- published: 15 Jul 2010
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A waterfall is a place where water flows over a vertical drop in the course of a stream or river. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf.
Waterfalls are commonly formed when a river is young. At these times the channel is often narrow and deep. When the river courses over resistant bedrock, erosion happens slowly, while downstream the erosion occurs more rapidly. As the watercourse increases its velocity at the edge of the waterfall, it plucks material from the riverbed. Whirlpools created in the turbulence as well as sand and stones carried by the watercourse increase the erosion capacity. This causes the waterfall to carve deeper into the bed and to recede upstream. Often over time, the waterfall will recede back to form a canyon or gorge downstream as it recedes upstream, and it will carve deeper into the ridge above it. The rate of retreat for a waterfall can be as high as one and half meters per year.
Often, the rock stratum just below the more resistant shelf will be of a softer type, meaning that undercutting due to splashback will occur here to form a shallow cave-like formation known as a rock shelter under and behind the waterfall. Eventually, the outcropping, more resistant cap rock will collapse under pressure to add blocks of rock to the base of the waterfall. These blocks of rock are then broken down into smaller boulders by attrition as they collide with each other, and they also erode the base of the waterfall by abrasion, creating a deep plunge pool or gorge.
Don't Go Jumping Waterfalls
Please Keep To The Lake
People Who Jump Waterfalls
Sometimes Cam Make Mistakes
And I Need Love, Yeah I Need Love
Like A Second Needs An Hour
Like A Raindrop Needs A Shower
Yeah I Need Love Every Minute Of The Day
And It Wouldn't Be The Same
If You Ever Should Decide To Go Away
And I Need Love, Yeah I Need Love
Like A Castle Needs A Tower
Like A Garden Needs A Flower
Yeah I Need Love Every Minute Of The Day
And It Wouldn't Be The Same
If You Ever Should Decide To Go Away
Don't Go Chasing Polar Bears
In The Great Unknown
Some Big Friendly Polar Bear
Might Want To Take You Home
And I Need Love, Yeah I Need Love
Like A Second Needs An Hour
Like A Raindrop Needs A Shower
Yeah I Need Love Every Minute Of The Day
And It Wouldn't Be The Same
If You Ever Should Decide To Go Away
Don't Run After Motor Cars
Please Stay On The Side
Someone's Glossy Motor Car
Might Take You For A Ride
And I Need Love, Yeah I Need Love
Like A Castle Needs A Tower
Like A Garden Needs A Flower
Yeah I Need Love, Said I Need Love
Like A Raindrop Needs A Shower
Like A Second Needs An Hour
Every Minute Of The Day
And It Wouldn't Be The Same
If You Ever Should Decide To Go Away
Don't Go Jumping Waterfalls
Please Keep To The Lake