describe the waterfalls that empty themselves into the river ? from english brook ,chapter Nilamun: A day among waterfalls
Answers
A waterfall is a river or other body of water's steep fall over a rocky ledge into a plunge poolbelow. Waterfalls are also called cascades.
The process of erosion, the wearing away of earth, plays an important part in the formation of waterfalls. Waterfalls themselves also contribute to erosion.
Often, waterfalls form as streams flow from soft rock to hard rock. This happens both laterally (as a stream flows across the earth) and vertically (as the stream drops in a waterfall). In both cases, the soft rock erodes, leaving a hard ledge over which the stream falls.
A fall line is the imaginary line along which parallel rivers plunge as they flow from uplands to lowlands. Many waterfalls in an area help geologists and hydrologists determine a region's fall line and underlying rock structure.
As a stream flows, it carries sediment. The sediment can be microscopic silt, pebbles, or even boulders. Sediment can erode stream beds made of soft rock, such as sandstone or limestone. Eventually, the stream's channel cuts so deep into the stream bed that only a harder rock, such as granite, remains. Waterfalls develop as these granite formations form cliffs and ledges.
A stream's velocity increases as it nears a waterfall, increasing the amount of erosion taking place. The movement of water at the top of a waterfall can erode rocks to be very flat and smooth. Rushing water and sediment topple over the waterfall, eroding the plunge pool at the base. The crashing flow of the water may also create powerful whirlpools that erode the rock of the plunge pool beneath them.
The resulting erosion at the base of a waterfall can be very dramatic, and cause the waterfall to "recede." The area behind the waterfall is worn away, creating a hollow, cave-like structure called a "rock shelter." Eventually, the rocky ledge (called the outcropping) may tumble down, sending boulders into the stream bed and plunge pool below. This causes the waterfall to "recede" many meters upstream. ⁸ waterfalls. Some scientists classify waterfalls based on the average volume of water in the waterfall. A Class 10 waterfall using this scale is Inga Falls, Democratic Republic of Congo, where the Congo River twists in a series of rapids. The estimated volume of water discharged from Inga Falls is 25,768 cubic meters per second (910,000 cubic feet per second).
Another popular way of classifying waterfalls is by width. One of the widest waterfalls is Khone Phapheng Falls, Laos. At the Khone Phapheng Falls, the Mekong River flows through a succession of relatively shallow rapids. The width of the Khone Phapheng Falls is about 10,783 meters (35,376 feet).
Waterfalls are also classified by height. Angel Falls, the world’s tallest waterfall, plummets 979 meters (3,212 feet) into a remote canyon in a rain forest in Venezuela. The water, from the Gauja River, often does not reach the bottom. The fall is so long, and so steep, that air pressure is stronger often than the water pressure of the falls. The water is turned to mistbefore it reaches the small tributary below.