河流水环境容量安全边际研究

水环境容量安全边际是污染物总量控制的关键。运用河流二维稳态水质模型,计算大宁河回水区内COD环境容量,并采用一阶误差分析法分析模型关键参数对大宁河COD环境容量影响程度,科学计算大宁河水环境容量安全边际值。结果表明,三峡库区坝前水位175 m时,大宁河回水区内COD环境容量为729.06 t/a;模型参数对环境容量影响顺序为:背景浓度(C0)>混合区长度(x)=水深(h)>流速(u)=扩散系数(E)y>降解系数(K);大宁河回水区内安全边际值为84.06 t/a,占环境容量的11.53%。文章科学地计算大宁河回水区内COD环境容量安全边际,而非人为定性提出,为三峡库区河流水环境容量安全边际确定提供理论依据。

Margin of Safety for River Water Environment Capacity

Margin of safety(MOS)for water environmental capacity is the key factor of pollution gross control.Two-dimensional steady-state river water quality model was used to calculate environmental capacity of COD in the backwater region of Daning River.Then first-order error analysis was used to analyze the degree of key factors impact on COD environmental capacity,and MOS for the River was calculated scientifically.Results showed that environmental capacity was 729.06 t/a in the backwater region of the River when 175 m water level of Three Gorges Dam was under operation.The key impact of factors on environmental capacity was ranked as background concentration of river>length of mixing zone=depth>velocity of flow=diffusion coefficient>degradation coefficient.MOS of COD in the River was 84.06 t/a,11.53% of environmental capacity for COD.MOS of COD environmental capacity in the River backwater region was calculated,rather than qualitative proposed by human determination,which would provide theoretical basis for MOS calculation of water environmental capacity in Three Gorges Reservoir area.