Azura-Edo Independent Power Plant Environmental Impact ... - IFC

also be required for the burial of the pipeline. The vegetation clearing will
impact upon several aspects of the soil characteristics including water flow,
microbial activity and nutrient content. The removal of the topsoil will result
in alterations to the drainage and surface run-off regime on the site,
particularly during the wet season, reduce the fertility of the site and result in
the potential for increased erosion. There may be potential changes in
siltation patterns as a result of construction activities which will destabilize
soils potentially leading to soil erosion during heavy rainfall and
sedimentation in downstream water bodies. In addition, the compaction of
the soil will also reduce the permeability and water infiltration of the soil.
This may result in increased surface water during the wet season, and hence
effective site drainage will be key.
The presence of diesel on site during construction may also result in spillages
and soil contamination.
It is not expected that additional fill material will be required from offsite to
level the site. All fill used will be sourced from excavations on site.
Impact Significance
Thus the resulting impacts will be negative and both direct and secondary.
The changes observed on site will be permanent, beyond the life of the Project;
the scale of the impacts will be at a local level. The magnitude of the impacts
are therefore considered to be high.
The soils on the site are not considered to be of high agricultural value and
have been disturbed by anthropogenic activity (agricultural and construction).
There are no water bodies in the immediate vicinity of the site. The sensitivity
of the receptor is considered to be low.
The significance of the impacts are therefore considered to be moderate prior
to mitigation.
7.5.2 Impact Description and Significance: Operation
Impact Description
The area occupied by the buildings and the roads on site will be paved or
otherwise covered by a surface with low permeability. Thus the area paved or
thus covered is expected to be as low as 25 percent of the total site during the
OCGT plant construction and operation. The rest of the site area will be
covered with gravel or another form of highly permeable surface.
The area which will be covered by hard standing (or less permeable surface)
may result in increased soil surface runoff and consequently continued
erosion, leaching and nutrient loss of adjacent land during the operational
phase. This is particularly relevant due to the characteristic heavy rainfall in
AZURA EDO IPP
7-38
DRAFT EIA REPORT