online_contraction_scour_clear_water:  Contraction scour under clear water conditions using Laursen equation 1963        Laursen formula 1963 ys / yo = {[( Ku Q 2 ) / ( Dm0.667W 2)] 0.429 (1/yo)}  -  1 [ ys, yo, Q, Dm and W in any consistent units ] [ Ku = 0.025 in SI units; Ku = 0.0077 in U.S. units ] Reference: Evaluating Scour at Bridges, FHWA Hydraulic Engineering Circular No. 18, Fifth Edition, 2012. INPUT DATA:      [Description]     [Sample Input] Select:       SI units (metric) U.S. Customary units Mean flow depth below the bridge, before scour yo :         Warning: Undefined variable $depthunits in /var/www/html/ponce/enlineacontraccionsocavacionaguaclara.php on line 196 Discharge in the contracted section Q :         Warning: Undefined variable $dischargeunits in /var/www/html/ponce/enlineacontraccionsocavacionaguaclara.php on line 204 Bottom width in the contracted section, excluding piers W :         Warning: Undefined variable $widthunits in /var/www/html/ponce/enlineacontraccionsocavacionaguaclara.php on line 212 Median diameter of the bed material D50 :         Warning: Undefined variable $dfiftyunits in /var/www/html/ponce/enlineacontraccionsocavacionaguaclara.php on line 219 OUTPUT: Warning: Undefined variable $unitsystems in /var/www/html/ponce/enlineacontraccionsocavacionaguaclara.php on line 250 SI units (metric) Contraction scour depth under clear water conditions ys :    Warning: Undefined variable $scourdepth in /var/www/html/ponce/enlineacontraccionsocavacionaguaclara.php on line 274 Deprecated: substr(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/html/ponce/enlineacontraccionsocavacionaguaclara.php on line 274   Warning: Undefined variable $depthunits in /var/www/html/ponce/enlineacontraccionsocavacionaguaclara.php on line 274 Press button to or recalculate   Your request was processed at  11:13:56 pm on April 3rd, 2025   [ 250403  23:13:56 ]. Thank you for running   online_contraction_scour_clear_water   Please call again.   [180222 15:00]