A hydrograph shows 2 graphs, one is rainfall as bars and the other is discharge as a line to show the relationship between rainfall and river discharge
Peak rainfall is the highest amount of rainfall per time unit. It is represented by the highest bar
Peak discharge is the highest recorded discharge following a rainfall event. It is represented by the top of the line graph
Falling limb shows the reduced discharge once the main effect of run off has passed
Base flow is the normal flow of a river when its water bed level is sustained by groundwater flow
Lag time is the time difference between peak rainfall and peak discharge
rising limb shows how quickly the discharge rises after a rain storm
