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

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.

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Considering the impact of intermittent discharges when modelling overflows

Water Science & Technology ◽

10.2166/wst.1998.0370 ◽

1998 ◽

Vol 38 (10) ◽

pp. 23-30

Author(s):

Sarah Jubb ◽

Philip Hulme ◽

Ian Guymer ◽

John Martin

Keyword(s):

Water Quality ◽

Dissolved Oxygen ◽

Preliminary Investigation ◽

Oxygen Demand ◽

Sediment Oxygen Demand ◽

Combined Sewer Overflows ◽

River Hydraulics ◽

Combined Sewer ◽

The Impact ◽

Curve Equation

This paper describes a preliminary investigation that identified factors important in the prediction of river water quality, especially regarding dissolved oxygen (DO) concentration. Intermittent discharges from combined sewer overflows (CSOs) within the sewerage, and overflows at water reclamation works (WRW) cause dynamic conditions with respect to both river hydraulics and water quality. The impact of such discharges has been investigated under both wet and dry weather flow conditions. Data collected from the River Maun, UK, has shown that an immediate, transient oxygen demand exists downstream of an outfall during storm conditions. The presence of a delayed oxygen demand has also been identified. With regard to modelling, initial investigations used a simplified channel and the Streeter-Phelps (1925) dissolved oxygen sag curve equation. Later, a model taking into account hydrodynamic, transport and dispersion processes was used. This suggested that processes other than water phase degradation of organic matter significantly affect the dissolved oxygen concentration downstream of the location of an intermittent discharge. It is proposed that the dynamic rate of reaeration and the sediment oxygen demand should be the focus of further investigation.

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Impact of the municipal merger on watershed management: a study of Lake Kasumigaura, Japan

Asia-Pacific Journal of Regional Science ◽

10.1007/s41685-021-00190-y ◽

2021 ◽

Author(s):

Takeshi Mizunoya ◽

Noriko Nozaki ◽

Rajeev Kumar Singh

Keyword(s):

Watershed Management ◽

Large Scale ◽

Environmental Changes ◽

Water Environment ◽

Reduction Rate ◽

Oxygen Demand ◽

Policy Implications ◽

Pollution Reduction ◽

Lake Kasumigaura ◽

The Impact

AbstractIn the early 2000s, Japan instituted the Great Heisei Consolidation, a national strategy to promote large-scale municipal mergers. This study analyzes the impact that this strategy could have on watershed management. We select the Lake Kasumigaura Basin, the second largest lake in Japan, for the case study and construct a dynamic expanded input–output model to simulate the ecological system around the Lake, the socio-environmental changes over the period, and their mutual dependency for the period 2012–2020. In the model, we regulate and control the following water pollutants: total nitrogen, total phosphorus, and chemical oxygen demand. The results show that a trade-off between economic activity and the environment can be avoided within a specific range of pollution reduction, given that the prefectural government implements optimal water environment policies, assuming that other factors constraining economic growth exist. Additionally, municipal mergers are found to significantly reduce the budget required to improve the water environment, but merger budget efficiency varies nonlinearly with the reduction rate. Furthermore, despite the increase in financial efficiency from the merger, the efficiency of installing domestic wastewater treatment systems decreases drastically beyond a certain pollution reduction level and eventually reaches a limit. Further reductions require direct regulatory instruments in addition to economic policies, along with limiting the output of each industry. Most studies on municipal mergers apply a political, administrative, or financial perspective; few evaluate the quantitative impact of municipal mergers on the environment and environmental policy implications. This study addresses these gaps.

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Impact of net pen aquaculture on lake water quality

Water Science & Technology ◽

10.2166/wst.2003.0659 ◽

2003 ◽

Vol 47 (12) ◽

pp. 293-300 ◽

Cited By ~ 5

Author(s):

J. Veenstra ◽

S. Nolen ◽

J. Carroll ◽

C. Ruiz

Keyword(s):

Water Quality ◽

Organic Carbon ◽

Dissolved Oxygen ◽

Water Temperature ◽

Ictalurus Punctatus ◽

Oxygen Demand ◽

Total Alkalinity ◽

Total Hardness ◽

Army Corps ◽

Lake Water Quality

A 3-year study was conducted by the U.S. Army Corps of Engineers assessing water quality related impacts of aquaculture of 250,000 channel catfish (Ictalurus punctatus) in floating net pens in the Rock Creek Arm of Lake Texoma, Oklahoma/Texas. Five large nylon nets suspended from a floating framework of galvanized metal anchored in open water 100 m offshore made up the net pens with fish stocking densities varying from 88 to 219 fish/m3. Water quality sampling was conducted biweekly from April to September and monthly from October to March at three locations. On all sampling dates field measurements of water temperature, pH, dissolved oxygen, and conductivity were recorded at 1 m depth intervals and water samples were collected at a depth of 0.5 m and near the bottom of the water column at each site. Sample analyses included: total alkalinity, total hardness, turbidity, chloride, sulfate, orthophosphate, total phosphorus, nitrate-N, nitrite-N, total Kjeldahl nitrogen, total organic carbon, dissolved organic carbon, biochemical oxygen demand, and chlorophyll a. The results showed statistically significant decreases in water temperature and dissolved oxygen and significant increases in field conductivity in surface waters near the net pens relative to other sampling sites. The most dramatic water quality effect observed during the study was decrease in dissolved oxygen levels near the net pens following lake turnover in the second year.

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Impact of Global Warming on Dissolved Oxygen and BOD Assimilative Capacity of the World’s Rivers: Modeling Analysis

Water ◽

10.3390/w13172408 ◽

2021 ◽

Vol 13 (17) ◽

pp. 2408

Author(s):

Steven C. Chapra ◽

Luis A. Camacho ◽

Graham B. McBride

Keyword(s):

Dissolved Oxygen ◽

Natural Waters ◽

Cold Water ◽

Oxygen Demand ◽

Oxygen Depletion ◽

Assimilative Capacity ◽

Mountainous Regions ◽

Modeling Analysis ◽

Lower Oxygen ◽

The Impact

For rivers and streams, the impact of rising water temperature on biochemical oxygen demand (BOD) assimilative capacity depends on the interplay of two independent factors: the waterbody’s dissolved oxygen (DO) saturation and its self-purification rate (i.e., the balance between BOD oxidation and reaeration). Although both processes increase with rising water temperatures, oxygen depletion due to BOD oxidation increases faster than reaeration. The net result is that rising temperatures will decrease the ability of the world’s natural waters to assimilate oxygen-demanding wastes beyond the damage due to reduced saturation alone. This effect should be worse for nitrogenous BOD than for carbonaceous BOD because of the former’s higher sensitivity to rising water temperatures. Focusing on streams and rivers, the classic Streeter–Phelps model was used to determine the magnitude of the maximum or “critical” DO deficit that can be calculated analytically as a function of the mixing-point BOD concentration, DO saturation, and the self-purification rate. The results indicate that high-velocity streams will be the most sensitive to rising temperatures. This is significant because such systems typically occur in mountainous regions where they are also subject to lower oxygen saturation due to decreased oxygen partial pressure. Further, they are dominated by salmonids and other cold-water fish that require higher oxygen levels than warm-water species. Due to their high reaeration rates, such systems typically exhibit high self-purification constants and consequently have higher assimilation capacities than slower moving lowland rivers. For slow-moving rivers, the total sustainable mixing-point concentration for CBOD is primarily dictated by saturation reductions. For faster flowing streams, the sensitivity of the total sustainable load is more equally dependent on temperature-induced reductions in both saturation and self-purification.

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Physico-chemical Parameters of Koshi River at Kushaha Area of Koshi Tappu Wildlife Reserve

Our Nature ◽

10.3126/on.v9i1.5746 ◽

1970 ◽

Vol 9 (1) ◽

pp. 156-167 ◽

Cited By ~ 1

Author(s):

D. Thapa Chhetry ◽

J. Pal

Keyword(s):

Dissolved Oxygen ◽

Water Temperature ◽

Air Temperature ◽

Oxygen Demand ◽

Summer Season ◽

Biological Oxygen Demand ◽

Total Alkalinity ◽

Total Hardness ◽

Chemical Parameters ◽

Wildlife Reserve

The Koshi river is the major tributaries of the Ganges which originates from the snowy peaks of Tibetan plateau in the central Himalayas. Its total catchment area is 60,400 km2, of which 28,140 km2 lies in Nepal, while the remainder is situated in Tibet. It passes from Nepal to India via the Koshi Tappu Wildlife Reserve area of Nepal. It destroys large area through floods, especially in India. This paper deals with the air temperature and phyco-chemical parameters like temperature, transparency, pH, oxygen, carbondioxide, alkalinity, hardness, chloride and biological oxygen demand of water of Koshi river at Kushaha area of Koshi Tappu Wildlife Reserve. The water temperature was recorded maximum in summer season but the transparency, pH, dissolved oxygen, total alkalinity and total hardness were recorded maximum in winter season. Similarly, free carbondioxide was maximum in rainy season and chloride and biological oxygen demand were recorded maximum in summer season. The air temperature and water temperature had positive and significant correlation with free carbondioxide and biological oxygen demand. Dissolved oxygen had positive and significant correlation with pH, total alkalinity and total hardness. Similarly, total alkalinity had positive and significant correlation with transparency, total hardness, chloride etc.DOI: http://dx.doi.org/10.3126/on.v9i1.5746

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How to Choose Pollution Indicators for Monitoring Landfill Leachates

Proceedings ◽

10.3390/proceedings2020051023 ◽

2020 ◽

Vol 51 (1) ◽

pp. 23

Author(s):

Aleksandra Wdowczyk ◽

Agata Szymańska-Pulikowska

Keyword(s):

Negative Impact ◽

Statistical Tests ◽

Water Environment ◽

Oxygen Demand ◽

Principal Component ◽

Ammonium Nitrogen ◽

Landfill Leachates ◽

Limit Of Quantification ◽

Pollution Indicators ◽

The Impact

Leachates are one of the main factors polluting the ground and water environment in the vicinity of landfills. This is connected with the need to systematically control the elements of the environment that are exposed to the negative impact of landfill emissions. In Poland, the scope of landfill leachate quality monitoring includes 10 obligatory parameters (pollution indicators). The paper presents an example of the application of selected statistical methods (basic statistics, statistical tests, principal component analysis) to assess the impact of individual pollution indicators on the quality of landfill leachates. Four landfills from the area of Lower Silesia were selected for analyzes, for which in the years 2018–2019 tests of leachate properties were conducted in an extended scope (in relation to the scope applicable during monitoring). Analyses of the obtained results showed significant differences between landfills, depending mainly on their age and method of operation. Specific factors for assessing differences between landfills were as follows: electrolytic conductivity, chemical oxygen demand (COD(Cr)), organic nitrogen, ammonium nitrogen, chlorides and calcium. The values of some of the parameters included in the monitoring studies did not show variability, remaining below the limit of quantification. The conducted analyses permit the determination of the level of leachate contamination from selected landfills and the proposal of indicators that could complement the monitoring range of landfills for many years.

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Quantifying the impact of human activities on water quality based on spatialization of social data: a case study of the Pingzhai Reservoir Basin

Water Science & Technology Water Supply ◽

10.2166/ws.2020.001 ◽

2020 ◽

Vol 20 (2) ◽

pp. 688-699 ◽

Cited By ~ 2

Author(s):

Yongrong Zhang ◽

Zhongfa Zhou ◽

Haotian Zhang ◽

Yusheng Dan

Keyword(s):

Water Quality ◽

River Basin ◽

Human Activities ◽

Water Environment ◽

Oxygen Demand ◽

Pollution Source ◽

Pollution Load ◽

Social Data ◽

Reservoir Basin ◽

The Impact

Abstract In water pollution source research, it is difficult to quantify the impact of human activities on water quality. Based on pollution load theory and the concept of spatialization of social data, this study integrates land-use type, slope gradient, and spatial position, and uses the contribution of human activities to quantify the impact of farmland fertilizers, livestock and poultry wastes, and human domestic pollution on water quality in the study area. The results show that livestock manure is the largest source of total phosphorus (TP) and total nitrogen (TN) discharges in the research area, and domestic pollution is the largest source of chemical oxygen demand (COD) discharges. The total equal standard pollution load (as well as the load of each pollution source and its pollutant amount) is the highest in the Nayong River Basin and the lowest in the Baishui River Basin. The contributions of human activities to TP and TN have similar spatial distributions. The impact of human activities on COD discharge is minimal. The quantitative results of this model are basically consistent with the actual conditions in the Pingzhai Reservoir Basin, which suggests that the model reasonably reflects the impact of human activities on the water environment of the basin.

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Impact of dissolved oxygen concentration on membrane filtering resistance and soluble organic matter characteristics in membrane bioreactors

Water Science & Technology ◽

10.2166/wst.2008.659 ◽

2008 ◽

Vol 57 (2) ◽

pp. 161-165 ◽

Cited By ~ 5

Author(s):

Kyung-Nan Min ◽

Sarina J. Ergas ◽

Anna Mermelstein

Keyword(s):

Molecular Weight ◽

Organic Matter ◽

Dissolved Oxygen ◽

Weight Fraction ◽

Total Resistance ◽

Soluble Organic Matter ◽

Aerobic Conditions ◽

Do Concentration ◽

The Impact ◽

Molecular Weight Fractions

This study investigated the impact of dissolved oxygen (DO) concentration on membrane filtering resistance, soluble organic matter (SOM) and extracellular polymeric substance (EPS) characteristics in a membrane bioreactor (MBR). A laboratory-scale MBR was operated under DO limited (0.2 mg L−1 DO) and fully aerobic (3.7 and 5.4 mg L−1 DO) conditions. Membrane filtering resistance was determined for the mixed liquor suspended solids (MLSS) and for resuspended microbial biomass after removing SOM. Regardless of the DO concentration, the cake resistance (Rc) was approximately 95 percent of the total resistance (Rt). The membrane cake resistance was found to decrease significantly after removing the SOM. The total resistance caused by the resuspended biomass was 29 percent of that caused by the MLSS under DO limited conditions, while the total resistance caused by resuspended biomass was 41 to 48 percent of that caused by the MLSS under fully aerobic conditions. Under DO limited conditions, SOM in the MLSS contained a larger amount of high molecular weight compounds, leading to higher cake resistance than under fully aerobic conditions. There was significant variation in the molecular weight fractions of the EPS, with no clear relationship with DO concentration. There was also no distinct relationship between membrane filtering resistance and molecular weight fraction of the EPS.

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Impact of hypolimnetic oxygenation on profundal macroinvertebrates in a eutrophic lake in central Alberta. I. Changes in macroinvertebrate abundance and diversity

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f97-122 ◽

1997 ◽

Vol 54 (9) ◽

pp. 2157-2169 ◽

Cited By ~ 9

Author(s):

W P Dinsmore ◽

E E Prepas

Keyword(s):

Dissolved Oxygen ◽

Water Temperature ◽

Eutrophic Lake ◽

Water Bodies ◽

Macroinvertebrate Communities ◽

South Basin ◽

The North ◽

Hypolimnetic Oxygenation ◽

Abundance And Diversity ◽

The Impact

Hypolimnetic oxygenation from 1988 to 1991 in the north basin of Amisk Lake increased mean summer (June-August) dissolved oxygen (DO) concentrations in the deep hypolimnion (25 m) from <0.4 mg ·L-1 during pretreatment years (1980-1987) to 2.7 mg ·L-1 during treatment. Mean summer hypolimnetic temperatures at 25 m also increased from 6.3 (pretreatment) to 8.1°C (treatment). Profundal (15-25 m) Chironomus spp. abundance in the treated basin increased from <100 to >2000 ·m-2 from 1988 to 1991 whereas Chaoborus spp., Tubificidae, and other taxa remained uncommon at similar depths. Shannon-Weaver indices of diversity decreased as oxygenation progressed, in contrast with previous studies. Similar patterns in densities and diversity were observed in the south basin of Amisk Lake, although the increase in DO concentrations was smaller relative to the north basin. The impact of increased water temperature on macroinvertebrates appeared minor relative to the effects of increased DO concentrations. No changes in macroinvertebrate communities were noted in a nearby reference lake during the study period. Responses to hypolimnetic oxygenation in Amisk Lake differed markedly from those reported for smaller, single-basined water bodies.

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Analysis of Leachate and Water Resource Quality Surrounding Municipal Solid Waste Landfill of Tamellast (Agadir, Morocco)

E3S Web of Conferences ◽

10.1051/e3sconf/202124002006 ◽

2021 ◽

Vol 240 ◽

pp. 02006

Author(s):

Saadia Asouam ◽

Farid Faik ◽

Zine El Abidine El Morjani

Keyword(s):

Electrical Conductivity ◽

Dissolved Oxygen ◽

Physicochemical Characterization ◽

Oxygen Demand ◽

Resource Quality ◽

Sodium Potassium ◽

Physico Chemical ◽

Dug Wells ◽

The Impact ◽

Surface And Groundwater

The aim of this work was to study the physicochemical characterization and heavy metal testing results carried out for leachate generated by the landfilling of household and similar waste in the Tamellast landfill of Agadir. The surface and groundwater resource (often used as drinking source) samples collected from Tamellast and different water sources wells surrounding the landfill were used to find out the impact of leachate percolation on surface and groundwater quality. The Physico-chemical parameters analyzed were, pH, Electrical Conductivity (EC), Dissolved oxygen, Sodium, Potassium, while biological parameters tested were Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), E.Coli and Coliform tot. The contamination was investigated by measuring the concentration of heavy metals (Pb, Zn, Cr, Ni, As, and Fe). The Electrical Conductivity (EC), COD, BOD, Sodium, Potassium, in leachate were found to be 13180 µs/cm, 3150 mgO2/l, 1000 mgO2/l, 2000 mg/L, and 10700 mg/L, respectively. The concentration in the surrounding dug wells varied from 8.33 – 9.13 mg/L for Dissolved Oxygen, 9.8 – 18 mg/L for potassium, 0.22 – 0.6 mg/L for Fe, and 0.012 – 0.1 mg/L for total Mn. The concentration of Mn, Fe, and other parameters decreased with increasing distance between the landfill and wells.

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