The $3.6 billion Hope Canal is unlikely to meet the December 31 completion deadline with one of the four major components, the high level outfall sluice only 47% completed and contractors continuing to face several challenges.
“The project completion means completion of all the four components. However, the NDIA (National Drainage and Irrigation Authority) is not optimistic that the eight door high level discharge sluice will be completed by the extended contract period of December 31, 2013,” Chief Executive Officer of the NDIA Lionel Wordsworth told Stabroek News on Saturday.
He emphasized that the extended contract period of December 31, 2013 remains unchanged and said that the NDIA and the consultants have been in discussion with the contractor for that component, Courtney Benn Contracting Services Ltd, to adopt sub-contracting methodology “which will allow for a large quantity work to take place concurrently and will see the project completion within the shortest possible time.”
Conceived following the Great Flood of 2005, the controversial project will drain water from the East Demerara Water Conser-vancy (EDWC) into the Atlantic Ocean, thereby eliminating the flooding of the Mahaica Creek and its environs. Currently, when the water reaches a high level in the EDWC, water is drained through the Maduni and Lama sluices into the Mahaica creek, resulting in overtopping and flooding in a vast area of inhabited communities.
Construction on the project started in February 2011, with an estimated 18 months for completion. However, the June 30 deadline was pushed down to August 31 and then later to December 31. It has four components: the Northern Relief channel which on completion will be 10.3km in length, from the sea defence embankment and extending to the EDWC, a high level outfall sluice, a conservancy head regulator and a public bridge being constructed at the Hope section.
Minister of Agriculture Dr Leslie Ramsammy had previously insisted that it would be completed within the deadline. Following a February 14, 2012 editorial in Stabroek News stating that the Hope Canal might not be functional until 2014, Ramsammy had said in a letter in response “The project will be completed in 2013 and we are confident, even with any slippage, that it would be functional in 2013 and not 2014. The conclusion by SN is reckless, if not mischievous.”
On Saturday, Wordsworth said that the excavation of the Northern Relief Channel is 96 % completed and trimming and shaping of embankments are continuing while stockpiled clay is being hauled to the section of the channel between the Crown Dam and the Conservancy Dam. That clay is being used for the construction of embankments between the conservancy and Crown Dam (approximately 3.5 km in length) which replaces the in-situ soil that is largely pegasse in nature, he said.
“It should be noted that the final completion of the channel and embankment is dependent on the completion of the bridge, head regulator and high level discharge sluice since the channel connection to these structures can only be implemented after these structures are completed,” he emphasized.
Meanwhile, the conservancy head regulator is 70% completed and the concrete base slab has been completed. Concrete works are currently being concentrated on the construction of the walls of the sluice structure which are near to completion, the NDIA head said. He disclosed that the public road bridge is 96% completed and the contractor is currently completing the approaches and transitions to connect to the existing roadway. “The high level outfall sluice is at 47% completion with works continuing on the casting of the base slab inclusive of the high level weir,” Wordsworth added.
The four components are being executed by three different contractors with the NDIA executing the channel and embankment works.
Consolidate
In terms of the work that remains to be done in relation to the channel, Wordsworth said that because earthen structures need time to consolidate (settle), the constructed embankments along the length of the channel are now being trimmed and shaped into their final design alignment and geometry. “Work is also underway to transport stockpiled clay to the section of the channel embankment between the Crown Dam and the conservancy. Poor soil conditions in this section require that the pegasse be removed, a clay sub-layer placed then a layer of geotextile fabric and the embankment constructed on top of that foundation,” he stated.
With regard to the head regulator, the NDIA boss said that the walls of the sluice are now being completed and then works can begin on the gantry columns and beam, bridge across the structure, gates and gabion baskets. There are also earthworks required to tie the structure into the conservancy dam as well as to transition the structure into the relief channel.
As it relates to the public road bridge, Wordsworth said that the only remaining works of major significance are the construction of the transitions and approaches that will connect the structure to the existing road. “Thereafter the remaining works are small and easily accomplished such as the installation of barriers and rails as well as street lighting and traffic signs,” he said.
The high level outfall sluice is way behind. “After the base slab is completed, work can begin on the walls of the structure and the activities will be quite similar to those of the head regulator with size being the only major difference between the two structures,” he asserted.
In terms of the challenges, Wordsworth said that due to the nature of the works for the channel, this project is very susceptible to the influence of the weather. “Although the consolidation of the already constructed embankments was expected to take a certain period of time, there were other activities planned to fill this time to ensure that all would be completed concurrently. The weather however has interfered with many of these planned activities,” he said.
“The stockpiled materials that are being hauled to the section of the channel between Crown and Conservancy Dams for embankment construction are faced with delays due primarily to wet weather whereby trucks and tractor and trailers transporting earth cannot traverse in wet conditions. Excessive rainfall often floods the stockpile pits and it takes weeks of round-the-clock pumping to empty the pits and to draw down the water level in the channel,” the NDIA boss added.
He said that the water in the channel (accumulated rain water) was also a hindrance to the works since the berms along which the tractors and trailers traverse to haul the materials were unstable as a result of being saturated. “These needed to be dried out in order to grant the hauling equipment access to the sections to be constructed. Despite these challenges, the NDIA has been implementing recovery plans to keep the works progressing while the December 31, 2013 completion remains unchanged,” Wordsworth emphasized.
Access
As it relates to the conservancy head regulator, he said that while the works are ongoing, the contractor has indicated that access has been one of the greatest challenges faced on this project. In order to cast concrete, equipment and materials (sand, stone, water, cement, steel and other construction materials) all have to be brought in to the project site from Flagstaff. The only way to undertake this activity is by use of a barge loaded by excavators, Wordsworth explained.
He added that use of the conservancy waterways is also very difficult to balance. “When the water level in the conservancy is very low, the barge can be grounded, when the weather is too wet, transport through the channels needs to be limited so that no additional strain is placed on the embankments lest there be overtopping or major embankment erosion. There are also other constraints, such as the available space within the empoldered area to stockpile the construction materials,” the NDIA head said.
Further, he said that when it rains in the conservancy, the pegasse which is very porous, causes seepage into the excavation area where there are ongoing works. “The contractor must therefore work diligently to keep the site from flooding while still managing casting and other works in a somewhat confined space,” he stated.
In terms of the public road bridge, Wordsworth said that in the context of the 94% completion figure of this particular project, most of the major challenges have already been met and surmounted by the contractor. Rain and shortage of aggregates will still affect the road construction works that are underway but there are no other foreseen difficulties at the moment. It is expected that this component will meet the December 31, 2013 extended completion contract period, he said.
Work on the high level outfall sluice has been hampered not only by factors such as weather, aggregate shortages and spikes in material costs as expressed by the contractor, Courtney Benn. “However, the NDIA has constantly raised with the contractor its concern about slow implementation of the project works,” Wordsworth declared.
Up to October 31, $2.5 billion was spent on the project. The design consultancy contract, compensation for residents and farmers, supply of steel sheet piles, purchase of Geotextile fabric, timber mats, two 4 x 4 vehicles and 14 excavators are included in this figure, Wordsworth said.
