Ecological Discharge Study of Changxinggang River Based on the MIKE 11 One-Dimensional Hydrodynamic–Water Quality Coupling Model

Abstract

In order to safeguard the ecological health of Changxinggang River’s water environment, conducting research on ecological discharge, including establishing reasonable ecological discharge control values, is of great importance. This study utilized monthly hydro-ecological data from the Xintang section of the Changxinggang River that spanned the years 2016 to 2020. It defined the water quality control indicators for both non-flood and flood periods in the Changxinggang River and utilized the MIKE 11 software to construct the MIKE 11 one-dimensional hydrodynamic–water quality coupling model. A comparison between simulated values and measured values showed that the model exhibits a relative error of less than 17%, indicating its suitability for practical use. The results indicate that the water quality control indicators for the non-flood period in the Changxinggang River encompass ammonium nitrogen (NH3-N), chemical oxygen demand (manganese) (CODMn), and biochemical oxygen demand (BOD), while those for the flood period include NH3-N, total phosphorus (TP), and CODMn. Reasonable ecological discharge control values for both non-flood and flood periods in the Changxinggang River are calculated to be 2.59 m3/s and 2.63 m3/s, respectively. The model developed in this study is applicable for ecological discharge calculations in the Changxinggang River, and the proposed ecological discharge control values are achievable.