<p>In recent years, the inefficient performance of weirs during extreme flood events has prompted efforts to optimize their geometry to maximize discharge capacity. This study investigates the discharge coefficient of arced and arced labyrinth weirs, focusing on the effects of the number of cycles, total arc angle, and semicircular openings at the top of the weir. The findings reveal that reducing the number of cycles increases the discharge coefficient by up to 35.94%, with arced weirs achieving higher discharge coefficients than arced labyrinth weirs. Additionally, increasing the total arc angle enhances the discharge coefficient by up to 32.4%. Conversely, the presence of semicircular openings results in a reduction of the discharge coefficient as the ratio of the opening diameter to the edge length of the weir increases, with decreases of 19.54% observed for arced labyrinth weirs and 12.08% for linear labyrinth weirs. A generalized equation was developed to estimate the discharge coefficient, demonstrating a strong correlation with experimental data (R = 0.9).</p>