Experiment and simulation of supersaturated total dissolved gas dissipation: Focus on the effect of confluence types

Shen, Xia; Li, Ran; Hodges, Ben R.; Feng, Jingjie; Cai, Huanjie; Ma, Xiaoyi

doi:10.1016/j.watres.2019.02.056

Cited by 33 publications

(36 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As Corbicula fluminea is a species with moderate resistance excessive nutrients make them difficult to survive (Burket et al, 2019;Siuda et al, 2020). In a normal range, the habitat suitability of Corbicula fluminea was well correlated to DO with a positive response (Riding et al, 2019), but supersaturated DO could also inhibit the spontaneous breathing process of aquatic organisms, leading to its death (Shen et al, 2019). This study showed that when DO was .13 mg L À1 , the habitat suitability of Corbicula fluminea was reduced to 0.…”

Section: Habitat Suitability Of Macroinvertebratesmentioning

confidence: 74%

Assessment of medium and small river health based on macroinvertebrates habitat suitability curves: a case study in a tributary of Yangtze River, China

Liu

et al. 2020

Water Policy

View full text Add to dashboard Cite

The health of medium and small river ecosystems is threatened by increasing hydropower development and human activities. How to properly diagnose rivers has become a global concern. As a well-accepted theory, the aquatic organism density can be an indicator of river health. A new river health assessment method based on macroinvertebrates habitat suitability curves (M-HSC) was proposed. In this study, the health of Qiaobian River (QBR), a tributary of Yangtze River, China was evaluated by investigating the distribution of macroinvertebrates, chemical and physical parameters during winter 2018 (low flow season) and summer 2019 (high flow season). Based on habitat suitability of dominant macroinvertebrates, the key habitat factors were screened by canonical correspondence analysis (CCA) and Pearson correlation analysis. Suitability curves were determined by Generalized Additive Model (GAM). Ecosystem health comprehensive index method was used to evaluate the health status. The results show most suitable conditions for Corbicula fluminea containing chemical oxygen demand (CODMn) of 1.48 mg L−1, total nitrogen (TN) of 0.27 mg L−1, dissolved oxygen (DO) of 11.17 mg L−1, pH of 8.42, turbidity of 1.76 NTU, and water depth (Dep) of 0.35 m. The health status of QBR is spatially heterogeneous with the apparently better upstream than the downstream. In general, 25, 12.5, 12.5% of the samples were classified as nature, health and sub-health status, respectively and the rest 50% were lower than sub-health. The results are consistent with the environmental quality standards for surface water in China (GB3838-2002), suggesting the applicability of macroinvertebrates habitat suitability for evaluating river health. By minimizing the temporal and spatial limitations of comprehensive evaluation method and indicator species method, this study, for the first time, used macroinvertebrates habitat suitability curves to assess the health of medium and small rivers. The study will provide new insights for future river health assessments.

show abstract

Section: Habitat Suitability Of Macroinvertebratesmentioning

confidence: 74%

Assessment of medium and small river health based on macroinvertebrates habitat suitability curves: a case study in a tributary of Yangtze River, China

Liu

et al. 2020

Water Policy

View full text Add to dashboard Cite

show abstract

“…Six distinct hydrodynamic regions were observed by Best (1987) and applied by Zhang et al (2015) to describe a confluence: a stagnation zone, a separation zone, several shear layers with associated vortex generation, flow deflection zone, an area of maximum velocity zone, and a flow recovery zone downstream from the flow-separation zone. The separation zone with low pressure, low mean velocity, and high turbulent energy is located near the tributary side of the main channel, which is captured in the model of Shen et al (2019). This area could be an LTS region suitable for fish shelter through two possible mechanisms: (a) the mixing region of main-stem and tributary water might be dominated by the low-TDGS tributary water, and/or (b) turbulence and lower pressure could enhance TDGS dissipation through increased bubble formation in the water.…”

Section: Confluence Hydrodynamicsmentioning

confidence: 99%

“…where  t is the Schmidt number, taken as 1.0 based on Gualtieri (2006) and Gualtieri et al (2017). C (mg/L) is the concentration of TDG, and T k (/s) is the dissipation coefficient of TDGS at confluences which can be found in Shen et al (2019). H (m) is the water depth.…”

Section: Transport Equationsmentioning

confidence: 99%

“…The numerical simulations, regression modeling, and field validation in this paper are organized as follows: Section 2 provides background on TDGS impacts on fish and research in confluence hydrodynamics to set the stage for the present work; Section 3 provides a brief synopsis of the 3D numerical simulation model, which in presented in more detail in Shen et al. (2019), and provides an overview of the statistical regression model and field study used for real‐world scale model validation; Section 4 provides an integrated presentation of results and discussion of the numerical simulations at laboratory scale and a comparison of real‐world simulations with field observations and results of the regression model for two river confluences. A summary of the findings is presented in Section 5.…”

Section: Introductionmentioning

confidence: 99%

“…The work is motivated by field observations of two river confluences (Minjiang and Shao nvping tributaries with Jinshajiang River in China) that show lower TDGS along one side of the river downstream of the confluence; that is, an LTS refuge area. We use the 3D validated laboratory model of Shen et al (2019) whose geometry is perturbed in a controlled way to identify and analyze how the junction angle and flow ratio of the main-stem and tributary at a confluence affect the LTS area. This laboratory work is an interim step toward understanding and predicting the dissipation of TDGS and the resulting LTS areas at real-world scale (full scale) river confluences.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Factors Influencing Distribution Characteristics of Total Dissolved Gas Supersaturation at Confluences

Shen

Hodges

et al. 2021

Water Resources Research

Self Cite

View full text Add to dashboard Cite

Total dissolved gas supersaturation (TDGS) produced by flood flows over a high dam has negative consequences on downstream fish. Reducing the total dissolved gas (TDG) levels and/or providing adequate low‐TDGS fish shelter areas remains a challenge. The presence of a low‐TDG‐saturation (LTS) zone at river confluences can protect the fish from harmful high TDG levels, but the effects of confluence hydrodynamics on the TDGS distribution are not well understood. In this study, three‐dimensional (3D) hydrodynamic simulations are performed to understand the influence of flow ratio and junction angle on the TDGS distribution downstream of river confluences. The simulation results show that the TDGS distribution is mainly affected by (a) inflow TDGS that determines the supply, (b) secondary flow that leads to rapid renewal of surface water for degassing, and (c) increased turbulence intensity that promotes dissipation of TDGS. Relationship between the LTS area, the flow ratio and the junction angle is constructed via regression analysis. The regression model is validated against a 3D numerical simulation that is compared to field observations at two river confluences along the Jinshajiang River (China). This study provides scientific basis for potential hydraulic modifications at confluences to enlarge an LTS zone and reduce fish fatality.

show abstract

Evolving Connectionist Systems Versus Neuro-Fuzzy System for Estimating Total Dissolved Gas at Forebay and Tailwater of Dams Reservoirs

Heddam

Kişi

2020

Springer Transactions in Civil and Environmental Engineering

View full text Add to dashboard Cite

Experiment and simulation of supersaturated total dissolved gas dissipation: Focus on the effect of confluence types

Cited by 33 publications

References 35 publications

Assessment of medium and small river health based on macroinvertebrates habitat suitability curves: a case study in a tributary of Yangtze River, China

Assessment of medium and small river health based on macroinvertebrates habitat suitability curves: a case study in a tributary of Yangtze River, China

Factors Influencing Distribution Characteristics of Total Dissolved Gas Supersaturation at Confluences

Evolving Connectionist Systems Versus Neuro-Fuzzy System for Estimating Total Dissolved Gas at Forebay and Tailwater of Dams Reservoirs

Contact Info

Product

Resources

About