The head of the Panama Canal Authority says officials might be forced to limit the draft of ships by the end of this year or early in 2015 if a drought continues and lowers the level of lakes that feed the waterway’s locks.

Jorge Luis Quintano tells Panama’s Channel 2 television station that unusually light rainfall has dropped the level of Lakes Gatun and Alajuela. He says he’s hoping for healthy rainfall in the normally rainy months of October, November and December. But he noted in the Sunday interview that last November’s rains were the lowest for that period in the 100-year history of the canal.

Thirty-eight to 40 ships transit the canal daily between the Pacific and Atlantic oceans, carrying some 5 percent of world maritime trade.