ABSTRACT With the growth of population and economy, water pollution has become increasingly severe. Taking the typical riverside city of Nanjing as an example, this study proposes a system dynamics (SD)–based methodological framework to predict and evaluate the change trend and control indicators of water environment carrying capacity (WECC), integrating three interconnected subsystems: water environment, society, and economy. Methodologically, we constructed the SD model, compiled model equations using the DYNAMO simulation language to graphically reflect the model's feedback loop, and conducted sensitivity analysis by adjusting 19 key parameters by ± 10%. Quantitatively, the model was validated with historical data (2010–2019) with most errors within 3%, and the simulation showed that the annual inflows of COD, NH 3 ‐N, TN, and TP into Nanjing's rivers in 2024 were 120 969.2, 13 638.48, 39 143.86, and 1579.66 t/a, respectively. The sensitivity analysis identified that most parameters are insensitive to the water supply and demand crisis, while the GDP growth rate is the most sensitive parameter for this crisis; overall, GDPGS and STR are the most sensitive parameters for the entire model system. Therefore, proper control of the population growth rate, appropriate slowdown of the economic development rate, and adjustment of the industrial structure are effective measures to improve Nanjing's WECC.
Song et al. (Mon,) studied this question.