No-discharge zones
The harmful impacts of sewage pollution in shallow coastal areas are well recognised, and many countries now require boats to have holding tanks that should only be emptied outside of No-Discharge Zones or in dedicated pump-out stations. Ships above 400 gross tonnage are subject to international MARPOL regulations and need to be 12 miles offshore. For smaller vessels, No-Discharge Zones (NDZs) often follow the coastline at a distance where the environmental impacts of small sewage discharges are negligible. This distance can vary between 500m in the case of Bermuda’s new rules, to 2 nautical miles in Denmark, 3 miles in parts of Australia and 12 miles in Spain. NDZs are also used to protect sensitive areas, such as marine reserves, semi-enclosed bodies of water or inland waterways.
Whatever the rules for NDZs there is increasing evidence that some boat operators simply ignore them, and leave their holding tanks open even when moored in popular anchorages. Some people simply forget to close them, while others don't like the idea of storing sewage in their holding tanks (but strangely don't mind polluting inshore waters).
To address this challenge, some countries have developed enforcement systems that are not always effective or popular. In some parts of Turkey, where there is a large and growing yacht charter industry, all vessels are required to carry a Blue Card and to pump-out sewage into shore-based facilities. The Blue Card records the times and volumes of sewage pumped out, and an official compares this volume to what it should be, based on the occupancy of the boat and the interval since the last pump-out. From online forums it is clear that this system is unpopular with boat operators and not very effective as it can easily by-passed.
A more effective and convenient system for enforcing No-Discharge Zones is clearly required, and we believe would be welcomed by the majority of boat operators, charter companies and governments who want to protect the health, beauty and biodiversity of our treasured coastal areas.
References:
International Convention for the Prevention of Pollution from Ships (MARPOL) http://www.imo.org/en/About/Conventions/ListOfConventions/Pages/International-Convention-for-the-Prevention-of-Pollution-from-Ships-(MARPOL).aspx
“Sailors for the Sea Boating Guide”, 2017
https://www.sailorsforthesea.org/programs/green-boating-guide/blackwater
Legislation for the use of holdings tanks and the discharge of pollution from boats. Summary of international legislation for holdings tanks . http://www.rya.org.uk/knowledge-advice/boating-abroad/Pages/holding-tanks.aspx
Troy A. Byrnes and Ryan J. K. Dunn. 2020. Boating- and Shipping-Related Environmental Impacts and Example Management Measures: A Review. Journal of Marine Science and Engineering. J. Mar. Sci. Eng. 2020, 8, 908; doi:10.3390/jmse8110908
Protection of The Seas From Pollution By Vessel’s Sewage With Reference To Legal Regulations. Koboević, P. Komadina, Ž. Kurtela: 2020. Traffic and Environment
Mallin, M.A.; Haltom, M.I.; Song, B.; Tavares, M.E.; Dellies,S.P. Bacterial source tracking guides management of boat head waste in a coastal resort area. J. Environ. Manag. 2010, 91, 2748–2753. https://www.sciencedirect.com/science/article/pii/S0301479710002471?via%3Dihub
The Necessity of Adoption of New National Regulations to Prevent the Pollution of Croatian Coastal Sea by Sewage from Various Vessels . Žarko Koboević, Branka Milošević-Pujo. 2018, TRANSACTIONS ON MARITIME SCIENCE
Marine Pollution from Vessel Sewage in Queensland Anna West. http://www.austlii.edu.au/au/journals/ANZMarLawJl/2004/9.pdf
Guide to the NEW Recreational Craft Directive 2013/53/EU Spring 2015. http://www.europeanboatingindustry.eu/boatingdownloadables/EUGUIDE_pdf_version.pdf
