Water jet cutting

The 1ft/year rate is how fast the edge of the falls move up river, not how deep it cuts the channel.

It used to be a lot faster but we reduced the flow, What is the Future of the Falls?

a.. The Falls will continue to erode, however, the rate has been greatly reduced due to flow control and diversion for hydro-power generation. b.. Recession for at least the last 560 years has been estimated at 1-1.5 m/yr. c.. Its current rate of erosion is estimated at 1 foot per year and could possibly be reduced to 1 foot per 10 years. d.. The current rate of recession is unclear; assessing its value remains the responsibility of the International Joint Commission. The International Boundary Waters Treaty stipulates the minimum amount of flow over the falls during daytime, nightime and the tourist season.

I know somebody who worked for a company that did this dry ice blasting for bridge repainting. No blasting grit made clean-up and control of jobsite debris much easier and cheaper.

And NO, it isn't a CO2 global warming issue, because the CO2 used is CO2 extracted from atmospheric CO2 in the first place, usually as a by-product of air liquifaction to generate liquid O2 for steel mills. Global warming CO2 comes from humans burning Carbon stored for millions of years as hydrocarbons and coal, and releasing them into the air as CO2 over a few centuries.

I was at a trade show in Philly in the early 90's and they had one of these things and they used it to cut a chocolate cake in wedges. Slicker than you could ever do with a knife, fast, and it didn't get the cake soggy, either. The water was traveling too fast. Incomprehensible a few years ago, matter-of-fact today. Wowie !

Flash

What's that Lassie? You say that Kirk Gordon fell down the old rec.crafts.metalworking mine and will die if we don't mount a rescue by Sun, 24 Jan 2010 14:24:50 -0500:

I hear they use it to clean crap off of very old paintings.

I just talked to the waterjet guy here.....we have actually cut 14" thick aluminum. Had to make a fixture so the part would actually sit down inside the tank. Very slow tho....like less than 1ipm. Biggest pain in the ass bout the machine is even tho it has a garnet reclaimer....it don't work worth a s*it. So every couple of months the machine is down while a couple of part timers get to climb in the tank and shovel all the sand out. Its a pretty big tank too....like 10' by

KG:

A foot a year, eh? Thats like 60 minutes X 24 hours X 365 days or

Sure, but given that the falls are 1060 feet long and 176 feet tall, that translates into 612.165 cubic inches of material removed every minute.

Yellow Bellied Sump Sucker (maybe). This one seems a little high, if you keep an eye on the auctions you can get them for less.

Well, here's a Q:

If the waterfall is being eroded back so quickly, how are the turbines able to still catch the water? Are they being moved back, to keep up?

On Sun, 24 Jan 2010 19:01:42 -0500, Stuart Wheaton wrote as underneath

And where does all the power come from to pull the CO2 out of the atmosphere, liquify it ,solidise it , cart it around the country! Just because a bit of the system is a by-product of a massively G warming industry doesnt mean that it doesnt really count!

Blink blink...ooookay.~ Good question!

Snip

What about one of those swimming pool cleaning units that used to flap arount the bottom of a swimming pool and collect all the dirt from it? They moved around in a random fashon, and eventually covered all the bottom of the pool. The water from it could be settled andreturned after filtering for re-use

Proly there are horizontal "catch tubes" for the turbine water? That mebbe already go back a cupla hundred feet into the upper river. But, as the erosion continues, those horizontal lengths become less and less supported..... We should be able to see those horizontal catch tubes in google maps. Inybody got a zip code??

Most of the water is diverted to ponds about 3-4 miles upstream.

Paul K. Dickman

Oh, yeah, saw sumpn about that on History.... really quite an engineering feat. Here ahm thinkin effing paddlewheels at the base of the falls..... :)

Still, that erosion rate is incredible. Who'da thunk?

The turbines (powerhouse) are not AT the falls, they are downstream in the gorge. They work on the difference in water height between the upstream and downstream side of the falls ... just like if a dam were present. The water to the powerhouse is diverted from the river a considerable distance upstream (above the falls), and brought to the powerhouse via a canal. From the canal at the top of the gorge, the water is then dropped to the turbines at the bottom via the usual penstocks (large tubes).

Variations of this are used in most waterfall-related power stations. Tthe falls themselves are usually not involved in the power generation at all.

Dan Mitchell ============

--- news://freenews.netfront.net/ - complaints: snipped-for-privacy@netfront.net ---

Gunner

Ther are a variety of power stations tapping the water resources of Niagara, some in the USA and some in Canada. Each uses a slight variation of the basic system I described earlier. Google: "Niagara power generation". For some examples see:

One of the oldest installations, the Schoellkopf Electric power station, was destroyed by a landslide in the 1950's, when the highwall collapsed onto the powerhouse. It was quite the mess.

There are motion picture films of this happening.

The results looked similar to the recent massive damage at the Russian dam and powerhouse, caused by poor maintenanace of the turbines. That incident was posted here earlier.

Dan Mitchell ============

--- news://freenews.netfront.net/ - complaints: snipped-for-privacy@netfront.net ---