Mearim River

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Mearim River – Tidal Bore Latest News

Recently, a Brazilian surfer, known for surfing the world’s longest tidal waves, uses the Mearim’s pororoca to raise awareness about climate change and ecological degradation.

The Mearim River is a major river located in Maranhão state, in northern Brazil.
It originates in southern Maranhão and drains northward into the Baía de São Marcos (São Marcos Bay), where it forms a common estuary with the Pindaré and Grajaú rivers.
The river is ~800 km long, flowing through the Atlantic Coastal Plain marshlands and passing through dense tropical rainforests and mangrove ecosystems.
The river’s upper and middle courses are marked by rapids, making them non-navigable, while only the lower course is suitable for navigation.
The Mearim River forms the southern boundary of the Tocantins–Araguaia–Maranhão moist forests ecoregion, an important biodiversity hotspot.

Tidal Bore (Pororoca) Phenomenon

The Mearim River is famous for its pororoca, a tidal bore that occurs when high tides from the ocean travel upstream into the river.
The term “pororoca” is derived from the Tupi Indigenous language, meaning “great roar”, referring to the thunderous sound generated by the collision of river and ocean waters.
A tidal bore is a positive surge of water created when rising ocean tides push against river currents, typically occurring during spring tides and supermoons.
The height of the bore is generally greater near the banks of the river than at the centre and can travel upstream for 30 minutes after the peak high tide.
The Mearim pororoca is one of the last remaining tidal bores of significant strength in Brazil, attracting surfers and researchers.

Mearim River – Tidal Bore FAQs

Q1: Where is the Mearim River located?
Ans: The Mearim River is located in the Maranhão state of northeastern Brazil and flows into the Atlantic Ocean.

Q2: What unique tidal phenomenon is observed in the Mearim River?
Ans: The Mearim River is known for the tidal bore called the “Pororoca,” where ocean tides push upstream against the river current, creating large waves.

Q3: Which other rivers globally experience tidal bores like the Mearim?
Ans: Rivers like the Amazon (Brazil), Qiantang (China), and Seine (France) also exhibit tidal bores.