Derivation of Unit Hydrographs
Derivation of Unit Hydrograph from a Simple Storm A number of isolated storm hydrographs caused by short spells of rainfall excess each of approximately same duration are elected from a.…
Unit Hydrograph
Definition of Unit Hydrograph This method was first suggested by Sherman in 1932 · A unit hydrograph is defined as the hydrograph of direct runoff resulting from one unit depth (1…
Base Flow Separation
Methods of Base Flow Separation The surface-flow hydrograph is obtained from the total storm hydrograph by separating the quick-response flow from the slow response runoff. It is usual to consider…
Stream Flow Hydrograph
Definition of Hydrograph The hydrograph which results due to an isolated storm is typically singlepeaked skew distribution of discharge and is known variously as storm hydrograph, flood hydrograph or simply…
Measurement of Runoff
Most hydrologic analyses involve runoff from a drainage area, and hence its measurement is of vital importance. If precipitation and runoff 'can be accurately measured, it is then possible to…
Estimation of Runoff-II
SCS Curve Number Method This method is developed by the Soil Conservation Service (SCS) in 1969. It is now known as Natural Resources Conservation Service (NRCS). The fundamental hypotheses of…
Estimation of Runoff-I
Empirical Formulae In the past, many empirical formulae have been developed, but these are applicable only to the region where they were derived. Furthermore, caution must be taken in their…
Components of Runoff and Factors Affecting Runoff
Components of Runoff Runoff means the draining or flowing off of precipitation from a catchment area through a surface channel enters into a stream channel. It represents the output from…
Channel Characteristics of Watersheds
Number of Channels and their Order Identification of first-order channels is the first step in applying channel order in hydrology. Application of stream ordering requires the use of a topographic…
Physical Characteristics of Watersheds
Watershed Area Basin area is defined as the area contained within the vertical projection of the drainage divide on a horizontal plane. Watershed area is comprised of two subcomponents: 1)…
