DESIGN & CALCULATION DETENTION BASIN

DESIGN PROCEDURE ( DP )

DESIGN NEEDS
-inflow hydrograph
-stage-storage
-stage-outflow
-storage-outflow function


inflow hydrograph
- tc
-ARI
-Fitted IDF equation coefficient
-Polynomial Equation
-Calculation

inflow hydrograph
effective runoff ( ER )
-temporal fraction
-losses

inflow hydrograph
Time – area method
time –area diagram isochrones or line of equal travel time
convolution process
qi = IiA1 + Ii-1A2 +……...+I1Ai
develop isochrones or line of equal travel time

estimate of storage
Volume of storage estimate ( Vs )
Critical storm at different durations > tc for major and minor ARI

estimate of storage
Volume by regression equation