Environmental and Social Impact Assessment - Gibe III

Gibe III – Environmental and Social Impact Assessment 300 ENV R CS 002 C - A9003099
Project
Scheme
Installed
capacity
Gibe I 184 MW
Gibe II 420 MW
Table 7.6: List of Existing and Proposed Hydropower Project
Time Frame
In operation since
2004
Under construction
and expected to be
commissioned by
end of 2009
Gibe III 1870 MW Under construction
Gibe IV 2000 MW
Under planning
stage
Distance from
Gibe III (km)
260 km upstream
Gibe III and 110
km from Gibe II
150 km upstream
160 km
downstream of
Gibe III
Cumulative
Resource
Water Resources
Water Quality
Fishery resources
Forestry and
natural vegetation
wildlife and
wildlife habitat
Socio-Economics
cultural heritage
sites
Agriculture and
grazing resources
Remark
A 40 m high dam was sufficient to
obtain a reservoir with a required
storage capacity. This regulates the
Gilgel Gibe river with a reservoir of
839 Mm 3 total storage and has a
gross head of 240 m.
It exploits the very large geodetic
head (i.e 505 m) existing between
the Gilgel Gibe river and the Omo
River by constructing a 26 km long
tunnel, which makes use of the
water regulated by the Gibe I
hydroelectric scheme
It comprises a 240 m high dam and
creates a reservoir with a surface
area of some 200 km 2
The Gibe IV is the last plant of the
cascade that uses entirely the
hydroelectric potential resources of
the Omo River. It is located 160 km
downstream of the Gibe III scheme
This section of the ESIA report briefly presents the cumulative impact assessment result. The objective is to
ensure that large-scale and potentially significant cumulative impacts if there are any will not be ignored and
will be addressed in the planning, design and operation phases of these projects.
Cumulative impacts are defined in CEQA Guidelines as two or more individual effects that together create a
considerable environmental impact or that compound or increase other impacts. “A cumulative impact
occurs from the change in the environment, which results from the incremental impact of the project when,
added to other closely related past, present, and reasonably foreseeable probable future projects. Cumulative
impacts can result from individually minor but collectively significant projects taking place over a period of
time” (guidelines 15355 [b]).
CESI SpA - Mid-Day International Consulting Engineers Page 237