Ria - wikipedia Ria This article is about the coastal landform. For the given name, see Ria ( given name ). For other uses, see RIA ( disambiguation ). Georges River, in the southern suburbs of Sydney, Australia is a ria, or drowned river valley. The deeply indented shape of the ria reflects the dendritic pattern of drainage that existed before the rise in sea level that flooded the valley. A ria ( / riːə / or / riə / ) is a coastal inlet formed by the partial submergence of an unglaciated river valley. It is a drowned river valley that remains open to the sea. Typically, rias have a dendritic, treelike outline although they can be straight and without significant branches. This pattern is inherited from the dendritic drainage pattern of the flooded river valley. The drowning of river valleys along a stretch of coast and formation of rias results in an extremely irregular and indented coastline. Often, there are islands, which are summits of partly submerged, pre-existing hill peaks. A ria coast is a coastline having several parallel rias separated by prominent ridges, extending a distance inland. The sea level change that caused the submergence of a river valley may be either eustatic ( where global sea levels rise ), or isostatic ( where the local land sinks ). The result is often a very large estuary at the mouth of a relatively insignificant river ( or else sediments would quickly fill the ria ). The Kingsbridge Estuary in Devon, England, is an extreme example of a ria forming an estuary disproportionate to the size of its river ; no significant river flows into it at all, only a number of small streams. Contents 1 Etymology 2 Examples 2.1 Europe 2.2 Africa 2.3 Asia 2.4 Oceania 2.5 North America 2.6 South America 3 Consequences 4 See also 5 References Etymology Look up ria in Wiktionary, the free dictionary. The word ria comes from Portuguese ria or Galician ría, which is related to Spanish and Galician río and Portuguese rio ( river ). Rias are present all along the Galician coast in Spain. As originally defined, the term was restricted to drowned river valleys cut parallel to the structure of the country rock that was at right angles to the coastline. However, the definition of ria was later expanded to other flooded river valleys regardless of the structure of the country rock. For a period of time, European geomorphologists regarded rias to include any broad estuarine river mouth, including fjords. These are long, narrow inlets with steep sides or cliffs, created in a valley carved by glacial activity. In the 21st century, however, the preferred usage of ria by geologists and geomorphologists is to refer solely to drowned unglaciated river valleys. It therefore excludes fjords by definition, since fjords are products of glaciation. Examples This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. ( October 2017 ) Europe Portugal : the country has no rias as such : the Ria de Aveiro in Aveiro, and Ria Formosa in Eastern Algarve are actually lagoons. Atlantic coast of Spain Galicia : The Rias Baixas, including the Ria of Vigo, Ria of Pontevedra, Ria de Arousa, Ria of Muros and Noia, Ria of Corcubion, Cee and Ria de Aldán. The Rias Altas, including the Ria of Corunna, Ria of Ares and Betanzos, Ria of Cedeira, Ria of O Barqueiro, Ria of Ferrol, Ria of Ortigueira, Ria of Viveiro, Ria of Foz and Ria of Ribadeo. Asturias : Ria of Avilés, Ria of Ribadeo, Ria of Navia, Ria of Villaviciosa, Ria of Ribadesella, Ria of Llanes, Ria of Tina Mayor. Ria of San Vicente de la Barquera in Cantabria, Spain Cantabria : Ria of Tina Mayor, Ria of Tina Menor, Ría de San Vicente de la Barquera, Ría of la Rabia, Ría of San Martín de la Arena, Ría of Mogro, Ría of Solía, Ría of Carmen, Ría of Boo, Ría of Tijero, Ría of Cubas, Ría de Ajo, Ría of Cabo Quejo, Ría of Treto, Ría of Oriñón. Basque Country : Ria of Bilbao, mouth of the rivers Nervión, Ibaizabal, and Cadagua. Andalusia : Ria of Carreras, Ria of Huelva at the mouth of the rivers Odiel and Tinto. Brittany : The rias in northern Brittany are called Abers : Aber Wrac'h ( 48 ° 35 ′ 59 '' N 4 ° 32 ′ 58 '' W ﻿ / ﻿ 48.599807 ° N 4.549376 ° W ﻿ / 48.599807 ; - 4.549376 ﻿ ( Aber Wrac'h ) ), Aber Benoît ( 48 ° 33 ′ 46 '' N 4 ° 34 ′ 48 '' W ﻿ / ﻿ 48.562747 ° N 4.579905 ° W ﻿ / 48.562747 ; - 4.579905 ﻿ ( Aber Benoît ) ), Aber Ildut ( 48 ° 28 ′ 22 '' N 4 ° 44 ′ 59 '' W ﻿ / ﻿ 48.472649 ° N 4.749602 ° W ﻿ / 48.472649 ; - 4.749602 ﻿ ( Aber Ildut ) ). Ireland : Bantry Bay located on the southwest coast of Ireland is an example of an Irish ria. Wales : Milford Haven in Pembrokeshire is a ria. Others include the River Towy and the River Loughor. England : The south coast of England is a submergent coastline which contains many rias, including Portsmouth Harbour, Langstone Harbour, Chichester Harbour, Pagham Harbour, Southampton Water, Poole Harbour, the estuaries of the Exe, Teign and Dart, then Kingsbridge Estuary, Plymouth Sound in Devon, and the estuaries of the River Fowey, River Fal and Helford River in Cornwall. On the north coast is the River Camel and the River Taw. In Essex is the Blackwater River and River Crouch. The River Severn also forms a large ria. Croatia : Lim, Ombla Montenegro : The Bay of Kotor Italy : The Fiordo di Furore on the Amalfi Coast in Campania is a ria, despite its name. Malta : Grand Harbour and Marsamxett Harbour Africa Kenya : Kilindini Harbour, which is a deep channel between Mombasa island and South Coast mainland, is a ria. Asia Sanriku Coast : North Japan, east coast of Honshū Island ( main island ). Sendai city, Miyagi Prefecture and Iwate Prefecture are included. Ago Coast in Shima ( Mie Prefacture ) is a well known Ria coast, special for its pearls. Coasts on western, southern sides of the Korean Peninsula : Rias formed by sea level rising after Ice Age. The Chinese east coast, from the Guangdong province ( Hong Kong coastlines included ) to Shanghai. Oceania Tory Channel, in New Zealand 's Marlborough Sounds Papua New Guinea : Rias formed by eroded volcanic lava flow are found all around the town of Tufi at Cape Nelson, in Papua New Guinea 's Oro Province. Australia : The east coast of Australia features several rias around Sydney, including Georges River, Port Hacking, and Sydney Harbour. There are many examples in Western Australia, including the Swan River around Perth and several rivers in the west Kimberley region. New Zealand : Rias of various scales abound on the eastern shores of the upper North Island. On the west coast, in contrast, they are fewer but larger. Kaipara Harbour is the country 's largest, and the Hokianga Harbour, further north, is of historical significance to the native Māori people. The Marlborough Sounds at the northern tip of the South Island form a large network of rias. North america United States : Narragansett Bay, New York Harbor, Delaware Bay, Indian River Bay, the Chesapeake Bay, and Charleston Harbor are rias on the East Coast. Willapa Bay and Grays Harbor in Washington and San Francisco Bay in California on the West Coast are also rias. Canada : Charlottetown Harbour, Prince Edward Island South america Argentina : Patagonia has the Deseado ria, on the coast of Santa Cruz Province, on the Atlantic Ocean. Also, the `` bay '' that is Bahía Blanca is a ría. Consequences Ria can amplify the effects of tsunami, as demonstrated in the seismicity of the Sanriku coast, most recently in the 2011 Tōhoku earthquake and tsunami. See also Estuary Firth List of waterways Loch References Jump up ^ `` ria ''. Oxford English Dictionary ( 3rd ed. ). Oxford University Press. September 2005. ( Subscription or UK public library membership required. ) ^ Jump up to : Cotton, C.A. ( 1956 ). `` Rias Sensu Stricto and Sensu Lato ''. The Geographical Journal. 122 ( 3 ) : 360 -- 364. doi : 10.2307 / 1791018. ^ Jump up to : Goudie, A. ( 2004 ) Encyclopedia of Geomorphology. Routledge. London, England. ^ Jump up to : Bird, E.C.F. ( 2008 ) Coastal Geomorphology : An Introduction, 2nd ed. John Wiley and Sons Ltd. West Sussex, England. Jump up ^ Gulliver, F.P. ( 1899 ). `` Shoreline Topography ''. Proceedings of the American Academy of Arts and Sciences. 34 ( 8 ) : 151 -- 258. doi : 10.2307 / 20020880. Coastal geography Landforms Anchialine pool Archipelago Atoll Avulsion Ayre Barrier island Bay Baymouth bar Bight Bodden Brackish marsh Cape Channel Cliff Coast Coastal plain Coastal waterfall Continental margin Continental shelf Coral reef Cove Dune cliff - top Estuary Firth Fjard Fjord Freshwater marsh Fundus Gat Geo Gulf Gut Headland Inlet Intertidal wetland Island Islet Isthmus Lagoon Machair Marine terrace Mega delta Mouth bar Mudflat Natural arch Peninsula Reef Regressive delta Ria River delta Salt marsh Shoal Shore Skerry Sound Spit Stack Strait Strand plain Submarine canyon Tidal island Tidal marsh Tide pool Tied island Tombolo Windwatt Beaches Beach cusps Beach evolution Coastal morphodynamics Beach ridge Beachrock Pocket beach Raised beach Recession Shell beach Shingle beach Storm beach Wash margin Processes Blowhole Cliffed coast Coastal biogeomorphology Coastal erosion Concordant coastline Current Cuspate foreland Discordant coastline Emergent coastline Feeder bluff Fetch Flat coast Graded shoreline Headlands and bays Ingression coast Large - scale coastal behaviour Longshore drift Marine regression Marine transgression Raised shoreline Rip current Rocky shore Sea cave Sea foam Shoal Steep coast Submergent coastline Surf break Surf zone Surge channel Swash Undertow Volcanic arc Wave - cut platform Wave shoaling Wind wave Wrack zone Management Accretion Coastal management Integrated coastal zone management Submersion Related Bulkhead line Grain size boulder clay cobble granule pebble sand shingle silt Intertidal zone Littoral zone Physical oceanography Region of freshwater influence Commons Retrieved from `` https://en.wikipedia.org/w/index.php?title=Ria&oldid=807159789 '' Categories : Coastal and oceanic landforms Hidden categories : Articles needing additional references from October 2017 All articles needing additional references Talk Contents About Wikipedia Адыгэбзэ Asturianu Azərbaycanca Беларуская Brezhoneg Català Deutsch Eesti Ελληνικά Español Esperanto Euskara Français Galego 한국어 Hrvatski Bahasa Indonesia Italiano ქართული Latina Magyar Nederlands 日本 語 Norsk Occitan Polski Português Русский Shqip Slovenščina Српски / srpski Svenska Türkçe Українська Tiếng Việt 中文 Edit links This page was last edited on 26 October 2017, at 08 : 08. 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Question: drowned valley forming and inlet of the sea
Answer: ria