Hydrology Question-Converting areas to volumes

dam821

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Many of the problems I need to complete involve converting areas into volumes. The text does not explain how to do this and I was unable to find any instruction online. Please advise on how I should go about doing these problems.

1) Two cm of runoff result from a storm on a drainage area of 100 km^2. Convert this amount to cubic meters and acre-feet (1 acre=43,650 square feet).

2) A vertical walled reservoir has a surface of 500,000m^2. There is an inflow of 1m^3/second. How many hours will it take to raise the reservoir level by 30 cm?

Your assistance would be appreciated.
 
dam821 said:
Many of the problems I need to complete involve converting areas into volumes. The text does not explain how to do this and I was unable to find any instruction online. Please advise on how I should go about doing these problems.

1) Two cm of runoff result from a storm on a drainage area of 100 km^2. Convert this amount to cubic meters and acre-feet (1 acre=43,650 square feet).

2) A vertical walled reservoir has a surface of 500,000m^2. There is an inflow of 1m^3/second. How many hours will it take to raise the reservoir level by 30 cm?

Your assistance would be appreciated.

Assume a rectangular parallelepiped with the given base area and given height. So to get the volume multiply the area with the required height (watch the units!)
 
dam821 said:
Many of the problems I need to complete involve converting areas into volumes ...

This is not properly worded; area may not be converted to volume. What you are trying to say is, "... involve obtaining volume from area and height."

dam821 said:
... (1 acre = 43,650 square feet) ... This is a transposition error; there are 43,560 square feet in one acre.

Subhotosh Khan said:
... Assume a rectangular parallelepiped ... (also known as a right rectangular prism or a cuboid)
 
Like the others have said, this is a problem of area times height. And keeping track of units is key.


1) Two cm of runoff result from a storm on a drainage area of 100 km^2. Convert this amount to cubic meters and acre-feet (1 acre=43,650 square feet).

2) A vertical walled reservoir has a surface of 500,000m^2. There is an inflow of 1m^3/second. How many hours will it take to raise the reservoir level by 30 cm?

Both of these are common engineering questions.

1a) Part A - Convert 100km^2 to m^2
1a) Part B - Convert 2cm to m
1a) A*B -> m^3

1b) Part A - Convert 100km^2 to acres
1b) Part B - Convert 2cm to feet
1b) A*B -> acre-feet

2) Part A - Convert 30cm to m
2) Part B - A*reservoir surface
2) Part C - Convert 1m^3/sec to m^3/hour (this will be a larger number)
2) B/C -> hour
 
Thank you everyone for your help. I understand the logic behind the solution to the problem however, please let me know if there is an online source that has similar type problems and explained solutions for further practice.

Thanks.
 
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