Ballast Water Management Under the Ballast Water Management Convention - Global Maritime Transport and Ballast Water Management: Issues and Solutions - page 104

Fig. 3 World map indicating the main intercontinental shipping routes ( blue lines ) and BWE areas
according to the BWM Convention ( red shading = 50 NM and pink shading = 200 NM limit to
nearest land and >200 m water depth) (After David et al. 2005 )
State to conduct BWM. The selective approach means that the appropriate BWM
measures to take vary depending on the different levels of risk posed by the intended
ballast water discharge, which also depends on the BWM feasibility in certain
circumstances.
Ballast Water Management Feasibility
Whenever possible and until the D-2 standard is required, BWE should be under-
taken as a risk reducing measure. Provided safety permits, it is assumed that most
vessels operating on oceanic voyages are enabled to undertake BWE that meets the
IMO water depth and distance to nearest land limits (see Fig. 3 ).
However, there are limitations in BWE applications, which are primarily due
to shipping patterns of a port (e.g., shipping routes, length of voyages) and local
specifi cs regarding the required/available conditions according to the BWM
Convention (i.e., distance from nearest land, water depth, BWEA). BWE has
also substantial limitations in its biological effectiveness especially in semi-
enclosed or enclosed areas. Ships in these areas usually sail within 50 nautical
miles distance from the nearest land, and therefore, according to the BWM
Convention, cannot meet the requirements to conduct BWE. Because of geo-
graphical specifi cs, not only ships in Short-Sea-Shipping fall into this category
(see Fig. 4 ).
Hence, from the most effective BWM perspective worldwide, the use of BWMS
would be essential.