highflyaddict wrote:But do you seriously think that reducing the natural erosion of a watercourse has a positive impact?
The Niagara Falls is very special because the canyon after the falls has a steep slope, so it does not change much downstream ... and given the very high speed of erosion falls (1.70m per year in average until the 50 years, but the annual speed varied according to the geological layers crossed which are very variable because the strata are in a quasi-vertical position, between 1m and 10m / year see more), they would disappear in a relatively short time causing the Emptying Lake Erie on 70m high ... today the erosion is 36cm / year on average ...