Lake Giba
{{short description|Ethiopian reservoir}}
{{Infobox body of water
| name = Lake Giba
| image = Giba dam under construction.jpg
| caption = Construction site of Giba dam
| image_bathymetry =
|pushpin_map=Ethiopia Tigray Region
| caption_bathymetry =
| location = Inderta, Dogu’a Tembien, Kilte Awula'ilo woredas
| coords = {{coord|13.620559|N|39.402124|E|type:waterbody_region:ET|display=inline,title}}
| type = Freshwater artificial lake
| inflow = Sulluh, Genfel and Agula'i Rivers
| outflow = Giba River
| catchment = {{convert|2394|km²|abbr=on}}
| basin_countries = Ethiopia
| length = {{convert|7|km|abbr=on}}
| width = {{convert|1.5|km|abbr=on}}
| area = {{convert|9|km2|abbr=on}}
| depth =
| max-depth = {{convert|75|m|abbr=on}}
| volume = {{convert|350|e6m3|acre.ft|abbr=on}}
| residence_time =
| shore =
| elevation = {{convert|2320|m|abbr=on}}
| frozen =
| islands =
| reference =
}}
Lake Giba is a reservoir under construction at the border of the Inderta; Kilte Awula'ilo and Dogu’a Tembien woredas of the Tigray Region in Ethiopia.{{cite journal |last1=Gebremedhin Berhane |first1=and colleagues |title=Geological challenges in constructing the proposed Geba dam site, northern Ethiopia |journal=Bulletin of Engineering Geology and the Environment |date=2013 |volume=72 |issue=3–4 |pages=339–352 |doi=10.1007/s10064-013-0480-9 |s2cid=128713402 |id={{ProQuest|1655734342}} }} {{As of|2020|post=,}} the earthen dam that holds the reservoir is under construction. It will collect the water from the catchments of Sulluh (969 km2), Genfel (733 km2), and Agula'i (692 km2) rivers.{{cite journal |last1=Amanuel Zenebe |first1=and colleagues |title=Spatial and temporal variability of river flows in the degraded semi-arid tropical mountains of northern Ethiopia |journal=Zeitschrift für Geomorphologie |date=2013 |volume=57 |issue=2 |pages=143–169 |doi=10.1127/0372-8854/2012/0080 |bibcode=2013ZGm....57..143Z |url=https://lirias.kuleuven.be/handle/123456789/400687 }}
Dam characteristics
Capacity
Average annual sediment input to the reservoir by the main rivers was calculated as 3.8 million tonnes:{{cite journal |last1=Vanmaercke |first1=M. and colleagues |title=Sediment dynamics and the role of flash floods in sediment export from medium-sized catchments: a case study from the semi-arid tropical highlands in northern Ethiopia |journal=Journal of Soils and Sediments |date=2010 |volume=10 |issue=4 |pages=611–627 |doi=10.1007/s11368-010-0203-9 |s2cid=53365853 |url=https://biblio.ugent.be/publication/854315 |hdl=1854/LU-854315 |hdl-access=free }}
- Sulluh: 862,410 t
- Genfel: 364,301 t
- Agula'i River: 2,618,528 t
Flooding
The dam will occupy the wide valley bottom at the river confluences, which is currently occupied by farmlands and bushlands. The reservoir will extend into the lower Genfel and Suluh gorges, in a place called Shugu’a Shugu’i. No people are permanently living in the area that will be flooded. Current dryland villages Ch’in Feres (in Inderta), Addi Atereman and Worgesha (in Dogu’a Tembien) will become lakeshore villages, and Genfel church in the homonymous gorge will be on the edge of Lake Giba.{{cite book |last1=Jacob |first1=M |last2=Nyssen |first2=J |title=Geo-trekking in Ethiopia's Tropical Mountains |chapter=Geo-Trekking Map of Dogu'a Tembien (1:50,000) |date=2019 |publisher=Springer Nature |location=Cham (CH) |pages=531–536 |doi=10.1007/978-3-030-04955-3_36 |series=GeoGuide |isbn=978-3-030-04954-6 |s2cid=199232439 }}
Anticipated seepage
The lithology of the dam building site is Antalo Limestone. Part of its water is anticipated to be lost through seepage;{{cite journal |last1=Gebremedhin Berhane |first1=and colleagues |title=Water leakage investigation of micro-dam reservoirs in Mesozoic sedimentary sequences in Northern Ethiopia |journal=Journal of African Earth Sciences |date=2013 |volume=79 |pages=98–110 |doi=10.1016/j.jafrearsci.2012.10.004 |bibcode=2013JAfES..79...98B }} the positive side-effect is that this will contribute to groundwater recharge in the downstream areas.{{cite journal |last1=Nigussie Haregeweyn |first1=and colleagues |title=Reservoirs in Tigray: characteristics and sediment deposition problems |journal=Land Degradation and Development |date=2006 |volume=17 |pages=211–230 |doi=10.1002/ldr.698 |s2cid=129834993 |doi-access=free }}