Peak discharge

Peak discharge is the highest point on the discharge curve.

In this example, discharge rises from 4 m³/s at hour 0 to the peak discharge of 20 m³/s at hour 4. The falling limb, also called the recession limb, follows as discharge decreases.

As storm water arrives, discharge increases along the rising limb, reaches peak discharge, then decreases along the falling limb. The delay between peak rainfall and peak discharge is the lag time. Changing how water is stored and transported across the landscape changes this response.