Erratum to: “The Ziway–Shala lake basin system, Main Ethiopian Rift: Influence of volcanism, tectonics, and climate forcing on basin formation and sedimentation” [Palaeogeography, Palaeoclimatology, Palaeoecology 150 (1999) 135–177]

2000 ◽  
Vol 156 (1-2) ◽  
pp. 175-176
Author(s):  
Caroline Le Turdu ◽  
Jean-Jacques Tiercelin ◽  
Elisabeth Gibert ◽  
Yves Travi ◽  
Kiram-Eddine Lezzar ◽  
...  
Keyword(s):  
Climate Forcing ◽  
Ethiopian Rift ◽  
Lake Basin ◽  
Main Ethiopian Rift ◽  
Basin Formation ◽  
Basin System

The Ziway–Shala lake basin system, Main Ethiopian Rift: Influence of volcanism, tectonics, and climatic forcing on basin formation and sedimentation

1999 ◽  
Vol 150 (3-4) ◽  
pp. 135-177 ◽  
Author(s):  
Caroline Le Turdu ◽  
Jean-Jacques Tiercelin ◽  
Elisabeth Gibert ◽  
Yves Travi ◽  
Kiram-Eddine Lezzar ◽  
...  
Keyword(s):  
Ethiopian Rift ◽  
Lake Basin ◽  
Climatic Forcing ◽  
Main Ethiopian Rift ◽  
Basin Formation ◽  
Basin System

scholarly journals AMS-14C Chronology of a Lacustrine Sequence from Lake Langano (Main Ethiopian Rift): Correction and Validation Steps in Relation with Volcanism, Lake Water and Carbon Balances

Radiocarbon ◽  
2002 ◽  
Vol 44 (1) ◽  
pp. 75-92 ◽  
Author(s):  
Elisabeth Gibert ◽  
Yves Travi ◽  
Marc Massault ◽  
Jean-Jacques Tiercelin ◽  
Tesfaye Chernet
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Regional Scale ◽  
Ethiopian Rift ◽  
Lake Basin ◽  
Main Ethiopian Rift ◽  
Tectonically Active ◽  
Half Graben ◽  
Rift Lake ◽  
The 1960S ◽  
Radiocarbon Chronology

Located in the Ziway-Shala Basin of the Main Ethiopian Rift, Lake Langano is part of an asymmetric half-graben, defined by a series of north-northeast-trending faults in the tectonically active zone of the rift. A 15-m deep succession of organic homogeneous muds, silts, bioclastic sands, and pyroclastic layers was cored in 1994. The definition of a certified radiocarbon chronology on these deposits required the indispensable establishment of modern hydrological and geochemical balances. The isotopic contents of the total dissolved inorganic carbon (TDIC) of surface water clearly show the influence of a deep CO2 rising along the main fault crossing the lake basin. The 5.8 pMC disequilibrium existing in 1994 with the atmosphere likely produces the aging of authigenic materials developing at the lake surface. However, with a mean residence time of ~15 years, this apparent 14C aging of Lake Langano water still integrates the 14C produced by the nuclear tests in the 1960s. Reconstructing the natural 14C activity of the lake TDIC allows for the quantification of the deep CO2 influence, and for the correction of AMS-14C datings performed along the core. The correction of the AMS-14C chronology defined on Lake Langano allows for a better understanding of paleohydrological changes at a regional scale for at least the last 12,700 cal BP.

scholarly journals The effect of hydrogeological and hydrochemical dynamics on landslide triggering in the central highlands of Ethiopia

2021 ◽  
Vol 29 (3) ◽  
pp. 1239-1260
Author(s):  
Tesfay Kiros Mebrahtu ◽  
Andre Banning ◽  
Ermias Hagos Girmay ◽  
Stefan Wohnlich
Keyword(s):  
Hydrostatic Pressure ◽  
Groundwater Flow ◽  
Volcanic Rocks ◽  
Chemical Characterization ◽  
Unconsolidated Sediments ◽  
Ethiopian Rift ◽  
Main Ethiopian Rift ◽  
Groundwater Level Fluctuations ◽  
Landslide Mass ◽  
Landslide Triggering

AbstractThe volcanic terrain at the western margin of the Main Ethiopian Rift in the Debre Sina area is known for its slope stability problems. This report describes research on the effects of the hydrogeological and hydrochemical dynamics on landslide triggering by using converging evidence from geological, geomorphological, geophysical, hydrogeochemical and isotopic investigations. The chemical characterization indicates that shallow to intermediate aquifers cause groundwater flow into the landslide mass, influencing long-term groundwater-level fluctuations underneath the landslide and, as a consequence, its stability. The low content of total dissolved solids and the bicarbonate types (Ca–Mg–HCO3 and Ca–HCO3) of the groundwater, and the dominantly depleted isotopic signature, indicate a fast groundwater flow regime that receives a high amount of precipitation. The main causes of the landslide are the steep slope topography and the pressure formed during precipitation, which leads to an increased weight of the loose and weathered materials. The geophysical data indicate that the area is covered by unconsolidated sediments and highly decomposed and weak volcanic rocks, which are susceptible to sliding when they get moist. The heterogeneity of the geological materials and the presence of impermeable layers embodied within the highly permeable volcanic rocks can result in the build-up of hydrostatic pressure at their interface, which can trigger landslides. Intense fracturing in the tilted basalt and ignimbrite beds can also accelerate infiltration of water, resulting to the build-up of high hydrostatic pressure causing low effective normal stress in the rock mass, giving rise to landslides.

scholarly journals Water Quality Threats, Perceptions of Climate Change and Behavioral Responses among Farmers in the Ethiopian Rift Valley

Climate ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 92
Author(s):  
Tewodros R. Godebo ◽  
Marc A. Jeuland ◽  
Christopher J. Paul ◽  
Dagnachew L. Belachew ◽  
Peter G. McCornick
Keyword(s):  
Climate Change ◽  
Water Quality ◽  
Surface Water ◽  
Water Availability ◽  
Agricultural Sector ◽  
Local Development ◽  
Irrigated Agriculture ◽  
Ethiopian Rift ◽  
Adaptation Mechanism ◽  
Main Ethiopian Rift

This work aims to assess water quality for irrigated agriculture, alongside perceptions and adaptations of farmers to climate change in the Main Ethiopian Rift (MER). Climate change is expected to cause a rise in temperature and variability in rainfall in the region, reducing surface water availability and raising dependence on groundwater. The study data come from surveys with 147 farmers living in the Ziway–Shala basin and water quality assessments of 162 samples from groundwater wells and surface water. Most groundwater samples were found to be unsuitable for long term agricultural use due to their high salinity and sodium adsorption ratio, which has implications for soil permeability, as well as elevated bicarbonate, boron and residual sodium carbonate concentrations. The survey data indicate that water sufficiency is a major concern for farmers that leads to frequent crop failures, especially due to erratic and insufficient rainfall. An important adaptation mechanism for farmers is the use of improved crop varieties, but major barriers to adaptation include a lack of access to irrigation water, credit or savings, appropriate seeds, and knowledge or information on weather and climate conditions. Local (development) agents are identified as vital to enhancing farmers’ knowledge of risks and solutions, and extension programs must therefore continue to promote resilience and adaptation in the area. Unfortunately, much of the MER groundwater that could be used to cope with declining viability of rainfed agriculture and surface water availability, is poor in quality. The use of saline groundwater could jeopardize the agricultural sector, and most notably commercial horticulture and floriculture activities. This study highlights the complex nexus of water quality and sufficiency challenges facing the agriculture sector in the region, and should help decision-makers to design feasible strategies for enhancing adaptation and food security.

scholarly journals The basin-landscape approach to the protection and condition optimization of the lakes of the national parks

2020 ◽  
Keyword(s):  
National Parks ◽  
Practical Importance ◽  
Ecological Status ◽  
Nature Management ◽  
Lake Basin ◽  
Landscape Approach ◽  
Nature Protection ◽  
Landscape Characteristics ◽  
Condition Optimization ◽  
Basin System

The essence of the basin-landscape approach to the protection of the lakes of the national parks as an actual direction of research, which is formed at the junction of nature protection landscaping, hydrology and geoecology has been substantiated. The research algorithm, peculiarities of analysis and assessment of the status of the lake-basin system (LBS) have been found out, the factors that worsen the geo-ecological state in the lake and basin subsystems have been revealed, optimization measures in the objects of the nature reserve fund located within the natural reserve have been substantiated. The purpose of the study is to determine the parameters of the structure of lake-basin landscapes (on the example of Zasvitske lake, Nobel National Natural Park, Ukraine), liminary and landscape-metric indicators of the geo-ecological status of the LBS and the factors influencing it as an information and analytical basis for ensuring the protection and management of the LBS located in nature conservation area. The materials of the study were the long-term field landscape-limnological and geo-ecological studies of the authors within the Polesia region of Ukraine and, in particular, the LBS of the Nobel National Nature Park. The research methodology was based on complex physical-geographical methods, hydrological profiling and creation of bathymetric models of reservoirs, hydrochemical diagnostics of water masses of the lakes, geochemical analyses of bottom sediments, landscape mapping using GIS-technologies. The results of geo-ecological (landscape-ecological) researches of the lake-basin system of Zasvitske lake have been presented, in particular, original profiles and bathymetric model of the reservoir, landscape maps of the aqual complex and the lake catchment, limno- and landscape characteristics of the LBS have been shown. Considering the level of anthropogenic transformations of the LBS and the presence of a high proportion of ecologically-stabilizing lands (forests, reservoirs of natural origin), the level of sustainability of the LBS is estimated as high. An assessment of the hydrological characteristics of the reservoir and hydrochemical characteristics allows to attribute this lake to an oligotrophic type. The results of a comprehensive analysis of the geo-ecological parameters of the state of Zasvitske lake and its landscape-limnological functioning indicate the expediency of recreational specialization of nature management in the Nobel National Park, that includes this lake. Scientific novelty. The application of proposed landscape-basin approach and the algorithm of the LBS study increase the possibilities of functional zoning of national parks with high index of lakes, as well as solving the problems of nature protection and optimization of nature management. Practical importance. The created electronic landscape maps and the base of limnometric parameters can be used as reference documents for the certification and cadastral evaluation of the transboundary protected areas of Ramsar type, geo-ecological monitoring and an integrated management of lakes by the basin approach in conditions of intense climate change.

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