Moreover, during the construction phase, surface waters may be polluted and heavily silted. There will be destruction of wildlife habitats, parks, recreation areas and historic sites. Because of the high silt content and the low slope of the Eastern Route, the channel may be badly silted. The overall effect of the silt on the channel is not known, but is likely to be significant and adverse. Consequently dredging and spoil disposal may be necessary, which could have severe environmental impacts.
Indirect impacts are also likely, such as contiguous land use.
In contrast, the influx of river water with a high content of nutrients and silt into the lakes may have beneficial effects like turbidity reduction, oxidation of organic material and coliform reduction, but there may also be detrimental effects like algae blooms, siltation, build-up of inorganic substances and lower reaeration. The most important impact on the biogeochemistry of the lakes will be a decrease of dissolved oxygen in the hypolimnion because of the differentiation of the reaeration and oxygen production in the epilimnion and the consumption of oxygen in the hypolimnion by the oxidation of organic materials originating in the epilimnion. Out of this, anaerobic conditions in the hypolimnion will follow. Because of the change of the redox milieu there will be a change of the oxidation number of Fe and Mn resulting in dissolution of precipitated Fe and Mn from the sediment into the water. By this co-precipitation, poisonous heavy metals will be freed and will have adverse effects on the aquatic habitats.