梯级水电开发下黄河上游龙-刘河段DOC时空分布特征及通量研究

Temporal and spatial distribution characteristics and fluxes of dissolved organic carbon in the upper Yellow River(Longyangxia-Liujiaxia)under cascade hydropower development

针对梯级水电开发影响下河流生源物质循环的科学问题,选取黄河上游梯级开发河段(龙羊峡-刘家峡段,共5个水库)为研究区域,以溶解性有机碳(DOC)为主要研究对象,采用采样监测方法分析DOC以及理化指标的时空分布特征,并且基于静态箱式算法模型估算各水库DOC的输移通量。结果表明:DOC及常规理化指标存在明显的时空异质性,DOC浓度呈现汛期(5.37~7.00 mg/L)高于非汛期(2.90~5.56 mg/L)的特征,汛期由于水库出现垂向水温分层现象,DOC在沿水深垂直方向上呈波动变化。在采样年里,龙羊峡-刘家峡段DOC的年输入通量为258.53 kt,年输出通量为192.23 kt,拦截率为25.6%,具有拦截效应的水库为龙羊峡、公伯峡和刘家峡,其余水库为输送效应。

Aiming at the problem of riparian biogenic material cycles brought upon by cascade hydropower development,the cascade hydropower development section of the upper Yellow River(Longyangxia-Liujiaxia section,a total of five reservoirs)was selected as the research area,and dissolved organic carbon(DOC)as the main research object.The distribution characteristics of DOC and physicochemical indicators were analyzed by sampling monitoring method,then the DOC transport flux in each reservoir was estimated based on the static box algorithm model.The results showed that DOC and conventional physicochemical indicators presented obvious spatiotemporal heterogeneity,and the concentration of DOC in the flood season(5.37-7.00 mg/L)was higher than that in the non-flood season(2.90-5.56 mg/L).Moreover,due to the vertical water temperature stratification of the reservoir,the DOC showed the characteristics of fluctuated change along the vertical direction of the water depth in the flood season.During the sampling year,the total input of DOC in the Long-Liu section was 258.53 kt,the total output was 192.23 kt,and the interception rate was 25.6%.The reservoirs which played the role of interception were Longyangxia,Gongboxia and Liujiaxia,and the rest were all transporters.