why do rivers flood, but lakes, oceans dont?
336494
Rivers & streams are parts of drainage basins (aka watersheds). This means that they drain most of the surface water from an area.\n\nWhen it rains very heavily, it runs off & goes into the rivers & streams b/c they are lower in elevation. This is called surface runoff.\n\nRivers are only capable of handling a certain amount of water at a time. When it reaches flood stage it will overflow it's banks.\n\nAlthough it is possible for a lake to flood, more than likely it will not. It is less likely to get all the surface runoff from the surrounding area.\n\nOceans are not going to flood unless sea level rises. There is no real "normal" flood stage for oceans. Over time they transgress & regress in response to climate change. Water is constantly being evaporated from the oceans as well.\n\nMost of our precipitation comes from water vapor that was evaporated from the oceans. This is simply b/c oceans cover the majority of the planet.\n\nHope this helps.
386599
A river is the main body of water, the tributaries are smaller streams etc that branch off it or into it...\n\nLike a tree... the trunk is the river, the branches are tributaries..
158964
Water retains temperature more than air, so the oceans stay warm in winter and cool in summer. They cool air currents that blow around the continents.
63593
When it rains and the rain hits mountains or other materials it cannot sink through small trickles appear in the direction of the downslope. The trickles come together eventually and pour looser materials with them (such as sand or loose earth for example). Eventually they can form a big enough stream to be a river. When a river runs with high speed it tends to have a straighter path, but if it becomes wide and slow it starts bend like a serpentine.
183244
Flowing water does.  I don't know about standing water.
325978
About 3% of earth's water is fresh water with two-thirds of this locked in glaciers and polar icecaps. So only 1% is in lakes and rivers.
235149
What happens in a massive river flood is that sedimanet is moved around.  So it's possible that the swollen riven carves early in it's journey and redeposits the silt farther downstream.  Not strange at all.\n\nOn the Rio Grande, it's documented that during one particularly strange day, a side river flooded into the Rio Grande causing it to flow backwards for nearly an hour.  Geology is not the slow, plodding horse teachers might lead you to believe, rather, it happens in spurts, earthquakes, floods, etc.  The everyday action just smooths the edges.
144386
Because in some cases there were no natural physical features like rivers or mountain ranges when the boundaries were determined.  Usually boundaries run along such features.
817654
Gravity...or if you mean why doesn't it come over the land...then that is because the land is higher then the sea, hence there is not enough water in the sea to raise it above the land.
233535
i always thought it was because there was no humidity in the air...probably wrong, anyway. or maybe its because the warm climate doesnt allow the moisture to turn back into water. who knows? prob a weatherman.
35014
That's really a very interesting question.  The short answer is that the water evaporates rises to form a cloud and drifts somewhere else (over land, lake or ocean) to fall as precipitation (rain or snow, etc.) returning to where it began but in a different spot upon the planet.  And don't forget that some of the water is broken down in plants to form hydrocarbons (perhaps the wood of a giant sequoia tree).\n\nThe fascinating answer is that some of the precipitation falls at the poles and is locked up for centuries within mile thick glaciers.  Some of the rain drifts to the poles with salt water and is chilled so cold it sinks to the bottom then finds its way to the seven seas in very cold currents that finally wend to the tropics and rise to replace evaporated seawater.  The bottoms of the oceans even at the tropics is dark and icy cold and the entire cycle from pole to tropics and back to the atmosphere can take centuries.  Some of the precipitation can drain into underground rivers and even refill huge aquifers that underlay many contiguous states.  The water in many aquifers has been there for centuries (even since the last glaciers retreated).  Although everything remains in a vague equilibrium (perhaps interrupted by ice ages) a drop of water that evaporates may be taken out or the normal water cycle for hundreds of years at a time.
455476
A lot of the water came from the river in the first place. There is a net loss through plants, evaporation so I can't imagine why there is a problem of excess. sometimes the water is hotter so fish, plants have trouble.\nWhy if it is so clean, do plants get more river water instead of their "clean" water?
470292
When sun shines on water, it warms it up and since heat is lighter, the water kinda floats up into the air. That's called evaporating. Then when it's high in the sky, many little water droplets come together and from clouds. When there's too many water droplets, the cloud becomes to watery and it rains. Then it starts all over again.
556213
There are levees that keep rivers from flooding out of their banks.  There are swamps and marshes that provide a buffer when a storm surge hits.  Breakwaters and barriers along some parts of the Louisiana shoreline that break up the waves before the wave can hit shore so that coastal erosion is reduced and the beaches can be rebuilt. \n\nNew Orleans also operates huge pumps that continually siphon water out of the city.\n\nNot sure what you're referring to, but hope this helps.
373784
The main parts of a river include a channel, in which the water flows, and a floodplain—a flat region of a valley on either side of the channel. Through the channel and floodplain, water and sediment—material transported by the river, such as sand and silt—are transferred from ridges and mountains to the sea or to a lake. A river starts on hillsides as small channels, or rills. The rills combine to make larger channels or tributaries that eventually come together, forming distinct streams. The largest channels formed by this convergence of tributaries are rivers, and they can carry large quantities of fresh water and sediment across continents.
115181
Heat from the sun that warms water in the Oceans, rivers,and lakes. The water evaporates goes up inot the clouds, evaporated watre dropplets cling to dust particles in the atmoshpere, These become clouds, and as soon as enough water is clinging to one drop it beginn, rivers to rain, as if the clouds are to heavy to hold anymore. If it is cold then it will snow. This falls to the ground and (if snow melts) runs into the ocean rivers and lakes. REpeat Process with heat from the sun. ^^
44697
rivers flow across various terrains hence eroding rocks and carrying sediments(salts)they meet sea and ocean they deposit the salt content which keeps concentarting as water evaporates but salt does not .