PicoSearch
 
back to front page Our Organisation contact us    
Tidal Bore Phenomenon
Tidal bore is a solitary wave formed when a rising tidal front tries to enter a shallow and narrowing river with high tidal range from abroad estuary. In the process, the tidal front is retarded by the river flow and the bed friction start to build up. When it reaches the critical point, it breaks and moves forward upstream as a rushing wave called tidal bore. As it travels upstream, it will decrease in height and velocity and eventually dies out due to energy dissipation. In Malaysia, tidal bore phenomenon can only be seen at Batang Lupar, Batang Sadong, Batang Samarahan and Batang Saribas in the state of Sarawak.

Sri Aman is situated about 194 kilometres by road from Kuching City. The unique phenomenon of tidal bore occurrs in Batang Lupar. Batang Lupar flows from the Klinkang Range to South China Sea with river length of 275 kilometres. Geographicaly, Batang Lupar has a big opening at the rivermouth and becomes narrow when it reaches upstream. It is believed that tidal bore starts at Pulau Seduku located about 44.6 kilometres from river mouth and 34.5 kilometres from Sri Aman town. Tidal bore or locally known as benak occurs everyday with different wave lengths and heights. However, during spring tide, normally on the third and eighteen day of  the Chinese Lunar Calendar, tidal bores with high magnitude can be observed clearly.

There is no detailled study on the tidal bore Batang Lupar. However, based on naked eyes observation, the velocity of the tidal bore is about 7 km/hr to 18km/hr with heights at times reaching to more than 3 metres. The formation of tidal bored depends on several factor as listed below:

 
  • Tidal range: neap tide & spring tide
  • Shape and slope of the river
  • Overall depth of the river channel
  • Weather condition and flow of river at upstream
Sarawak State Government recognises Pesta Benak (Tidal Bore Carnival) in Sri Aman as one of yearly activity in the Sarawak tourism calendar. The objective of Pesta Benak Sri Aman is to introduce Sri Aman town through tourism and encourage tourist from in and outside the country to visit Sri Aman. Apart from it, Pesta Benak is also to encourage harmonial spirit among local community.
Pesta Benak 2003 was been held in Sri Aman on 17 April to 20 April 2003. In conjuction with this festival, there were many events organized such as development exhibition, food fair, karaoke competition, Pesta Benak Sri Aman Seminar 2003, culture and art performances, development exhibitions and others.  In conclusion, tidal wave festival has made the area a popular spot in Sarawak for visitors, you can join in the fun and hitch a ride with the longboats or just watch the boatman braving the waves. You can even immerse yourself with the local culture at the food fair, good music and dance performances that are part and parcel of the festival.

Photo gallery of the Tidal Bore at Sri Aman