This quote is emphasizing the difficulties of both downward and upward communication in a business.
It is saying that downward communication tends to be excessive and that upward communication tends to be insufficient. Downward communication is, in one way, easily achieved. Superiors can always force subordinates to listen to them. This happens easily and often. However, it can happen too often and be very unfocused. The "water" just gushes down and splashes all over everyone in a imprecise way.
Upward communication is very important, but does not happen enough. Subordinates' ideas and input tend to be discounted by those above them. This means that their communications do not get heard.
Both of these are problems that good businesses must overcome as much as possible so that the right amount of communication each way can occur.