Dear Editor,
I refer to an article in KN dated October 2 on the subject ‘Works on $3 Billion Hope/Dochfour Canal begin’ and to a statement from the lead consultant from Cemco stating that the terrain between the crown dam and the EDWC is creating serious problems for the consultants and that the drilling rig keeps sinking in the soil. If a lightly loaded drilling rig can sink on its own in the pegasse soil what will happen to the trucks transporting the heavy, selected soil material to the site? You will have to build a concrete roadway supported on piles to transport the trucks. There is no guarantee that machines working on timber mats will not sink as well. Many years ago this same type of pegasses material floated away during construstion of a sluice.
The consultants’ proposal as well to use a geotextile material between the dam and the pegasse sub-soil to increase its strength is also questionable.
Even the consultants expressed some concern on their website not knowing how the two will interact. It has never been used before on pegasse foundation material. In engineering it is better to be safe than sorry afterwards. If there were a failure in the dam the result could be catastrophic.
A portion of the dam in the MMA was built on pegasse, but it was designed and built differently. It is still in good condition today some 30 years later.
I had previously written two letters to SN warning about the soil in this area. In the ’70s the Hydraulics Division attempted to carry out drainage works in the Nabaclis area and abandoned the work on account of the above-stated poor soil conditions.
It is a shame that such an expensive project was embarked upon without the consultants first carrying out preliminary surveys and soil exploration to determine its viability before embarking on modelling works inside the EDWC and elsewhere costing millions.
Under the circumstances it is for the government to decide how they want to proceed.
Yours faithfully,
M. Alli
