基于贝叶斯层次分析法的沙颍河生态流量研究

Ecological Flow Response in Shaying River Based on Bayesian Hierarchical Model

维持河道内生态流量是协调水资源开发利用与河流生态保护的重要举措,现有的生态流量计算方法大多受限于生态数据不足、生态建模困难。为此,建立了基于浮游植物生物量的贝叶斯层次模型,研究探讨了河流水文—生态响应关系,以沙颍河为例,分析计算了汛前、汛期、汛后的浮游植物生物量与流量、水温的关系。结果表明,贝叶斯层次模型可识别水文—生态的复杂响应关系,分层分析产生的优势借用提高了短系列数据的可用性;生物量—流量关系参数β汛前大于0的概率为0.683,汛期小于0的概率为0.577,汛前河道内流量的保证及汛期泄流的控制对浮游植物生物量有正向影响;在符合设计要求的生态流量条件下,预测生物量最大和最小改善分别发生在河段7(汛前+32.05%,汛期+871.80%,汛后+81.79%)和河段3(汛前+3.91%,汛期+1.16%,汛后+2.89%)。

Maintaining ecological flow in a river is an important initiative to coordinate water resources development and utilization with river ecological protection.Most of the existing ecological flow calculation methods are limited by insufficient ecological data,difficult ecological modeling.In this paper,a Bayesian hierarchical model based on phytoplankton biomass was established to investigate the hydrological-ecological response relationship.The relationship between phytoplankton biomass and flow and water temperature in pre-flood,flood and post-flood periods was analyzed by taking the Shaying River as a case study.The results show that the Bayesian hierarchical model can identify the complex hydrological-ecological response relationship,and the advantage of hierarchical analysis improves the availability of short series data;The probability of biomass-flow covariate parameter β greater than 0 in pre-flood is 0.683,and the probability of less than 0 in flood is 0.577,and the guarantee of flow in the river channel in pre-flood and the control of discharge in flood have positive effects on phytoplankton biomass;Under the ecological flow conditions that meet the design requirements,the predicted maximum and minimum biomass improvements occur in river section 7(+32.05% before flood,+871.80% during flood,and +81.79% after flood) and river section 3(+3.91% before flood,+1.16% during flood,and +2.89% after flood),respectively.