Elements of a Hydrograph

A hydrograph is described by the following properties:

Rising Limb - The initial part of the hydrograph where flow increases from the base flow rate towards the peak.
Peak Flow - The peak flow rate is defined as the maximum flow rate on the hydrograph and will occur when runoff is fully developed.
Time to Peak - The time from the beginning of runoff to the peak.
Falling Limb - The recession side of the hydrograph where the flow rate decreases from the peak to the base flow.
Duration - The hydrograph duration is the time from the beginning of runoff to the end.
Volume - Volume is represented as the area under the hydrograph.
Base Flow - The base flow is the part of the hydrograph that represents the normal flow in a perennial stream, or in other words the flow in a river before the rainfall event.

You can move your cursor over words below to better understand these different elements.