Environmental and Social Impact Assessment - Gibe III
Environmental and Social Impact Assessment - Gibe III
Environmental and Social Impact Assessment - Gibe III
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<strong>Gibe</strong> <strong>III</strong> – <strong>Environmental</strong> <strong>and</strong> <strong>Social</strong> <strong>Impact</strong> <strong>Assessment</strong> 300 ENV R CS 002 C - A9003099<br />
The biomass of the woodl<strong>and</strong> on the hill slopes at Terraces II <strong>and</strong> <strong>III</strong> was estimated in 20m x 20m (400 m 2 )<br />
at three different sites. Biomass of the forest vegetation in terrace IV was estimated at two different sites.<br />
The geographical coordinate of each stop is recorded as degree decimal <strong>and</strong> UTM using a Garmin GPS.<br />
The presence of terrestrial <strong>and</strong> aquatic animals species i.e. insects, lizards, birds, primates, ungulates,<br />
warthogs, forest hogs, porcupines, various ungulates <strong>and</strong> their predators <strong>and</strong> aquatic animal species such as<br />
fish, crocodiles <strong>and</strong> hippos as well as birds were noted <strong>and</strong> their food web speculated.<br />
Omo Valley is part of the Broad-leaved deciduous woodl<strong>and</strong> of Western Ethiopia described in Pichi-Sermoli<br />
1957. The vegetation on the hill slopes of the valley is characterized by deciduous phenology of the<br />
woodl<strong>and</strong> species which shed their leaves during the dry season <strong>and</strong> regain them during the wet season as an<br />
adaptive mechanism for the prolonged dry season. Important species include Boswellia pirote, Lannea<br />
schimperi, Anogeissus leiocarpus, Terminallia browni, Combretum molle, Tamarindus indica,<br />
Stereospermum kunthianum <strong>and</strong> Gardenia ternifolia. There is also a distinct narrow zone of riparian<br />
vegetation along river <strong>and</strong> stream banks owing to the relatively moist conditions Pichi-Sermoli (1957). The<br />
species composition of the riparian vegetation is similar to that of the hill slopes except that the individual<br />
trees are larger in size.<br />
The altitudinal ranges, temperature, humidity <strong>and</strong> the floristic <strong>and</strong> physiognomy composition of the<br />
vegetation in the Omo river basin along with the system in <strong>Gibe</strong> Basin provide ideal conditions for Tsetse fly<br />
infestation (Getachew, 1983; NMSA, 1996; Reid, R., et al. 1997, Reid et al., 2000).<br />
5.2.2.1 Forest <strong>and</strong> Vegetation Resources<br />
The existing vegetation in the project area is broadly classified into two parts, namely the woodl<strong>and</strong> <strong>and</strong> the<br />
riparian. However, the proposed reservoir area is neither contiguous with, nor in close proximity with any of<br />
the nationally or regionally protected forest areas.<br />
The l<strong>and</strong>scape on either side of the valley had four distinct terraces, terrace I on the plateau (above 2300 m<br />
asl), Terrace II at 1600 m asl, Terrace <strong>III</strong> at 1000 <strong>and</strong> Terrace IV at the river bank.<br />
The dry woodl<strong>and</strong> l<strong>and</strong>scape can be partitioned into three distinct types (Pichi-Semoli, 1957) namely:<br />
• the highl<strong>and</strong> vegetation which is remnant of the vegetation of the plateau referred to as the dry<br />
evergreen mountain forest <strong>and</strong> the associated grassl<strong>and</strong>s at Terrace I;<br />
• the broadleaved deciduous woodl<strong>and</strong> of the low-lying altitude at terrace II <strong>and</strong> <strong>III</strong>; <strong>and</strong><br />
• the riparian vegetation at Terrace IV.<br />
The Highl<strong>and</strong> Vegetation: The highl<strong>and</strong> vegetation could be encountered on the plateau at 2300 m asl <strong>and</strong><br />
above at Wolayita, Waka <strong>and</strong> the vicinity before the dissent to the valley as part of the agroforestry system.<br />
The species include Erythrina brucei, Prunus africana, Podocarpus gracilior, Juniperus procera, Croton<br />
macrostachyus <strong>and</strong> Arunidnaria alpina interspaced in with enset <strong>and</strong> Eucalyptus plantations.<br />
The Lowl<strong>and</strong> Broadleaved Deciduous Woodl<strong>and</strong>: The plant species of the Omo Valley have over time<br />
developed adaptive mechanisms <strong>and</strong> traits that allow them either to survive fire, to germinate after the heat<br />
shock or to regenerate after a fire episode. The selective pressure of fire on the plant communities has<br />
produced plant species, which are fire resistant, or pyrophytes (Kuhnholtz-Lordat, 1938). In the Omo valley,<br />
the bush fires occur between late February <strong>and</strong> early April. The combination of climatic factors such as<br />
CESI SpA - Mid-Day International Consulting Engineers Page 125