The reduced drafts means some ships may have to load less cargo. For example, Hapag-Lloyd told American Shipper on Friday that "The Panama Canal Authorities regularly announce update draft for locks, which are subject to the water level of Gatun lake. From March to end of May, we expect a cargo deadweight reduction on our SWX vessels of around 5 to 6 percent." The SWX service is between the West Coast of South America and North Europe.
The drafts are specified for tropical fresh water because Gatun is a freshwater lake, fresh water is less dense and provides less buoyancy than sea water, and warm water is less dense and provides less buoyancy than cold water.
ACP said the maximum authorized draft for ships transiting the Panamax locks also will be reduced to 38.5 feet on May 28, down from 39.5 feet currently.
Carlos Vargas, the vice president of environment and water for the ACP, told the Associated Press, “These low levels in the Panama Canal are the product of four or five months of almost zero precipitation. It really has been the driest dry season we’ve had in the history of the canal. The flow of rivers to the lake is down 60%.”
ACP notifies vessels of any change in draft four weeks in advance so they can plan accordingly.
The canal noted that it has in place a number of water conservation measures. These include water-saving basins for the new Neopanamax locks, which recycle 60% of the water used per transit. Other measures consist of the closure of the Gatun hydropower station, not using hydraulic assist at the locks and encouraging tandem lockages in which two ships move through the locks together.