THE UNIT-HYDROGRAPH MODEL FOR HYDROGRAPH SEPARATION

Procedures are presented for baseflow separation based on the unit hydrograph theory. When a mathematical model is used to represent the baseflow unit hydrograph, the parameters derived from a recession limb of the baseflow hydrograph can be further used to determine the rising limb of the baseflow hydrograph. The simple procedures involve estimation of the two parameters of the model using discharge data with simple equations. Once parameters have been estimated, the mathematical model for an entire baseflow hydrograph can be used to determine both the temporal processes and total quantity of a baseflow hydrograph. Using this method the separated component of baseflow during study periods is about 63% of the total storm runoff from two small rural catchments in Australia.