An "'instantaneous unit hydrograph "'is a further refinement of the concept; for an IUH, the input rainfall is assumed to all take place at a discrete point in time ( obviously, this isn't the case for actual rainstorms ).
12.
This method involves building a graph in which the discharge generated by a rainstorm of a given size is plotted over time, usually hours or days . It is called the unit hydrograph method because it addresses only the runoff produced by a particular rainstorm in a specified period of time-the time taken for a river to rise, peak, and fall in response to a storm.
