Oceans The majority of precipitation falls back into the oceans or onto land, where it runs over the ground as surface runoff owing to gravity. A part of runoff joins rivers in landscape valleys, with streamflow carrying water to the seas. Another part evaporates from or melts into the ground, contributing to atmospheric moisture. Lakes The remaining portion of precipitation that falls into lakes is absorbed by the water, which cannot be absorbed any further. This results in a rise in water level called an inundation. Flooding can occur if the water rises high enough to overflow its banks and cause damage to property and infrastructure. An example is Lake Nyasa, which forms part of the border between Tanzania and Malawi. It gained notoriety after flooding caused by heavy rainfalls in July 2007 led to the deaths of over 200 people.
Streams Water that cannot be absorbed by its destination is discharged back into the source river or other body of water. This occurs either during or just after a rainfall when the streambeds are full, or when the stream is very wide and shallow for its length (such as in a canyon). If the discharge is not controlled, the amount and type of material entering the source river may have an adverse effect on the environment there. For example, if the source river is used for drinking water, this could lead to problems if the material contains bacteria or toxic chemicals.
The majority of precipitation that falls on land, however, is not absorbed by the soil and is referred to as runoff. This runoff accumulates in streams and rivers before draining into the ocean. Runoff includes both liquid and solid material that is carried by rain or melted snow.
Runoff that reaches bodies of water must either evaporate or enter the water through natural openings such as springs or holes in the ground. If it does not enter the water in this way, the only other option is infiltration- the passage of precipitation through the soil from one layer to another. Infiltration can be slow or rapid depending on many factors such as soil type and moisture content. Any infiltration that does not result in runoff is called recharge. Recharge helps to fill groundwater reserves and may also contribute nutrients that flow down slope toward agricultural areas or urban centers.
Infiltration and recharging are important processes for maintaining adequate supplies of water for humans and the environment. However, these processes can be slowed by building structures like houses or industrial facilities that block the flow of water through the soil. Such structures can also cause erosion by pushing away soil particles that would otherwise act as filters for small particles that may reach waterways due to rainfall.
Environmental issues can also arise when there is too much precipitation or when the quality of precipitation is changed by human activity.
Water falls to the earth in the form of precipitation, which includes rain, hail, sleet, and snow. When precipitation reaches the earth's surface, part of it will runoff and enter surface water bodies such as lakes, streams, and rivers. The remainder soaks or percolates into the soil, a process known as recharge. Recharge is the return of water to the ground through the movement of air and moisture cycles. Soil plays an important role in determining how much of this precipitation will be recharged.
The amount of precipitation that reaches the ground as runoff varies depending on many factors such as the size of the rainfall event, land use, elevation, and local climate. For example, if you live in a region that experiences extensive flooding due to heavy rains, you may want to consider moving to a place with less severe weather conditions.
Runoff from precipitation that does not soak into the soil contributes to flood events. Flooding can cause damage by reaching houses with their foundations on high ground or in low-lying areas, causing loss of property. It can also cause drowning for people who try to cross flooded roads. Runoff from precipitation that does not soak into the soil enters our waterways when there are openings in the riverbank protection devices such as dikes and levees. This occurs most often during major storm events when these banks are breached at one location or another.
Only around one-third of the precipitation that falls on land flows off into streams and rivers, eventually reaching the seas. The remaining two-thirds evaporates, transpires, or infiltrates into groundwater. Humans can also redirect surface drainage for their own purposes. For example, in the United States, about 1 in 10 gallons of precipitation that falls on land is lost through runoff from roads and other surfaces. That's why it's important not to pave over natural areas.
The amount of water that reaches the oceans varies by season and region. In general, sea levels rise when more water flows into the ocean than leaves. Fluctuations in sea level are caused by factors such as the amount of ice in the world's glaciers and alpine zones, changes in the volume of water in lakes and other aquatic bodies, and rain versus snow melt. Over time, these factors can have an impact on global sea level rise.
In addition to causing sea levels to rise, this water is also responsible for creating oceanic currents like the Gulf Stream. As water moves from a high altitude to a lower one, it cools down and becomes denser. This is why clouds often form at higher altitudes during periods of heavy rainfall. As these clouds descend, they release much of their energy as heat, which causes surrounding air to cool down and become more dense.
Recharge is important because it returns moisture to the ground and uses some of this moisture for future growth of plants. Water that does not reenter the ground evaporates or flows into deeper groundwater sources.
The water that crosses Earth's surface after a rain event is known as run-off. It may be contained in lakes, reservoirs, and stream networks, or it may discharge directly into the ocean. Run-off can also be referred to as floodwater or infiltration. Run-off occurs when there is enough precipitation that will not soak into the ground and cannot be held in place by natural forces such as slope or bedrock. The amount of run-off depends on many factors such as the type and amount of precipitation, the size and shape of the land area, and its distance from sources of water. Run-off can cause problems if it gets into areas where it does not belong like into homes through open doors and windows or under cars through missing caps. It can also cause problems if it contains bacteria or other organisms that make people sick.
Run-off flows into aquatic systems through various pathways.
When precipitation falls on the land, it takes a variety of pathways in its succeeding courses. Some of it evaporates and returns to the atmosphere, while others soak into the earth as soil moisture or groundwater, and still others flow off into rivers and streams. Where will most of this rain-fall go? The answer is not so simple as you might think!
Most rain that falls as precipitation ends up being absorbed by the Earth's surface. But this isn't always the case. If the rain falls close to the ground or if there are strong winds blowing, some of it can be lifted into the air instead. This happens when it rains quickly enough that most of it doesn't run off before it reaches the ground - it gets absorbed by plants or blown away by wind.
For example, if it rains very slowly, all of it will run off a land surface and be lost in drainage channels or soaked up by the soil. However, if it rains quickly, some of it will be caught in low-lying areas such as puddles or swept away from the site before it has time to drain off.
Another factor that affects how much of it goes into drains vs. getting washed out to sea is the type of terrain.