| Source of Water Quality Impact during Construction Phase |
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Cofferdam demolition (ie involves wet excavation by backhoes along the central line of the designed river course) after river widening, formation of flood detention pond and embankment; |
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Drainage from foundation pit for construction of new embankment |
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Construction of boundary fence and boundary patrol road; and |
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Site runoff and pollutants entering the receiving waters. |
| Source of Water Quality Impact during Operation Phase |
|
Changes to the hydrodynamics through the river regulation and thereby affecting the local erosion and sedimentation pattern and water quality; and |
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Maintenance dredging which may lead to disturbance and re-suspension of river sediments and thereby affecting water quality.
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