The construction of a Kra canal poses several significant engineering challenges.
First, although the Malay Peninsula is only 26.5 miles wide at its narrowest point, (from the Kra River estuary to the Bay of Sawi), it is dominated by a long granite mountainous ridge, the Tenasserim Hills, that runs down the middle of the peninsula.
The ridge is more than 1,000 miles in length and varies in height from approximately 4,600 to 250 feet above sea level. Digging through the ridge has been the principal problem that has stymied historic attempts at digging a canal.
A system of locks could solve the problem of getting over the ridge. Locks, however, are usually between 10 and 20 times more expensive to build per running foot than normal excavation.
A system of locks sufficient to move ships over a 200+ foot ridge would require around six to 10 separate locks, three to five on each side of the ridge, and would still necessitate significant excavation. The highest vertical distance currently handled by locks is 370 feet at China's Three Gorges dam.
The current $30 billion to $50 billion construction estimate is based on a sea level canal and does not anticipate any lock construction. Any such construction would dramatically increase the expected cost.
Moreover, it is not clear that there is sufficient water available to permit the function of a lock system. Water used in the locks could be captured and recycled, but this would likely increase operating costs significantly.
The actual physical dimensions of the canal would depend on how large a ship it was designed to accommodate. A canal capable of handling a ULCC would need to be much larger than the 61-mile by 1,300-foot-wide and 82-foot-deep proposal that was first unveiled.
At a depth of 82 feet, including the dredging of the approaches to the canal, the entire waterway would be 120 miles long. At a depth of 164 feet, sufficient to handle ULCCs, the length of the canal becomes 250 miles.
Without a definitive route and design, it's impossible to determine exactly how much earth would need to be excavated to build a sea level canal. However, based on the current proposal and the likely possible routes, it has been estimated that upward of 1.3 billion cubic yards of earth would have to be moved.
To put this quantity in perspective, the initial construction of the Panama Canal required the excavation of about 260 million cubic yards. Subsequent expansion of the canal required an additional 200 million cubic yards to be removed.
The initial construction of the Suez Canal required excavating 100 million cubic yards. Its subsequent expansion, including the most recent phase that ended in 2016, required an additional 340 million cubic yards.
All told, the Suez Canal and the Panama Canal required a total of between 430 and 460 million cubic yards of earth to be removed. The proposed Kra canal would require approximately three times the amount of excavation. 1.3 billion cubic yards of earth is enough to bury the entire island of Manhattan under 60 feet of debris.
