Water Environmental Capacity Accounting and Upstream Capacity Allocation of Baiyangdian Lake

According to years of water quality monitoring data, designed hydrologic conditions and parameters such as water quality targets, and based on division of the control unit of distributed capacity, the capacities of chemical oxygen demand (COD_Cr) and ammonia nitrogen (NH₃-N) were calculated using the method of pollutant capacity estimation in shallow lakes. The water environmental capacity allocation strategies reflecting social and economic features were given and their fairness evaluated using Gini coefficient. The results showed that the capacity of COD_Cr in Nanliuzhuang, Shaochedian and Caiputai was 2 526.8, 328.5 and 1 430.8 t/a, respectively, and the capacity of ammonia nitrogen was 155.0, 73.0 and 255.5 t/a, respectively. The Gini coefficients of the control units in the upstream of Baiyangdian Lake were all smaller than 0.4 and the allocation strategies were relatively rational.