Sensitivity analysis of thermal equilibrium parameters of MIKE 11 model: A case study of Wuxikou Reservoir in Jiangxi Province of China

Sensitivity analysis of thermal equilibrium parameters in the reservoir module of MIKE 11 model was conducted for the Wuxikou Reservoir in Jiangxi Province of China in order to apply the module to the environmental impact assessment to accurately predict water temperature of reservoirs. Results showed that radiation parameter A and evaporation-first parameter were much more sensitive than other parameters. The values of the radiation parameter A ranged from 0.10 to 0.34. The values of evaporation-first parameter varied from 0 to 10. The sensitivity of solar absorption parameters was less than that of evaporation parameter, of which light attenuation values ranged from 0.5 to 0.7, and this parameter would not impact model results if it was more than 2. Constants in Beer’s law ranged from 0.2 to 0.7. Radiation parameter B was not more sensitive than evaporation parameter and its reasonable range was higher than 0.48. The fitting curves showed consistent changing tendency for these parameters within the reasonable ranges. Additionally, all the thermal equilibrium parameters had much more important effects on surface water temperature than deep water temperature. Moreover, if no observed data could be obtained, the local empirical value would be used to input to the MIKE 11 model to simulate the changes in the discharged outflow-water temperature qualitatively.