标题: 尼亚加拉大瀑布的水未来会干涸吗？会不会断流？ [打印本页] 作者: 旅行达人 时间: 2017-9-26 03:26 标题: 尼亚加拉大瀑布的水未来会干涸吗？会不会断流？ What is the future of the falls?
The falls will continue to erode, however, the rate has been greatly reduced due to flow control and diversion for hydro-power generation.
Recession for at least the last 560 years has been estimated at 1 to 1.5 metres per year.
Its current rate of erosion is estimated at 1 foot per year and could possibly be reduced to 1 foot per 10 years.
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, nighttime and the tourist season.
Erosive forces include the action of frost from the spray, the dissolving action of the spray itself, and abrasion action of the softer shales by fallen limestone boulders.
No one knows when the next major rock fall will occur in the Horseshoe Falls; the effect could be to speed up erosion. A stable position is abandoned when the crest line develops a notch configuration and the Falls retreats relatively rapidly until a new stable position is attained.
It’s also possible that the current or future flow and volume of the river will not be sufficient to carve out a deep enough plunge pool to accommodate rock falls; in this case, the Canadian Falls could be supported by talus in much the same way as the American Falls.
The Cascade Rapids above the Falls are about 15 metres (50 ft.) higher than the falls today; once that ledge has been breached, the falls will have an extra 15 metres of force.
Climate change is also an influencing factor on the future of the Niagara River as an integral part of the Great Lakes Basin; models indicate a drying up of the Basin.
Isostatic rebound continues to affect the Great Lakes Basin and consequently the flow of water through the Niagara River.
All things considered, scientists speculate that perhaps 2,000 years from now the American Falls could dry up. It is a stationary feature collapsing by rock falls and landslides, carrying less than seven percent of flow before diversion; this bit of water is shallow and spread out, therefore ineffective as a major erosive power.
As a dry falls, it could appear like the Glen does today.
The Horseshoe Falls will notch back for about 15,000 years, traveling back about four miles to a softer riverbed (from the southern end of Navy Island to Buffalo/Fort Erie the riverbed is no longer the erosion-resistant limestone but soft Salina shale) after which the rate of erosion will change significantly (remember the bedrock tilts downward to Lake Erie).
The falls could be replaced by a series of rapids.
50,000 years from now, at the present rate of erosion, the remaining 20 miles to Lake Erie will have been undermined. There won’t be a falls anymore, but there will still be a river at work.