Small floating dredges can fix siltation problems –Dutch experts

Jul 19, 2016 News

Siltation has become synonymous with flooding in Guyana and to address the issue, the Dutch Risk Reduction Team recommends that the government make use of small floating dredges to remedy the recurring problem.

According to the report since dredging has been the standard way to combat siltation, these dredges can be used in channels inaccessible by excavators, thereby, enhancing the country’s ability to deal with siltation.
Silt is the fine sand or clay which is carried by running water and deposited as sediment especially in a channel or harbour.
The DRR Team suggested, too, that the National Drainage and Irrigation Authority (NDIA) should exploit its own cutter suction dredge for the maintenance of the outfall channels as well as river and river mouth sections. If this is done, then the small floating dredges can be used in municipal and residential areas.
The report said that sedimentation reduces the cross-sectional flow area of many drainage channels. It noted, too, that an expanding coastline contributes to siltation in-front of the outfalls which reduce the drainage capacity.
Recently, there were two instances of flooding in Guyana, particularly in the county of Berbice. In June, villages along the coast of Region Five were severely affected by flood waters. The hardest hit communities were Lovely Lass, Trafalgar and Union.
During the initial stages of the flooding, one complication which arose was the presence of silt at the main sluice located in the village of Trafalgar. It was related to this publication that during the El Nino season the unwanted sediments had built up in the outfall channel of the sluice. This resulted in a blockage causing water not to run off the land as it should have.
More recently another case of flooding came up in Region Six. Currently, Gibraltar and Fyrish villages are affected by flooding. The councillor who contacted Kaieteur News said that the reason for the water not draining off the land was the blockage at the sluice door. Again, there was a build-up of silt. It was reported that the high tide brings sediments into the land and are lodged at the door.
When drainage by sluice is stalled, there is a greater dependence on the use of pumps to get excess water off the land as was the case in Trafalgar. In Gibraltar a pump had been set up to work round the clock.
Despite dredging the outfall channels as an option to move unwanted silt; the report stated that there will still be an accumulation of the material.
The DRR was approached by the government in October 2015 to examine the state of drainage in Guyana, and to make recommendations which can be implemented to fix the faults in the system.