摘要
支流库湾水体富营养化是三峡水库带来的主要环境问题之一,三峡水库进入常态调度运行后,支流库湾水体富营养化问题日益突出。为厘清易发生水华的支流库湾水体富营养化的驱动力因素,本文以重庆市奉节县梅溪河为典型支流,采用三维水动力与水环境模拟技术解析了支流库湾水动力的驱动机制及营养盐来源及其组成。干-支流水温差导致的密度流是梅溪河支流库湾蓄水期及枯水运行期的主要驱动力,密度流对支流库湾的水动力影响自河口向上游逐渐减弱,干流倒灌输入的N、P营养盐占梅溪河易发生水华的库湾尾部区营养盐收支比重不足20%,而陆域面源输入(>70%)成为梅溪河支流库湾水体富营养演化的主要营养来源。因此,在长江干流水质及干支流水温难以有效调控的条件下,遵循“源头控制-过程阻断-末端拦截-水体原位削减-水生态系统修复”的系统治理思路有针对性支流库湾富营养化水体调控对策措施,可为三峡水库水体富营养化程度较重的支流库湾水污染治理及水质目标适应性管理提供参考。
Eutrophication of the tributary bay is one of the main environmental problems brought in by the Three Gorges Reservoir.Clarifying the driving forces of the eutrophication in the tributary reservoir bay is the key to solving the problem.This paper takes the Meixi River in the Fengjie County as the study ob⁃ject,which is a typical tributary.The driving mechanism of hydrodynamics and the nutrient sources and composition of the tributary bay are investigated through the 3-D simulation technology for hydrodynamics and water environment.Investigations indicate that the density flow caused by the temperature difference be⁃tween the mainstem and the tributary water is the main driving force in the formation of the Meixi River tributary reservoir bay.From the estuary to the upstream,the hydrodynamics influence of density flow on the tributary bays gradually weakens.The input of nitrogen and phosphorus nutrients from the mainstream backflow accounts for less than 20%of the nutrients in the tail area of Meixi River where the algal bloom is prone to occur.However,terrestrial input accounts for 70%and thus is the main source of nutrients for the eutrophication of the reservoir bay of the Meixi River.As a matter of fact,the water quality of the mainstem of the Yangtze River and the water temperature of the main and tributary streams are difficult to control.It is therefore suggested that such treatment ideas be followed as“source control-process interrup⁃tion-terminal interception-in-situ reduction of water body-water ecosystem restoration”.On this ba⁃sis,regulation measures for the eutrophic water body of the tributary reservoir bay have been developed,which are expected to provide support for water pollution control and water quality target adaptive manage⁃ment in tributary bays.
作者
齐德轩
马巍
党承华
宋婷婷
孙磊
QI Dexuan;MA Wei;DANG Chenghua;SONG Tingting;SUN Lei(China Institute of Water Resources and Hydropower Research,Institute of Water Environment,Beijing 100038,China;Hebei University of Engineering,School of Water Conservancy and Hydroelectric Power,Handan 056038,China)
出处
《中国水利水电科学研究院学报》
北大核心
2021年第3期318-328,共11页
Journal of China Institute of Water Resources and Hydropower Research
基金
国家重点研发计划(2017YFC0505305)。
关键词
三峡水库
支流库湾
水体富营养
营养源解析
调控对策
Three Gorges Reservoir
tributary bay
eutrophication
nutrient source analysis
control strategy
