How does a waterfall keep dumping such volume of water to a lower place without stopping?
In: Physics
You might be interested in reading about the water cycle. Rivers constantly dump water into the sea, but water evaporation does the trick here.
A waterfall is just water falling over an incline and does not reduce the total freshwater volume of the river.
Water vapour from plants, water evaporated from the ocean, etc. form clouds which then rain on land and replenishes the fresh water supply of rivers and etc. It’s all about equilibrium, otherwise every river in the world would not exist.
Watershed from upstream. Storms drop an incredible amount of water, it’s just spread out. Afterward, rainwater and/or snowmelt flow downhill, forming small streams which join up to larger ones which feed larger rivers. And this happens over time, so as long as there is precipitation upstream, it will keep the river flowing and any waterfalls along the way going.
The same way a river keeps on flowing. A waterfall is simply a vertical step in a river. The river just keeps on flowing the same way after the waterfall, it’s the same amount of water. When this water is in a normal part of a river, you don’t see it well, but a waterfall makes it all visible and it seems like it’s more.
When it rains the water collects to thousands of trickles, which connect into hundreds of streams, which connect into a larger river. Smaller waterfalls often do stop if it hasn’t rained in a while.
Rain and/or snowmelt from upriver is feeding it. The large rivers of the world drain *enormous* amounts of land. Niagra Falls is draining much of Canada towards the ocean.
It may not be raining near the waterfall right now, but there’s rain or snow *somewhere* almost all the time.
That said, many rivers do run shallower in dryer seasons – or even stop entirely during droughts.
It’s being replenished at an incredible rate upstream. A little watercourse in a valley is gathering all the rainfall from the surrounding hills and concentrating it. If its a huge fall, it might have a ‘catchment area’ that spans hundreds or thousands of square kilometres. Every little stream feeding into this one brings more hills into the fold. This process might take days for the water to work it’s way down, so the stream and falls can be high even if it’s currently dry
The way water pressures and speeds work the waterfall’s volume/time is dependant on how much of this rain is coming in. It will die back in dry seasons and then grow in the wet ones.
Waterfalls can vary on their flow based on season, ie. high in the spring as snow melt makes its way to streams, rivers, etc. that flow into the waterfall but taper off unless there’s been recent rains as summer and fall progress. Others get steady flow of water from rains draining into rivers and streams (ie. the ones in places like Hawaii)
Yeah I’ve often wondered this also when watching Niagara Falls – it’s amazing the volume of water going over the falls every second and it never ends. It’s mind blowing when you think about it.
To move that much volume, that consistently for that long, requires a HUGE feeder area. There are likely thousands of feeder rivers and streams that dump into it all day every day. You would think it would dry up/slow down a little but it just keeps going and going.
A river has something called a watershed or a basin. This is the area of land where all precipitation eventually flows into the river.
If you look at something like Niagara Falls, its basin is composed of most of the great lakes, since they all flow into one another and out Lake Ontario and the St Lawrence River. This means it has a *huge* basin, with many watersheds flowing into them.
https://en.wikipedia.org/wiki/Great_Lakes_Basin
Rainwater or meltwater from the surrounding area drains into a river to supply the waterfall so long as this water continues so does the waterfall.
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