Abstract: The implementation of the water sediment regulation scheme (WSRS) is a typical example of artificially controlling land-source input. During WSRS, the water discharge of the Yellow River will increase significantly, and so will the input of terrigenous materials. In this study, we used a natural geochemical tracer ²²²Rn to quantify terrestrial inputs under the influence of the 2014 WSRS in the Yellow River Estuary. The results indicated that during WSRS the concentration of ²²²Rn in the estuary increased by about four times than in the period before WSRS. The high-level ²²²Rn plume disappeared quickly after WSRS, indicating that ²²²Rn has a very short 'memory effect' in the estuary. Based on the investigation conducted from 2015 to 2016, the concentration of ²²²Rn tended to be stable in the lower reaches of the Yellow River. During WSRS, the concentrations of ²²²Rn in the river water increased sharply at about 3 – 5 times greater than in the non-WSRS period. Based on the ²²²Rn mass balance model, the fluxes of ²²²Rn caused by submarine groundwater discharge (SGD) were estimated to be (3.5 ± 1.7) × 10³, (11 ± 3.9) × 10³, and (5.2 ± 1.9) × 10³ dpm m⁻² d⁻¹ in the periods before, during, and after WSRS, respectively. This finding indicated that SGD was the major source of ²²²Rn in the Yellow River Estuary, which can be significantly increased during WSRS. Furthermore, the SGD-associated nutrient fluxes were estimated to be 9.8 × 10³, 2.5 × 10², and 1.1 × 10⁴ μmol m⁻² d⁻¹ for dissolved inorganic nitrogen, phosphorus, and silicon, respectively, during WSRS or about 2 – 40 times greater than during the non-WSRS period.