 For two days of this recovery period, diversion of water from the Niagara River for hydroelectric generation was increased to the maximum level, normally used only at night and in winter in order to maintain the scenic appearance of Niagara Falls.The resultant drop in the river level below the falls meant that the Maid of the Mist tour boats could not dock safely, and their operation had to be suspended.The Petro-Canada refinery in Oakville had to perform an emergency shutdown due to the lack of power.