Large Medium Small Very Small
Coastal Breakwater 39 (29.8%) 105 (33.2%) 281 (23.8%) 388 (13.0%)
Coastal Natural 26 (19.8%) 89 (28.2%) 474 (40.1%) 1529 (51.4%)
Coastal Tide gates 5 (3.8%) 5 (1.6%) 18 (1.5%) 11 (0.4%)
Lake or Canal 3 (2.3%) 6 (1.9%) 26 (2.2%) 32 (1.1%)
Open Roadstead 18 (13.7%) 17 (5.4%) 97 (8.2%) 450 (15.1%)
River Basins 7 (5.3%) 20 (6.3%) 23 (1.9%) 27 (0.9%)
River Natural 25 (19.1%) 59 (18.7%) 248 (21.0%) 518 (17.4%)
River Tide gates 7 (5.3%) 14 (4.4%) 12 (1.0%) 14 (0.5%)
Total 131 (100%) 316 (100%) 1181 (100%) 2875 (100%)
Source: adapted from National Geospatial-intelligence Agency (2005) World Port Index, Eighteenth Edition, http://164.214.12.145/pubs/pubs_j_wpi_sections.html
World Harbor Types and Sizes
The larger the port, the more likely investments were made to improve its sheltering (breakwater or tide gates) or capacity (basins).