1. Identify the x and y-axes. The x-axis of a hydrograph typically represents time, while the y-axis represents water discharge or stage.
2. Find the peak discharge or stage. The peak discharge or stage is the highest point on the hydrograph. This represents the maximum amount of water flowing through the river or stream at a given time.
3. Note the time to peak. The time to peak is the amount of time it takes for the river or stream to reach its peak discharge or stage.
4. Identify the rising and falling limbs. The rising limb of a hydrograph is the part of the graph that shows the increase in discharge or stage over time. The falling limb is the part of the graph that shows the decrease in discharge or stage over time.
5. Calculate the duration of the hydrograph. The duration of the hydrograph is the amount of time between the beginning of the rising limb and the end of the falling limb.
6. Interpret the hydrograph. The shape of a hydrograph can tell you a lot about the characteristics of the river or stream. For example, a steep rising limb indicates that the river or stream is responding quickly to rainfall, while a gradual rising limb indicates that the river or stream is responding more slowly. A long duration indicates that the river or stream is draining a large area, while a short duration indicates that the river or stream is draining a small area.