Ballast Water Management Decision Support System Model Application - Global Maritime Transport and Ballast Water Management: Issues and Solutions - page 282

the blanket BWM approach does not foresee measures such as deviation and/or
slowing-down of vessels.
RA was conducted for the purposes of the DSS model. When combining the RA
results with the ballast water discharges under the blanket approach it was recog-
nized that 45,243 m 3 of high risk, and 8,645 m 3 of ballast water assessed as extreme
risk would be discharged unmanaged (see Table 7 ). Without conducting BWRA this
would be the actual ballast water discharge situation, but the risk posed would
remain unknown.

Application of the Blanket Approach with the Designated Ballast
Water Discharge Area

The blanket approach assumes that a BWEA would be designated as discussed
above, and all vessels would be required to use it to complete BWE. It was recog-
nised that all vessels sailing from ballast water source ports in the central Adriatic
(CA) would need to deviate from their intended routes and be delayed for more than
8 h on average (i.e., ranging from less than 1 h up to 18.21 h) to complete BWE in
the BWEA. Therefore, this approach was considered as inappropriate especially
considering the relatively short voyage distances and the need for intensive
slow-down of certain vessels to fully complete BWE (i.e., vessel 1 would need to
slow down approximately to 1/10 of her normal speed) (see Table 8 ).
The same calculations were applied for all remaining vessels sailing from source
ports in the southern Adriatic and Mediterranean Sea area close to the Adriatic Sea.
It was recognised that eight vessels would need to slow-down, with three of them

Table 8 Vessels sailing to the Port of Koper from the source ports in the central Adriatic (CA) and
expected delay time in hours to complete BWE in the BWEA

Potential
+ BWEA
SEQ
factor

Potential
+ BWEA
PT
factor

Potential
+ BWEA
distance

Vessel
speed

BW for
disch.

BWEA
distance

SEQ
factor

PT
factor

Vessel Source Port Area Delay

(m 3 ) (knots) (NM) (NM) (h)

1 ŠIBENIK CA 14 3,426 15 0.06 0.04 45 0.17 0.11 18.21

2 SPLIT CA 14 348 30 0.32 0.22 60 0.65 0.43 4.47

3 SPLIT CA 15 720 30 0.16 0.11 60 0.32 0.21 10.60

4 SPLIT CA 15 400 30 0.31 0.21 60 0.63 0.42 4.37

5 VELA LUKA CA 15 470 60 0.26 0.17 90 0.39 0.26 11.43

6 ORTONA CA 15 751 20 0.12 0.08 50 0.31 0.21 9.37

7 ORTONA CA 15 700 20 0.13 0.09 50 0.32 0.21 9.05

8 ORTONA CA 15 352 20 0.22 0.15 50 0.56 0.37 4.62

9 VASTO CA 15 200 30 0.74 0.50 60 1.49 0.99 0.69

Enhanced after David ( 2007 )