This study investigates the downstream impact of sand mining in a riverine system, focusing on how different positions of floodplain rectangular sand mining pits affect the flow characteristics of a low sinuous channel. Three scenarios are considered: a sinuous channel without mining pits, a sinuous channel with two mining pits, and a sinuous channel with three mining pits. The research employs both experimental and numerical approaches, both methods are employed only for the first scenario for the validated purposes, and the other two scenarios were simulated numerically only. The results show that the streamwise velocity is concentrated with a higher magnitude at the inner bank, while secondary currents are more pronounced at the outer bank. The presence of an extra mining pit in the third scenario narrows down the highest zone of streamwise velocity and reduces the concentration of secondary currents at the outer bank. Vorticity exhibits clockwise circulation at the inner bank and anti-clockwise rotation at the outer bank. Turbulence intensity is found to be highest at the inner bank and lowest at the outer bank, with an approximately 8% increase in intensity when an extra mining pit is present in the third scenario. These findings provide valuable insights into the flow characteristics under different positions of sand mining pits, aiding river management practices and potentially extending to the study of sediment transport phenomena. The experimental and numerical approaches complement each other, enhancing the understanding of the riverine system's behavior. However, there is a discrepancy in the quantitative results, with errors ranging from 18 to 34% between the experimental and numerical simulations. Despite this, the qualitative agreement between the two approaches is promising.