Landscape with Waterfall. A waterfall is an area where water flows over a vertical drop or a series of steep drops 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 in the upper course of a river in steep mountains.
Because of their landscape position, many waterfalls occur over bedrock fed by little contributing area, so may be ephemeral and flow only during rainstorms or significant snowmelt. The further downstream, the more perennial a waterfall can be. Waterfalls can have a wide range of widths and depths.
When the river courses over resistant bedrock, erosion happens slowly and is dominated by impacts of water-borne sediment on the rock, while downstream the erosion occurs more rapidly. As the watercourse increases its velocity at the edge of the waterfall, it may pluck material from the riverbed, if the bed is fractured or otherwise more erodible.
Hydraulic jets and hydraulic jumps at the toe of a falls can generate large forces to erode the bed, especially when forces are amplified by water-borne sediment. Horseshoe-shaped falls focus the erosion to a central point, also enhancing riverbed change below a waterfalls. A process known as potholing involves local erosion of a potentially deep hole in bedrock due to turbulent whirlpools spinning stones around on the bed, drilling it out. Sand
Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls are commonly formed in the upper course of a river in steep mountains.
Because of their landscape position, many waterfalls occur over bedrock fed by little contributing area, so may be ephemeral and flow only during rainstorms or significant snowmelt. The further downstream, the more perennial a waterfall can be. Waterfalls can have a wide range of widths and depths.
When the river courses over resistant bedrock, erosion happens slowly and is dominated by impacts of water-borne sediment on the rock, while downstream the erosion occurs more rapidly. As the watercourse increases its velocity at the edge of the waterfall, it may pluck material from the riverbed, if the bed is fractured or otherwise more erodible.
Hydraulic jets and hydraulic jumps at the toe of a falls can generate large forces to erode the bed, especially when forces are amplified by water-borne sediment. Horseshoe-shaped falls focus the erosion to a central point, also enhancing riverbed change below a waterfalls. A process known as potholing involves local erosion of a potentially deep hole in bedrock due to turbulent whirlpools spinning stones around on the bed, drilling it out. Sand
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