Investigating spatial variability of vertical water fluxes through the streambed in distinctive stream morphologies using temperature and head data

Wang, Liping; Jiang Weiwei,; Song, Jinxi; Dou, Xinyi; Guo, Hongtao; Xu, Shaofeng; Zhang, Guotao; Wen, Ming; Long, Yongqing; Li, Qi

Investigating spatial variability of vertical water fluxes through the streambed in distinctive stream morphologies using temperature and head data | Etude de la variabilité spatiale des flux verticaux d’eau à travers le lit d’une rivière, pour différentes morphologies de cours d’eau, en utilisant les données de température et de charge hydraulique Investigación de la variabilidad espacial de los flujos verticales de agua a través de un lecho en morfologías características de una corriente usando datos de temperatura y de carga hidráulica 基于温度和水头法测试分析不同河流地貌河床垂直渗流量空间变化特性 Investigando a variabilidade espacial dos fluxos de água verticais através do leito de rio em morfologias de correntes distintas utilizando dados de temperatura e carga hidráulica

2017

Investigating the interaction of groundwater and surface water is key to understanding the hyporheic processes. The vertical water fluxes through a streambed were determined using Darcian flux calculations and vertical sediment temperature profiles to assess the pattern and magnitude of groundwater/surface-water interaction in Beiluo River, China. Field measurements were taken in January 2015 at three different stream morphologies including a meander bend, an anabranching channel and a straight stream channel. Despite the differences of flux direction and magnitude, flux directions based on vertical temperature profiles are in good agreement with results from Darcian flux calculations at the anabranching channel, and the Kruskal-Wallis tests show no significant differences between the estimated upward fluxes based on the two methods at each site. Also, the upward fluxes based on the two methods show similar spatial distributions on the streambed, indicating (1) that higher water fluxes at the meander bend occur from the center of the channel towards the erosional bank, (2) that water fluxes at the anabranching channel are higher near the erosional bank and in the center of the channel, and (3) that in the straight channel, higher water fluxes appear from the center of the channel towards the depositional bank. It is noted that higher fluxes generally occur at certain locations with higher streambed vertical hydraulic conductivity (K ᵥ) or where a higher vertical hydraulic gradient is observed. Moreover, differences of grain size, induced by stream morphology and contrasting erosional and depositional conditions, have significant effects on streambed K ᵥ and water fluxes.

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