We say water availability per person per year is 5000 m^3, it means 5^6 litres of water/year, if we have 5000 mm of water (river discharge) per year, how much would that be in terms of litres or m^3. Thank you
The river has a watershed or basin dimension that would be necessary to include to calculate. So if watershed was 1 sq km, that’s 1 million sq meters, and take that times the 5 m depth of water discharge, that would be 5 million cubic meters, or 5 billion liters. This would be an extremely wet area to have 5000 mm depth of water yield, which is sometimes used in water yield discussions. Unless there are underground springs contributing, one would need rainfall of well over 5 meters depth per year.
So I would check that figure.
https://www.unitconverters.net/volume/milliliter-to-cubic-millimeter.htm
As William F. Hansen mentioned, you need more dimensions. mm is a measure of length whereas liter is a measure of volume.
Thank you all. So if the watershed area is 9000 sq km, precipitation is 1500 mm/year and the discharge per year is 1500 mm as well, then we have a yield of 13.5 * 10^11 litres of water?
Check again. I think it’s 1.35 x 10^13 Liters.
Remember that only a portion of rainfall becomes streamflow. A water balance is sometimes used to estimate, Q = P - ET - change in soil storage and/or groundwater recharge, and net change in storage of lakes or dams. Q = flow, P = Precipitation, ET = is evapotranspiration. We have areas with 1.5 m of rainfall, and it is not unusual for Q to be less than 50% of P. In studies at a NC hydrologic station, grasslands, hardwoods and pinelands had ET values of roughly 0.25 m, 0.5 m, and 0.75 m. Heavily urbanized lands and intensively gullied or barren lands can have higher amounts of Q in comparison to forests and grasslands. Worldwide, many experimental watershed studies have been undertaken, and collectively their results may help address generalized questions pertaining to water yield for various ecosystems, land uses, vegetation types, etc.
Yep! my mistake, it's 1.35 x 10^13 liters, William F. Hansen you've been such a great help. Thank you so much.
William F. Hansen I have a similar problem to solve. If I add 1 Litre of water to a potted plant, with the pot having a 30 cm diameter (width) and 30 cm depth. How much water is that in mm (millimetres)?
The total amount of soil placed in the pot is 12kg.
Olwetu Antonia Sindesi , In this case, you don't need to take into account the depth of the pot.
The depth of the water applied is simply (the volume of water applied) divided by (the area of the top of the pot).
If you put out an empty can on your pot, ( https://img.wonderhowto.com/img/35/93/63475921516954/0/diy-tin-can-cookie-cutters-from-recycled-tuna-fish-cans.w1456.jpg ), and irrigated evenly, the depth of water in the can (say, 10 mm), would be the amount of irrigation you applied (in this example, 10 mm).
In your example, if I do the math correctly. Area of the top of the pot is 15 cm ^ 2 * pi. = 707 cm^2. 1 L = 1000 cm^3. So, 1000cm^3 / 707cm^2 = 1.4 cm. = 14 mm.
Sal Mangiafico Thank you very much it is very clear for me now.
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