摘要
出于防洪、发电与航运需求,三峡水库在汛期维持145 m低水位运行,在非汛期抬升水位至175m维持高水位运行。水库运行期按水位变化分为:水位下降期(175~145 m)、低水位运行期(145 m)、水位上升期(145~175m)和高水位运行期(175 m)。基于2011-2018年三峡水库出库断面水质因子(DO、CODMn和NH3—N)监测周报数据,采用综合水质标识指数Pi和自回归综合移动平均模型ARIMA模型评价预测水质,研究三峡水库水位调度对出库断面水质的影响,探究水质对水位变化的响应,并预测水质变化趋势。结果表明:三峡水库季节性水位调度对出库水质影响显著。水质因子(DO、CODMn、NH3—N)浓度随水位运行期的改变而出现周期性变化,不同水位运行期水质因子浓度存在差异。高水位运行期DO浓度显著高于低水位运行期,CODMn和NH3—N浓度小于低水位运行期;各运行期的综合水质标识指数Pi均符合综合水质指标Ⅰ级标准,其中高水位运行期水质最好,低水位运行期水质最差;ARIMA预测结果显示未来水质符合Ⅰ级标准。水库水文条件受季节性水位调度影响,水质与水位、流量和外源污染输入相关。评价结果有利于在高时间精度下掌握水质实情,进行水资源管理。
The Three Gorges Reservoir operates at a low water level of 145 m during flood season and a high water level of 175 m during the non-flood season for the purposes of flood control,power generation and shipping. According to the changes of the water level,the operation period of the reservoir can be divided into four stages,which are descent stage (175-145 m),low level stage (145 m),ascent stage (145-175 m) and high level stage (175 m). In this study,the outflow water quality in different water levels of the Three Gorges Reservoir was evaluated by using comprehensive water quality identification indicator based on the weekly water quality monitoring data of water quality indicators (DO,CODMnand NH3—N) from 2011 to 2018,and a classical time series autoregressive integrated moving average (ARIMA) model was used to predict future water quality changing trends. The objective of this research is to study the influence of water level scheduling of the Three Gorges Reservoir on the outflow water quality and its response to the changes of water level,so as to predict water quality change tendency. The results showed that the seasonal water level scheduling of the reservoir had a significant influence on the outflow water quality. The concentration of the water quality indicators (DO、CODMn、NH3—N) presented cyclical changes in response to different operation stages. The concentration of DO was much higher at high level stage than that at low level stage,whereas the concentration of CODMnand NH3—N was the opposite. Moreover,Piat different stages all maintained ClassⅠstandard of comprehensive water quality,with the best water quality occurring at high level stage and worst at low level stage. Predicting outcomes of ARIMA model show that the water quality will maintain Class Ⅰ standard in the future. It is found that the water quality of the reservoir is affected by the water level,flow and exogenous pollution input under the influence of seasonal water level scheduling. This study can help better manage water resources with the approach of high precision water quality information.
作者
黄玥
黄志霖
肖文发
曾立雄
马良
HUANG Yue;HUANG Zhilin;XIAO Wenfa;ZENG Lixiong;MA Liang(Key Laboratory of Forest Ecology and Emwironment,State Forestry and Grassland Administration,Research Insitute of Forest Ecology,Environment and Protection,Chinese Academy of Forestry,Beijing 100091,China)
出处
《水资源与水工程学报》
CSCD
2020年第4期78-85,共8页
Journal of Water Resources and Water Engineering
基金
国家重点研发计划项目(2017YFC05053)。
关键词
出库水质
水位调度
影响评价
综合水质标识指数
差分自回归移动平均预测模型(ARIMA)
三峡水库
outflow water quality
water level scheduling
impact assessment
comprehensive water quality identification indicator
autoregressive integrated moving average(ARIMA)prediction model
Three Gorges Reservoir