KOMPAS.com - The roar of the waves filled the ears of the surfers, as well as those watching on land watching them wade out to the waves. One can assume that this scene took place in Bali, Australia and Hawaii, but in fact it is none of the above.
Known as bono waves, from the Melayu language term for ‘brave’, the breakers roll the length of the estuary from the villages of Pulau Muda to Teluk Meranti and Tanjung Mentangor.
In the estuary, bono waves can reach speeds of 50 to 60 km, though it moves at an average speed of 40 km an hour, and heights of four to five meters. The waves will shrink no more than 70 centimeters to one meter the farther it gets from the estuary.
These big waves are distinct from their ocean going counterparts because they flow against the river current. And unlike the swells of the open sea, bono waves can reach lengths of 200 meters to two kilometers, depending on the river shores.
Confluence of three currents
While bono waves is distinct from ocean tides, they still owe their formation to the open sea.
"Bono waves are created when waves from the Malacca Strait and the South China Sea converge with the mouth of the Kampar River," said Ministry of Marine Affairs and Fisheries coastal environment researcher Guntur Adhi Rahmawan.