Let’s look at an example:
Lake A is getting water from River B and we want to know the loading of rubber ducks into Lake A.
The first thing you’ll need to find is the river discharge – how much water is flowing from River B into Lake A.
Let’s say this is 1,000 L/m, or 1,000 litres per minute.
Once we have that, then we’ll need to know how many rubber ducks are in a certain volume or water. This is the concentration of rubber ducks.
Let’s say this is 10 rubber ducks per litre, or 10 rd/L.
Now we can calculate the loading of rubber ducks into Lake A by multiplying the river discharge by the concentration of rubber ducks.
That will look like this:
Rubber duck load into Lake A = 1,000 L/m x 10 rd/L = 10,000 rd/m
What this does is tell us how many rubber ducks are entering Lake A per minute. That’s a lot of ducks!