Fluid dynamics and pressure type question.

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To determine if water can be pumped from a 55-gallon drum back to a roof deck, calculating the pressure in pascals is essential. The pressure is influenced by the weight density of the water and the height it needs to reach. However, the geometry of the hose, particularly its diameter, significantly affects the flow and pressure dynamics. Concentrating a large pressure into a small hose can lead to inefficiencies and may not provide sufficient force to move the water uphill. Therefore, the design must consider both pressure calculations and the impact of hose geometry on water flow.
Gersty
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Let's say I want to install a 55 gallon drum on the ground to collect rain water as it runs off the roof. What if for some strange reason I wanted to run a hose from a spigot in the bottom of the drum back up to water the plants on the roof deck (I'm looking into green roofs). Could we just calculae the pressure in pascals and then determine if that would be enough force to push a hosefull of water back up to the roof?
 
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Pressure is just the weight density times height. Geometry - such as concentrating a large pressure into a small hose - plays no role whatsoever, so what you are describing can't be done.
 

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