The Panama Canal Authority (ACP) has issued an advisory to shipping, setting a draft restriction as the water levels fall due to a drought caused by El Nino.
El Niño is a disruption of the ocean-atmosphere system in the Tropical Pacific which has important consequences for weather and climate around the globe.
According to the authority, the maximum draft will be reduced to 11.89m in tropical fresh water (TFW) and the new rule will be effective from 8 September 2015.
The current draft limit is 39.5ft and a similar action was taken in 1998 because of the drought.
A statement from Panama Canal Authority stated that the El Niño has triggered a drought in the Canal Watershed and it saw the water levels of Gatun and Alhajuela Lakes falling below their average.
The new development is expected to affect 18.5% of the vessels transiting through the canal.
The authority is expected to impose a further cut, which will restrict the maximum draft to 11.73m, if the situation does not improve. The new rule would be imposed from 16 September.
ACP said, if further draft restrictions are confirmed, the customers will be informed at least four weeks in advance to allow time for proper planning.
Moreover, improvements in rainfall may result in the lifting of the scheduled draft restriction.
The next stage of the Panama Canal expansion programme started with the filling of Cocoli's locks on the Pacific side, after similar work on the Atlantic side was completed.
Lock filling and subsequent testing activities are expected to take three months, and the expansion programme is scheduled for completion next year.
Once completed, PSA Panama will have an annual handling capacity of two million TEU containers.