So why turn it off, you ask? Basically there are plans to replace a pair of bridges that were originally built in 1901. This allowed tourists to access to small islands near the waterfalls, but in order to build said bridges, it will have to involve temporarily halting the flow of the falls in order for the project proceed.
Nothing has been confirmed yet, but New York State Parks staff are expected to meet this week to discuss the course of action. This is actually not the first time the falls have been turned off. The flow of the falls was actually halted once back in 1969 when scientists wanted to study the efforts of erosion.
Assuming that this is the plan that is agreed upon, it will still probably be years before it goes into effect, something to take note off if you’ve been meaning to make a trip to look at it.