Impacts on Water Quality. Ruiru River is the main surface water within the footprint of the Project Site. However, along the proposed water transmission footprint, other streams and seasonal rivers have been identified. Consultations with some of the households along the footprint, and the Village Elders indicated that these rivers and streams are reliable sources of water for domestic use to a number of households. The proposed Project will involve removal of top soil, pipeline excavation and soil compaction during the construction phase. Some of these activities may be proximal to the identified water bodies. Potential erosion of the loose or bare soil surfaces with surface run off into these water bodies may increase the sediment load of adjacent rivers and streams. More so, there is a possibility of run-off containing petroleum contaminants (fuel, lubricants and used oil) especially if there are leakages from the project machinery and equipment. In addition, compaction of the ground from construction equipment will lead to increased surface runoff and directed flow due to decreased infiltration capacity of compacted soils. Through percolation of contaminated waters, underground water in the AoI may be degraded too. The above impacts may degrade the quality of river and underground waters and pose health risks for other users as well as risking the aquatic life therein. Mitigation/Management Measures • Where possible construction activities close to these rivers should be scheduled for the dry seasons. In this regard, the developer and Contractor will be cognisant of local weather forecasts and the seasonal climate characteristics of the Project Site. • The removal of vegetation and soil cover will be restricted to only those areas necessary for excavation work. In particular, the unnecessary removal of groundcover vegetation from the AoI will be avoided. • Disturbed areas will be rehabilitated as soon as possible to prevent erosion. • Fuel, oil and used oil storage areas will be contained in bunds of 110% capacity of the stored material. Fuels will be stored in above-ground storage tanks. • Spill containment and clean up kits will be available onsite and clean-up from any spill will be appropriately contained and disposed of. • Construction vehicles and equipment will be serviced regularly and off site. • Construction vehicles will remain on designated and prepared compacted gravel roads. • Any drainage lines on working sites will be covered with appropriately designed culverts...
