HEADING PAGE - port of ploce authority * welcome

ENVIRONMENTAL IMPACT STUDY
Rn: 03-033 CONTAINER TERMINAL PLOCE PAGE: 9
Due to the possible environmental pollution by increased quantity of exhaust
gases, machines and transport vehicles shall also be constantly monitored in
respect of the quantity and quality of exhaust gases, in conformity with
allowed values.
C.1.2.3. SEA POLLUTION PROTECTIVE MEASURES
C.1.2.3.1. SUBMARINE EXCAVATION
The level of heavy metals and polycyclic aromatic hydrocarbons in sea
sediment on the area of planned construction is low. Pollution by
polychlorinated biphenyls has not been proved. Regardless of this quite
favourable report, place and method of disposal of the excavated material has
to be elaborated. The excavated material obtained by deepening port basin
shall be used for the construction of a new embankment required for the
container terminal and possible surplus of dredged material shall be deposited
on the port area for new areas development for further port development. In
any case, disposal of dredged material has to be avoided on sensitive areas
of the coastal sea and on sea areas which are not degraded (Fig.1).
Deepening of the port basin is accompanied with a number of problems and
dangers for direct environment. Sediment resuspension increases turbidity of
water within the port area and suspend and colloidal particles can reach the
external sea too. Water turbidity reduces penetration of light needed for
photosynthesis and resettling of suspended particles on sea bottom can
damage benton bioceonoses. Removal of sediment includes, although
temporarily, removal of habitats of bottom-dwelling sea organisms. It may be
proposed to implement following measures in order to reduce all these
negative effects of dredging to sea ecosystem:
- Dredging has to be carried out in the most possible short time, in the
period when damages to sea ecosystem shall be the least observable..
This is a period with no fish spawning and migration of fish and winter
period when development of phytoplankton is limited by ecological
factors.
- Dredging works have to be executed out of bathing season in order to
avoid possible disruption of esthetic sea appearance.
- Less loading the water from waters leaching from dredged material
being deposited on land with suspended substances and this water
shall be again discharged into the sea.
Taking into consideration input data on submarine excavation required for
embankment formation
o Total required embankment 500.000 m3
o Possible excavation per hour 2.000 m3
o Daily excavation within 16 hours 32.000 m3
o Embankment/water proportion 40/60
o Actual daily excavation 32.000 x 0.4 = ca 13.000 m3
o Total required days 500/13 = 38
and condition that no excavated waste material (being deposited on inshore
part for years) is permitted to be disposed back in sea, the following
technology for carrying out works has been proposed.
RIJEKAPROJEKT d.o.o.