基于水质-水量-水源地耦合模型的生态补水量研究

Study on Ecological Water Replenishment Based on Coupling Model of Water Quality, Water Quantity and Water Source

为研究受损河流生态修复所需的补水量,基于QUAL-2K水质模型模拟断面水质,Tennant法确定河道生态流量,构建了以水质达标、生态水量达标、对水源地影响最小为目标的耦合模型,并将耦合模型应用于四川省某中小河流,在水质目标下,通过对河流现状水质因子评价分析,选取氨氮、总磷两种水质因子达到Ⅲ类水为目标,对该河流出境断面水质进行模拟;水量目标下,以多年平均流量的30%和50%分别作为非汛期和汛期的生态流量;水源地目标下,生态补水不应侵占水源地本身生态流量和其他用水户用水。结果表明,水质目标下全年引水量为7 197万m^(3),水量目标下全年引水量为6 808万m^(3),综合水源地可引水量,确定补水月份为1-6月,全年引水量为1.01亿m^(3)。研究成果证明生态补水可作为短期内改善因缺水而受损的生态系统的一种手段,能够为跨区补水河流项目生态补水量的确定提供决策依据。

In order to study the water replenishment needed for river ecological restoration,the QUAL-2K water quality model was used to simulate the sectional water quality and the Tennant method was used to determine the ecological flow of the river.The coupling model was established with the objectives of the water quality up to the standard,the ecological water quantity up to the standard and the minimum impact on the water source.And it was applied to a small and medium river in Sichuan Province.Under the objective of the water quality,through the evaluation and analysis of the current water quality factors of the river,the two water quality factors of ammonia nitrogen and total phosphorus were selected as the objective to reach classⅢwater.And these two factors were used in the simulation of the exit section.Under the objective of the water quantity,30%and 50%of the annual average discharge were used as the ecological discharge in non-flood season and flood season,respectively.Under the objective of the water source,ecological water replenishment should not encroach on the ecological flow of water source and the water of other water users.The results show that the annual water diversion under the water quality target is 71.97million m^(3)and the annual water diversion under the water quantity target is 68.08 million m^(3).The months of water replenishment are determined to be from January to June,and the annual water diversion is determined to be 101 million m^(3).The research results show that ecological water replenishment can be used as a means to improve the damaged ecosystem due to water shortage in a short term,and can provide a decision-making basis for the determination of ecological water replenishment amount of river projects.