Authors:
[ Etafa Emama Ligdi ] - Water
Resources and Watershed Management, Water Resources R&D
Directorate, Ministry of Water and Energy, Ethiopia; and Freelance
consultant
Management Research Group, Antwerp (Wilrijk), Belgium
 Abstract:
The paper forms part of an UNESCO-IHP’s FRIEND/ Nile-phase II
Project with an overall aim of using ecohydrology as an important tool
for integrated water resource management, IWRM in improving the
sustainability of freshwater resources in the Nile basin. With a case
study site at Lake Tana in Northwestern Ethiopia, the main objective of
the study was to conduct a background preliminary review and investigate
the sedimentation status of the lake and 15 reservoirs (in 6 river
basins) in Ethiopia to recognize prospects and explore the possibility
for sustainable sediment management in inland water bodies in the
country. In an overall conclusion, the study demonstrated that several
of the inland waterbodies considered here-in exhibit extremely high
values of catchment sediment yield (incoming sediment loads) and
sedimentation rates resulting in severe economic, social, and
environmental concerns. It also revealed that most of the artificial
storage facilities (reservoirs) exhibitphysical limitations hampering
the use of hydrologic sediment management techniques such as flushing
and sluicing. The study further implicated that sedimentation was only
an aspect of the anthropogenic effects/threats to the water ecosystems,
and it is usually linked up with other correlated/associated adverse
ecological and hydrological effects. Besides, emerging new and /or
exacerbated ecological and hydrological conditions previously
unaccounted for are resulting in deterioration of quantity and quality
of water, loss of ecosystem services and eutrophication of water bodies.
Hence, the study verified that most of the storages facilities in the
country generally require separate and /or additional complementary
sediment management options to reduce their sedimentation and associated
problems. As a consequence, it was deduced that ecohydrology and
phytotechnology, in complement to the conventional hydro technical
technologies, has the potential to address the problems of sedimentation
and the associated adverse effects. Moreover, future research areas
were recommended along with suggestion of some
potential phyto-technologies for trial and use in the case study area.
Finally, the summary of the identified ecohydrological issues of the
case study area, existing knowledge gaps, and proposals on ways to fill
them were acknowledged and presented.
Keywords:
FRIEND/Nile II, reservoir sedimentation, anthropogenic effects,
sediment loads, controlling sediment yield, ecohydrological system
solutions, knowledge gaps.
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