Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Combined 3D Hydrodynamic and Watershed Modelling of Lake Tana, Ethiopia
KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik, Vattendragsteknik.
KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik, Vattendragsteknik.
2011 (engelsk)Inngår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 398, nr 1-2, 44-64 s.Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

 The growing high demand for lake Tana water portends a disturbing future. The main objective of this paper is to make a contribution to the development of a sustainable use of the water of Lake Tana. A fully three-dimensional hydrodynamic model was combined with a watershed model and together, these models were successfully validated for the year 2006. The flow structure is characterized by large recirculation and secondary flow regions. Secondary flows are induced by hydrodynamic instabilities occurring at the interfaces of layers with a velocity gradient and the interaction with the irregularities of the bed. The weak stratification process in Lake Tana is characterized by a classic summer profile, which is more pronounced during January-February. Mixing processes in the lake are controlled by wind, the mixing energy induced by both river inflows and the lake outlet, and convective mixing due to the negative buoyancy. An alarming fall of the water levels in Lake Tana was found in response to the planned water withdrawal. The long flushing time (19 months) will not allow a fast decay of contaminated materials released into the lake. The flow structure will not be significantly modified by the planned water withdrawal but the flushing time will decrease. The hydrodynamics of Lake Tana resemble a closed system similar to a shallow reservoir with an overflow type outlet. The implication is that the lake is vulnerable to changes in external conditions and sustainable use of the water resource of the lake will require awareness of this vulnerability. The combined watershed and hydrodynamic models would be effective tools to achieve this awareness. It is also necessary to address the impact of climate change on the fate of the lake. These are all difficult challenges that need to be addressed to safeguard the sensitive eco-system of the area.

sted, utgiver, år, opplag, sider
2011. Vol. 398, nr 1-2, 44-64 s.
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-12023DOI: 10.1016/j.jhydrol.2010.12.009ISI: 000287267600005Scopus ID: 2-s2.0-78951473738OAI: oai:DiVA.org:kth-12023DiVA: diva2:294424
Merknad
QC 20110307 Ändrad från submitted till published 20110307Tilgjengelig fra: 2010-02-17 Laget: 2010-02-17 Sist oppdatert: 2017-12-12bibliografisk kontrollert
Inngår i avhandling
1. Modelling Hydrological and Hydrodynamic Processes in Lake Tana Basin, Ethiopia
Åpne denne publikasjonen i ny fane eller vindu >>Modelling Hydrological and Hydrodynamic Processes in Lake Tana Basin, Ethiopia
2010 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Lake Tana Basin is of significant importance to Ethiopia concerning water resources aspects and the ecological balance of the area. The growing high demands in utilizing the high potentials of water resource of the Lake to its maximal limit, pictures a disturbing future for the Lake. The objective of this study was to assess the influence of topography, soil, land use and climatic varia-bility on the hydrological and hydrodynamic processes of the Lake Tana Basin. The physically based SWAT model was successfully calibrated and validated for flow and sediment yield. Se-quential uncertainty fitting (SUFI-2), parameter solution (ParaSol) and generalized likelihood un-certainty estimation (GLUE) calibration and uncertainty analysis methods were compared and used for the set-up of the SWAT model. There is a good agreement between the measured and simulated flows and sediment yields. SWAT and GIS based decision support system that uses multi-criteria evaluation (MCE) was used to identify the most vulnerable areas to soil erosion in the basin. The results indicated that 12 to 30.5% of the watershed is high erosion potential. Pro-jected changes in precipitation and temperature in the basin for two seasons were analyzed using outputs from fifteen global climate models (GCMs). A historical-modification procedure was used to downscale large scale outputs from GCM models to watershed-scale climate data. The results showed significant changes in streamflow and other hydrological parameters in the period between 2045-2100. SWAT was combined with a three dimensional hydrodynamic model, GEMSS to investigate the flow structure, stratification, the flushing time, lake water balance and finally the Lake‘s water level response to planned water removal. We have found an alarming and dramatic fall of the water levels in Lake Tana as response to the planned water withdrawal. The combination of the two models can be used as a decision support tools to better understand and manage land and water resources in watersheds and waterbodies. The study showed that the Lake Tana Basin may experience a negative change in water balance in the forthcoming decades due to climate change as well as over abstraction of water resources.

sted, utgiver, år, opplag, sider
Stockholm: KTH, 2010. viii, 66 s.
Serie
Trita-LWR. PHD, ISSN 1650-8602 ; 1057
Emneord
Lake Tana, Climate Change, SWAT, Hydrological Modeling, Hydrodynamic, GEMSS, MCE, Streamflow, Sediment yield
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-12024 (URN)978-91-7415-558-7 (ISBN)
Disputas
2010-03-05, F3, Lindstedtsvägen 26, KTH, Stockholm, 10:15 (engelsk)
Opponent
Veileder
Merknad
QC 20100720Tilgjengelig fra: 2010-02-17 Laget: 2010-02-17 Sist oppdatert: 2018-01-12bibliografisk kontrollert

Open Access i DiVA

Fulltekst mangler

Andre lenker

Forlagets fulltekstScopus

Søk i DiVA

Av forfatter/redaktør
Dargahi, BijanSetegn, Shimelis Gebriye
Av organisasjonen
I samme tidsskrift
Journal of Hydrology

Søk utenfor DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric

doi
urn-nbn
Totalt: 189 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf