Water environment capacity estimation and pollutant reduction of Yanghe Reservoir Basin in Hebei Province, China, via 0-D water quality model

There are many reservoirs in China, and the reservoir serves as an important source of drinking water. With the increasing pollution discharge upstream of the reservoir, the water quality of the reservoir is seriously threatened. Therefore, it is necessary to control the total amount of pollution and reduce the pollutants under the target water quality. In this paper, the upstream basin of the Yanghe Reservoir in Qinhuangdao City, Hebei Province was used as the study area, and the 0-D water quality model was used to estimate the water environment capacity of the study area under the Class II water quality target. And compared with the current pollutants, proposed reduction targets and measures. The results indicated that the water environmental capacity of total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), and ammonia–nitrogen (NH3-N) in the study area were 3226.9t, 264.6t, 71,200.6t, and 5575.7 t, respectively. The COD and NH3-N water environmental capacity cannot be fully utilized. The TN and TP exceeded the standard seriously, exceeding 1.47 times and 1.13 times of the TN and TP water environmental capacity under the water quality target of Class II, respectively. TN and TP need to be reduced by 57% and 53% for satisfying quality requirements, respectively. Through the analysis of pollutant sources, practical and feasible pollutant emission reduction measures are discussed.