Correct Answer - Option 1 : Unit hydrograph
Explanation:
Unit Hydrograph:
(i) A unit hydrograph is defined as the hydrograph of direct runoff resulting from one unit depth of rainfall excess occurring uniformly over the basin and at a uniform rate for a specified duration.
(ii) The term Unit here refer to a unit depth of rainfall excess which is usually taken as 1 cm.
Hydrograph:
(i) A hydrograph is the graphical representation of the discharge flowing in a river at the given location, with the passage of time.
(ii) A hydrograph is capable of representing discharge fluctuation in the river at a given site over a given time period. Hydrograph gives us the peak flow, which is important for the design of hydraulic structure at that site.
Direct Runoff hydrograph:
(i) The hydrograph obtained after deducting the base flow from the flood hydrograph is known as DRH.
