scholarly journals Primary production and phosphorus modelling in LakeVegoritis, Greece

2014 ◽  
Vol 5 (1) ◽  
pp. 18
Author(s):  
Soultana K. Gianniou ◽  
Vassilis Z. Antonopoulos
Keyword(s):  
Water Quality ◽  
Primary Production ◽  
Model Simulation ◽  
Soluble Reactive Phosphorus ◽  
Quality Model ◽  
Lake Water Quality ◽  
Phytoplankton Primary Production ◽  
Reactive Phosphorus ◽  
Phosphorus Modelling

Primary production and phosphorus are two of the most important determinants of the water quality of lakes. Phytoplankton primary production and phosphorus cycling were modelled within a one-dimensional lake water quality model. The model was calibrated and applied to Lake Vegoritis in Greece for two different years (1981 and 1993) using daily meteorological variables and inflow rates as input data. Monthly profiles of temperature, chlorophyll-a, and oxygen concentration for these two years were used to calibrate the model. Simulation results indicate that the thermal regime of the lake strongly affects phosphorus profiles and that phytoplankton concentrations throughout the year are tightly correlated with soluble reactive phosphorus concentrations. The significant decrease in the depth and the volume of the lake from 1981 to 1993 resulted in important changes in phytoplankton and phosphorus concentrations. A sensitivity analysis was conducted to estimate the errors resulting from the uncertainty in the biochemical variables of the model and the limited data on phosphorus and phytoplankton.

scholarly journals Impacts of drying and reflooding on water quality of a tropical semi-arid reservoir during an extended drought event

2019 ◽  
Vol 31 ◽  
Author(s):  
Jéssica Nayara de Carvalho Leite ◽  
Vanessa Becker
Keyword(s):  
Water Quality ◽  
Electrical Conductivity ◽  
Chlorophyll A ◽  
Total Phosphorus ◽  
Algal Biomass ◽  
Soluble Reactive Phosphorus ◽  
Drought Event ◽  
Reactive Phosphorus ◽  
Semi Arid

Abstract Aim The aim of this study was to analyze the water quality of a tropical, semi-arid reservoir after a reflooding. In terms of impact on water quality after a drought event, it is expected that there will be improvements with the reflooding. Less algal biomass, increased water transparency, decreased turbidity and low nutrient concentration. Methods This study was performed in a tropical, semi-arid man-made lake (Dourado Reservoir), during an extended drought period. This study consisted of a comparison of three distinct periods determined by water accumulation. The limnological variables, including water transparency, turbidity, electrical conductivity, pH, total phosphorus, soluble reactive phosphorus, and chlorophyll-a were analyzed. A principal component analysis (PCA) was also performed to verify the patterns of the variables in relation to the sample units in the studied periods. Results After water renewal, there was an expressive reduction in chlorophyll-a. Electrical conductivity, pH, and turbidity variables also reduced after the reflooding, indicating an improvement in water quality. There was no reduction in total phosphorus and soluble reactive phosphorus after the reflooding compared to the previous periods. Conclusions The significant reduction in algal biomass after reflooding in Dourado indicates water quality improvement in terms of eutrophication due to the change of the trophic state from eutrophic to mesotrophic.

scholarly journals Water quality analysis and model simulation for the second largest polluted lake in Egypt

2018 ◽  
Vol 7 (3) ◽  
pp. 1762
Author(s):  
Diaa SeifSeif ◽  
Mahmoud Nasr ◽  
Mohamed R. Soliman ◽  
Medhat Moustafa ◽  
Walid Elbarki
Keyword(s):  
Water Quality ◽  
Model Simulation ◽  
Principal Component ◽  
Fish Growth ◽  
Quality Analysis ◽  
Lake Water Quality ◽  
Aquatic Life ◽  
North East ◽  
Burullus Lake

This study investigated the spatial variation in the water quality parameters of Burullus Lake using multivariate analysis and MIKE21 model. The lake was classified into zone-1 at north-east (Z1), zone-2 at south-east (Z2), zone-3 at north-middle (Z3), zone-4 at south-middle (Z4), zone-5 at north-west (Z5), zone-6 at south-west (Z6), and zone-7 at west (Z7). The obtained parameters were temperature 21.5±5.0 ºC, pH 8.2±0.6, dissolved oxygen (DO) 5.9±1.0 mg/L, biological oxygen demand (BOD) 23.9±5.7 mg/L, NH3-N 2.5±0.3 mg/L, NO2-N 1.9±0.3 mg/L, NO3-N 1.2±0.3 mg/L, PO4-P 1.9±0.3 mg/L, SiO4 3.2±0.1 mg/L, Chlorophyll-a (Chl-a) 88.2±10.8 µg/L, and salinity 3.2±1.0 g/L. Principal component analysis showed that agricultural drainage water was the key factor influencing the water quality characteristics of Burullus Lake. Water quality index (WQI) varied between “Bad” to “Medium”, suggesting that the lake wasn’t suitable for irrigation and fish growth; however, it was appropriate for some aquatic life. A MIKE21 model was developed to provide a recommendation scenario that could be used to enhance the water quality of Burullus Lake. By improving the water quality of precise drains (namely drains 7 and 8), the WQI at Z4 and Z6 modified from “Bad” to “Medium”. The period required to achieve this self-purification was 5 months.  

scholarly journals Citizen Science Tools Reveal Changes in Estuarine Water Quality Following Demolition of Buildings

2021 ◽  
Vol 13 (9) ◽  
pp. 1683
Author(s):  
Nandini Menon ◽  
Grinson George ◽  
Rajamohananpillai Ranith ◽  
Velakandy Sajin ◽  
Shreya Murali ◽  
...  
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Citizen Science ◽  
Secchi Depth ◽  
Lake Water Quality ◽  
Demolition Waste ◽  
Water Colour ◽  
Water Quality Variables ◽  
The Impact

Turbidity and water colour are two easily measurable properties used to monitor pollution. Here, we highlight the utility of a low-cost device—3D printed, hand-held Mini Secchi disk (3DMSD) with Forel-Ule (FU) colour scale sticker on its outer casing—in combination with a mobile phone application (‘TurbAqua’) that was provided to laymen for assessing the water quality of a shallow lake region after demolition of four high-rise buildings on the shores of the lake. The demolition of the buildings in January 2020 on the banks of a tropical estuary—Vembanad Lake (a Ramsar site) in southern India—for violation of Indian Coastal Regulation Zone norms created public uproar, owing to the consequences of subsequent air and water pollution. Measurements of Secchi depth and water colour using the 3DMSD along with measurements of other important water quality variables such as temperature, salinity, pH, and dissolved oxygen (DO) using portable instruments were taken for a duration of five weeks after the demolition to assess the changes in water quality. Paired t-test analyses of variations in water quality variables between the second week of demolition and consecutive weeks up to the fifth week showed that there were significant increases in pH, dissolved oxygen, and Secchi depth over time, i.e., the impact of demolition waste on the Vembanad Lake water quality was found to be relatively short-lived, with water clarity, colour, and DO returning to levels typical of that period of year within 4–5 weeks. With increasing duration after demolition, there was a general decrease in the FU colour index to 17 at most stations, but it did not drop to 15 or below, i.e., towards green or blue colour indicating clearer waters, during the sampling period. There was no significant change in salinity from the second week to the fifth week after demolition, suggesting little influence of other factors (e.g., precipitation or changes in tidal currents) on the inferred impact of demolition waste. Comparison with pre-demolition conditions in the previous year (2019) showed that the relative changes in DO, Secchi depth, and pH were very high in 2020, clearly depicting the impact of demolition waste on the water quality of the lake. Match-ups of the turbidity of the water column immediately before and after the demolition using Sentinel 2 data were in good agreement with the in situ data collected. Our study highlights the power of citizen science tools in monitoring lakes and managing water resources and articulates how these activities provide support to Sustainable Development Goal (SDG) targets on Health (Goal 3), Water quality (Goal 6), and Life under the water (Goal 14).

scholarly journals Simulating Diurnal Variations of Water Temperature and Dissolved Oxygen in Shallow Minnesota Lakes

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1980
Author(s):  
Bushra Tasnim ◽  
Jalil A. Jamily ◽  
Xing Fang ◽  
Yangen Zhou ◽  
Joel S. Hayworth
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Shallow Lakes ◽  
Quality Model ◽  
Lake Water Quality ◽  
Ecological Processes ◽  
Turbulent Diffusion Coefficient ◽  
Hourly Data ◽  
Mean Square Errors

In shallow lakes, water quality is mostly affected by weather conditions and some ecological processes which vary throughout the day. To understand and model diurnal-nocturnal variations, a deterministic, one-dimensional hourly lake water quality model MINLAKE2018 was modified from daily MINLAKE2012, and applied to five shallow lakes in Minnesota to simulate water temperature and dissolved oxygen (DO) over multiple years. A maximum diurnal water temperature variation of 11.40 °C and DO variation of 5.63 mg/L were simulated. The root-mean-square errors (RMSEs) of simulated hourly surface temperatures in five lakes range from 1.19 to 1.95 °C when compared with hourly data over 4–8 years. The RMSEs of temperature and DO simulations from MINLAKE2018 decreased by 17.3% and 18.2%, respectively, and Nash-Sutcliffe efficiency increased by 10.3% and 66.7%, respectively; indicating the hourly model performs better in comparison to daily MINLAKE2012. The hourly model uses variable hourly wind speeds to determine the turbulent diffusion coefficient in the epilimnion and produces more hours of temperature and DO stratification including stratification that lasted several hours on some of the days. The hourly model includes direct solar radiation heating to the bottom sediment that decreases magnitude of heat flux from or to the sediment.

scholarly journals Natural stochasticity vs. management effort: use of year-to-year variance for disentangling significance of two mutually confounding factors affecting water quality of a Norwegian cold dimictic lake

2014 ◽  
Vol 11 (11) ◽  
pp. 12489-12518
Author(s):  
A. T. Romarheim ◽  
K. Tominaga ◽  
G. Riise ◽  
T. Andersen
Keyword(s):  
Water Quality ◽  
Lake Water ◽  
Phytoplankton Biomass ◽  
Light Attenuation ◽  
System Structure ◽  
Confounding Factors ◽  
Lake Water Quality ◽  
Management Effort ◽  
Stochastic Event

Natural stochasticity can pose challenges in managing the quality of the environment, or hinder understanding of the system structure. It is problematic because unfavourable stochastic event cancels the costly management effort and because favourable stochastic event overestimates success of the management effort. This paper presents a variance-based modelling method that can be used to quantify the extent to which the natural stochasticity can affect the target environment. We use a case study of a lake water quality assessment in a Norwegian lake of Årungen, together with a lake model MyLake, in order to present the method, and how this method could assist in answering scientific and managerial questions. Specifically, the case study's goal was to disentangle the respective significance of nutrient loading (management) and weather (the confounding natural stochasticity). Many scientifically and managerially relevant understandings have been revealed. For example, variation in runoff volume was most prevalent during autumn and winter, while variation in phosphorus inflow was most extensive from late winter to early spring. Thermal related properties in the lake were mostly determined by weather conditions, whereas loading was the most important factor for phytoplankton biomass and water transparency. Mild winters and greater inputs of suspended matter and phosphorus were followed by increased phytoplankton biomass and light attenuation. These findings suggest also that future changes in the global climate may have important implications for local water management decision-making. The present method of disentangling mutually confounding factors is not limited to lake water quality studies and therefore should provide certain utility in other application field of modelling.

Relationships of Phytoplankton Biomass with Soluble Nutrients, Primary Production, and Chlorophyll a in Lake Erie, 1970

1976 ◽  
Vol 33 (3) ◽  
pp. 601-611 ◽  
Author(s):  
M. Munawar ◽  
N. M. Burns
Keyword(s):  
Primary Production ◽  
Chlorophyll A ◽  
Phytoplankton Biomass ◽  
Lake Erie ◽  
Soluble Reactive Phosphorus ◽  
Distribution Patterns ◽  
Statistical Procedure ◽  
Annual Average ◽  
Average Distribution ◽  
Reactive Phosphorus

Comparison of the annual average distribution patterns of phytoplankton biomass, chlorophyll a, primary production, soluble reactive phosphorus, nitrate + nitrite, and ammonia concentrations revealed that these six variables had very similar distributions in Lake Erie during 1970. However, statistical analysis of the data only revealed a few consistent relationships between these variables. The phytoplankton biomass was correlated with chlorophyll a only in the summer and fall as was primary production with chlorophyll a and biomass. There was no correlation between these three variables during the spring. Also, there was no consistent relationship between biomass and soluble nutrients. The primary production and activity coefficient (mg Cassimilated per milligram phytoplankton biomass per day) were found to be unrelated to temperature. The statistical procedure of factor analysis showed that in the spring, primary production correlated with the phosphorus and nitrogen soluble nutrients only, whereas during summer, primary production correlated with biomass, chlorophyll a, the major plankton groups (Cyanophyta, Chlorophyta, Chrysomonadinae, and Diatomeae), and the phosphorus nutrients. In the fall, production was positively correlated with phytoplankton biomass and with the Chlorophyta in particular. The use of chlorophyll a and temperature as variables in the equation to estimate phytoplankton growth in Lake Erie was found to be questionable.

Impact of Further Impoundments on the Oxygen Balance and Water Quality of the Danube in Germany

1990 ◽  
Vol 22 (5) ◽  
pp. 69-78 ◽  
Author(s):  
D. Müller ◽  
V. Kirchesch
Keyword(s):  
Water Quality ◽  
Quality Parameters ◽  
Nitrifying Bacteria ◽  
Oxygen Balance ◽  
Quality Model ◽  
Model Calculations ◽  
River Bed ◽  
The Impact ◽  
The Mathematical Model

The construction of two or three impounding dams in the remaining freely flowing reach (73 km) of the Danube is under discussion. The purpose of these impoundments is to guarantee a minimum navigable depth of 3 m needed for modern cargo ships and to produce electric power. The impact of these developments is discussed on the basis of experience with similar impoundments further upstream and of the results from water quality model calculations. The mathematical model used is of the deterministic type, calculating the growth of slowly-growing organisms (nitrifying bacteria, algae and zooplanktons) according to MONOD and MICHAELIS-MENTEN. Compared with impoundments on other German rivers or the Iron Gate impoundments on the Danube, the effect of the impoundments under discussion on water quality parameters is likely to be fairly small, reflecting the slight changes in morphology which would be necessary for attaining the water depth required. Therefore, the more important effects of these developments would be the changes in the ecologic situation at the river bed and near the banks of the river.

scholarly journals Model simulation of heavy metals in river systems: Case study the Negro river basin

2019 ◽  
pp. 19-35
Author(s):  
Carlos Alberto Palacio-Tobón ◽  
Sara Cristina Vieria-Agudelo ◽  
Julio César Saldarriaga-Molina ◽  
Luis Miguel Ruíz-Jaramillo
Keyword(s):  
Heavy Metals ◽  
Water Quality ◽  
Model Simulation ◽  
Management Tool ◽  
Predictive Capability ◽  
Quality Model ◽  
River Systems ◽  
Negro River ◽  
1D Modeling

This work describes a water quality model for heavy metals simulation in river systems. The proposed strategy comprises an 1D modeling approach with an ADZ-QUASAR extension to represent the behavior of heavy metals. This methodology seeks to strengthen their predictive capability based on the integration of variables which play an important role in the adsorption and desorption of these particles. The methodology was implemented in a reach of the Negro river (eastern side of Antioquia, Colombia), using Chromium, Copper and Nickel as heavy metals, because these are the heavy metals representative of the currents in the study area. Results are showing, with some degree of uncertainty, the capacity of the methodology to predict the behavior of environmental interesting substances, which makes it an important management tool.

scholarly journals Management Transition to the Great Lakes Nearshore: Insights from Hydrodynamic Modeling

2019 ◽  
Vol 7 (5) ◽  
pp. 129 ◽  
Author(s):  
Chenfu Huang ◽  
Anika Kuczynski ◽  
Martin T. Auer ◽  
David M. O’Donnell ◽  
Pengfei Xue
Keyword(s):  
Water Quality ◽  
Great Lakes ◽  
Soluble Reactive Phosphorus ◽  
Quality Standard ◽  
Transport Processes ◽  
Greater Toronto Area ◽  
Regulatory Guidelines ◽  
Reactive Phosphorus ◽  
Biogeochemical Transformations ◽  
Footprint Area

The emerging shift in Great Lakes management from offshore to nearshore waters will require attention to complexities of coastal hydrodynamics and biogeochemical transformations. Emphasizing hydrodynamics, this work resolves transport processes in quantifying discharge plume and pollutant of concern (POC) footprint dimensions, the latter being the portion of the plume where water quality standards are not met. A generic approach, isolated from pollutant-specific biokinetics, provides first-approximation estimates of the footprint area. A high-resolution, linked hydrodynamic-tracer model is applied at a site in the Greater Toronto Area on Lake Ontario. Model results agree with observed meteorological and hydrodynamic conditions and satisfactorily simulate plume dimensions. Footprints are examined in the context of guidelines for regulatory mixing zone size and attendant loss of beneficial use. We demonstrate that the ratio of the water quality standard to the POC concentration at discharge is a key determinant of footprint dimensions. Footprint size for traditional pollutants (ammonia, total phosphorus) meets regulatory guidelines; however, that for soluble reactive phosphorus, a presently unattended pollutant, is ~1–2 orders of magnitude larger. This suggests that it may be necessary to upgrade treatment technologies to maintain consistency with regulatory guidelines and mitigate manifestations of the eutrophication-related soluble reactive phosphorus POC.

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