"Baptism is unto repentance." So, why did they need to remove water to a trickle, and replace the river with a booth whereby a womanless man croucheth on the other side?? a booth?

The riverside, and sharing of guilt and shame, to baptize and let them be washed away in front of all, as you are born anew to your goals, is what was/is meant.

I go to the river a lot, it is perfect for confession and baptism but it's simply more fun to just listen to families at play and the sound of birds.