Elementary Engineering Hydrology

6

Hydrograph

Chapter Outline

6.1 Definition

6.2 Separation of base flow

6.3 Excess rainfall

6.4 Unit hydrograph

6.5 Changing of time of unit precipitation

6.6 Derivation of unit hydrograph

6.7 Averaging of unit hydrograph

6.8 Synthetic unit hydrograph

6.9 Distribution graph

6.10 Triangular unit hydrograph

6.11 Instantaneous unit hydrograph

6.1 DEFINITION

A hydrograph may be defined as a graphical representation of time versus discharge (Fig. 6.1).

6.1.1 Units

The unit for time on the x-axis may be:

1. Hours
2. Days
3. Months

Fig. 6.1 Hydrograph

This unit is selected depending upon the purpose and the nature of the study. If the study is floods ...