dc.contributor.author | Olaka, L.A | |
dc.contributor.author | Trauth, M.H | |
dc.contributor.author | Kniess, U, | |
dc.contributor.author | Odada, E.O, | |
dc.contributor.author | Olago, D.O | |
dc.date.accessioned | 2013-06-10T15:57:37Z | |
dc.date.issued | 2011 | |
dc.identifier.uri | http://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/31087 | |
dc.description.abstract | The hydrogeology of rift lakes is complex due to the potential influence of faults and
porous volcanic and volcanoclastic media on groundwater flow. We conducted a
comprehensive study that integrated geological and hydrogeological data as well as the
application of a linear decay model to estimate the groundwater flow between the two of
the best-studied lake systems in East Africa, the adjacent Lakes Naivasha and Nakuru-
Elmenteita. Whereas both lake basins host relatively shallow lakes today, paleo-shorelines
and sediments suggest >100 m deep lakes. during a wetter climate during the Early
Holocene during the so-called African Humid Period. The linear-reservoir depletion
model simulates the decline of the Early Holocene lakes in both basins to the modern
levels. The altitude difference of ca. 100 m of both paleo-lake levels enables us to
estimate the duration of the groundwater decline and the connectivity of the two basins
via the Eburru/Gilgil barrier. The results suggest that a decline of the groundwater levels
during ca. 5 kyrs if there is no recharge, and between 2-2.7 kyrs with the modern
recharge of 0.52 mlyr as the end_members of the delay time introduced by subsurface
water flow to the hydrology of the lake system. The latter value suggests that ca. 31.5
cubic kilometres of water flowed from Lake Naivasha to Nakuru-Elmenteita at maximum lake level in the Early Holocene following the hydraulic gradient concurrent to
the topographic slope. The unexpectedly large volume, more than half of the volume of
the paleo-Lake Naivasha during the Early Holocene, emphasizes the importance of
groundwater in hydrological modelling of paleo-lakes in rifts Moreover, the subsurface
connectivity of rift lakes also causes a significant lag time to the system introduci.ng a
nonlinear component to the system that has to be considered while interpreting paleo-
lake records. | |
dc.description.sponsorship | The hydrogeology of rift lakes is complex due to the potential influence of faults and
porous volcanic and volcanoclastic media on groundwater flow. We conducted a
comprehensive study that integrated geological and hydrogeological data as well as the
application of a linear decay model to estimate the groundwater flow between the two of
the best-studied lake systems in East Africa, the adjacent Lakes Naivasha and Nakuru-
Elmenteita. Whereas both lake basins host relatively shallow lakes today, paleo-shorelines
and sediments suggest >100 m deep lakes. during a wetter climate during t~e Early
Holocene during the so-called African Humid Period. The linear-reservoir depletion
model simulates the decline of the Early Holocene lakes in both basins to the modern
levels. The altitude difference of ca. 100 m of both paleo-lake levels enables us to
estimate the duration of the groundwater decline and the connectivity of the two basins
via the Eburru/Gilgil barrier. The results suggest that a decline of the groundwater levels
during ca. 5 kyrs if there is no recharge, and between 2-2.7 kyrs with the modern
recharge of 0.52 mlyr as the end_members of the delay time introduced by subsurface
water flow to the hydrology of the lake system. The latter value suggests that ca. 31.5
cubic kilometres of water flowed from Lake Naivasha to Nakuru-Elmenteita at
maximum lake level in the Early Holocene following the hydraulic gradient concurrent to
the topographic slope. The unexpectedly large volume, more than half of rhe volume of
the paleo-Lake Naivasha during the Early Holocene, emphasizes the importance of
groundwater in hydrological modelling of paleo-lakes in rifts ~Ioreover, the subsurface
connectivity of rift lakes also causes a significant lag time to the system introduci.ng a
nonlinear component to the system that has to be considered while interpreting paleo-
lake records. | en |
dc.language.iso | en | en |
dc.title | The significance of groundwater flow for the hydrologic budgets of paleo-lakes in the East African rift | en |
dc.type | Article | en |
local.publisher | Department of Geology, University of Nairobi, | en |
local.publisher | Universite Joseph Fourier LGIT, | en |