3 research outputs found
A systematic review of studies on freshwater lakes of Ethiopia
Get PDFStudy Region: The study covers the freshwater lakes of Ethiopia, which constitute about 87 billion cubic meters of water volume. The lakes are facing continued ecosystem degradation threats. Study Focus: The aim of this study was to make an inventory of existing literature regarding the freshwater lakes of Ethiopia and identify gaps and priorities for future research directions. This was done through a systematic review of published scientific literature related to the lakes and characterizing each study based on different criteria. New Hydrological Insights for the Region: We found a total of 231 articles on freshwater lakes of Ethiopia published in peer-reviewed journals between 1930 and March 2021. Most studies were focused on hydrochemical and biological characteristics of lakes, with less attention to physical structure and processes (including siltation, lake morphometry and catchment biophysical characteristics). Furthermore, (a) less attention was given to the spatial and temporal dynamics of variables that affect the freshwater lakes, (b) there was limited linkage between landscape hy drological dynamics and freshwater lakes and (c) the smaller highland lakes were given limited attention. Future research should be oriented to the study of the relationship between catchment biophysical dynamics and lake hydrological characteristics
Multispectral remote sensing of the impacts of drought and climate variability on water resources in semi-arid regions of the Western Cape, South Africa
Get PDF>Magister Scientiae - MScThe occurrence of droughts is a threat to global water resources and natural ecosystems, with the impact being more profound in semi-arid environments. The frequency of droughts is likely to increase because of climate change, and this poses a huge threat to the available water resources, to livelihoods and to ecosystems. Routine drought monitoring is fundamental for developing an early warning system and an area-specific drought mitigation and adaptation framework. Surface waterbodies, especially those in arid and semi-arid environments, are vulnerable to the impacts of drought. The development of moderate-resolution sensors, such as the Landsat 8 Operational Land Imager (OLI) and the Sentinel-2 Multispectral Instrument (MSI), allow new opportunities to monitor droughts and their impact on surface waterbodies
Combining multisource satellite data to estimate storage variation of a lake in the Rift Valley Basin, Ethiopia
Get PDFIntegration of remote sensing data sets from multiple satellites is tested to simulate water storage variation of Lake Ziway, Ethiopia for the period 009-2018. Sixty Landsat ETM+/OLI images served to trace temporal variation of lake surface area using a water extraction index. Time series of lake levels were acquired from two altimetry databases that were validated by in-situ lake level measurements. Coinciding pairs of optical satellite based lake surface area and radar altimetry based lake levels were related through regression and served for simulating lake storage variation. Indices for extracting lake surface area from images showed 91–99 % overall accuracy. Lake water levels from the altimetry products well agreed to in-situ lake level measurements with R2=0.92 and root mean square error of 11.9 cm. Based on this study we conclude that integrating satellite imagery and radar altimetry is a viable approach for frequent and accurate monitoring of lake water volume variation and for long-term change detection. Findings indicate water level reduction (4 cm/annum), surface area shrinkage (0.08km2/annum) and water storage loss (20.4Mm3/annum) of Lake Ziway (2009–2018)
