Ports of Los Angeles and Long Beach are to invest US$1 million to $2.5 million a day on infrastructure to accommodate the mega ships, reckoned at 13,000 TEU - that will transit the expanded Panama Canal.
"Ships got bigger and a whole lot faster than anybody anticipated," said LA port development director Mike Christensen, reported the Long Beach Press Telegram.
Big-ship capability continues to redefine the term 'big ship ready', he added.
The story is much the same for neighbouring Port of Long Beach which handles 14,000 containerships and at least three to four vessels of 10,000 TEU weekly since first welcoming a 12,500 TEUer back in 2012.
The economies of scale in a bigger vessel mean that the newer engines of megaships save on fuel costs while the more containers on board drive down cost per TEU further.
Investment in larger ships by carriers will reduce total costs and being able to handle megaships gives you a competitive edge over other ports, said Kyser Centre for Economic Research economist Ferdinando Guerra.
"It's all about profit maximisation and the bottom line," said Mr Guerra, with investment in development of taller cranes, water depth and on-dock rail additional benefits.
LA has spent $140 million on dredging its main channels to at least 53 feet and in supporting these bigger ships acquired suitable handling equipment in taller dockside cranes.
Investment in the $510 million TraPac Container Terminal, with its $1 billion projected expansion over a five years, will extend its wharves 4,600 feet, deepen water berths and lay in new rail facilities in 2016.
The completion of $155 million rail yard at Berth 200 by end of the year will help to eliminate 2,300 daily truck trips from the roads.
Federal grants help to support a $383-million transportation improvement programme, which include the $72-million South Wilmington Grade Separation and improvements to the 110/47 interchange at $20 million.
Port of Long Beach has made a long-term $1 billion investment in a new $400 million rail facility in El Paso, Texas to support cargo flow in rail capacity increases of 55 to 90 trains per day.
Long Beach port director Noel Hacegaba said the $4.5 billion capital programme intends to move cargo efficiently by building infrastructure, including the $1.3 billion Gerald Desmond Bridge replacement to provide ships more air draft.
Mr Hacegaba is overseeing the surveying of port waters so that a colour-coded map can tell port pilots depths and which part of the port is too shallow. Charts are updated to support ongoing dredging work, according to Shipping Gazette.