channels from PLD; Modification of all locks structures to allow an additional draft of about ; Deepening of the Pacific and Atlantic entrances; Construction of a new spillway in Gatun, for flood control. These improvements enlarged the capacity from 300 million PCUMS (2008) to 340 PCUMS (2012). These improvements were started before the new locks project, and are complementary to it. Competition The canal faces increasing competition from other quarters. Because canal tolls have risen as ships have become larger, some critics have suggested that the Suez Canal is now a viable alternative for cargo en route from Asia to the US East Coast. The Panama Canal, however, continues to serve more than 144 of the world's trade routes and the majority of canal traffic comes from the "all-water route" from Asia to the US East and Gulf Coasts. On June 15, 2013, Nicaragua awarded the Hong Kong-based HKND Group a 50-year concession to develop a canal through the country. The increasing rate of melting of ice in the Arctic Ocean has led to speculation that the Northwest Passage or Arctic Bridge may become viable for commercial shipping. This route would save on the route from Asia to Europe compared with the Panama Canal, possibly leading to a diversion of some traffic to that route. However, such a route is beset by unresolved territorial issues and would still hold significant problems owing to ice. Water issues Gatun Lake is filled with rainwater, and the lake accumulates excess water during wet months. The water is lost to the oceans at a rate of per downward lock cycle. Since a ship will have to go upward to Gatun Lake first and then descend, a single passing will cost double the amount; but the same waterflow cycle can be used for another ship passing in the opposite direction. The ship's submerged volume is not relevant to this amount of water. During the dry season, when there is less rainfall, there is also a shortage of water in Gatun Lake. As a signatory to the United Nations Global Compact and member of the World Business Council for Sustainable Development, the ACP has developed an environmentally and socially sustainable program for expansion, which protects the aquatic and terrestrial resources of the canal watershed. The expansion guarantees the availability and quality of water resources by using water-saving basins at each new lock. These water-saving basins diminish