- Online calculators - Calculation of sediment discharge by the Modified Lane relation online_modified_lane Calculation of parameter k1 in the Modified Lane relation online_modified_lane k1 Calculation of minimum Froude number for initiation of Motion online_initiation_froude Online k1 calculator online_k1_calculator Calculation of bridge scour using the HEC-18 formula online_scour_hec18 Calculation of sediment discharge using the Einstein-Brown formula online_einstein_brown Calculation of equilibrium channel top width using the Lane et al. theory online_lane_shape Calculation of culvert hydraulics online_culvert Evaporation from sparse crops using the Shuttleworth-Wallace energy combination formula online_shuttleworth_wallace USGS methods for determining magnitude and frequency of floods in California online_usgs_floods_california