HULHULE-MALE’ BRIDGE PROJECT

EIA for the proposed Hulhule-Male’ Bridge Project
sewage, garbage and waste oil into sea, these wastes should be gathered and disposed together
with pollutants on the bridge construction site.
6.2.2 Analysis for impact of bridge deck runoff on marine water quality during
operating period
After the bridge is constructed and commissioned, the pollutants discharged out by various
vehicles, particles from wearing of automobile tyre, particles adhered on the vehicle frame, oil
leaked by vehicles in poor operating condition and other pollutants that are deposited on the
road, may all enter into the drainage system of road along with bridge deck runoff due to rain.
These pollutants may enter into marine water. The study shows that, within 30 mins from
preliminary stage of rainfall to runoff, the concentration of suspended matters in the rainwater
and oily substances are higher. After half an hour, the concentration may decline rapidly along
with receding rainfall. After 40~60 mins of rainfall, the pavement will be rinsed thoroughly; the
concentration of pollutants produced by pavement runoff is lower level.
Based on design document of the project, the bridge deck runoff is directly discharged from
drainpipe set on both sides of bridge through 3 m intervals. After the bridge deck runoff is
discharged into water body, the instantaneous concentration of pollutants within the small range
adjacent to runoff water dropping point will be high. However, due the strong tidal current flow
in the area, mixing within the water column and dispersal will occur rapidly. Thus, impacts from
runoff are not expected to be significant.
6.3 Impact assessment on marine ecology
6.3.1 Impact analysis and mitigation measures during construction period
6.3.1.1 Analysis for impact on plankton during construction period
Health and growth of phytoplankton communities depend on availability of sunlight, and clear
water conditions. Increased levels of suspended solids at this site during the bridge pier
construction will reduce clarity of water, and reduce sunlight reaching phytoplankton population.
Hence, this may impact growth of planktons at this site.
The construction process of the bridge section in the proposed project easily disturbs the bottom
mud, which is basic construction process. Based on geological condition of the project, the castin-situ
bored pile foundation is adopted for main bridge and approach bridge construction in the
proposed project. The construction process is conducted in the casing, the slurry is recycled, and
the precipitated waste slag is discharged onto slurry transportation ship and transported it to the
reclamation area for hydraulic reclamation. The integral steel casing scheme is adopted for
Prepared by: CDE Consulting & China Shipping Environment Technology
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