Niagara Flower and Garden Show

That was a super site, Kathleen. I'm still wondering about the erosion and what they decided to do about it. I'm going to try to find something 'cuz now I'm curious!

I found this site that has a section on the erosion. It was in 1969 that the US Corp of Engineers 'unwatered' the Am. Falls. Sounds like they put some rods in some places and drilled bore holes in other place to decrease the pressure which is very high by the AM. Falls. There's a whole list of the things they discovered. Most not too exciting to non-geology majors. :) http://www.wonderclub.com/WorldWonders/NiagaraHistory.html

Also had this:
In 1896, Thomas Martin wrote that the annual recession of the American Falls was 7½ inches per year and the Horseshoe Falls was 2.18 feet per year.

From 1842 to 1905, the average rate of erosion of the Horseshoe Falls was 1.16 meters (3.8 feet) per year.

From 1906 to 1927, this rate of erosion was reduced to .70 meters (2.3 feet) per year. This reduction coincided with the large quantity of water being diverted for hydro-electric generation.

The mean rate of erosion was 3.5 meters (5 feet) per year. Since 1942 the rate has been much slower.

Today, through increased water diversion and anti-erosion remedial steps, the rate of recession at the Horseshoe Falls has been reduced to a fraction of what it used to be. Today it is estimated that erosion of the Horseshoe Falls is less than one foot per year. In the future, through remedial efforts and further water diversion that the amount of erosion at the Horseshoe Falls has been projected to be reduced to approximately 1 foot every 10 years.

Today, erosion of the American Falls is estimated at 3 - 4 inches every 10 years. The water flow which is regulated at a minimum level of 10% of the estimated 100,000 cubic feet per second during the summer (50,000 cubic feet per second during winter) is insufficient to cause major erosion.

Very interesting!

edited to add: should have mentioned that you need to scroll down a ways to the erosion section.



This message was edited Jun 15, 2004 2:10 PM

When I was a kid, we used to go to Niagara Falls on vacation once in a while, so I associate the place with pure joy. We went back a couple years ago, this time with DH, who had never been there before. He expected it to be out in the wilderness like Yosemite or something. Boy, was he surprised!

As for the rocks, I think it was around 1969 when they dried up the American Falls. The rocks were cleared away because they were obscuring the height of the fall so much. My guess is that the rocks are back to their pre-1969 height again. So much water goes over the Horseshoe Falls that there is a deep pool carved out below, as deep as the falls are high, and the fallen rock never can build up like it does on the American side. I read that the Horseshoe Falls erode back 3 feet every year.