Modeling Spatial Patterns of Dissolved Oxygen and the Impact Mechanisms in a Cascade River

Abstract

Dissolved oxygen (DO) concentration is an essential indicator for assessment of river ecosystems. A hydrodynamic and water quality mathematical model coupling one-dimensional and two-dimensional models is developed in this study. The characteristics of study area, flow velocity, temperature, and organic contamination are taken as consideration in the scenario setting. The changing processes of DO concentration are simulated in different scenarios, and the effects on DO concentration are discussed. Results indicate that: 1) A negative relation was present between DO concentration in Yongjiang River and releasing discharge of the Laokou hydro-project, since reoxygenation is greater than oxygen consumption along the river, DO concentration increases from upstream to downstream. 2) DO concentration increases with the releasing of DO in the water, which also varies along with the releasing of biochemical oxygen demand (BOD) concentration. Laokou exhibits the greatest increase of BOD, which ranges from 0.1 mg/L to 0.75 mg/L 3) The increasing of water temperature results in increased reoxygenation and a decrease in oxygen consumption. Our study shows that the water temperature increased from 19°C to 29 °C, and correspondingly saturated DO decreased from 9.25 mg/L to 7.54 mg/L. The study provides scientific support for ecology operation in the cascade river, and is expected to improve the water environment by reservoir regulation.

Seasonal and Tidal variations of DO, BOD, and Nutrients in Major Rivers within Eastern Niger Delta, Nigeria

“…The range of DO obtained in this study is consistent with 3.07 -6.53 mg/L reported in Bomadi Creek, Niger Delta Area of Nigeria by Iwegbue et al [55]. The reported DO range for the studied rivers is however; lower than 7.54 -9.25 mg/L obtained in Cascade River in Nanning City, China by Zhong et al [56]. The mean value of DO recorded (3.40±1.15 mg/L) is below the 4.0 mg/L standard by NESREA, [57].…”

Water quality assessment of Kuwano River, Basti (U.P.) India, with reference to statistical analysis

“…The correlation study showed that TDS, EC, and TH are strongly correlated with each other and are likely influenced by the presence of minerals in the water. The significance of dissolved oxygen (DO) is not only from the perspective of addressing water quality issues (Agnieszka et al, 2014) but also for comprehending the mechanisms and causes that influence its dynamics in water bodies (Hondzo et al, 2013;Zhong et al, 2021). Reduced dissolved oxygen (DO) in rivers has a negative effect on physiological functions, leading to a decline in benthic fauna (Bu et al, 2021).…”

Impacts of Climate Change on Water Quality using GIS Technique in Water Courses at Egyptian Delta Governorates

“…concentration in the river. Thus, with the increasing water temperature, the saturated dissolved oxygen decreases, and the re-oxygenation effect in the river decreases accordingly (Zhong et al, 2021).…”