Things have happened lately for you in perhaps the last few years. These things may form a pattern, a trend. Combining the collection of similar points or elements into a pattern and then combining that pattern with a concentrated flow of time produces, in my lexicon, velocity.
Your life, Your River, may have a velocity to it in recent times. There has emerged a natural power and momentum that will take something fundamentally new or different or in opposition to it for a clear change to be effected.
The same thing may be true for some other, earlier part of your life. For a while, a period that can be defined and measured, you experienced a collection of similar points along the way, and from them came velocity.
Whenever you take stock of yourself, be sure to see if there has been velocity at work.
Can you look back from right now to, say, two or five or ten years past, and see velocity at work in Your River?