3.3 Water Quality 3.3.1 During construction phase, potential water pollution sources have been identified as construction site runoff, alteration of natural streams, possible groundwater from contaminated area, and sewage from workforce. Mitigation measures including the implementation of cofferdams or diaphragm walls during stream diversion and good site practices in accordance with ProPECC PN 1/94 are recommended to mitigate any potential water quality impact.