Supersizing an historic waterway

For the first time in 90 years, large-scale construction is back on the Panama Canal system as it undergoes a massive expansion to accommodate a new generation of larger ships. This time, the project is not expected to take 34 years or cost 25,000 workers’ lives.   BY ALAN TITCHALL

Panama.jpgOne of the world’s great engineering achievements, and vital to the development of global freight for almost a century, the Panama Canal waterway system starts from Panama City on the Pacific Ocean and cuts 80 kilometres north to Colon on the Caribbean Sea.

Tenders have already gone out for an ambitious US$5.25 billion (NZ$6.88 billion) project to build a second canal lane with a new set of locks at each entrance to double shipping capacity. Construction is expected to be completed by 2014, in time for the canal’s centenary.

The original project was a sea-level canal, started in 1880 by Frenchman Ferdinand de Lesseps who had built the Suez Canal some years before. In the following 13 years, 22,000 workers died of malaria or yellow fever in the swampy terrain before the project was abandoned.

In stepped the US government, keen to build up its naval supremacy in the region, and, with the help of 75,000 workers from 50 countries and the US Army Corp of Engineers, designed and built a waterway system using three locks at each entrance to accommodate the vastly different sea levels between the two oceans. The tide on the Pacific side can vary by six metres, but less than a metre at the Atlantic entrance. Most of the passage through the canal is at 26 metres above sea level.

Construction began in 1904 and was completed two years ahead of schedule in 1914 at a cost of US$375 million. Despite better understanding of tropical diseases by the turn of the 20th century, a further 5600 workers perished during construction. The waterway was operated by the US until 1999, when it was ceded to Panama and taken over by the Panama Canal Authority.

The canal has near reached its capacity and needs upgrading to accommodate bigger ships and increased shipping volumes. There are queues of ships (mostly freighting between Asia and the US) waiting to transit the canal on both sides every day and, with operational costs of up to US$40,000 a day and waits of up to a week for passage, that can prove an expensive traffic jam.

In the past, major shipping companies built vessels called Panamax ships, designed to fit the canal’s 33.5 metre wide lock chambers. More and more modern ships are far too large to fit the canal and have to off-load their US east coast bound cargo at Pacific ports, or take the long route via the lock-less Suez Canal.

By 2011, it is estimated that 37 percent of the global shipping fleet will be too large to fit into the Panama Canal’s narrow lock systems.

Ambitious project goes to tender

The gigantic supersizing project to bring the canal into the 21st century represents a formidable challenge, equal to the original and planned to double its capacity by providing access channels for ships of up to 12,000 container capacity (up from a maximum of 4000 container ships). The Panama Canal Authority believes it can finish the project in seven or eight years and with fewer than 7000 workers.

At a cost of more than US$5 billion, the project will be such an economic burden to the country of three million residents that it had to put to a referendum last year and three quarters of Panama’s population voted in favour of it going ahead.

The scale of the project is understandably massive, and involves dredging 130 million cubic metres of rock and soil, or half the amount excavated during the original construction.

More than half the budget will be spent on two new sets of triple locks, one at the Atlantic entrance to the waterway and one at the Pacific, and new channels to connect these locks to existing shipping lanes. The reinforced concrete locks will augment the existing locks, not replace them, and will be 61 metres wide, 427 metres long and 18.3 metres deep. The old locks are 33.5 metres wide, 305 metres long and 12.5 metres deep. Each new lock complex will measure a total of 2.5 kilometres in length – the longest lift complex in the world.

A huge volume of fresh water is required to move each ship through the locks and the old system has relied on Gatun Lake, a man-made reservoir topped up by Panama’s seven-month rainy season, to supply the billions of litres used every day.  The lake will be deepened and widened, and raised by half a metre to provide the extra water, while the new locks will be capable of capturing and recycling 60 percent of this water as they are emptied (the water used in the old locks is flushed out to sea). This means the new lock chambers will use seven times less water during each transit, although they will hold 65 percent more water.

The new locks will also use tugboats to align ships in the chambers, not the famous electric ‘mule’ locomotives used to manoeuver ships into position in the old system. They will also feature pairs of lock gates (actually a 19th century European design) that roll out of wall recesses on tracks to seal the chambers, not the old hinged miter lock gates, a design from medieval times, that have been another interesting engineering feature of the old canal.

The Panama Canal Authority got its project off the ground back in May with the release of the first construction tender for dry excavation along the north access channel on the Pacific end of the canal. This project, the first construction-related expansion tender, only represents about 16 percent of the total excavation for the new access channel to the Pacific locks.

This was followed by tenders for the conceptual design studies of the new locks. While the Atlantic lock configuration contract was negotiated directly with the US Army Corps of Engineers (the original 1904 canal designers), the second contract for the Pacific side was tendered internationally and closed 18 October.

Other tenders related to the expansion projects and advanced locks designs, will follow. 

Contractor Vol.31 No.10 November 2007
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