Temperature - European Investment Bank

WEST AFRICAN POWER POOL (WAPP) PÖYRY ENERGY LTD.
Mount Coffee HPP ESIA and RAP 2012-09-18
ESIA Report Page 30
6.4 Impacts
The main impact on soils is the erosion and contamination of soils due to construction
activities.
6.5 Mitigation Measures
Good engineering practices will help controlling soil erosion both at construction sites
and in peripheral areas, particularly in borrow and dumping areas and along access
roads. Following measures have been mentioned:
� Install sediment traps
� Drainage channels where necessary
� Prevent steep slopes, define optimum height of work evaluating the instability of
the rock, soil etc.
� Stabilise, compact and strengthen steep slopes
� Adequate selection of road tracks, taking into account the landscape, technical
environmental and social aspects
� Construct drainage ditches at roads if there are passing through mountainous
area If the slope is more that 16 % they have to be paved
� install culverts with enough capacity for strong rains, drainage pipes and
channels have to be of an adequate size and should be equipped with screens at
entrance and exit points to reduce the risk of clogging
� Re-vegetation
Following mitigation measures should be implemented to reduce the contamination of
soils:
� The maintenance of machinery and lorries has to be done in work-shops, liquids
including cleaning water should be collected in tanks.
� Storage of fuel and lubricants has to be in tight containers placed on sealed
surfaces under nice a roof. The storage has to be equipped with all safety
measures to prevent oil spilling including fire fighting equipment. The area
needs to be marked.
� In the case of an oil spill sufficient quantities of oil absorbent have to be stocked.
The contaminated absorbent has to be disposed of properly.
� Hazardous waste has to be stored in designated closed tanks or areas.
� Solid waste generated during construction and at campsites will be properly
treated and safely disposed of only in demarcated waste disposal sites.
� All activities which could contaminate the soil have to be carried on a sealed
surface and if accidental spillage occurs that the contaminated soil has to be
excavated and disposed properly.
� Awareness has to be raised within the workforce to properly dispose of the
waste.