Rain and snow are an essential elements in the Earth"s water cycle, i m sorry is critical to every life ~ above Earth. Rainfall is the main means that the water in the skies comes under to Earth, where it fills our lakes and rivers, recharges the underground aquifers, and provides drinks to plants and also animals.

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A localized heavy summer rainstorm in Colorado

Here is a classic summer rainstorm; they are often small but intense. Other rain events are an ext "frontal" in nature, with huge nimbostratus types of clouds pass precipitation over a big area. 

Credit: Howard Perlman, civicpride-kusatsu.net

Fortunately because that everyone, water is a renewable source that moves in a cycle through neither start nor finish (but, you deserve to put in your vote regarding where girlfriend think it begins). Water vapor (evaporated indigenous oceans, lakes, forests, fields, animals, and also plants) condenses and returns to planet as precipitation, when again replenishing reservoirs, lakes, rivers, secret aquifers, and also other sources of water and providing the moisture required by plants and also animals... An countless water cycle.

The amount of precipitation that falls approximately the people may range from much less than 0.1 inch per year in part deserts to much more than 900 inches every year in the tropics. One of the driest point out on planet is Iquique, Chile, wherein no rain dropped for 14 years. The world"s wettest spot, Mawsynram, in Northeastern India, competent a average of 494 inch of rain a year during the years 1989-2010, replacing the ahead placeholder, Cherrapunji, likewise in Northeastern India, whereby a median of 471 inches fell during the very same period.

In case you"re wondering, the wettest ar in the joined States, as shown by data gathered by the Western local Climate Center, is on Mt. Waialeale, Hawaii, where an median of 373 customs of rain has fallen annually in between the year 1949 and also 2008. Mt. Waialeale also experienced more 보다 642 inches of rain native July 1947 come July 1948! If girlfriend think that"s something, Cherrapunji holds the single year record of 905 inch measured in 1861!

By contrast, the conterminous (the 48 "lower" states) United says receives enough precipitation throughout an average year to cover the says to a depth of about 30 inches. This is tantamount to about 1,430 cubic miles of water each year. What wake up to the water after that reaches the ground counts upon countless factors such as the rate of rainfall, topography, soil condition, thickness of vegetation, temperature, and the level of urbanization.


Wide spread flooding in Lithia Springs, Georgia just west the downtown Atlanta, after epos rainfall, 22 Sept. 2009. Impervious surfaces and also urban buildup reasons rainfall come runoff much quicker, and with greater flooding consequences, throughout heavy rains.

Credit: NASA

For example, the direct runoff in a very urbanized area is relatively great, no only due to the fact that of the thickness of roofs and impermeable pavements permits much less rain come infiltrate the ground, but additionally because storm-sewer systems carry more water straight to the streams and also lakes. In a an ext natural or undeveloped area, the straight runoff would certainly be substantially less.

In the joined States, an mean of part 70 percent of the yearly precipitation returns to the atmosphere by evaporation indigenous land and also water surfaces and by transpiration from vegetation. The remaining 30 percent eventually reaches a stream, lake, or ocean, partly by overland runoff during and also immediately after rain, and also partly by a lot slower course by moving though the ground.

Much that the rain that enters the ground filter down right into subsurface water-bearing rocks (aquifers) and eventually reaches lakes, streams, and also rivers where these surface-water bodies intercept the aquifers. The portion of the precipitation the reaches the streams produce an average annual streamflow in the United claims of roughly 1,200 billion gallons a day. By comparison, the Nations"s homes, farms, and factories withdraw and use about 355 exchange rate gallons a day (2010).


Amount that water received when an inch of rain occurs

Have you ever wondered just how much water falls onto your yard during a rainstorm? utilizing a 1-inch rainstorm as an example, the table below gives instance of just how much water falls throughout a storm for assorted land areas.


AreaArea (square miles)Area (square kilometers)Amount the water (gallons)Amount that water (liters)
A roof (40 x 70 feet)0.00010.0002571,7436,601
1 acre (1 square mile = 640 acres)0.001560.00427,154102,789
1 square mile12.617,380,00065,780,000
Atlanta, Georgia132.4342.92,293,000,0008,680,000,000
United States3,537,4389,161,92261,474,000,000,000232,700,000,000,000


Consider because that a moment just how much rainwater part cities might receive throughout a year. For example, Atlanta, Ga. Averages around 45 inch of precipitation every year; multiplying this by the 2.293 billion gallons shown in the table as the number of gallons in 1 customs reveals that part 103.2 billion gallons that water fall on Atlanta in an median year. In a city the size of Atlanta, the every capita water usage is about 110 gallons per day or 40,150 gallons per year. Thus, the water from a year"s precipitation, if it can be accumulated and save without any type of loss, would certainly supply the demands of about 2,574,000 people.




Use our interaction Rainfall Calculator (English units or Metric units)to uncover out exactly how much rain falls on your roof or yard, in her city block, or town.



When it rains, where does it go?

Once top top the land, rainfall one of two people seeps into the floor or i do not care runoff, i beg your pardon flows right into rivers and lakes. What wake up to the rain ~ it drops depends on numerous factors such as:

The rate of rainfall: A most rain in a short period tends to operation off the land right into streams rather than soak right into the ground.The topography the the land: Topography is the put of the land -- the hills, valleys, mountains, and also canyons. Water falling on uneven land drains downhill till it becomes part of a stream, finds a hollow place to accumulate, favor a lake, or soaks right into the ground.Soil conditions: over there is a lot of of thick clay in the southeastern United claims that rain has actually a difficult time soaking into. Contrast that to the sandy soils in more desert areas, which permit water to conveniently be absorbed, at least initially.Density of vegetation: It has actually long been well-known that plant expansion helps diminish erosion resulted in by flow water. If friend look at hills there is no vegetation you"ll see gullies dug out by running water. Land with plant cover slow the speed of the water flow on it and also thus help to keep soil native eroding.


Water Equivalents (approximate)

The adhering to equivalents display the relationship in between the volume and also weight that water and between the volume and speed of flow water.

Volume and also weight

One customs of rain fallout’s on 1 acre of ground is equal to about 27,154 gallons and also weighs about 113 tons.An inch of snow falling evenly on 1 acre of soil is tantamount to around 2,715 gallons of water. This figure, however, based upon the "rule-of-thumb" that 10 inch of eye is equal to 1 inch of water, deserve to vary considerably, relying on whether the snow is heavy and also wet, or powdery and dry. Heavy, wet snow has a very high water content—4 or 5 customs of this sort of eye contains around 1 inch of water. Thus, an inch of really wet snow over one acre could amount to much more than 5,400 gallons the water, while an inch of powdery snow could yield only about 1,300 gallons.One acre-foot of water (the amount of water covering 1 acre come a depth of 1 foot) equates to 326,000 gallons or 43,560 cubic feet that water, and also weighs 2.7 million pounds.One cubic mile of water equates to 1.1 sunshine gallons, 147.2 exchange rate cubic feet, or 3.38 million acre-feet, and weighs 9.2 trillion pounds (4.6 billion tons).

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Rate of flow (in a stream)

Water flow at the steady price of 1 gallon per minute is indistinguishable to: 1,440 gallons every day; 0.00223 cubic foot every second; 192.7 cubic feet per day; or 0.00442 acre-foot the water every day.Water flow at the steady price of 1 cubic foot per second is equivalent to: 449 gallons per minute; 646,000 gallons every day; 86,400 cubic feet per day; or 1.98 acre-feet the water per day.Water flowing at the steady rate of 1 acre-foot per day is indistinguishable to: 226 gallons every minute; 326,000 gallons per day; 0.504 cubic foot per second; or 43, 560 cubic feet that water every day.Water flowing at the steady price of 1 cubic mile per day is equivalent to: 764.6 million gallons every minute; 1.1 trillion gallons per day; 1.7 million cubic feet per day; or 3.38 million acre-feet the water every day.