Dear Editor,
It was earlier reported that the 10.3km canal for the Hope project would be a high level canal, ie, material would be transported to build the embankment. It has now been changed to an excavated canal and government force account workers will carry out the work. Excavators have been already purchased for the construction. Secondly, the two sluices at the sea defence and the EDWC ends were originally to be 4-door gated sluices, now they have been changed to 8 doors and 3 doors respectively. The length of the outfall channel for the sea defence sluice has also been changed.
As far as I know conditions have not changed to warrant these major changes to the original Preliminary Design Report. The Minister previously stated that his engineers were guessing their way to solve the EDWC problems. I would also like to ask the Minister if these experts are also not guessing their way as well.
The experienced government force account workers were disbanded many years ago, and I am wondering if the government has the requisite experience to build such a canal, part of which will be built on a pegasse foundation. I have estimated that the canal will contain some 265 million gallons of water at optimum level based on a 30-metre canal bottom width, invert level 46.0 GD, water level 61.0 GD and side slopes 1:2 with no allowance for benching.
The entire canal embankment will require regular maintenance and monitoring after construction, and knowing the government’s penchant for poor maintenance over the years, there should be some concern for safety since the conservancy would now be brought out into the populated areas. The outfall for the 8-door sluice at the sea defence end may also require frequent desilting. How the geotubes perform in protecting the side slopes is debatable, since they have never been used before in Guyana.
It would be also tough designing and constructing the sluice at the EDWC end, the foundation also being on pegasse material. I hope the designer and contractor are up to the task. Many years ago, a sluice built on similar material floated away during construction on the West Coast. One also cannot forget the failure of the famous floating wharf in the Pomeroon a few years ago.
I am aware there is a problem with the EDWC caused by poor maintenance over the last 40 years, resulting in a build-up of siltation and vegetation inhibiting storage levels and absorption capacity, that causes the water level to rise to alarming levels after a heavy rainfall. The burrow trench that channels the water to the Land of Canaan Sluice (LOC) is also silted up.
Hydraulics knew about this problem since the ’70s, but there were no funds available to correct the problem. The government should tackle the EDWC problem differently by carrying out hydrographic surveys before and after removing the rubbish in the reservoir, and then establishing the capacity of the reservoir and re-digging the burrow trench that will enable the LOC to drain to at least 90% efficiency rather than its present 40%. The LOC main canal should also be refurbished to its original design level.
The recent dry weather was an excellent time and opportunity to carry out these works, which in my opinion would be much cheaper and safer than the Hope Project.
Hydraulics’ intention was also to carry the MMA project to the EDWC and build a dam and a reservoir behind the EDWC where there is good soil, with another drainage outlet to the Demerara River and then regulate the water level in the EDWC to remove the pressure on the dam, which we knew was very fragile.
Unfortunately, it is not possibly to do so now on account of the siltation of the Abary River, caused by the poor operation of the MMA scheme.
Yours faithfully,
M Alli
