<p>Predicting scour parameters downstream of sluice gates due to the high velocity of a jet and submerged hydraulic jumps seems to be essential with accurate physical models. The present study investigated the scour parameters downstream of a gate via laboratory approach in three cases for the sedimentary bed, including uniform (<i>σ</i>_<i>g</i> = 1.25), semi-uniform (<i>σ</i>_<i>g</i> = 1.35), and nonuniform (<i>σ</i>_<i>g</i> = 1.45). Four scour parameters were measured as the maximum depth of scour hole (<i>d</i>_<i>se</i>), its longitudinal distance from the end of the apron (<i>x</i>_<i>se</i>), the maximum dune height (<i>h</i>_<i>d</i>), and its horizontal location from the beginning of the sediment bed (<i>x</i>_<i>d</i>), and became dimensionless by dividing by the gate opening (<i>b</i>₀). The comparison of velocity profiles indicated acceptable accuracy of the results with the previous empirical equation. The difference between the scour proposed equations in the present study and the previous formulas is adding parameter <i>σ</i>_<i>g</i>, which could provide better reality of the physical features of the variation in the uniformity of the sediment bed grains. Statistical analysis revealed that multiple nonlinear regression analysis (MNLRA) could calculate <i>d</i>_<i>se</i><i>/b</i>₀ more accurately than multiple linear regression analysis (MLRA) with <i>R</i>² = 0.957, RMSE = 0.263. Furthermore, proposed equation for <i>x</i>_<i>se</i><i>/b</i>₀, <i>h</i>_<i>d</i><i>/b</i>₀, and <i>x</i>_<i>d</i><i>/b</i>₀ has better performance in MNLRA compared to MLRA.</p>