There need not be any water at all in the hose! The capacity of the hose is 1.67 cubic feet.
230 * 1/12 = 19.166.. cubic feet = 542.74 litres
7.35 Is what you need
For every inch of paracord you will need 1 foot
Since one foot is 12 inches a four percent slope is .04X12 = 0.48 inch drop
One quarter inch per foot is standard "slope". This equates to a quarter bubble on a level. If you don't have at least one eighth of an inch "slope", your drain will not work properly and will clog constantly.
42.4 cubic feet = 1.6 cubic yards (rounded)
There need not be any water at all in the hose! The capacity of the hose is 1.67 cubic feet.
230 * 1/12 = 19.166.. cubic feet = 542.74 litres
7.35 Is what you need
For every inch of paracord you will need 1 foot
Since one foot is 12 inches a four percent slope is .04X12 = 0.48 inch drop
4,000 linear feet.
Approximately 96 square feet.
A single layer will require 144 bricks.
You need a steep slope from one inlet to another.
Volume = 120/12= 10 cubic feet for each 1 inch of depth= 2 bags for each 1 inch of depth.