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Fijian ring ditch at Monasavu

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When Robert Smith as Senior Advisor Marine Geophysicist at SOPAC began his exploration of the Monasavu Hydro to determine the amount of sedimentation in the lake, as part of a survey that he began in 1991, in reviewing the data collected with state of the art mapping tools he found more than sedimentation, he discovered a Fijian ring ditch.

The use of the Fijian ring ditch was used for fortification, found all over the country and dates back hundreds and hundreds of years.

Mr. Smith shared his find during his presentation to participants in the SOPAC/STAR meeting in Nadi recently.

Because the lake was never cleared of trees and bush when it was filled, the ring ditch was never discovered. But it is now very much a part of the lakebed sitting under 10 metres of water at Monasavu.  The ring ditch is shown in the lower centre end of the reservoir (circled)

As for the sedimentation?  Mr. Smith said that it would take at least 93 years before the sediment would begin to impact on the minimum operating water level of the reservoir.  Sediment for years and years to come will not affect the hydro operation.

 

Last Updated on Tuesday, 03 May 2011 17:02  

Newsflash

Tuesday 22 April 2014, Secretariat of the Pacific Community (SPC), Honiara – Staff of SPC's Solomon Islands Country Office were saddened to witness the human tragedy of the recent floods. The loss of life when the Mataniko and other rivers burst their banks and the old Mataniko bridge collapsed highlighted the plight of poor squatters with little choice but to occupy land that regularly floods.

Country Office Manager, Mia Rimon, contacted SPC Director-General Dr Colin Tukuitonga and the Director of SPC's Applied Geoscience and Technology Division (AGTD) Mike Petterson with a request for assistance. A request came also from the Solomon Islands Ministry of Lands, Housing and Survey (MLHS) to provide a geohazards assessment.

SPC responded to these appeals for help; the AGTD Director arrived in Honiara with his team and met with the permanent secretaries of the Ministry of Foreign Affairs and External Trade, MLHS and the Ministry of Energy, Mines and Rural Electrification (MEMRE). They presented unmanned aerial vehicle (UAV, or drone) technology to the government to obtain precise imagery of the flooded areas.