A key component of water management is ensuring that the water you use does not end up being wasted as runoff. This formula can help you avoid this situation.

How long should I wait if I want to refill the profile and not have runoff or leaching?                                
    NST =   ra + dep – (TAWC – WB)                            
                                     ETC                          
    Where:                            
    ra         = rainfall allowance (How much rain do you expect next 5 days?)                            
    dep      = planned effective irrigation depth (How much water are you going to put on?)                            
    TAWC  = total available water capacity (What is the full point set at?)                            
    WB      = water balance (What is the current volumetric water content of the soil?)                            
    ETC     = forecast crop water use (What is the crop actually using per day?)                            
                                
    Rainfall Allowance    0.5    Inches                    
    Planned irrigation application    1.0    Inches                    
    Full Point Volumetric Water    10.0    Inches                    
    Current Volumetric Water Content    8.0    Inches                    
    Average Daily Water Use    0.25    Inches                    
                                
    Time Left Before Irrigation    -48    Hours                    
    Time Left Before Irrigation    -2.00    Days