To date, the Head Regulator (HR) for the Canal is 34% completed and the High Level Outfall structure is 33% completed, Chief Executive Officer of the National Drainage and Irrigation Authority (NDIA) Lionel Wordsworth told Stabroek News.
In contrast, the excavation of the canal itself is 90% completed, with various other associated works such as trimming and shaping the embankment, stockpiling and draining suitable clay for construction of the embankment, the installation of geo-textile as well as construction of alternative drainage channels being 53% completed. The other major component—the public road bridge—is 79% completed.
The construction of the high level sluice outfall structure (HLSOS) at the Atlantic Ocean end (North of the Hope Secondary School) is the responsibility of Courtney Benn Contracting Services Ltd while construction of the head regulator on the East Demerara Water Conservancy (EDWC) to link the channel to the conservancy is the responsibility of BK International. The construction of the public road bridge is the responsibility of DIPCON Engineering Ser-vices Ltd, while the NDIA is responsible for the canal itself.
Wordsworth emphasised that following the completion of the foundation levels for the HR and the HLSOS, work is expected to move faster. “While the completion figures for the HR and the HLSOS seem to be low, there are activities that are underway, such as cutting and bending of steel reinforcement for structural concrete works, fabrication of formworks which, once completed, will cause a significant jump in percentage completion,” he said adding that this is scheduled to be completed within the next four to six weeks. “These two structures are currently still within the foundation levels [and] this stage of construction is often the most onerous in terms of materials and time required,” he said.
As it relates to the head regulator, Wordsworth said that driving of foundation piles and steel sheet piles as well as sand-filling have been completed. “Pile caps have already been cast and work on blinding has begun, with the next stage being placement of steel reinforcement for the foundation slab after which the slab will be cast in concrete,” he said. The NDIA head explained that after that point, the superstructure will need to be constructed first via the placement of formwork, then reinforcement and finally casting in concrete. Thereafter, the other works, such as installation of ropes, pulleys, doors, and winches, will be completed.
In terms of the high level sluice outfall structure, the foundation stage is sand-filled and blinding works are underway. “Because this structure is so massive, works on the sand-filling have been started at the northern end and are almost nearing completion on the southern end along with the casting of pile caps while blinding has started on the north and will similarly follow the sand filling and casting of pile caps,” Wordsworth said. Works on the placement of reinforcement and the casting of concrete are about to commence, he stated. After this point the remaining activities are largely similar to those required for the completion of the head regulator but on a larger scale, he added.
For the earthen channel, works are underway on trimming and shaping of the embankment that was previously placed in the earlier stages of the construction. “It was necessary for some amount of soil consolidation to take place before this activity could continue but it is now underway on both sides of the relief channel. At sections where the soil type changes from clay to pegasse and clay mixtures and then further down to largely just pegasse, work is underway to cut and place layers of Geotextile fabric – PP300 in order to give stability and strength to the embank- ments in these sections where the pegasse is present,” Wordsworth disclosed.
He said that a section to connect the channel from the railway embankment to the HLSOS is to be done and will be completed in the final stages of the project when the bridge and outfall sluice are nearing completion. Work is ongoing on the construction of alternative drainage for farmers, he stated.
In terms of the bridge, the NDIA CEO said that the foundations piles are in place, the pile caps were cast and the Eastern and Western Abutments and Piers were constructed. Upon these, three out of six post-tensioned 40-metre long beams that will carry the deck of the bridge have been constructed across the span, 12 shorter (17 metres) pre-stressed beams that will connect the span to the roadway are already in place and works are underway on the formwork and reinforcement of the diaphragms as well as the approach sections of the road. The deck will be constructed above this. After these components are completed, then the finishing touches, such as surfacing of the deck and approach road, installation of rails and painting can be completed.
Work has started on the construction of the alternative drainage channels parallel to the main discharge channel, Wordsworth noted.
He said that the completion date remains at August 31st. “It must be understood however that days lost due to legitimate reasons are catered for contractually which allows for legitimate extensions of time awarded base on these delays,” he added.
Asked about difficul- ties being encountered, Wordsworth said that the wet season and the constant heavy rain has resulted in a slowdown in the progress of works at all worksites.
On the channel, the earthen embankments and berms are harder to traverse with excavators due to the soil being unable to support the excavators and requiring the use of mats, since additional time is taken to manoeuvre such mats and equipment, he said.
Wordsworth also pointed out that the wet conditions also affect the placement of the geotextile materials, since every pit open for geotextile placement has to be dewatered continually until they are completely filled with earthen material.
“At the head regulator, the integrity of the conservancy dam is always maintained and the transport of materials for this site using the channel was not possible during very low water levels, also the level of works that can be done in proximity to the dam can be affected by the prevailing wet conditions, since more soil stabilisation has to be done to withstand the load of heavy equipment,” he emphasised. He noted too that the contractors at all the sites have so far been working slowly due to various reasons and urged them to improve the overall pace of works.
Asked about the money spent thus far, Wordsworth said that to date, the total monies spent on the project is $2.3 billion. Included in these figures are the consultancy contracts for design of the structures, supervision as well as mobilisation ad-vances awarded to the three contractors at the beginning of the contract periods, he said.
In addition, compensation for residents and farmers, supply of steel sheet piles (100% completed), supply of geotextile fabric (100% completed), supply of timber mats (100% completed), supply of two 4 x 4 vehicles and supply of 14 long reach excavators (100% completed) are included in the $2.3 billion.
The $3.6 billion canal, when completed, is expected to help drain the EDWC into the Atlantic Ocean. Curren-tly, when the water reaches a high level in the EDWC, water is drained through the Maduni and Lama sluices into the Mahaica and Mahaicony creeks, resulting in overtopping and flooding in these areas.