If we are considering the number 164, it in fact is a rational number because it can be written as the quotient of two integer numbers, for example 164/1 (164 divided by one).
If we are talking about the rationality of the quantity 164 kilometers of water, that is another issue, because water is not measured in kilometers it is measured in units of volume (like gallons, cubic centimeters, etc.) So I would say that it is absurd to assign those units to water.