online_return_period:    Calculation of return period T based on risk R and design life n INPUT DATA: Risk R :     (fraction of 1)  [Allowable range: 0.01-0.75] Design life n :     (No. of years)  [Allowable range: 1-200] Display full table Inlet in urban drainage. Formula: T = 1/[1 - (1-R)1/n] Reference OUTPUT: Return period T :  Warning: Undefined variable $returnperiod in /var/www/html/ponce/onlinereturnperiod.php on line 149 Deprecated: round(): Passing null to parameter #1 ($num) of type int|float is deprecated in /var/www/html/ponce/onlinereturnperiod.php on line 149 0 years   Your request was processed at  10:48:22 pm on April 3rd, 2025   [ 250403  22:48:22 ]. Thank you for running online_return_period.   Please call again.   [180208]