Editing North Sea (section)

==Geography==
{{main|Geography of the North Sea}}
{{See also|List of rivers discharging into the North Sea}}
{{Annotated image | float=right| caption=Sk{{=}}[[Skagerrak]]&nbsp;&nbsp;&nbsp;Ka=[[Kattegat]]<br />Eng Ch=[[English Channel]] | image=North Sea map-en.png | width=240 | height=313
|image-width=250
|annotations=
{{Annotation|81|0|'''[[Norwegian Sea|Norwegian<br />Sea]]'''}}
{{Annotation|195|90|'''[[Skagerrak|Sk]]'''}}
{{Annotation|225|105|'''[[Kattegat|Ka]]'''}}
{{Annotation|24|298|'''[[English Channel|Eng Ch]]'''}}
}}
The North Sea is bounded by the [[Orkney Islands]] and east coast of [[Great Britain]] to the west<ref name="Britannica">{{cite encyclopedia
|last = L.M.A.
|editor = University of Chicago
|encyclopedia =Encyclopædia Britannica Macropædia
|title = Europe
|edition = Fifteenth
|year = 1985
|publisher = Encyclopædia Britannica Inc.
|volume =18
|location = U.S.A.
|isbn =978-0-85229-423-9
|pages = 832–835
}}
</ref> and the northern and [[central Europe]]an mainland to the east and south, including [[Norway]], [[Denmark]], [[Germany]], the [[Netherlands]], [[Belgium]], and [[France]].<ref name="American">{{cite book
|last=Ripley
|first=George
|author2=Charles Anderson Dana
|title=The American Cyclopaedia: A Popular Dictionary of General Knowledge
|url=https://books.google.com/books?id=GEpMAAAAMAAJ&pg=PA499
|year=1883
|publisher=D. Appleton and company
|page=499
|access-date=17 February 2020
|archive-date=17 April 2023
|archive-url=https://web.archive.org/web/20230417083622/https://books.google.com/books?id=GEpMAAAAMAAJ&pg=PA499
|url-status=live
}}</ref> In the southwest, beyond the [[Strait of Dover|Straits of Dover]], the North Sea becomes the [[English Channel]] connecting to the Atlantic Ocean.<ref name="Britannica"/><ref name="American"/> In the east, it connects to the [[Baltic Sea]] via the [[Skagerrak]] and [[Kattegat]],<ref name="American"/> narrow straits that separate Denmark from Norway and [[Sweden]] respectively.<ref name="Britannica"/> In the north it is bordered by the [[Shetland Islands]], and connects with the [[Norwegian Sea]], which is a marginal sea in the [[Arctic Ocean]].<ref name="Britannica"/><ref>{{cite web|last=Helland-Hansen|first=Bjørn|author2=Fridtjof Nansen|title=IV. The Basin of the Norwegian Sea.|work=Report on Norwegian Fishery and Marine-Investigations Vol. 11 No. 2|year=1909|publisher=Geofysisk Institutt|url=http://web.gfi.uib.no/The%20Norwegian%20Sea/TNS-002.htm|access-date=9 January 2009|url-status=dead|archive-url=https://web.archive.org/web/20090114230040/http://web.gfi.uib.no/The%20Norwegian%20Sea/TNS-002.htm|archive-date=14 January 2009}}</ref>

The North Sea is more than {{convert|970|km|mi}} long and {{convert|580|km|mi}} wide, with an area of {{convert|750000|km2|sqmi}} and a volume of {{convert|54000|km3}}.<ref name="Safety">{{cite web|title = About the North Sea: Key facts|publisher = Safety at Sea project: Norwegian Coastal Administration|year = 2008|url = http://www.safetyatsea.se/index.php?section=northsea|access-date = 2 November 2008|url-status = dead|archive-url = https://web.archive.org/web/20081209095426/http://www.safetyatsea.se/index.php?section=northsea|archive-date = 9 December 2008}}</ref> Around the edges of the North Sea are [[List of the largest islands in the North Sea|sizeable islands]] and [[archipelago]]s, including [[Shetland]], [[Orkney]], and the [[Frisian Islands]].<ref name="American"/> The North Sea receives freshwater from a number of European continental watersheds, as well as the [[British Isles]]. A large part of the European [[drainage basin]] empties into the North Sea, including water from the [[Baltic Sea]]. The largest and most important rivers flowing into the North Sea are the [[Elbe]] and the [[Rhine]] – [[Meuse (river)|Meuse]].<ref name="Ray">{{cite book
|last=Ray
|first=Alan
|author2=G. Carleton
|author3=Jerry McCormick-Ray
|title=Coastal-marine Conservation: Science and Policy
|url=https://books.google.com/books?id=E7xLaYVGEF4C&q=%22North+Sea%22+watershed&pg=PA262
|year=2004
|edition=illustrated
|publisher=Blackwell Publishing
|isbn=978-0-632-05537-1
|page=262
|access-date=2 October 2020
|archive-date=17 April 2023
|archive-url=https://web.archive.org/web/20230417083657/https://books.google.com/books?id=E7xLaYVGEF4C&q=%22North+Sea%22+watershed&pg=PA262
|url-status=live
}}</ref> Around 185&nbsp;million people live in the [[drainage basin|catchment area]] of [[List of rivers discharging into the North Sea|the rivers discharging into the North Sea]] encompassing some highly industrialized areas.<ref name="NorthSeaPDF">{{cite web
 |title       = Chapter 5: North Sea
 |work        = Environmental Guidebook on the Enclosed Coastal Seas of the World
 |publisher   = International Center for the Environmental Management of Enclosed Coastal Seas
 |year        = 2003
 |url         = http://www.emecs.or.jp/guidebook/eng/pdf/05north.pdf
 |access-date  = 24 November 2008
|url-status     = dead
 |archive-url  = https://web.archive.org/web/20081217143715/http://www.emecs.or.jp/guidebook/eng/pdf/05north.pdf
 |archive-date = 17 December 2008
}}
</ref><!-- see [http://www.emecs.or.jp/guidebook/eng/guidebookeng.html Emecs website, Enclosed Coastal Seas] -->

===Major features===
For the most part, the sea lies on the European [[continental shelf]] with a mean depth of {{convert|90|m}}.<ref name="Britannica"/><ref name="Calow">{{cite book
|last=Calow
|first=Peter
|title=Blackwell's Concise Encyclopedia of Environmental Management
|url=https://books.google.com/books?id=L7V-JtHroGkC&pg=PA100
|access-date=26 December 2008
|year=1999
|publisher=Blackwell Publishing
|isbn=978-0-632-04951-6
|archive-date=17 April 2023
|archive-url=https://web.archive.org/web/20230417083622/https://books.google.com/books?id=L7V-JtHroGkC&pg=PA100
|url-status=live
}}</ref> The only exception is the [[Norwegian trench]], which extends parallel to the Norwegian shoreline from [[Oslo]] to an area north of [[Bergen]].<ref name="Britannica"/> It is between {{convert|20|and|30|km|mi}} wide and has a maximum depth of {{convert|725|m}}.<ref name="Lis">{{cite web| title=Limits in the seas: North Sea continental shelf boundaries| work=U.S. Department of State| publisher=United States Government| date=14 June 1974| url=https://2009-2017.state.gov/documents/organization/62000.pdf| access-date=17 June 2013| archive-date=11 June 2020| archive-url=https://web.archive.org/web/20200611210859/https://2009-2017.state.gov/documents/organization/62000.pdf| url-status=live}}</ref>

The [[Dogger Bank]], a vast [[moraine]], or accumulation of unconsolidated glacial debris, rises to a mere {{cvt|15|to|30|m|round=5}} below the surface.<ref name="Ostergren">{{cite book
|last=Ostergren
|first= Robert Clifford
|author2=John G. Rice
 |title=The Europeans: A Geography of People, Culture, and Environment
|url=https://archive.org/details/europeansgeograp00oste
|url-access=registration
|year=2004
|publisher=Guilford Press
|location=Bath, UK
|isbn= 978-0-89862-272-0
|page=[https://archive.org/details/europeansgeograp00oste/page/62 62]
}}</ref><ref>{{Cite book
 |publisher    = Maptech Online MapServer
 |title        = Dogger Bank
 |date         = 1989–2008
 |url          = http://mapserver.maptech.com/homepage/index.cfm?lat=54.74456315454079&lon=2.3527509224287115&scale=1500000&zoom=50&type=0&icon=0&width=498&height=498&searchscope=dom&CFID=1719760&CFTOKEN=33728793&scriptfile=http%3A%2F%2Fmapserver.maptech.com%2Fhomepage%2Findex.cfm&latlontype=DMS
 |url-status   = dead
 |access-date  = 20 July 2007
|archive-date = 11 July 2012
|archive-url  = https://archive.today/20120711211708/http://mapserver.maptech.com/homepage/index.cfm?lat=54.74456315454079&lon=2.3527509224287115&scale=1500000&zoom=50&type=0&icon=0&width=498&height=498&searchscope=dom&CFID=1719760&CFTOKEN=33728793&scriptfile=http://mapserver.maptech.com/homepage/index.cfm&latlontype=DMS
}}</ref> This feature has produced the finest fishing location of the North Sea.<ref name="Britannica"/> The [[Long Forties]] and the [[Broad Fourteens]] are large areas with roughly uniform depth in [[fathom]]s (forty fathoms and fourteen fathoms or {{cvt|73|and|26|m|disp=or}} deep, respectively). These great banks and others make the North Sea particularly hazardous to navigate,<ref name="Tuckey">{{cite book
|last=Tuckey
|first=James Hingston
|title=Maritime Geography and Statistics ...
|url=https://books.google.com/books?id=EMMBAAAAYAAJ&pg=PA420
|year=1815
|publisher=Black, Parry & Co.
|isbn=9780521311915
|page=445
|access-date=17 February 2020
|archive-date=17 April 2023
|archive-url=https://web.archive.org/web/20230417083623/https://books.google.com/books?id=EMMBAAAAYAAJ&pg=PA420
|url-status=live
}}</ref> which has been alleviated by the implementation of [[Global navigation satellite system|satellite navigation systems]].<ref name="Bradford">{{cite book
|last=Bradford
|first=Thomas Gamaliel
|title=Encyclopædia Americana: A Popular Dictionary of Arts, Sciences, Literature, History, Politics, and Biography, Brought Down to the Present Time; Including a Copious Collection of Original Articles in American Biography; on the Basis of the Seventh Edition of the German Conversations-lexicon
|url=https://books.google.com/books?id=cxsPAAAAYAAJ&pg=PA445
|year=1838
|publisher=Thomas, Cowperthwait, & co.
|isbn=9780521311915
|page=445
|access-date=17 February 2020
|archive-date=17 April 2023
|archive-url=https://web.archive.org/web/20230417083623/https://books.google.com/books?id=cxsPAAAAYAAJ&pg=PA445
|url-status=live
}}</ref> The [[Devil's Hole (North Sea)|Devil's Hole]] lies {{convert|320|km|mi|abbr=}} east of [[Dundee]], Scotland. The feature is a series of asymmetrical trenches between {{convert|20|and|30|km|mi}} long, {{convert|1|and|2|km|mi|spell=in|1}} wide and up to {{convert|230|m}} deep.<ref>{{cite journal| journal=The Edinburgh Geologist| issue=14| date=Autumn 1983| title=The Devil's Hole in the North Sea| author=Alan Fyfe| url=http://www.edinburghgeolsoc.org/edingeologist/z_14_04.html/| access-date=2 November 2008| url-status=dead| archive-url=https://web.archive.org/web/20081201164653/http://www.edinburghgeolsoc.org/edingeologist/z_14_04.html/| archive-date=1 December 2008}}</ref>

Other areas which are less deep are [[Cleaver Bank]], [[Fisher Bank]] and [[Noordhinder Bank]].

===Extent===
The [[International Hydrographic Organization]] defines the limits of the North Sea as follows:<ref>{{cite web|url=https://iho.int/uploads/user/pubs/standards/s-23/S-23_Ed3_1953_EN.pdf|title=Limits of Oceans and Seas, 3rd edition|year=1953|publisher=International Hydrographic Organization|access-date=28 December 2020|archive-url=https://web.archive.org/web/20111008191433/http://www.iho.int/iho_pubs/standard/S-23/S-23_Ed3_1953_EN.pdf|archive-date=8 October 2011}}</ref>

<blockquote>''On the Southwest.'' A line joining the ''Phare de Walde'' (Walde Lighthouse, in France, 50°59'37"N, 1°54'53"E) and [[Leathercoat Point]] (England, 51°10'01.4"N 1°24'07.8").<ref>The Walde Lighthouse is {{convert|6|km|0|abbr=on}} east of [[Calais]] ({{Coord|50|59|06|N|1|55|00|E|display=inline}}), and Leathercoat Point is at the north end of [[St Margaret's Bay, Kent]] ({{Coord|51|10|00|N|1|24|00|E|display=inline}}) </ref> northeast of Dover.

''On the Northwest.'' From [[Dunnet Head]] (58°40'20"N, 3°22'30"W) in [[Scotland]] to Tor Ness (58°47'N) in the Island of [[Hoy, Orkney|Hoy]], thence through this island to the Kame of Hoy (58°55'N) on to Breck Ness on [[Mainland, Orkney|Mainland]] (58°58'N) through this island to [[Costa Head]] (3°14'W) and Inga Ness (59'17'N) in [[Westray]] through Westray, to Bow Head, across to Mull Head (North point of [[Papa Westray]]) and on to Seal Skerry (North point of [[North Ronaldsay]]) and thence to [[Horse Holm|Horse Island]] (South point of the [[Shetland]] Islands).

''On the North.'' From the North point (Fethaland Point) of the [[Mainland, Shetland|Mainland]] of the Shetland Islands, across to Graveland Ness (60°39'N) in the Island of [[Yell, Shetland|Yell]], through Yell to Gloup Ness (1°04'W) and across to Spoo Ness (60°45'N) in [[Unst]] island, through Unst to [[Hermaness|Herma Ness]] (60°51'N), on to the SW point of the Rumblings and to [[Muckle Flugga]] ({{coord|60|51|N|0|53|W|display=inline}}) all these being included in the North Sea area; thence up the meridian of 0°53' West to the [[61st parallel north|parallel of 61°00' North]] and eastward along this parallel to the coast of Norway, the whole of Viking Bank is thus included in the North Sea.

''On the East.'' The Western limit of the [[Skagerrak]] [A line joining [[Hanstholm]] ({{coord|57|07|N|8|36|E|display=inline}}) and the Naze ([[Lindesnes]], {{coord|58|N|7|E|display=inline}})].</blockquote>

===Hydrology===
====Temperature and salinity====
[[File:NorthSeaCurrents.png|thumb|upright=1.25|[[Ocean current]]s mainly entering via the north entrance exiting along the Norwegian coast]]
[[File:Tiden loc.png|thumb|upright=1.25|• Localization of the tide-gauges listed<br/>• [[Norwegian Sea#Hydrology|Tide times after Bergen]] (negative = before)<br/>• The three amphidromic centers<br/>• Coasts:<br/>&nbsp;&nbsp;marshes = green<br/>&nbsp;&nbsp;mudflats = greenish blue<br/>&nbsp;&nbsp;lagoons = bright blue<br/>&nbsp;&nbsp;dunes = yellow<br/>&nbsp;&nbsp;sea dikes= purple<br/>&nbsp;&nbsp;moraines near the coast= light brown<br/>&nbsp;&nbsp;rock-based coasts = greyish brown]]
The average temperature is {{convert|17|°C|°F}} in the summer and {{convert|6|°C|°F}} in the winter.<ref name="Safety"/> The average temperatures have been trending higher since 1988, which has been attributed to [[climate change]].<ref>{{Cite web |date=9 September 2009 |title=North Sea cod 'could disappear' even if fishing outlawed |url=http://www.telegraph.co.uk/earth/environment/globalwarming/6162167/North-Sea-cod-could-disappear-even-if-fishing-outlawed.html |url-status=dead |archive-url=https://web.archive.org/web/20090914053346/http://www.telegraph.co.uk/earth/environment/globalwarming/6162167/North-Sea-cod-could-disappear-even-if-fishing-outlawed.html |archive-date=14 September 2009 |website=The Telegraph}}</ref><ref>{{cite web
|title = Global Warming Triggers North Sea Temperature Rise
|work = Agence France-Presse
|publisher = Terra Daily
|date = 14 November 2006
|url = http://www.terradaily.com/reports/Global_Warming_Triggers_North_Sea_Temperature_Rise_999.html
|access-date = 1 December 2008
|archive-date = 3 January 2009
|archive-url = https://web.archive.org/web/20090103150607/http://www.terradaily.com/reports/Global_Warming_Triggers_North_Sea_Temperature_Rise_999.html
|url-status = live
}}</ref> Air temperatures in January range on average between {{convert|0|and|4|C|F}} and in July between {{convert|13|and|18|C|F}}. The winter months see frequent gales and storms.<ref name="Britannica"/>

The [[salinity]] averages between {{convert|34|and|35|g/L|g/usgal|0}} of water.<ref name="Safety"/> The salinity has the highest variability where there is [[fresh water]] inflow, such as at the Rhine and Elbe estuaries, the Baltic Sea exit and along the coast of Norway.<ref name="Reddy">{{cite book
|last=Reddy
|first=M. P. M.
|title=Descriptive Physical Oceanography
|chapter-url=https://books.google.com/books?id=2NC3JmKI7mYC&pg=PA120
|access-date=3 December 2008
|year=2001
|publisher=Taylor & Francis
|isbn=978-90-5410-706-4
|page=114
|chapter=Annual variation in Surface Salinity
|archive-date=17 April 2023
|archive-url=https://web.archive.org/web/20230417083623/https://books.google.com/books?id=2NC3JmKI7mYC&pg=PA120
|url-status=live
}}</ref>

====Water circulation and tides====
The main pattern to the flow of water in the North Sea is an [[anti-clockwise]] rotation along the edges.<ref>{{cite web
|title = Met Office: Flood alert!
|publisher = Met office UK government
|date = 28 November 2006
|url = http://www.metoffice.gov.uk/education/secondary/students/flood.html
|archive-url = https://web.archive.org/web/20061231073713/http://www.metoffice.gov.uk/education/secondary/students/flood.html
|archive-date = 31 December 2006
|access-date = 2 November 2008}}
</ref>

The North Sea is an arm of the Atlantic Ocean receiving the majority of [[ocean current]] from the northwest opening, and a lesser portion of warm current from the smaller opening at the English Channel. These tidal currents leave along the Norwegian coast.<ref name="SaS">{{cite web
 |title        = Safety at Sea
 |work         = Currents in the North Sea
 |year         = 2009
 |url          = http://www.safetyatsea.se/index.php?art=2041&group=400
 |access-date  = 9 January 2009
 |url-status   = dead
 |archive-url  = https://web.archive.org/web/20081209094254/http://www.safetyatsea.se/index.php?art=2041&group=400
 |archive-date = 9 December 2008
 }}</ref> Surface and deep water currents may move in different directions. Low salinity surface coastal waters move offshore, and deeper, denser high salinity waters move inshore.<ref>{{cite book
|last=Freestone
|first=David
|author2=Ton IJlstra
|title=The North Sea: Perspectives on Regional Environmental Co-operation
|chapter-url=https://books.google.com/books?id=sGSMw7gCOLYC&pg=PA67
|access-date=3 December 2008
|year=1990
|publisher=Martinus Nijhoff Publishers
|isbn=978-1-85333-413-9
|pages=66–70
|chapter=Physical Properties of Sea Water and their Distribution Annual: Variation in Surface Salinity
|archive-date=17 April 2023
|archive-url=https://web.archive.org/web/20230417083634/https://books.google.com/books?id=sGSMw7gCOLYC&pg=PA67
|url-status=live
}}</ref>

The North Sea located on the continental shelf has different waves from those in deep ocean water. The wave speeds are diminished and the wave amplitudes are increased. In the North Sea there are two [[amphidromic point|amphidromic]] systems and a third incomplete amphidromic system.<ref name="Dyke">{{cite book
|last=Dyke
|first=Phil
|title=Modeling Coastal and Offshore Processes
|url=https://books.google.com/books?id=c3MOQKCru6sC&pg=PA328
|access-date=4 December 2008
|year=1974
|publisher=Imperial College Press
|isbn=978-1-86094-674-5
|pages=323–365
|archive-date=17 April 2023
|archive-url=https://web.archive.org/web/20230417083656/https://books.google.com/books?id=c3MOQKCru6sC&pg=PA328
|url-status=live
}} p. 329 tidal map showing amphidromes</ref><ref name="Carter">{{cite book
|last=Carter
|first=R. W. G.
|title=Coastal Environments: An Introduction to the Physical, Ecological and Cultural Systems of Coastlines
|url=https://books.google.com/books?id=STBKHpqMt6MC&pg=PA157
|access-date=4 December 2008
|year=1974
|publisher=Academic Press
|isbn=978-0-12-161856-8
|pages=155–158
|archive-date=17 April 2023
|archive-url=https://web.archive.org/web/20230417083702/https://books.google.com/books?id=STBKHpqMt6MC&pg=PA157
|url-status=live
}} p. 157 tidal map showing amphidromes</ref> In the North Sea the average tide difference in wave amplitude is between zero and {{convert|8|m|ft|spell=in}}.{{clarify|reason= There are two averages: The average tide in any given place, which is an average over time, of may tides, and then there is an average of those average tides at all those places. So this was and is technically correct, if someone could think of a way to clarify, that might help readers understand. "In wave amplitude" also invites misinterpretation, people could think that was about sea wave height, which it isn't. This is especially bad since it directly follows a discussion of actual sea wave speeds and heights.|date=March 2025}}<ref name="Safety"/> 

The Kelvin tide of the Atlantic Ocean is a semidiurnal wave that travels northward. Some of the energy from this wave travels through the English Channel into the North Sea. The wave continues to travel northward in the Atlantic Ocean, and once past the northern tip of Great Britain, the [[Kelvin wave]] turns east and south and once again enters the North Sea.<ref name="Changing">{{cite book
|last=Pugh
|first=D. T.
|title=Changing Sea Levels: Effects of Tides, Weather, and Climate
|url=https://books.google.com/books?id=Ysa4ymmEotYC&pg=PA93
|year=2004
|publisher=Cambridge University Press
|isbn=978-0-521-53218-1
|page=93
|access-date=1 July 2020
|archive-date=17 April 2023
|archive-url=https://web.archive.org/web/20230417083624/https://books.google.com/books?id=Ysa4ymmEotYC&pg=PA93
|url-status=live
}} p. 94 shows the amphidromic points of the North Sea</ref>

{| class="wikitable mw-collapsible mw-collapsed" 
|+Selected&nbsp;tidal&nbsp;ranges
! Tidal range <small>([[Metre|m]])</small><br/><small>(from&nbsp;calendars)</small> !! width=70pt|Maximum tidal range <small>(m)</small> !! Tide-gauge !! Geographical and historical features
|-
| align="center" | 0.79–1.82 || align="center" | 2.39 || [[Lerwick]]<ref>Tide table for Lerwick: [http://www.tide-forecast.com/locations/Lerwick-Shetland-Islands-Scotland/tides/latest tide-forecast] {{Webarchive|url=https://web.archive.org/web/20140426232252/http://www.tide-forecast.com/locations/Lerwick-Shetland-Islands-Scotland/tides/latest |date=26 April 2014 }}</ref> || [[Shetland]] Islands
|-
| align="center" | 2.01–3.76 || align="center" | 4.69 || [[Aberdeen]]<ref>Tide table for Aberdeen: [http://www.tide-forecast.com/locations/Aberdeen-Scotland/tides/latest tide-forecast] {{Webarchive|url=https://web.archive.org/web/20140805091018/http://www.tide-forecast.com/locations/Aberdeen-Scotland/tides/latest |date=5 August 2014 }}</ref> || Mouth of [[River Dee, Aberdeenshire|River Dee]] in [[Scotland]]
|-
| align="center" | 2.38–4.61 || align="center" | 5.65 || [[North Shields]]<ref>Tide table for North Shields: [http://www.tide-forecast.com/locations/North-Shields-England/tides/latest tide-forecast] {{Webarchive|url=https://web.archive.org/web/20140426201938/http://www.tide-forecast.com/locations/North-Shields-England/tides/latest |date=26 April 2014 }}</ref> || Mouth of [[River Tyne|Tyne]] estuary
|-
| align="center" | 2.31–6.04 || align="center" | 8.20 || [[Kingston upon Hull]]<ref>Tide tables for Kingston upon Hull: [https://www.tideschart.com/United-Kingdom/England/City-of-Kingston-upon-Hull/Hull-(Albert-Dock)/ Tides Chart] {{Webarchive|url=https://web.archive.org/web/20190415215651/https://www.tideschart.com/United-Kingdom/England/City-of-Kingston-upon-Hull/Hull-(Albert-Dock)/ |date=15 April 2019 }} and [http://www.tide-forecast.com/locations/Hull-England/tides/latest Tide-Forecast] {{Webarchive|url=https://web.archive.org/web/20140307142404/http://www.tide-forecast.com/locations/Hull-England/tides/latest |date=7 March 2014 }}</ref> || Northern side of [[Humber]] estuary
|-
| align="center" | 1.75–4.33 || align="center" | 7.14 || [[Grimsby]]<ref>Tide table for Grimsby: [http://www.tide-forecast.com/locations/Grimsby/tides/latest Tide-Forecast] {{Webarchive|url=https://web.archive.org/web/20140307152140/http://www.tide-forecast.com/locations/Grimsby/tides/latest |date=7 March 2014 }}</ref> || Southern side of [[Humber]] estuary farther seaward
|-
| align="center" | 1.98–6.84 || align="center" | 6.90 || [[Skegness]]<ref>Tide tables for Skegness: [https://www.tideschart.com/United-Kingdom/England/Lincolnshire/Skegness/ Tideschart] {{Webarchive|url=https://web.archive.org/web/20200612052508/https://www.tideschart.com/United-Kingdom/England/Lincolnshire/Skegness/ |date=12 June 2020 }} und
[http://www.tide-forecast.com/locations/Skegness/tides/latest Tide-Forecast] {{Webarchive|url=https://web.archive.org/web/20140307140443/http://www.tide-forecast.com/locations/Skegness/tides/latest |date=7 March 2014 }}</ref> || [[Lincolnshire]] coast north of [[the Wash]]
|-
| align="center" | 1.92–6.47 || align="center" | 7.26 || [[King's Lynn]]<ref>Tide tables for King's Lynn: [https://www.tideschart.com/United-Kingdom/England/Norfolk/Kings-Lynn/ Tideschart] {{Webarchive|url=https://web.archive.org/web/20200612040543/https://www.tideschart.com/United-Kingdom/England/Norfolk/Kings-Lynn/ |date=12 June 2020 }} und
[http://www.tide-forecast.com/locations/Kings-Lynn/tides/latest Tide-Forecast] {{Webarchive|url=https://web.archive.org/web/20140307141015/http://www.tide-forecast.com/locations/Kings-Lynn/tides/latest |date=7 March 2014 }}</ref> || Mouth of [[River Great Ouse|Great Ouse]] into [[the Wash]]
|-
| align="center" | 2.54–7.23 || align="center" | || [[Hunstanton]]<ref>Tide tables for Hunstanton: [https://www.tideschart.com/United-Kingdom/England/Norfolk/Hunstanton/ Tideschart] {{Webarchive|url=https://web.archive.org/web/20200612030249/https://www.tideschart.com/United-Kingdom/England/Norfolk/Hunstanton/ |date=12 June 2020 }}</ref> || Eastern edge of [[the Wash]]
|-
| align="center" | 2.34–3.70 || align="center" | 4.47 || [[Harwich]]<ref>{{cite web|url=http://www.tide-forecast.com/locations/Harwich-England/tides/latest|title=Tide Times and Tide Chart for Harwich|work=tide-forecast.com|access-date=26 April 2014|archive-date=29 August 2013|archive-url=https://web.archive.org/web/20130829064731/http://www.tide-forecast.com/locations/Harwich-England/tides/latest|url-status=live}}</ref> || [[East Anglia]]n coast north of [[Thames Estuary]]
|-
| align="center" | 4.05–6.62 || align="center" | 7.99 || [[London Bridge]]<ref>{{cite web|url=http://www.tide-forecast.com/locations/London-Bridge-England/tides/latest|title=Tide Times and Tide Chart for London|work=tide-forecast.com|access-date=26 April 2014|archive-date=8 February 2014|archive-url=https://web.archive.org/web/20140208084433/http://www.tide-forecast.com/locations/London-Bridge-England/tides/latest|url-status=live}}</ref> || Inner end of [[Thames Estuary]]
|-
| align="center" | 2.38–6.85 || align="center" | 6.92 || [[Dunkerque]]<ref>Tide tables for Dunkerque: [https://www.tideschart.com/France/Hauts--de--France/Departement-du-Nord/Dunkerque/ Tides Chart] {{Webarchive|url=https://web.archive.org/web/20190415215651/https://www.tideschart.com/France/Hauts--de--France/Departement-du-Nord/Dunkerque/ |date=15 April 2019 }} and [http://www.tide-forecast.com/locations/Dunkerque-France/tides/latest tide forecast] {{Webarchive|url=https://web.archive.org/web/20140306233424/http://www.tide-forecast.com/locations/Dunkerque-France/tides/latest |date=6 March 2014 }}</ref> || Dune coast east of the [[Strait of Dover]]
|-
| align="center" | 2.02–5.53 || align="center" | 5.59 || [[Zeebrugge]]<ref>Tide tables for Zeebrugge: [https://www.tideschart.com/Belgium/Flanders/Provincie-West--Vlaanderen/Zeebrugge/ Tides Chart] {{Webarchive|url=https://web.archive.org/web/20190415215700/https://www.tideschart.com/Belgium/Flanders/Provincie-West--Vlaanderen/Zeebrugge/ |date=15 April 2019 }} and [http://www.tide-forecast.com/locations/Zeebrugge-Belgium/tides/latest tide forecast] {{Webarchive|url=https://web.archive.org/web/20140306235132/http://www.tide-forecast.com/locations/Zeebrugge-Belgium/tides/latest |date=6 March 2014 }}</ref> || Dune coast west of [[Rhine–Meuse–Scheldt delta]]
|-
| align="center" | 3.24–4.96 || align="center" | 6.09 || [[Antwerp]]<ref>{{cite web|url=http://www.tide-forecast.com/locations/Antwerpen-Belgium/tides/latest|title=Tide Times and Tide Chart for Antwerpen|work=tide-forecast.com|access-date=26 April 2014|archive-date=8 October 2014|archive-url=https://web.archive.org/web/20141008113252/http://www.tide-forecast.com/locations/Antwerpen-Belgium/tides/latest|url-status=live}}</ref> || Inner end of the southernmost estuary of [[Rhine–Meuse–Scheldt delta]]
|-
| align="center" | 1.48–1.90 || align="center" | 2.35 || [[Rotterdam]]<ref>{{cite web|url=http://www.tide-forecast.com/locations/Rotterdam-Netherlands/tides/latest|title=Tide Times and Tide Chart for Rotterdam|work=tide-forecast.com|access-date=7 March 2014|archive-date=23 February 2014|archive-url=https://web.archive.org/web/20140223095839/http://www.tide-forecast.com/locations/Rotterdam-Netherlands/tides/latest|url-status=live}}</ref> || Borderline of estuary delta<ref>Ahnert. F.(2009): Einführung in die Geomorphologie. 4. Auflage. 393 S.</ref> and sedimentation delta of the Rhine
|-
| align="center" | 1.10–2.03 || align="center" | 2.52 || [[Katwijk]]<ref>{{cite web|url=http://www.surf-forecast.com/breaks/Katwijkaan-Zee/tides/latest|title=Katwijk aan Zee Tide Times & Tide Charts|work=surf-forecast.com|access-date=7 March 2014|archive-date=21 February 2014|archive-url=https://web.archive.org/web/20140221175125/http://www.surf-forecast.com/breaks/Katwijkaan-Zee/tides/latest|url-status=live}}</ref> || Mouth of the Uitwateringskanaal of the [[Oude Rijn (Utrecht and South Holland)|Oude Rijn]] into the sea
|-
| align="center" | 1.15–1.72 || align="center" | 2.15 || [[Den Helder]]<ref>{{cite web|url=http://www.tide-forecast.com/locations/Den-Helder-Netherlands/tides/latest|title=Tide Times and Tide Chart for Den Helder|work=tide-forecast.com|access-date=7 March 2014|archive-date=23 February 2014|archive-url=https://web.archive.org/web/20140223095934/http://www.tide-forecast.com/locations/Den-Helder-Netherlands/tides/latest|url-status=live}}</ref> || Northeastern end of [[Holland]] dune coast west of [[IJsselmeer]]
|-
| align="center" | 1.67–2.20 || align="center" | 2.65 || [[Harlingen, Netherlands|Harlingen]]<ref>{{cite web|url=http://www.tide-forecast.com/locations/Harlingen-Netherlands/tides/latest|title=Tide Times and Tide Chart for Harlingen|work=tide-forecast.com|access-date=7 March 2014|archive-date=23 February 2014|archive-url=https://web.archive.org/web/20140223100203/http://www.tide-forecast.com/locations/Harlingen-Netherlands/tides/latest|url-status=live}}</ref> || East of [[IJsselmeer]], outlet of [[IJssel]] river, the eastern branch of the Rhine
|-
| align="center" | 1.80–2.69 || align="center" | 3.54 || [[Borkum]]<ref>{{cite web|url=http://www.tide-forecast.com/locations/Borkum-Germany/tides/latest|title=Tide Times and Tide Chart for Borkum|work=tide-forecast.com|access-date=7 March 2014|archive-date=23 February 2014|archive-url=https://web.archive.org/web/20140223100148/http://www.tide-forecast.com/locations/Borkum-Germany/tides/latest|url-status=live}}</ref> || Island in front of [[Ems (river)|Ems]] river estuary
|-
| align="center" | 2.96–3.71 || align="center" | || [[Emden]]<ref>{{Cite web|url=https://www.windfinder.com/forecast/emden|archive-url=https://web.archive.org/web/20140221160235/http://de.windfinder.com/tide/Emden_Neue_Seeschleuse_Germany|url-status=dead|title=Windfinder.com – Wind, waves, weather & tide forecast Emden|archive-date=21 February 2014|website=Windfinder.com}}</ref> || East side of [[Ems (river)|Ems]] river estuary
|-
| align="center" | 2.60–3.76 || align="center" | 4.90 || [[Wilhelmshaven]]<ref>{{cite web|url=http://www.tide-forecast.com/locations/Wilhelmshaven-Germany/tides/latest|title=Tide Times and Tide Chart for Wilhelmshaven|work=tide-forecast.com|access-date=7 March 2014|archive-date=23 February 2014|archive-url=https://web.archive.org/web/20140223100201/http://www.tide-forecast.com/locations/Wilhelmshaven-Germany/tides/latest|url-status=live}}</ref> || [[Jade Bight]]
|-
| align="center" | 2.66–4.01 || align="center" | 4.74 || [[Bremerhaven]]<ref>{{cite web|url=http://www.tide-forecast.com/locations/Bremerhaven-Germany/tides/latest|title=Tide Times and Tide Chart for Bremerhaven|work=tide-forecast.com|access-date=7 March 2014|archive-date=23 February 2014|archive-url=https://web.archive.org/web/20140223100153/http://www.tide-forecast.com/locations/Bremerhaven-Germany/tides/latest|url-status=live}}</ref> || Seaward end of [[Weser]] estuary
|-
| align="center" | 3.59–4.62 || align="center" | || [[Bremen]]-[[Oslebshausen]]<ref>{{cite web|url=http://gezeiten-kalender.de:9099/locations/473.html?y=2014&m=2&d=22|title=Gezeitenkalender für Bremen, Oslebshausen, Germany (Tidenkalender) – und viele weitere Orte|author=Guido Gerding|work=gezeiten-kalender.de|access-date=7 March 2014|archive-date=22 February 2014|archive-url=https://web.archive.org/web/20140222165136/http://gezeiten-kalender.de:9099/locations/473.html?y=2014&m=2&d=22|url-status=dead}}</ref> || [[Ports of Bremen|Bremer Industriehäfen]], inner [[Weser]] estuary
|-
| align="center" | 3.3–4.0 || align="center" | || [[Bremen]] Weser barrage<ref>{{cite web|url=http://www.bsh.de/cgi-bin/gezeiten/was_tab.pl?ort=DE__752P&zone=Gesetzliche+Zeit+%B9&niveau=NN|archive-url=https://archive.today/20140217155825/http://www.bsh.de/cgi-bin/gezeiten/was_tab.pl?ort=DE__752P&zone=Gesetzliche+Zeit+%B9&niveau=NN|url-status=dead|archive-date=17 February 2014|title=Gezeitenvorausberechnung|work=bsh.de|access-date=7 March 2014}}</ref> || Artificial tide limit of river Weser, 4&nbsp;km upstream of the city centre
|-
| align="center" | <span style="color:purple;"> 2.6–4.0 </span>|| ||<span style="color:purple;"> Bremerhaven 1879</span><ref name="Franzius">calculated from [[Ludwig Franzius]]: ''Die Korrektion der Unterweser'' (1898). suppl. B IV.: weekly average tide ranges 1879</ref>||<span style="color:purple;"> Before start of [[Weser Correction]] (Weser straightening works)</span>
|-
| align="center" | <span style="color:purple;"> 0–0.3</span> || ||<span style="color:purple;"> Bremen city centre 1879</span><ref name="Franzius"/> ||<span style="color:purple;"> Before start of [[Weser Correction]] (Weser straightening works)</span>
|-
| align="center" | <span style="color:blue;"> 1.45</span> || ||<span style="color:blue;"> Bremen city centre 1900</span><ref>telephonical advice by Mrs. Piechotta, head of department of hydrology, Nautic Administration for Bremen ([http://www.wsv.de/wsa-hb/ WSA Bremen] {{Webarchive|url=https://web.archive.org/web/20140327220829/http://www.wsv.de/wsa-hb/ |date=27 March 2014 }})</ref> ||<span style="color:blue;"> [[Große Weserbrücke]], 5 years after completion of [[Weser Correction]] works</span>
|-
| align="center" | 2.54–3.48 || align="center" | 4.63 || [[Cuxhaven]]<ref>{{cite web|url=http://www.tide-forecast.com/locations/Cuxhaven-Germany/tides/latest|title=Tide Times and Tide Chart for Cuxhaven|work=tide-forecast.com|access-date=7 March 2014|archive-date=23 February 2014|archive-url=https://web.archive.org/web/20140223100158/http://www.tide-forecast.com/locations/Cuxhaven-Germany/tides/latest|url-status=live}}</ref> || Seaward end of [[Elbe]] estuary
|-
| align="center" | 3.4–3.9 || align="center" | 4.63 || [[Hamburg]] St. Pauli<ref>{{cite web|url=http://www.tide-forecast.com/locations/Hamburg-Germany/tides/latest|title=Tide Times and Tide Chart for Hamburg|work=tide-forecast.com|access-date=7 March 2014|archive-date=12 March 2014|archive-url=https://web.archive.org/web/20140312105840/http://www.tide-forecast.com/locations/Hamburg-Germany/tides/latest|url-status=live}}</ref><ref>{{cite web|url=http://www.bsh.de/cgi-bin/gezeiten/was_tab.pl?ort=DE__508P&zone=Gesetzliche+Zeit+%B9&niveau=KN|archive-url=https://archive.today/20140217155834/http://www.bsh.de/cgi-bin/gezeiten/was_tab.pl?ort=DE__508P&zone=Gesetzliche+Zeit+%B9&niveau=KN|url-status=dead|archive-date=17 February 2014|title=Gezeitenvorausberechnung|work=bsh.de|access-date=7 March 2014}}</ref> || [[St. Pauli Piers]], inner part of [[Elbe]] estuary
|-
| align="center" | 1.39–2.03 || align="center" | 2.74 || [[Westerland, Germany|Westerland]]<ref>{{cite web|url=http://www.tide-forecast.com/locations/Westerland-Germany/tides/latest|title=Tide Times and Tide Chart for Westerland|work=tide-forecast.com|access-date=7 March 2014|archive-date=23 February 2014|archive-url=https://web.archive.org/web/20140223100146/http://www.tide-forecast.com/locations/Westerland-Germany/tides/latest|url-status=live}}</ref> || [[Sylt]] island, off the [[Nordfriesland]] coast
|-
| align="center" | 2.8–3.4 || align="center" | || [[Dagebüll]]<ref>{{cite web|url=http://www.bsh.de/cgi-bin/gezeiten/was_tab.pl?ort=DE__635P&zone=Gesetzliche%20Zeit&niveau=KN|title=Gezeitenvorausberechnung|work=bsh.de|access-date=17 February 2014|archive-url=https://web.archive.org/web/20140223104352/http://www.bsh.de/cgi-bin/gezeiten/was_tab.pl?ort=DE__635P&zone=Gesetzliche%20Zeit&niveau=KN|archive-date=23 February 2014|url-status=dead}}</ref> || Coast of [[Wadden Sea]] in [[Nordfriesland]]
|-
| align="center" | 1.1–2.1 || align="center" | 2.17 || [[Esbjerg]]<ref name="DMI">{{cite web|url=http://www.dmi.dk/en/hav/maalinger/tidal-tables/|title=Tidal tables|work=dmi.dk|access-date=17 March 2014|archive-url=https://web.archive.org/web/20140316211710/http://www.dmi.dk/en/hav/maalinger/tidal-tables/|archive-date=16 March 2014|url-status=dead}}</ref><ref>{{cite web|url=http://www.tide-forecast.com/locations/Esbjerg-Denmark/tides/latest|title=Tide Times and Tide Chart for Esbjerg, Denmark|work=tide-forecast.com|access-date=7 March 2014|archive-date=23 February 2014|archive-url=https://web.archive.org/web/20140223095931/http://www.tide-forecast.com/locations/Esbjerg-Denmark/tides/latest|url-status=live}}</ref> || Northern end of Wadden Sea in [[Denmark]]
|-
| align="center" | 0.5–1.1 || align="center" | || [[Hvide Sande]]<ref name="DMI"/> || [[Denmark|Danish]] dune coast, entrance of [[Ringkøbing Fjord]] lagoon
|-
| align="center" | 0.3–0.5 || align="center" | || [[Thyborøn]]<ref name="DMI"/> || Danish dune coast, entrance of ''Nissum Bredning'' [[lagoon]], part of [[Limfjord]]
|-
| align="center" | 0.2–04 || align="center" | || [[Hirtshals]]<ref name="DMI"/> || [[Skagerrak]]. [[Hanstholm]] and [[Skagen]] have the same values.
|-
| align="center" | 0.14–0.30 || align="center" | 0.26 || [[Mandal, Norway|Tregde]]<ref name="Vannstand">[http://vannstand.no/index.php/nb/english-section/tide-table Vannstand – Norwegian official maritime Information → English version] {{webarchive|url=https://web.archive.org/web/20150429091718/http://vannstand.no/index.php/nb/english-section/tide-table |date=29 April 2015 }}</ref> || [[Skagerrak]], southern end of [[Norway]], east of an [[amphidromic point]] 
|-
| align="center" | 0.25–0.60 || align="center" | 0.65 || [[Stavanger]]<ref name="Vannstand"/> || North of that amphidromic point, tidal rhythm irregular
|-
| align="center" | 0.64–1.20 || align="center" | 1.61 || [[Bergen]]<ref name="Vannstand"/> || Tidal rhythm regular
|}

=== Coasts ===
{{main|Coastline of the North Sea}}
[[File:Wattenmeer-Nordfriesland.jpg|thumb|The German North Sea coast]]
The eastern and western coasts of the North Sea are jagged, formed by [[glacier]]s during the [[Quaternary glaciation|ice ages]]. The coastlines along the southernmost part are covered with the remains of deposited glacial sediment.<ref name="Britannica"/> The Norwegian mountains plunge into the sea creating deep [[fjord]]s and [[archipelago]]s. South of Stavanger, the coast softens, the islands become fewer.<ref name="Britannica"/> The eastern Scottish coast is similar, though less severe than Norway. From [[North East England|north east of England]], the cliffs become lower and are composed of less resistant [[moraine]], which erodes more easily, so that the coasts have more rounded contours.<ref name="EastRiding">{{cite web| title = Development of the East Riding Coastline| url = http://www.eastriding.gov.uk/aspirelinks/coastal/1development.pdf| publisher = East Riding of Yorkshire Council| access-date = 24 July 2007| archive-url = https://web.archive.org/web/20070810055627/http://www.eastriding.gov.uk/aspirelinks/coastal/1development.pdf <!-- Bot retrieved archive -->| archive-date = 10 August 2007| url-status = dead}}</ref><ref name="Eurosion">{{cite web| title = Holderness Coast United Kingdom| url = http://copranet.projects.eucc-d.de/files/000164_EUROSION_Holderness_coast.pdf| publisher = EUROSION Case Study| access-date = 24 July 2007| archive-date = 11 May 2011| archive-url = https://web.archive.org/web/20110511113054/http://copranet.projects.eucc-d.de/files/000164_EUROSION_Holderness_coast.pdf| url-status = live}}</ref> In the Netherlands, Belgium and in [[East Anglia]] the [[littoral]] is low and marshy.<ref name="Britannica"/> The east coast and south-east of the North Sea ([[Wadden Sea]]) have coastlines that are mainly sandy and straight owing to [[longshore drift]], particularly along Belgium and Denmark.<ref name="GHC">{{Cite book
 |title        = Overview of geography, hydrography and climate of the North Sea (Chapter II of the Quality Status Report).
 |publisher    = [[Convention for the Protection of the Marine Environment of the North-East Atlantic]] (OSPAR)
 |year         = 2000
 |url          = http://www.ospar.org/eng/doc/pdfs/R2C2.pdf
 |access-date  = 4 December 2007
 |url-status   = dead
 |archive-url  = https://web.archive.org/web/20070710023601/http://www.ospar.org/eng/doc/pdfs/R2C2.pdf
 |archive-date = 10 July 2007
 }}<!--This citation covers the entire paragraph for the intro--></ref>

=== Coastal management ===
{{further|Afsluitdijk|Delta Works|Flood control in the Netherlands|Thames Barrier|Zuiderzee Works}}
[[File:Afsluitdijk 1031.jpg|thumb|The [[Afsluitdijk]] (Closure-dike) is a major dam in the Netherlands]]

The southern coastal areas were originally [[flood plain]]s and swampy land. In areas especially vulnerable to storm surges, people settled behind elevated levees and on natural areas of high ground such as [[spit (landform)|spits]] and [[geest]]land.<ref name="Wefer"/>{{rp|[302,303]}} As early as 500 BC, people were constructing [[artificial dwelling hill]]s higher than the prevailing flood levels.<ref name="Wefer"/>{{rp|[306,308]}} It was only around the beginning of the [[High Middle Ages]], in 1200 AD, that inhabitants began to connect single ring dikes into a dike line along the entire coast, thereby turning amphibious regions between the land and the sea into permanent solid ground.<ref name="Wefer">{{cite book
|last=Wefer
|first=Gerold
|author2=Wolfgang H. Berger
|author3=K. E. Behre
|author4=Eystein Jansen
|title=Climate Development and History of the North Atlantic Realm: With 16 Tables
|orig-year=2002
|url=https://books.google.com/books?id=NACgnCN_jaEC&pg=PA308
|access-date=4 December 2008
|year=2002
|publisher=Springer
|isbn=978-3-540-43201-2
|pages=308–310
|archive-date=17 April 2023
|archive-url=https://web.archive.org/web/20230417083652/https://books.google.com/books?id=NACgnCN_jaEC&pg=PA308
|url-status=live
}}</ref>

The modern form of the dikes supplemented by overflow and lateral diversion channels, began to appear in the 17th and 18th centuries, built in the Netherlands.<ref>{{cite web
 |last         = Oosthoek
 |first        = K. Jan
 |publisher    = Environmental History Resources
 |title        = History of Dutch river flood defences
 |date         = 2006–2007
 |url          = http://www.eh-resources.org/floods.html
 |access-date  = 24 July 2007
 |archive-date = 26 June 2007
 |archive-url  = https://web.archive.org/web/20070626085020/http://www.eh-resources.org/floods.html
 |url-status   = live
}}</ref> The North Sea Floods of 1953 and 1962 were the impetus for further raising of the dikes as well as the shortening of the coast line so as to present as little surface area as possible to the punishment of the sea and the storms.<ref>{{cite web
|publisher = Compare Infobase Limited
|title =North Sea Protection Works – Seven Modern Wonders of World
|date =2006–2007
|url =http://www.allwondersoftheworld.com/seven-modern-wonders/north-sea-protection-works.html
|access-date = 24 July 2007 |archive-url = https://web.archive.org/web/20070525134637/http://www.allwondersoftheworld.com/seven-modern-wonders/north-sea-protection-works.html <!-- Bot retrieved archive --> |archive-date = 25 May 2007}}</ref> Currently, 27% of the Netherlands is below sea level protected by dikes, dunes, and beach flats.<ref>{{cite web
 |last         = Rosenberg
 |first        = Matt
 |work         = About.com – Geography
 |title        = Dykes of the Netherlands
 |date         = 30 January 2007
 |url          = http://geography.about.com/od/specificplacesofinterest/a/dykes.htm
 |access-date  = 19 July 2007
 |archive-url  = https://web.archive.org/web/20090201074700/http://geography.about.com/od/specificplacesofinterest/a/dykes.htm
 |archive-date = 1 February 2009
 |url-status   = dead
 }}</ref>

[[Coastal management]] today consists of several levels.<ref name="BASF">{{cite web
 |title        = Science around us: Flexible covering protects imperiled dikes – BASF – The Chemical Company – Corporate Website
 |publisher    = BASF
 |url          = http://www.basf.com/group/corporate/en/content/news-and-media-relations/science-around-us/imperiled-dikes/index
 |archive-url  = https://archive.today/20130102043157/http://www.basf.com/group/corporate/en/content/news-and-media-relations/science-around-us/imperiled-dikes/index
 |url-status   = dead
 |archive-date = 2 January 2013
 |access-date  = 16 January 2009
 }}</ref> The dike slope reduces the energy of the incoming sea, so that the dike itself does not receive the full impact.<ref name="BASF"/> Dikes that lie directly on the sea are especially reinforced.<ref name="BASF"/> The dikes have, over the years, been repeatedly raised, sometimes up to {{convert|9|m|ft}} and have been made flatter to better reduce wave erosion.<ref>{{cite web
 |last         = Peters
 |first        = Karsten
 |author2      = Magnus Geduhn
 |author3      = Holger Schüttrumpf
 |author4      = Helmut Temmler
 |title        = Impounded water in Sea Dikes
 |publisher    = ICCE
 |date         = 31 August – 5 September 2008
 |url          = http://icce2008.hamburg.baw.de/downloads/intern/Paper/BookOfAbstracts/0863_Peters.pdf
 |access-date  = 16 January 2009
 |url-status   = dead
 |archive-url  = https://web.archive.org/web/20090205005638/http://icce2008.hamburg.baw.de/downloads/intern/Paper/BookOfAbstracts/0863_Peters.pdf
 |archive-date = 5 February 2009
 }}</ref> Where the dunes are sufficient to protect the land behind them from the sea, these dunes are planted with beach grass (''[[Ammophila arenaria]]'') to protect them from erosion by wind, water, and foot traffic.<ref>{{cite web
 |title        = Dune Grass Planting
 |work         = A guide to managing coastal erosion in beach/dune systems – Summary 2
 |publisher    = [[Scottish Natural Heritage]]
 |year         = 2000
 |url          = http://www.snh.org.uk/publications/on-line/heritagemanagement/erosion/appendix_1.2.shtml
 |access-date   = 2 November 2008
|archive-url  = https://web.archive.org/web/20081212154705/http://www.snh.org.uk/publications/on-line/heritagemanagement/erosion/appendix_1.2.shtml
 |archive-date  = 12 December 2008
|url-status     = dead
}}</ref>

=== Storm tides ===
{{main|Storm tides of the North Sea}}
[[File:Watersnoodramp 1953.jpg|thumb|[[Zuid-Beveland]], [[North Sea flood of 1953]]]]
[[Storm surge]]s threaten, in particular, the coasts of the Netherlands, Belgium, Germany, and Denmark and low-lying areas of eastern England particularly around [[The Wash]] and [[The Fens|Fens]].<ref name="GHC"/>
Storm surges are caused by changes in [[Atmospheric pressure|barometric pressure]] combined with strong wind created [[Ocean surface wave|wave action]].<ref>{{cite book
|last=Ingham
|first=J. K.
|author2=John Christopher Wolverson Cope
|author3=P. F. Rawson
|title=Atlas of Palaeogeography and Lithofacies
|chapter-url=https://books.google.com/books?id=0I6BNSgx3_cC&pg=RA1-PA150
|access-date=15 December 2008
|year=1999
|publisher=Geological Society of London
|isbn=978-1-86239-055-3
|page=150
|chapter=Quaternary
|archive-date=17 April 2023
|archive-url=https://web.archive.org/web/20230417083625/https://books.google.com/books?id=0I6BNSgx3_cC&pg=RA1-PA150
|url-status=live
}}</ref>

The first recorded storm tide flood was the ''Julianenflut'', on 17 February 1164. In its wake, the [[Jadebusen]], (a bay on the coast of Germany), began to form.
A storm tide in 1228 is recorded to have killed more than 100,000 people.<ref name="Morin">{{cite web
 |last         = Morin
 |first        = Rene
 |title        = Social, economical and political impact of Weather
 |publisher    = EMS annual meeting
 |date         = 2 October 2008
 |url          = http://www.emetsoc.org/annual_meetings/documents/Morin_SilverMedalLecture_2008.pdf
 |access-date  = 4 December 2008
 |url-status   = dead
 |archive-url  = https://web.archive.org/web/20081217143715/http://www.emetsoc.org/annual_meetings/documents/Morin_SilverMedalLecture_2008.pdf
 |archive-date = 17 December 2008
 }}</ref> In 1362, the [[Saint Marcellus' flood|Second Marcellus Flood]], also known as the ''Grote Manndrenke'', hit the entire southern coast of the North Sea. Chronicles of the time again record more than 100,000 deaths, large parts of the coast were lost permanently to the sea, including the now legendary [[lost city]] of [[Rungholt]].<ref name="Untergang">{{cite web
|title =scinexx &#124; Der Untergang: Die Grote Manndränke – Rungholt Nordsee
|publisher =MMCD NEW MEDIA
|date =24 May 2008
|url =http://translate.google.ca/translate?hl=en&sl=de&u=http://www.g-o.de/dossier-detail-395-8.html&sa=X&oi=translate&resnum=5&ct=result&prev=/search%3Fq%3D1362%2BGroote%2BManndr%25C3%25A4nke%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-GB:official%26sa%3DG
|language =de
|access-date =4 December 2008
|archive-date =12 May 2011
|archive-url =https://web.archive.org/web/20110512012345/http://translate.google.ca/translate?hl=en&sl=de&u=http://www.g-o.de/dossier-detail-395-8.html&sa=X&oi=translate&resnum=5&ct=result&prev=/search%3Fq%3D1362%2BGroote%2BManndr%25C3%25A4nke%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-GB:official%26sa%3DG
|url-status =live
}}</ref>
In the 20th century, the [[North Sea flood of 1953]] flooded several nations' coasts and cost more than 2,000 lives.<ref>{{Cite book
 |publisher  = Investigating Rivers
 |title      = Coastal Flooding: The great flood of 1953
 |url        = http://www.naturegrid.org.uk/rivers/gt%20stour%20case%20study-pages/fld-cstl.html
 |archive-url = https://web.archive.org/web/20021126105045/http://www.naturegrid.org.uk/rivers/gt%20stour%20case%20study-pages/fld-cstl.html
 |url-status   = dead
 |archive-date = 26 November 2002
 |access-date = 24 July 2007
}}</ref>
315 citizens of Hamburg died in the [[North Sea flood of 1962]].<ref name="Lamb">{{cite book
|last=Lamb
|first=H. H.
|title=Weather, Climate & Human Affairs: A Book of Essays and
|url=https://books.google.com/books?id=m5IOAAAAQAAJ&q=North+Frisian+Flood+of+1981&pg=PA131
|edition=illustrated
|year=1988
|publisher=Taylor & Francis
|isbn=9780415006743
|page=187
|access-date=2 October 2020
|archive-date=17 April 2023
|archive-url=https://web.archive.org/web/20230417083632/https://books.google.com/books?id=m5IOAAAAQAAJ&q=North+Frisian+Flood+of+1981&pg=PA131
|url-status=live
}}</ref>{{rp|[79,86]}}

=== Tsunamis ===
Though rare, the North Sea has been the site of a number of historically documented [[tsunami]]s. The [[Storegga Slide]]s were a series of underwater landslides, in which a piece of the Norwegian continental shelf slid into the Norwegian Sea. The immense landslips occurred between 8150 BCE and 6000 BCE, and caused a tsunami up to {{convert|20|m|ft}} high that swept through the North Sea, having the greatest effect on Scotland and the [[Faroe Islands|Faeroe Islands]].<ref name="spiegel">{{cite news
 |first        = Axel
 |last         = Bojanowski
 |work         = Spiegel Online
 |title        = Tidal Waves in Europe? Study Sees North Sea Tsunami Risk
 |date         = 11 October 2006
 |url          = http://www.spiegel.de/international/0,1518,441819,00.html
 |access-date  = 24 July 2007
 |archive-date = 1 November 2007
 |archive-url  = https://web.archive.org/web/20071101180658/http://www.spiegel.de/international/0,1518,441819,00.html
 |url-status   = live
 }}</ref><ref>{{cite journal | first = Stein | last = Bondevik | author2 = Sue Dawson | author3 = Alastair Dawson | author4 = Øystein Lohne | date = 5 August 2003 | title = Record-breaking Height for 8000-Year-Old Tsunami in the North Atlantic | journal = Eos, Transactions, American Geophysical Union | volume = 84 | issue = 31 | pages = 289, 293 | doi = 10.1029/2003EO310001 | bibcode = 2003EOSTr..84..289B | hdl = 1956/729 | doi-access = free | hdl-access = free }}</ref>
The [[1580 Dover Straits earthquake|Dover Straits earthquake of 1580]] is among the first recorded earthquakes in the North Sea measuring between 5.6 and 5.9 on the Richter scale. This event caused extensive damage in [[Calais]] both through its tremors and possibly triggered a [[tsunami]], though this has never been confirmed. The theory is a vast underwater landslide in the [[English Channel]] was triggered by the earthquake, which in turn caused a tsunami.<ref name="Belgium"/> The tsunami triggered by the [[1755 Lisbon earthquake]] reached Holland, although the waves had lost their destructive power. The largest earthquake ever recorded in the United Kingdom was the [[1931 Dogger Bank earthquake]], which measured 6.1 on the [[Richter magnitude scale]] and caused a small tsunami that flooded parts of the British coast.<ref name="Belgium">{{Cite book
 |publisher    = Royal Belgian Institute of Natural Sciences
 |title        = A tsunami in Belgium?
 |year         = 2005
 |url          = http://www.naturalsciences.be/active/sciencenews/archive2005/tsunami
 |access-date  = 2 November 2008
 |url-status   = dead
 |archive-url  = https://web.archive.org/web/20140425180447/http://www.naturalsciences.be/active/sciencenews/archive2005/tsunami
 |archive-date = 25 April 2014
 }}</ref>

In 1995, the {{convert|25.6|m|ft|abbr=on}} tall [[Draupner wave]] occurred in the North Sea, becoming the first [[rogue wave]] to be observed using scientific instruments.<ref name="TheWeek2">{{cite web |date=27 September 2010 |title=The last word: Terrors of the sea |url=http://theweek.com/articles/490823/last-word-terrors-sea |access-date=15 January 2016 |website=TheWeek}}</ref>