Tidal bore

Scientific studies have been carried out at the River Dee[10] in Wales in the United Kingdom, the Garonne[11][12][13][14][15] and Sélune[16] in France, the Daly River[17] in Australia, and the Qiantang River estuary[18] in China. The force of the tidal bore flow often poses a challenge to scientific measurements, as evidenced by a number of field work incidents in the River Dee,[10] Rio Mearim, Daly River,[17] and Sélune River.[16]

• Ganges–Brahmaputra, India and Bangladesh
• Indus River, Pakistan
• Sittaung River, Burma
• Qiantang River, China, which has the world's largest bore,[2][18] up to 9 m (30 ft) high, traveling at up to 40 km/h (25 mph)
• Batang Lupar or Lupar River, near Sri Aman, Malaysia. The tidal bore is locally known as benak.[6]
• Batang Sadong or Sadong River, Sarawak, Malaysia.
• Bono, Kampar River, at Meranti Bay, Pelalawan, Indonesia. The phenomenon is feared by the locals to sink ships. It is reported to break up to 130 km (81 mi) inland, but usually up to 40 km (25 mi) with 6 m (20 ft) height.[20]

• Styx River, Queensland
• Daly River, Northern Territory

• River Shannon, up the Shannon Estuary to Limerick, Ireland: 21 September 2013

The Trent Aegir seen from West Stockwith, Nottinghamshire, 20 September 2005

The Trent Aegir at Gainsborough, Lincolnshire, 20 September 2005

• River Dee, Wales and England
• River Mersey. The second highest tidal bore after the Severn bore, up to 1.7 meters (6 ft) high. The bore tends to form around the Manchester Ship Canal.
• The Severn bore on the River Severn, Wales and England, up to 2 meters (7 ft) high
• The Trent Aegir on the River Trent, England, up to 1.5 meters (5 ft) high. Also other tributaries of the Humber Estuary.
• River Parrett
• River Welland
• The Arnside Bore on the River Kent
• River Great Ouse
• River Ouse, Yorkshire. Like the Trent bore, this is also known as "the Aegir".
• River Eden
• River Esk
• River Nith
• River Lune, Lancashire
• River Ribble, Lancashire
• River Yealm, Devon
• River Leven, Cumbria

Tidal bore on the River Ribble

• Durme, Flanders

The phenomenon is generally named un mascaret in French.[21] but some other local names are preferred.[19]

• Seine had a significant bore until the 1960s, locally named la barre. Since then, it has been practically eliminated by dredging and river training.[19]
• Bay of Mont-Saint-Michel including Couesnon, Sélune, and Sée[19]
• Arguenon[19]
• Baie de la Frênaye[19]
• Vire[19]
• Sienne[19]
• Vilaine, locally named le mascarin
• Dordogne[19]
• Garonne[19]

• Fly River[22]
• Turama River

Tidal bore on the Petitcodiac River

• The Turnagain Arm of Cook Inlet, Alaska. Up to 2 meters (7 ft) and 20 km/h (12 mph).
• Historically, the Colorado River had a tidal bore up to 6 feet, that extended 47 miles up river.
• The Savannah River up to 10 miles (16 km) inland.
• Small tidal bores, only a few inches in height, have been observed advancing up tidal bayous on the Mississippi Gulf Coast.

Most rivers draining into the upper Bay of Fundy between Nova Scotia and New Brunswick have tidal bores. Notable ones include:

• The Petitcodiac River formerly had the highest bore in North America at over 2 metres (6.6 ft) in height, but causeway construction between Moncton and Riverview in the 1960s led to subsequent extensive sedimentation which reduced the bore to little more than a ripple. After considerable political controversy, the causeway gates were opened on April 14, 2010, as part of the Petitcodiac River Restoration Project and the tidal bore began to grow again.[23] The restoration of the bore has been sufficient that in July 2013, professional surfers rode a 1 metre (3.3 ft)-high wave 29 kilometres (18.0 mi) up the Petitcodiac River from Belliveau Village to Moncton to establish a new North American record for continuous surfing.
• The Shubenacadie River, also off the Bay of Fundy in Nova Scotia. When the tidal bore approaches, completely drained riverbeds are filled. It has claimed the lives of several tourists who were in the riverbeds when the bore came in. Tour boat operators offer rafting excursions in the summer.
• The bore is fastest and highest on some of the smaller rivers that connect to the bay including the River Hebert and Maccan River on the Cumberland Basin, the St. Croix and Kennetcook rivers in the Minas Basin, and the Salmon River in Truro.[24]

Historically, there was a tidal bore on the Gulf of California in Mexico at the mouth of the Colorado River. It formed in the estuary about Montague Island and propagated upstream. It was once very strong, but diversions of the river for irrigation have weakened the flow of the river to the point the tidal bore has nearly disappeared.

• Amazon River in Brazil and Orinoco River in Venezuela, up to 4 meters (13 ft) high, running at up to 13 mph (21 km/h). It is known locally as the pororoca.[25]
• Mearim River in Brazil
• Araguari River in Brazil. Very strong in the past, it's considered lost since 2015, due to buffaloes farming, irrigation, and dam construction along the river, leading to substantial loss of water flow.

• Nitinat Lake on Vancouver Island has a sometimes dangerous tidal bore at Nitinat Narrows where the lake meets the Pacific Ocean. The lake is popular with windsurfers due to its consistent winds.