case of Shafe and Baso Catchments, Gamo Highland, Southern Ethiopia. Geotechnical and Geological Engineering, 40(1), 83-101.
6. Endale, T., Diels, J., Tsegaye, D., Kassaye, A., Belayneh, L., & Verdoodt, A. (2022). Farmer-science-based soil degradation metrics guide prioritization of catchment-tailored control measures. Environmental Development, 100783.

Reviews
1. Shano, L., Raghuvanshi, T. K., & Meten, M. (2020). Landslide susceptibility evaluation and hazard zonation techniques–a review. Geoenvironmental Disasters, 7(1), 1-19.

Conference Abstract
1. Spatial and Temporal Variability in Suspended Sediment Yield for two tropical mountain catchments draining into the Southern Ethiopian Rift Valley (oral presentation)
2. The paleoenvironmental history of the wetland Gelba in the Gamo Highlands of Ethiopia: a Holocene vegetation reconstruction with sedimentary ancient DNA (involved as co-author)(Tilahun et al., 2022)

MSc Theses Supervised
1. Fikiru Damte et al., (2020) Effects of River Morphological change on Kulfo river Flooding. Mr. Fikiru Damte Darota (Arba Minch University, Master of Science in Hydraulics and Water Resources Engineering, Graduation year, 2020)
2. Ayele Bekele et al., (2021) Quantification of Sediment Yield using observed data and sediment export model at Elgo catchment: A Case of Rift valley basin Chamo lake. Mr. Ayele Bekele Mekonnen (Arba Minch University, Master of Science in Hydraulics and Water Resources Engineering, Graduation year 2021)
3. Sara S. et al., (2021) The spatial distribution of riverbank erosivity in two tropical highland rivers The Elgo and Shafe catchments, Ethiopia. Sara Stoffel (Joint Master of VUB and KU Leuven, Master of Science in Geography, Graduation year 2021)
4. Nansol et al., (2021) Alluvial fan dynamics for rivers draining to Lake Abaya and Lake Chamo, Southwest Ethiopia. Nansol Choi., (VUB, Master of Science in Geography, Graduation year 2021)
5. Monika Barač (Master of Sciences in water engineering, Graduation year 2020). Thesis title: Soil salinization in the lowlands of Sile - Elgo interfluve near Arba Minch, Ethiopia
6. Feleke Faltamo (Master of Sciences in watershed management Graduation year 2021, Department of natural resource management). Thesis title: Effects of soil bund on selected physio-chemical properties of soil in deli sub-watershed Tercha district, Dawuro zone, Southern Ethiopia
7. Dusha Dunse (Master of sciences in watershed management, Graduation year 2021, Department of natural resource management). Thesis title: Evaluating the effectiveness of soil and water conservation measures on soil physicochemical properties in Baba watershed of Bonke district
8. Habtamu Abera (2020). Community-based Analysis of Causes, Impacts, and controlling measures of Gullies and landslides in Abaya-Chamo Catchment, Southern Ethiopia (MSc in Geography and end Environmental studies, Arba Minch University).
9. Abiyot Akirso Shago (2020), Impact of land cover dynamics on vegetation density and land surface temperature distribution: The case of Abaya-Chamo Lake catchment, southern Ethiopia.