Reference water level

Imagine you have a big jar full of water. The water level in the jar is like a measuring stick that tells you how much water is in there. Now, let's say you want to measure how much water is in a smaller cup. You can use the water level in the big jar as a reference point.

Reference water level is a way of saying that you use something known to compare to something else. In this case, the known thing is the water level in the big jar, and we compare it to the water level in the smaller cup.

So, if you pour some water from the big jar into the smaller cup, you can look at the water level in the big jar and say, "Okay, the water level in the big jar is the reference point, and the water level in the cup is the water level compared to the reference."

This way, you can know exactly how much water is in the cup by comparing it to the reference water level in the big jar. It's like having a ruler to measure the water in the cup.

People use reference water levels in different situations, like measuring how much water is in a swimming pool, or checking the amount of rainfall in a rain gauge. By comparing the water level to a known reference, we can find out how much water there is.