Huge Tunnel project "Big Becky" they are about 6 mos into a 2 year tunnel under the city of Niagara Falls to divert more water presently 60% is diverted from the Falls and will now be increased to 70% for Hydro Electric projects here. It is using a much larger version of the Chunnel machine . TheStar.com - News - Big dig Niagara
There is a binational commission that decided back in the 50s about how much water was requiered to maintain the Falls and divided the remainder between the US and Canada to use for Hydro Electric power. As it stands usually only 30% of the possible water goes over the falls it will soon be 25%. There are 4 tunnels 2 in the US and 2 in Canada already in use and one open canal . This will allow Canada to maximize its portion .They have been able for about 60yrs to control how much water is diverted. The red arrows pic shows the upper river and indicates where the intakes are and the control dam . The Golden Hawks pic shows the generating area where they achieve the maximun drop or most power the Robert Moses plant by Con ED is just out of sight the the Hawks nose