Background to Cork Harbour

Cork Harbour is a  Ria  formed by post-glacial sea-level rise.

Hard sandstones (anticlines) alternate with softer limestone valley floors (synclines) to contain the harbour and its channels.

Over time the river eroded faults in the sandstone to connect the limestone basins and form the natural features we see today.

The morphology of the harbour is a product of the Cenozoic era beginning 66 million years ago and is repeated by the east west trending river valleys of the wider Munster Basin.

Rising sea-levels following the last glacial maximum (24,000ya) created the shorelines of today's harbour.

This   Geological Survey of Ireland  ( GSI ) map shows the harder sandstones of the uplands as brown and green, with the valleys occupied by the harbour and its channels shown as blue and purple. For more information see  The geology of the Cork Harbour area (ougs.org) 

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Commercial navigation follows the estuary and paleochannel channel of the river Lee in the harbour. This is clearly indicated by navigation buoys.

Dredging maintains low tide depths of around 15 - 20m for tankers, liners, container ships and bulk carriers.

 Admiralty charts  delineate the navigable areas of the harbour and mark depths as chart datum, which is the depth at the lowest astronomical tide. Tidal amplitude for Cork Harbour is in the region of 5m.

Navigation in the harbour is controlled by the   Port of Cork Company .

The image for this slide is 3 D rendition of  Admiralty Chart Chart 1777  by  https://www.latitudekinsale.com/ 

Ireland's underwater territory is 880,000km^2 and 10   times larger than its landmass. Under international law this is Ireland's Exclusive Economic Zone ( EEZ ).

 INFOMAR   is a joint project of the Marine Institute and Geological Survey of Ireland to map Ireland's seafloor.

Mapping this vast territory unlocks the potential of this huge resource and enables the sustainable management of its resources.

 Multibeam echosounders  acquire bathymetry and backscatter data to produce high resolution maps of the topographic, substrate and habitats of the seafloor.

Cork Harbour is a mixing zone for fresh water from inflowing rivers and salt water from the ocean. Mixing of fresh and salter is tidally modulated and characterised by gradients in salinity and temperature with increasing depth, and distance from the freshwater inputs.

 Tidal dynamics  are responsible for the physical properties of the harbour and  estuary  floor including the habitats and ecology of the SPAs and SACs.

Tides in the harbour are  semidiurnal  with two peaks of high and low water each day.

Training survey  CTD  (Conductivity Temperature & Depth) data shows an surface plume of brackish estuary water undercut by an intrusion of denser sea water. This phenomenon is called a  salt wedge estuary  .

Under the Convention on Wetlands ( Ramsar, 1971 ), Cork Harbour is designated as internationally important for overwintering birds. Up to 20,000 birds are supported by four separate intertidal mud and sand flats in the harbour.

Overwintering and non-breeding birds are given wider protection by the designation of all intertidal flats as a  Special Protected Area  (SPA) by the  EU Birds Directive .

The Great Island Channel is an internationally important Atlantic Salt Meadow habit and designated as a Special Area of Conservation ( SAC ) under the  EU Habitats directive .

SPAs and SACs comprise  Natura 2000 , the EU mandated network of ecologically important habitats.

Cork Harbour has many recreational and cultural amenities for residents and tourists. You can explore these on  Ireland's Marine Atlas  hosted by the Marine Institute.

 Marine Spatial Planning  in Ireland is guided by the National Marine Planning Framework ( NMPF ) published in 2021. The NMPF is framed around the UN Sustainable Development Goals ( SDGS ) and developed by government and the  National Marine Planning Stakeholder Advisory Group .

Stakeholders are any group or individual with an interest in the harbour and the activities that take place there.

Stakeholder engagement is a “ societal challenge ” and a requirement of the  EU Integrated Maritime Policy .