How do I prevent the flow out of my pond from being jagged or spiky?
If you go into the calculation options (Analysis > Calculation Options) for the scenario and try to reduce the calculation time step that should help. In the screen shot above the calculation time step was 1.5 minutes. On the first go around it was reduced to 1 minute, which helped, but there was still some jagged edges on the flow graph. After further reducing the time step down to 30 second the graph was much smoother.