paragraph_text: The Fluvià () is a river in Catalonia. It rises in the Serralada Transversal, passes through Olot, and flows into the Mediterranean Sea near Sant Pere Pescador. The ancient city of Empúries was founded near the mouth of the Fluvià, when it was 6 km south of its present location.

paragraph_text: The Syas River () is a river in Lyubytinsky District of Novgorod Oblast and Tikhvinsky and Volkhovsky Districts of Leningrad Oblast, Russia. The Syas River flows from Valdai Hills north into Lake Ladoga. A town of Syasstroy is located at its mouth. It is long, and the area of its basin . The largest tributary of the Syas is the Tikhvinka River (right).

paragraph_text: The Cheakamus River (pron. CHEEK-a-mus) is a tributary of the Squamish River, beginning on the west slopes of Outlier Peak in Garibaldi Provincial Park upstream from Cheakamus Lake on the southeastern outskirts of the resort area of Whistler. The river flows into Cheakamus Lake before exiting it and flowing northwest until it turns south and enters Daisy Lake. Between the outlet of Daisy Lake and its mouth, much of its length is spent going through Cheakamus Canyon, where the river flows through swift rapids and even one good sized waterfall. The river flows south from the lake and through the canyon before joining the Squamish River at Cheekye, a few miles north of the town of Squamish. The river's name is an anglicization of the name of Chiyakmesh ("people of the fish weir"), a village of the Squamish people and a reserve of the Squamish Nation.

paragraph_text: In the Mouth of Madness is a 1994 American horror film directed and scored by John Carpenter and written by Michael De Luca. It stars Sam Neill, Julie Carmen, Jürgen Prochnow, David Warner and Charlton Heston. Informally, the film is the third installment in Carpenter's "Apocalypse Trilogy", preceded by "The Thing" and "Prince of Darkness".

paragraph_text: The Igaraçu River, also called the Igarassu River, is a distributary of the Parnaíba River in northern Piauí state in Brazil. It flows from its origin on the Parnaiba River southwest of the city of Parnaíba to the mouth on the Atlantic Ocean near the city of Luís Correia.

paragraph_text: The Betka River rises south of in the Croajingolong National Park, just east of the Princes Highway, and flows generally northeast, then southeast, then east by north, before reaching its mouth with Bass Strait north of the Aerodrome in the Shire of East Gippsland. The river descends over its course.

paragraph_text: By way of his voyages in the 1770s, Captain James Cook proved that waters encompassed the southern latitudes of the globe. Since then, geographers have disagreed on the Southern Ocean's northern boundary or even existence, considering the waters as various parts of the Pacific, Atlantic, and Indian Oceans, instead. However, according to Commodore John Leech of the International Hydrographic Organization (IHO), this situation has no scientific sense since it has different ecosystem and life from the three oceans mentioned before and is located on a southern portion of Earth, hence the name of an ocean. This remains the current official policy of the IHO, since a 2000 revision of its definitions including the Southern Ocean as the waters south of the 60th parallel has not yet been adopted. Others regard the seasonally - fluctuating Antarctic Convergence as the natural boundary.

paragraph_text: Murrumbidgee River (), a major tributary of the Murray River within the Murray–Darling basin and the second longest river in Australia. It flows through the Australian state of New South Wales and the Australian Capital Territory. It descends as it flows in a west-northwesterly direction from the foot of Peppercorn Hill in the Fiery Range of the Snowy Mountains towards its confluence with the Murray River near Boundary Bend.

paragraph_text: River Júcar flows first southward and then eastward through the towns of Cuenca, Alcalá del Júcar, Cofrentes, Alzira, Sueca and Cullera, a town located near its mouth into the Gulf of Valencia, Mediterranean Sea. It crosses the provinces of Cuenca, Albacete and Valencia

paragraph_text: The river's source is Scotia Lake, a small lake east of Halfway Lake Provincial Park in Sudbury District. From there, it flows north and east, taking in two small tributaries and continuing to a point 20 kilometres southwest of the Ishpatina Ridge, where it turns south. After approximately 60 kilometres, the river flows into Lake Wanapitei in the northeastern portion of Greater Sudbury. At the south end of the lake, the river continues, flowing south until it joins the French River near the latter's mouth on Georgian Bay on Lake Huron. The river is approximately in length and is a popular wilderness canoeing route.

paragraph_text: The Cooper Creek (formerly Cooper's Creek) is one of the most famous rivers in Australia because it was the site of the death of the explorers Burke and Wills in 1861. It is sometimes known as the Barcoo River from one of its tributaries and is one of three major Queensland river systems that flow into the Lake Eyre basin. The flow of the creek depends on monsoonal rains falling months earlier and many hundreds of kilometres away in eastern Queensland. At in length it is the second longest inland river system in Australia after the Murray-Darling system.

paragraph_text: Marlo is a small village in the Gippsland region of Victoria, Australia. It is located east near the mouth of the Snowy River where the Snowy River meets and flows into the Southern Ocean.

paragraph_text: An artificial river mouth was cut through the sand dunes adjacent to the Stirling Wetlands in 1880 to allow it to flow directly into Geographe Bay.

paragraph_text: The Murray River (or River Murray) (Ngarrindjeri: Millewa, Yorta Yorta: Tongala) is Australia's longest river, at 2,508 kilometres (1,558 mi) in length. The Murray rises in the Australian Alps, draining the western side of Australia's highest mountains, and then meanders across Australia's inland plains, forming the border between the states of New South Wales and Victoria as it flows to the northwest into South Australia. It turns south at Morgan for its final 315 kilometres (196 mi), reaching the ocean at Lake Alexandrina.

paragraph_text: Mouth Maze Cave is a large, labyrinthine river cave in Trelawny, Jamaica. It is the only exit of the Mouth River from a small valley which, during intense rainfall, becomes flooded as the flow backs up. Because of this it can only safely be visited in very dry periods.

paragraph_text: Formed by the confluence of the Yeerung River West Branch and the Yeerung River East Branch, the Yeerung River rises in the Cape Conran Coastal Park, and flows generally south before reaching its mouth with Bass Strait, east of Cape Conran in the Shire of East Gippsland. The river descends over its course.

paragraph_text: The Red River is the second - largest river basin in the southern Great Plains. It rises in two branches in the Texas Panhandle and flows east, where it acts as the border between the states of Texas and Oklahoma. It forms a short border between Texas and Arkansas before entering Arkansas, turning south near Fulton, Arkansas, and flowing into Louisiana, where it flows into the Atchafalaya River. The total length of the river is 1,360 miles (2,190 km), with a mean flow of over 57,000 cubic feet per second (1,600 m / s) at the mouth.

paragraph_text: The Saloum River rises about 105 kilometers east of Kaolack, Senegal, and flows into the Atlantic Ocean. The significant Saloum Delta is located at its mouth, which is protected as Saloum Delta National Park. The river basin lies within the Serer pre-colonial Kingdom of Saloum.

paragraph_text: The Benedore River rises in the Benedore River Reference Area and flows generally south southeast, through the Seal Creek Reference Area, before reaching its mouth with Bass Strait within the Croajingolong National Park in the Shire of East Gippsland. The river descends over its course.

paragraph_text: Murray Mouth is the point at which the River Murray meets the Southern Ocean. The Murray Mouth's location is changeable. Historical records show that the channel out to sea moves along the sand dunes over time. At times of greater river flow and rough seas, the two bodies of water would erode the sand dunes to create a new channel leaving the old one to silt and disappear.

Question: When did the ocean that the Murray Mouth flows into become a thing?
Answer: the 1770s