Статті в журналах: "Water quality state estimation"

1

Munavalli, G. R., and M. S. Mohan Kumar. "Water Quality Parameter Estimation in Steady-State Distribution System." Journal of Water Resources Planning and Management 129, no. 2 (March 2003): 124–34. http://dx.doi.org/10.1061/(asce)0733-9496(2003)129:2(124).

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Xu, Daxing, Hailun Wang, and Lu Zhang. "A new water quality state estimation method with an unknown state model." DESALINATION AND WATER TREATMENT 217 (2021): 174–80. http://dx.doi.org/10.5004/dwt.2021.26755.

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Łangowski, Rafał, and Mietek Brdys. "Monitoring of Chlorine Concentration in Drinking Water Distribution Systems Using an Interval Estimator." International Journal of Applied Mathematics and Computer Science 17, no. 2 (June 1, 2007): 199–216. http://dx.doi.org/10.2478/v10006-007-0019-y.

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Monitoring of Chlorine Concentration in Drinking Water Distribution Systems Using an Interval EstimatorThis paper describes the design of an interval observer for the estimation of unmeasured quality state variables in drinking water distribution systems. The estimator utilizes a set bounded model of uncertainty to produce robust interval bounds on the estimated state variables of the water quality. The bounds are generated by solving two differential equations. Hence the numerical efficiency is sufficient for on-line monitoring of the water quality. The observer is applied to an exemplary water network and its performance is validated by simulations.

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4

Choi, Hyoung-Sub, In-Cheol Cho, Jong-Hwan Byun, Byung-Hyun Moon, and Jong-Soo Heo. "Estimation of Water Quality and Trophic State in the Hapcheon Lake." Korean Journal of Environmental Agriculture 22, no. 1 (March 31, 2003): 1–6. http://dx.doi.org/10.5338/kjea.2003.22.1.001.

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Munavalli, G. R., and M. S. Mohan Kumar. "Water quality parameter estimation in a distribution system under dynamic state." Water Research 39, no. 18 (November 2005): 4287–98. http://dx.doi.org/10.1016/j.watres.2005.07.043.

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Rauch, W., M. Henze, L. Koncsos, P. Reichert, P. Shanahan, L. Somlyódy, and P. Vanrolleghem. "River water quality modelling: I. State of the art." Water Science and Technology 38, no. 11 (December 1, 1998): 237–44. http://dx.doi.org/10.2166/wst.1998.0473.

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River water quality models are used extensively in research as well as in the design and assessment of water quality management measures. The application of mathematical models for that purpose dates back to the initial studies of oxygen depletion due to organic waste pollution. Since then, models have been constantly refined and updated to meet new and emerging problems of surface water pollution, such as eutrophication, acute and chronic toxicity, etc. In order to handle the complex interactions caused by the increased influence of human activities in rivers it is today mandatory to couple river water quality models with models describing emissions from the drainage and sewerage system (such as the IAWQ Activated Sludge model No. 1). In this paper-which is the first of a three-part series by the IAWQ Task Group on River Water Quality Modelling-the state of the art is summarized with the above aim in mind. Special attention is given here to the modelling of conversion processes but also the methods and tools to work with the models, i.e. parameter estimation, measurement campaign design, and simulation software, are discussed.

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7

Łangowski, Rafał, and Mietek A. Brdys. "An Interval Estimator for Chlorine Monitoring in Drinking Water Distribution Systems Under Uncertain System Dynamics, Inputs and Chlorine Concentration Measurement Errors." International Journal of Applied Mathematics and Computer Science 27, no. 2 (June 27, 2017): 309–22. http://dx.doi.org/10.1515/amcs-2017-0022.

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AbstractThe design of an interval observer for estimation of unmeasured state variables with application to drinking water distribution systems is described. In particular, the design process of such an observer is considered for estimation of the water quality described by the concentration of free chlorine. The interval observer is derived to produce the robust interval bounds on the estimated water quality state variables. The stability and robustness of the interval observer are investigated under uncertainty in system dynamics, inputs, initial conditions and measurement errors. The bounds on the estimated variables are generated by solving two systems of first-order ordinary differential equations. For that reason, despite a large scale of the systems, the numerical efficiency is sufficient for the on-line monitoring of the water quality. Finally, in order to validate the performance of the observer, it is applied to the model of a real water distribution network.

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8

Shakhman, I. A., and N. S. Loboda. "Water quality estimation at the gauge station of the Ingulets River, town of Snigurivka, by hydrochemical parameters." Ukrainian hydrometeorological journal, no. 17 (October 29, 2017): 123–36. http://dx.doi.org/10.31481/uhmj.17.2016.14.

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The article contains the results of water quality estimation by hydrochemical parameters at the gauge station of the Ingulets River, town of Snigurivka, during the observation period of 2001-2014 based on modern calculation methods. The analysis of anthropogenic factors affecting change of quality of surface water of the Ingulets River was used. It was found that by hydrochemical parameters waters are mostly "contaminated", "very contaminated", or "catastrophically contaminated". River flow appears to be the main source of water supply for the population and the economy. There is an acute deficit of water in the South of Ukraine. Because of use of rivers for economic activity of Mykolaiv region estimation of the ecological state of the Ingulets River should be carried out. Starting from 2010 a tendency of quality improvement via reducing of petroleum products concentration was discovered. Dynamics of changes pollutants’ concentration shows a decrease of petroleum products’ concentration but over the last years the chemical composition of water in the river has not significantly improved, ability of the river to cleanse and restore itself does not re-turn. The ecological state of the river is characterized as an ecological regress. There is a necessity of further research using modern methods of complex estimation of surface waters sources’ quality.

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Hohls, D., G. du Plessis, S. N. Venter, M. C. Steynberg, C. M. E. De Wet, N. Rodda, and R. Kfir. "Estimation of the fate of microbial water quality contaminants in a South African river." Water Science and Technology 31, no. 5-6 (March 1, 1995): 271–74. http://dx.doi.org/10.2166/wst.1995.0623.

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The aim of this study was to evaluate the validity of assumptions, regarding assimilative capacity for microbial contaminants, implicit in microbial water quality management in South Africa. A one dimensional steady state stream water quality model, assuming first order decay of microbial water quality variables, was employed in an attempt to describe and predict microbial water quality in the chosen catchment. Based on the faecal coliform counts the results indicated that the processes of decay and dilution were inadequate to yield water quality which complied with South African and international guidelines for the domestic and recreational use of water. It was also found that a first order decay model can, with fairly limited data, allow a manager to investigate different microbial water quality scenarios in a cost-effective manner.

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Rajakumar, Anjana G., M. S. Mohan Kumar, Bharadwaj Amrutur, and Zoran Kapelan. "Real-Time Water Quality Modeling with Ensemble Kalman Filter for State and Parameter Estimation in Water Distribution Networks." Journal of Water Resources Planning and Management 145, no. 11 (November 2019): 04019049. http://dx.doi.org/10.1061/(asce)wr.1943-5452.0001118.

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Giovanelli, Luan B., Rubens A. Oliveira, Jair C. Oliveira-Filho, Júlio C. M. Baptestini, Fábio T. Delazari, and Gilberto C. Sediyama. "Reference evapotranspiration estimation by the Irrigameter in Southern Tocantins State, Brazil." Revista Brasileira de Engenharia Agrícola e Ambiental 21, no. 5 (May 2017): 293–97. http://dx.doi.org/10.1590/1807-1929/agriambi.v21n5p293-297.

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ABSTRACT The choice for the most appropriate method to estimate evapotranspiration depends on the availability of meteorological data, required level of precision and cost of equipment acquisition. For this estimate, the Irrigameter is simple to operate, precise and economically viable to farmers. In addition, it collaborates in the application of the necessary water depth to crops, thus avoiding unnecessary energy consumption, environmental degradation, and increasing crop yield and improving crop quality. In this context, the objective of this research was to estimate the reference evapotranspiration using the Irrigameter, for the climatic conditions of the Southern Tocantins state, Brazil. The experimental design was completely randomized with Irrigameters operating with seven water heights in the evaporator, as treatments, with three replicates. The reference evapotranspiration was obtained by FAO-56 Penman-Monteith method. For the analyzed climatic conditions, the water height in the evaporator recommended to estimate the reference evaporation in the spring is 3.4 cm; summer, 4.0 cm; fall, 3.8 cm; and winter, 2.3 cm.

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Díaz, Sarai, Roberto Mínguez, and Javier González. "Probabilistic leak detectability assessment via state estimation in water transport networks." Stochastic Environmental Research and Risk Assessment 32, no. 7 (January 22, 2018): 2111–28. http://dx.doi.org/10.1007/s00477-018-1515-3.

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Vieira, J. M. P., J. L. S. Pinho, N. Dias, D. Schwanenberg, and H. F. P. van den Boogaard. "Parameter estimation for eutrophication models in reservoirs." Water Science and Technology 68, no. 2 (July 1, 2013): 319–27. http://dx.doi.org/10.2166/wst.2013.248.

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Excessive eutrophication is a major water quality issue in lakes and reservoirs worldwide. This complex biological process can lead to serious water quality problems. Although it can be adequately addressed by applying sophisticated mathematical models, the application of these tools in a reservoir management context requires significant amounts of data and large computation times. This work presents a simple primary production model and a calibration procedure that can efficiently be used in operational reservoir management frameworks. It considers four state variables: herbivorous zooplankton, algae (measured as chlorophyll-a pigment), phosphorous and nitrogen. The model was applied to a set of Portuguese reservoirs. We apply the model to 23 Portuguese reservoirs in two different calibration settings. This research work presents the results of the estimation of model parameters.

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14

Gopchak, І. V., and T. O. Basiuk. "ESTIMATION OF ANTHROPOGENIC LOAD ON THE VESELUKHA SMALL RIVER BASIN." Міжвідомчий тематичний науковий збірник "Меліорація і водне господарство", no. 1 (July 22, 2019): 82–87. http://dx.doi.org/10.31073/mivg201901-163.

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Relevance of research. As a result of economic activities and irrational use of water and land resources in small river basins there are problems connected with pollution, destruction of natural landscape complexes of river valleys and adjoining territories, engineering reorganization of canals and floodplains as a result of melioration works. All these changes in river basins require operational control and response, which is possible only if real estimation of the level of anthropogenic load on river basins is carried out and the limits of permissible economic interference in their ecosystem are determined. The purpose of research – assessment of the ecological condition of the basin of the Veselukha River by the criteria of anthropogenic load. Research methods. The analysis of anthropogenic load and evaluation of the ecological condition of the Veselukha River basin was carried out in accordance with "Methodology for calculation of anthropogenic load and classification of the ecological state of small river basins of Ukraine". The calculation was made using the logic-mathematical model "Small River Basin", for four independent models of the main subsystems of the river basin: radioactive contamination of the territory, land use, use of river runoff, water quality. The quantitative and qualitative anthropogenic conditions by various indicators of four subsystems for classification of the ecological state of the river basin were estimated. Research results. According to the state of radioactive contamination, the area of the river catchment was estimated as "satisfactory". Based on the results of the analysis, the integrated value of land use was 3.7 and the state of the subsystem "Use of land" in the basin of the Veselukha river was determined as "good". The general state of river runoff use in the basin based on the joint effect of all these indicators of anthropogenic load on the state of the subsystem "Use of river runoff" was evaluated as "good" with a quantitative value of 3.0. The general condition of the subsystem "Water Quality" in the basin of the Veselukha River is characterized by the IV class of water quality, it corresponds to "polluted", with a quantitative level of -1. According to the results of the integrated assessment of all subsystems of the river basin, an induction coefficient of anthropogenic load (ICAN) was specified as is -1.0 and classifies the ecological state of the Veselukha River basin as "minor changes".

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Rodriguez-Mata, Abraham Efraim, Yaneth Bustos-Terrones, Victor Gonzalez-Huitrón, Pablo Antonio Lopéz-Peréz, Omar Hernández-González, and Leonel Ernesto Amabilis-Sosa. "A Fractional High-Gain Nonlinear Observer Design—Application for Rivers Environmental Monitoring Model." Mathematical and Computational Applications 25, no. 3 (July 16, 2020): 44. http://dx.doi.org/10.3390/mca25030044.

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The deterioration of current environmental water sources has led to the need to find ways to monitor water quality conditions. In this paper, we propose the use of Streeter–Phelps contaminant distribution models and state estimation techniques (observer) to be able to estimate variables that are very difficult to measure in rivers with online sensors, such as Biochemical Oxygen Demand (BOD). We propose the design of a novel Fractional Order High Gain Observer (FOHO) and consider the use of Lyapunov convergence functions to demonstrate stability, as it is compared to classical extended Luenberger Observer published in the literature, to study the convergence in BOD estimation in rivers. The proposed methodology was used to estimated Dissolved oxygen (DO) and BOD monitoring of River Culiacan, Sinaloa, Mexico. The use of fractional order in high-gain observers has a very effective effect on BOD estimation performance, as shown by our numerical studies. The theoretical results have shown that robust observer design can help solve problems in estimating complex variables.

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Suleiman, Ahmad Abubakar, Usman Aliyu Abdullahi, Aminu Suleiman, Suleiman Abubakar Suleiman, and Hassan Umar Abubakar. "Correlation and Regression Model for Physicochemical Quality of Groundwater in the Jaen District of Kano State, Nigeria." Journal of Statistical Modelling and Analytics 4, no. 1 (April 20, 2022): 14–24. http://dx.doi.org/10.22452/josma.vol4no1.2.

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Thirty (30) samples of groundwater from various locations in the district of Jaen were obtained and analysed for drinking and other domestic purposes. Twelve (12) physical and chemical (physicochemical) groundwater quality parameters such as electrical conductivity (EC), pH, total dissolved solid (TDS), total hardness (TH), calcium (Ca), magnesium (Mg), nitrate (NO3), potassium (K), zinc (Zn), chromium (Cr), copper (Cu) and Manganese (Mn) were selected and analyzed in this study. The conventional remote sensing techniques used for monitoring and estimation of water parameters are typically based on the spectral response or dispersion reflected from the water. An attempt was made in this paper to assess and estimate groundwater elements on the basis of regression analysis. Using a correlation matrix to classify strongly correlated water quality parameters, Pearson's correlation coefficient (r) values are calculated. EC and TDS; Ca and Mg; pH and TH are highly correlated. The results show significant correlation between NO3 and Zn (r=0.860), TH and Zn (r=0.829), pH and Zn (r=0.808), TH and NO3 (r=0.732), pH and NO3 (r=0.686), Cr and Cu (r=0.635), NO3 and K (r=0.513), TH and K (r=0.500), indicate the increase in the pollution load due to industrial and anthropogenic activities. All physicochemical water variables in this study are significant at 1% and 5% level of significance. Groundwater is suitable for drinking and other domestic uses in the study area with reference to the requirements for the quality of drinking water set out in the Nigerian. Industrial Standard NIS and World Health Organization (WHO, 2011). The findings proved the effectiveness of linear regression equations for rapid water quality monitoring and estimation.

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Msusa, Anastazia Daniel, Dalin Jiang, and Bunkei Matsushita. "A Semianalytical Algorithm for Estimating Water Transparency in Different Optical Water Types from MERIS Data." Remote Sensing 14, no. 4 (February 11, 2022): 868. http://dx.doi.org/10.3390/rs14040868.

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Water transparency (or Secchi disk depth: ZSD) is a key parameter of water quality; thus, it is very important to routinely monitor. In this study, we made four efforts to improve a state-of-the-art ZSD estimation algorithm that was developed in 2019 on the basis of a new underwater visibility theory proposed in 2015. The four efforts were: (1) classifying all water into clear (Type I), moderately turbid (Type II), highly turbid (Type III), or extremely turbid (Type IV) water types; (2) selecting different reference wavelengths and corresponding semianalytical models for each water type; (3) employing an estimation model to represent reasonable shapes for particulate backscattering coefficients based on the water type classification; and (4) constraining likely wavelength range at which the minimum diffuse attenuation coefficient (Kd(λ)) will occur for each water type. The performance of the proposed ZSD estimation algorithm was compared to that of the original state-of-the-art algorithm using a simulated dataset (N = 91,287, ZSD values 0.01 to 44.68 m) and an in situ measured dataset (N = 305, ZSD values 0.3 to 16.4 m). The results showed a significant improvement with a reduced mean absolute percentage error (MAPE) from 116% to 65% for simulated data and from 32% to 27% for in situ data. Outliers in the previous algorithm were well addressed in the new algorithm. We further evaluated the developed ZSD estimation algorithm using medium resolution imaging spectrometer (MERIS) images acquired from Lake Kasumigaura, Japan. The results obtained from 19 matchups revealed that the estimated ZSD matched well with the in situ measured ZSD, with a MAPE of 15%. The developed ZSD estimation algorithm can probably be applied to different optical water types due to its semianalytical features.

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Sherjah, P. Y., N. Sajikumar, and P. T. Nowshaja. "Semi-analytical model for TSI estimation of inland water bodies from Sentinel 2 imagery." Journal of Hydroinformatics 24, no. 2 (February 23, 2022): 444–63. http://dx.doi.org/10.2166/hydro.2022.151.

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Abstract Regular monitoring of inland water bodies is essential to identify the areas of deteriorating water quality and to take measures to curb the impairment. The present study aims to develop a semi-analytical model for estimating Trophic State Index (TSI) from Sentinel 2 (S2) imagery. A semi-analytical algorithm, QAA-v6, is parameterized for S2 data (referred to as QAA-S2) based on the correlation between the retrieved inherent optical properties (IOPs) from S2 imagery and the measured TSI data of Milford Lake in the USA. The accuracy of estimation of TSI by this modified model from three different lakes located in USA and from one lake in India has increased by almost 50%, when compared with that of QAA-v6. A correlation analysis of the retrieved IOPs from QAA-S2 using the outputs of three atmospheric correction processors (ACPs) (namely C2RCC, Acolite and Sen2Cor) was carried out and C2RCC gave the least mean absolute percentage error (MAPE<8%) for TSI estimation. TSI estimation using single-scattering albedo (u) at B5 and B6 bands of S2 was reasonable (MAPE<12%) to mark them as computationally efficient estimators of TSI. These results indicate the usefulness and transferability of the QAA-S2 to the various parts of the globe for estimating TSI.

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Dick, Asiton-a. Asifamabia, and Susan Chioma Okparanta. "Drinking Wells and River Water Quality Assessment in Oproama Community, Rivers State, Nigeria." Archives of Current Research International 23, no. 3 (March 18, 2023): 33–41. http://dx.doi.org/10.9734/acri/2023/v23i3563.

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Aims: The hand-dug wells and river water in Oproama Community, Rivers State, Nigeria was assessed for its quality. Study Design: The study involved ten (10) sampling stations consisting of seven (7) hand-dug wells and three (3) points along the Oproama River. Place and Duration of Study: Oproama Community in Asari-toru Local Government Area of Rivers State, Nigeria between January and December, 2011 to cover both dry and wet seasons. Methodology: The parameters assessed were Vibrio (bacteria), salinity, calcium, magnesium concentrations as well as saltwater intrusion status employing standard laboratory procedures and estimation model. Results: The results reveal that Vibrio counts ranged from 2 x102 to 1.375 x104 cfu/100ml and the bacteria species identified from the water sources were Vibrio cholera and Vibrio parahaemolyticus. The study also reveals that salinity ranged from 11.97 to 13,772mg/l, calcium, 0.15 to 126.33mg/l and magnesium, 0.09 to 43.02mg/l. All parameters assessed exhibited seasonal variation during the study period; Calcium/magnesium (Ca/Mg) ratios for each well water sample ranged from 1.67 to 12.33 and indicate absence of saltwater intrusion which stands at a Ca/Mg limit of 1. Conclusion: Salinity (particularly well water samples), calcium and magnesium concentrations were within recommended limit; Vibrio counts were high and its presence in drinking water has public health risk; therefore, the use of sanitary buckets and point-of-use (households use) treatment and safe storage practices of water is strongly advocated.

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Suzuki, M., K. Chihara, M. Okada, H. Kawashima, and S. Hoshino. "Development of Dialog System Model for Eutrophication Control between Discharging River Basin and Receiving Water Body – Case Study of Lake Sagami (Japan)." Water Science and Technology 21, no. 12 (December 1, 1989): 1821–24. http://dx.doi.org/10.2166/wst.1989.0178.

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A computer program based on expert system software was developed and proposed as a prototype model for water management to control eutrophication problems in receiving water bodies (Suzuki etal., 1988). The system has several expert functions: 1. data input and estimation of pollution load generated and discharged in the river watershed; 2. estimation of pollution load run-off entering rivers; 3. estimation of water quality of receiving water bodies, such as lakes; and 4. assisting man-machine dialog operation. The program can be used with MS-DOS BASIC and assembler in a 16 bit personal computer. Five spread sheets are utilized in calculation and summation of the pollutant load, using multi-windows. Partial differential equations for an ecological model for simulation of self-purification in shallow rivers and simulation of seasonal variations of water quality in a lake were converted to computer programs and included in the expert system. The simulated results of water quality are shown on the monitor graphically. In this study, the expert system thus developed was used to estimate the present state of one typical polluted river basin. The river was the Katsura, which flows into Lake Sagami, a lake dammed for water supply. Data which had been actually measured were compared with the simulated water quality data, and good agreement was found. This type of expert system is expected to be useful for water management of a closed water body.

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Masliev, I., and L. Somlyódy. "PROBABILISTIC METHODS FOR UNCERTAINTY ANALYSIS AND PARAMETER ESTIMATION FOR DISSOLVED OXYGEN MODELS." Water Science and Technology 30, no. 2 (July 1, 1994): 99–108. http://dx.doi.org/10.2166/wst.1994.0033.

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Water quality models are essential to the development of least-cost water quality control strategies based on ambient criteria. Such policies are particularly important if financial resources are limited which is currently the case in Central and Eastern European countries. In turn, the derivation of realistic model parameters is a pre-requisite of successful model application. Often, longitudinal water quality profile measurements are performed for the above purpose, but the traditional evaluation of this data encounters significant difficulties due to measurement and other uncertainties. Thus, probabilistic methods are preferred. This paper discusses two of them: the Hornberger‒Spear‒Young procedure using Monte Carlo simulation and a Bayesian approach. Both methods are rather generic, but they are applied here solely for the traditional Streeter‒Phelps model and its extensions. For the purpose of illustration, water quality measurements from the highly polluted Nitra River in Slovakia are employed as a part of a policy oriented study. The BOD decay rate obtained was rather high due to partial biological wastewater treatment and small water depth, but overall, derived parameter values were in harmony with literature findings. Alternative dissolved oxygen models (2‒3 state variables and 2‒5 parameters) could also be calibrated to the data set. Ranges of probability density functions (PDFs) for model parameters were rather broad calling for a well suited formulation of a water quality management model.

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Jarek, Tiago Miguel, Jorge Luiz Moretti de Souza, Nerilde Favaretto, and Lucimeris Ruaro. "Water quality of the reservoirs used for irrigation in São José dos Pinhais, Paraná State, Brazil." Ciência Rural 46, no. 4 (April 2016): 626–31. http://dx.doi.org/10.1590/0103-8478cr20150420.

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ABSTRACT: Land use outside its agricultural potential and low vegetation cover in the watershed impair the quality of water used for irrigation and may contribute to the spread of pathogenic coliform bacteria. The objective of this study was to relate the quality of irrigation water with the intensity and type of land use and the rainfall in a vegetable-producing region of São José dos Pinhais, Paraná. Water samples were collected monthly in 2013 from two reservoirs and one preserved source. After collection, the samples were chilled in Styrofoam boxes and transported to the laboratory for analyses of the total and thermotolerant coliforms. Effect of land use was analyzed by probability estimation trees. High land use and weekly above average rainfall increased the probability of thermo tolerant coliforms exceeding the limit allowed under legislation. In regards to thermo tolerant coliforms in the analyzed period, the water from only one reservoir was in accordance with the legislation for the quality of water to irrigate vegetables that are consumed raw. Results of this study are an alert to the local government for the necessity of environmental preservation to maintain the water quality of the county.

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Ciavatta, S., R. Pastres, Z. Lin, M. B. Beck, C. Badetti, and G. Ferrari. "Fault detection in a real-time monitoring network for water quality in the lagoon of Venice (Italy)." Water Science and Technology 50, no. 11 (December 1, 2004): 51–58. http://dx.doi.org/10.2166/wst.2004.0670.

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In the context of monitoring water quality in natural ecosystems in real time, on-line data quality control is a very important issue for effective system surveillance and for optimizing maintenance of the monitoring network. This paper presents some applications of recursive state-parameter estimation algorithms to real-time detection of signal drift in high-frequency observations. Two continuous-discrete recursive estimation schemes, namely the Extended Kalman Filter and the Recursive Prediction Error algorithm, were applied to assuring the quality of the dissolved oxygen (DO) time series, as obtained from the Lagoon of Venice (Italy) during August 2002, through the real-time monitoring network of the Magistrato alle Acque (the Venice Water Authority). Results demonstrate the effectiveness of the methodology in early detection of a probable drift in the DO signal. Comparison of these results with those obtained from the application of a related recursive scheme (a Dynamic Linear Regression procedure) suggests the strong benefits of approaching the problem of on-line data quality control with several (not merely a single) independent such estimation methods.

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Kolisnyk, A. V. "Current situation of water quality Dniester River basin in transboundary areas." Ukrainian hydrometeorological journal, no. 16 (October 29, 2017): 202–8. http://dx.doi.org/10.31481/uhmj.16.2015.27.

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Introduction. Today there are significant problems of transboundary pollution of the Dniester River basin in Ukraine, including within the Vinnitska oblast. Purpose. The aim is to assess the current state of the watercourses of the Dniester River basin in transboundary areas with the Republic of Moldova, within the Vinnytska oblast by 2013. Methods. Evaluation of current watercourses quality in Dnister basin was performed based on the Methodology of environmental assessment of watercourses quality for the relevant category and on the Methods integrated assessment of groundwater contamination. Results. The results of water quality evaluation of the river Dniester basin in cross-border areas are assigned to them "satisfactory" and "bad" (the average and maximum environmental indices) features state and "dirty" and "dirty" qualifications purity by the Method of environmental assessment of watercourses quality in the relevant categories. By the Method of integral estimation of water courses contamination within the basin of river Dnister in Vinnytska oblast contamination status changed from "harmless" to "intensive". This shows a significant contamination of the river Dniester water basin. Conclusion. In order to improve the ecological state of the river basin it is necessary to conduct comprehensive monitoring of rivers, set GDS the priority given indicators of water quality, improve the culture of land and water use in watersheds. Priority execution of these measures should be in parts of the basin, characterized by the worst quality. Improvement of the situation with river Dnister basin in the cross-border region with Republic of Moldova should only be done on the state level with help of Euroregion "Dniester" initiative.

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Langovic, Marko, and Vojislav Dedjanski. "Water Supply in the Republic of Serbia – State and Perspectives." Annals of Valahia University of Targoviste, Geographical Series 17, no. 1 (April 1, 2017): 28–36. http://dx.doi.org/10.1515/avutgs-2017-0003.

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Abstract Water supply has pronounced priority, over other forms of water use. The term water supply includes the ensure of high quality water in general terms, for households, public needs and economic activities. The Republic of Serbia disposes with considerable underground and surface water resources, which are used for supplying, but it is required their rational utilization. The aim of this study is to show the current state of water supply on the territory of Serbia based on the analysis of the different indicators. One of the goal is to scan prevalent conditions and problems related to it and to propose optimal solutions. The survey includes an explanation of the long - term needs of the Republic of Serbia for fresh water (as well as share of different sources in the total water supply) and estimation of the possibility of satisfying that needs from available resources. On the base of that, there are adopted conclusions about basic directions of further development in the field of water management and water supply in Serbia.

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KAMIYAMA, Juichi, Syunya TOKUMARU, Shinya FUKUMOTO, Masayuki KASHIMA, Mutsumi WATANABE, Taro KAKINUMA, and Tetsuya TANEDA. "Research on estimating state of water quality by Unmanned Surface Vehicle." Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) 2020 (2020): 2P1—N15. http://dx.doi.org/10.1299/jsmermd.2020.2p1-n15.

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27

Chugai, A. V., and О. V. Derevenska. "Estimation of pollution level of lake Yalpuh as an object of fishing purpose." Ukrainian hydrometeorological journal, no. 22 (December 3, 2018): 133–39. http://dx.doi.org/10.31481/uhmj.22.2018.13.

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The work offers estimation of Lake Yalpuh's water quality for a long period as a fishery object. The preliminary analysis of the dynamics of water quality indicators change showed that there was a decrease of concentrations of almost all quality indicators during the period of the study (2003 - 2017). According to the results of the estimation, the water quality of Lake Yalpuh in the top section was characterized by the "very dirty" category, the quality class was marked as IVc-IVd. Most often such indicators as dry residue, magnesium, chlorides, sulfates were taken as limiting indicators of pollution. During the research the quality of lake water was did not change significantly. The maximum level of pollution was observed in 2004. The water of the lake at the water intake section was also characterized by the "very dirty" category, the quality class was marked as IVb - IVd. Most often such indicators as magnesium and sulfates were taken as limiting indicators of pollution. During the period of research there was a tendency towards a decrease of the lake's level of water pollution. The maximum level was observed in 2003 – 2004. The waters of the lake in the 13th km section was characterized by the "dirty" (quality class ІІІa-ІІІb) and "very dirty" (quality class IVa-IVc) categories. Most often such indicators as magnesium and sulfates were taken as indicators of limiting pollution. Significant fluctuations of the level of the lake water pollution were observed. The maximum level was observed in 2004. The general analysis of the dynamics of change of the combinatorial index of water pollution in Yalpuh Lake at three sections for 2003 - 2017 showed that the maximum level of water pollution in the lake was observed at the first section (top), the minimum – at the 13th km section. There is a tendency towards decrease of the value of the combinatorial index of pollution. Virtually the entire territory of the Yalpuh River Basin is located at the southern part of Moldova where the state of wastewater treatment is unsatisfactory. Therefore, the level of pollution in the lake often exceeds the permissible standards. In recent years, due to decrease mineral fertilizers and pesticides use in Moldova's agricultural sector, the situation improved though.

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Hu, Minqi, Ronghua Ma, Zhigang Cao, Junfeng Xiong, and Kun Xue. "Remote Estimation of Trophic State Index for Inland Waters Using Landsat-8 OLI Imagery." Remote Sensing 13, no. 10 (May 19, 2021): 1988. http://dx.doi.org/10.3390/rs13101988.

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Remote monitoring of trophic state for inland waters is a hotspot of water quality studies worldwide. However, the complex optical properties of inland waters limit the potential of algorithms. This research aims to develop an algorithm to estimate the trophic state in inland waters. First, the turbid water index was applied for the determination of optical water types on each pixel, and water bodies are divided into two categories: algae-dominated water (Type I) and turbid water (Type II). The algal biomass index (ABI) was then established based on water classification to derive the trophic state index (TSI) proposed by Carlson (1977). The results showed a considerable precision in Type I water (R2 = 0.62, N = 282) and Type II water (R2 = 0.57, N = 132). The ABI-derived TSI outperformed several band-ratio algorithms and a machine learning method (RMSE = 4.08, MRE = 5.46%, MAE = 3.14, NSE = 0.64). Such a model was employed to generate the trophic state index of 146 lakes (> 10 km2) in eastern China from 2013 to 2020 using Landsat-8 surface reflectance data. The number of hypertrophic and oligotrophic lakes decreased from 45.89% to 21.92% and 4.11% to 1.37%, respectively, while the number of mesotrophic and eutrophic lakes increased from 12.33% to 23.97% and 37.67% to 52.74%. The annual mean TSI for the lakes in the lower reaches of the Yangtze River basin was higher than that in the middle reaches of the Yangtze River and Huai River basin. The retrieval algorithm illustrated the applicability to other sensors with an overall accuracy of 83.27% for moderate-resolution imaging spectroradiometer (MODIS) and 82.92% for Sentinel-3 OLCI sensor, demonstrating the potential for high-frequency observation and large-scale simulation capability. Our study can provide an effective trophic state assessment and support inland water management.

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Somova, Yuliya, Elena Degodia, Elena Kasatkina, Aleksey Peryatinskiy, and Aleksandr Kudryashov. "Investigation of surface water quality in magnitogorsk industrial area for the environmental estimation of technogenic watercourse state." Eastern-European Journal of Enterprise Technologies 3, no. 10 (87) (June 22, 2017): 74–81. http://dx.doi.org/10.15587/1729-4061.2017.102374.

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30

Kreklow, Jennifer, Bastian Steinhoff-Knopp, Klaus Friedrich, and Björn Tetzlaff. "Comparing Rainfall Erosivity Estimation Methods Using Weather Radar Data for the State of Hesse (Germany)." Water 12, no. 5 (May 16, 2020): 1424. http://dx.doi.org/10.3390/w12051424.

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Rainfall erosivity exhibits a high spatiotemporal variability. Rain gauges are not capable of detecting small-scale erosive rainfall events comprehensively. Nonetheless, many operational instruments for assessing soil erosion risk, such as the erosion atlas used in the state of Hesse in Germany, are still based on spatially interpolated rain gauge data and regression equations derived in the 1980s to estimate rainfall erosivity. Radar-based quantitative precipitation estimates with high spatiotemporal resolution are capable of mapping erosive rainfall comprehensively. In this study, radar climatology data with a spatiotemporal resolution of 1 km2 and 5 min are used alongside rain gauge data to compare erosivity estimation methods used in erosion control practice. The aim is to assess the impacts of methodology, climate change and input data resolution, quality and spatial extent on the R-factor of the Universal Soil Loss Equation (USLE). Our results clearly show that R-factors have increased significantly due to climate change and that current R-factor maps need to be updated by using more recent and spatially distributed rainfall data. Radar climatology data show a high potential to improve rainfall erosivity estimations, but uncertainties regarding data quality and a need for further research on data correction approaches are becoming evident.

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Quiñones-Huatangari, Lenin, Luis Ochoa, Manuel Emilio Milla-Pino, José Federico Bazán, Oscar Andrés Gamarra, and Jesús Rascón. "Water quality index using fuzzy logic Utcubamba River, Peru." Revista de Ciencias Agrícolas 37, no. 1 (June 20, 2020): 6–18. http://dx.doi.org/10.22267/rcia.203701.124.

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Water is a fundamental nutrient in the life of any living being. Therefore, it is necessary to estimate its quality, because it is an issue of increasing concern countries around the world for reasons such as the health of the population, regional, national and international economic development, and the environmental quality of the ecosystems. One tool that has been used to know the state of the water is the water quality indexes (WQI). The objective of this research was to develop a WQI based on fuzzy logic, which allows for the estimation of water quality in the Utcubamba River. The methodology used was proposed by Icaga in 2007. To evaluate the proposed WQI called "Diffuse Water Quality Index" (DWQI), sixteen points from the sampling conducted by the Research Institute for Sustainable Development during October 2014 on the Utcubamba River and its tributaries were used. To validate the index, it was necessary to estimate the correlation coefficient R2 between the results obtained and those of the NSF WQI wáter quality index reported by the Water Research Center. This new index presented results and reasonable correlation, R2 = 0.81. It is concluded that DWQI can be used as a tool for decision making in the water management of the Utcubamba River.

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Anthwal, Tushar, and M. K. Pandey. "Assessing State of the Art on Artificial Neural Network Paradigms for Level of Eutrophication Estimation of Water Bodies." IAES International Journal of Artificial Intelligence (IJ-AI) 5, no. 4 (December 1, 2016): 135. http://dx.doi.org/10.11591/ijai.v5.i4.pp135-142.

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With growing power of computer and blend of intelligent soft wares, the interpretation and analytical capabilities of the system had shown an excellent growth, providing intelligence solutions to almost every computing problem. In this direction here we are trying to identify how different geocomputation techniques had been implemented for estimation of parameters on water bodies so as to identify the level of contamination leading to the different level of eutrophication. The main mission of this paper is to identify state-of-art in artificial neural network paradigms that are prevailing and effective in modeling and combining spatial data for anticipation. Among this, our interest is to identify different analysis techniques and their parameters that are mainly used for quality inspection of lakes and estimation of nutrient pollutant content in it, and different neural network models that offered the forecasting of level of eutrophication in the water bodies. Different techniques are analyzed over the main steps;-assimilation of spatial data, statistical interpretation technique, observed parameters used for eutrophication estimation and accuracy of resultant data.

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Baik, Jongjin, Jongmin Park, and Minha Choi. "Estimation and Assessment of Total Phosphorus and Trophic State Index Estimated from Landsat 8 Dataset on 2018 at Daecheong Reservoir." Journal of Korean Society of Environmental Engineers 42, no. 9 (September 30, 2020): 415–23. http://dx.doi.org/10.4491/ksee.2020.42.9.415.

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Objectives : Remote sensing of water quality parameters (WQPs) has been widely applied along with the emerging importance of obtaining the spatial pattern of water quality at inland reservoir. This study retrieved the Total Phosphorus (TP) via remote sensing imagery at Daecheong reservoir and used it for acquiring the spatial distribution of Trophic State Index (TSI).Methods : First, stepwise regression for TP was established using the ground-based TP measurement and reflectance of Landsat 8 collocated in space and time. With the developed regression model, we estimated the spatial distribution of TSI and evaluated the severity of eutrophication at Daecheong reservoir.Results and Discussion : The result confirmed that predicted TP yielded reasonable statistics compared against measured TP with R<sup>2</sup> of 0.956 and p-value of 0.022. Seasonal variation of TP was highly influenced by the precipitation. Similarly, precipitation also influenced to the spatial pattern of TSI. Before the rainfall event (e.g., August 22 2018) at Daecheong reservoir, TSI metric indicated the oligotrographic stage. However, TSI of Daecheong reservoir after the rainfall (e.g., October 25 2018) indicated the mesotrophic and eutrophic stage.Conclusions : These results confirmed that the retrieval of WQP from remote sensing imagery can serve as a robustness tool to monitor the water quality over the large scale area.

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Rocha, Lucas Gonçalves, Karinnie Nascimento de Almeida, José Antonio Tosta dos Reis, Antonio Sergio Ferreira Mendonça, and Fernando das Graças Braga da Silva. "Sewage treatment efficiencies estimation for urban areas located in the River Pardo’s watershed by associating nonlinear programming and water quality modeling." Revista Brasileira de Ciências Ambientais (Online) 56, no. 1 (2020): 65–75. http://dx.doi.org/10.5327/z2176-947820200731.

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Estimating efficiencies required for sewage treatment plants within a river watershed, where there are usually multiple sewage discharges and water withdrawals points in watercourses, presenting different quality conditions and sewage assimilation capacities, is a complex task. In this context, combined optimization techniques and water quality modeling can be important tools to support sewage treatment efficiencies appropriation processes. In the present paper, QUAL-UFMG water quality model and Nonlinear Programming (NLP) are jointly applied to sewage treatment levels selection for the river Pardo’s (watercourse located in Espírito Santo State, Southern region, Brazil) watershed different urban areas. Four different optimization models were tested for estimating the minimum organic matter removal efficiencies. The results indicate strong dependence between the estimated minimum organic matter removal efficiencies within the watershed and equity measures incorporated in the optimization models.

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Nurfadillah, Nurfadillah, Irma Dewiyanti, Sri Riska Rahayu, Siswani Sari, Indri Karina, and Hasfiandi Hasfiandi. "Trophic status analysis and estimation of fish production in Aneuk Laot Lake aquatic resources management, Sabang City." Depik 11, no. 3 (October 31, 2022): 469–75. http://dx.doi.org/10.13170/depik.11.3.27499.

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Aneuk Laot Lake is located in Sabang City, Weh Island, Aceh Province. Changes in water quality can affect the life of aquatic organisms found in Aneuk Laot Lake. The purpose of this research estimates fish production and trophic status for the aquatic resource management of Aneuk Laot Lake, Sabang. This research was conducted in September 2019 in Lake Aneuk Laot using the TRIX, TSI (Trophic State Index) and Nygaard index methods to determine fish production and trophic status. Observation stations were determined using stratified random sampling method and analysis of chlorophyll-a was done using the Trichomatic method. The results showed that the waters of Aneuk Laot Lake can be categorized as eutrophic to hypereutrophic. The estimated value of fish production in Aneuk Laot Lake based on the chlorophyll-a approach is 109.84 kg/ha/year, with a lake area of 61.6 ha. Water quality parameters are still in a state that can be tolerated by aquatic organisms in Aneuk Laot Lake.Keywords:Fish production potential Water qualityTRIX indexBiomass productionWater productivity

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Krutys, Pawel, Zbigniew Gomolka, Boguslaw Twarog, and Ewa Zeslawska. "Synchronization of the vector state estimation methods with unmeasurable coordinates for intelligent water quality monitoring systems in the river." Journal of Hydrology 572 (May 2019): 352–63. http://dx.doi.org/10.1016/j.jhydrol.2019.02.038.

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Rodríguez-López, Lien, David Bustos Usta, Lisandra Bravo Alvarez, Iongel Duran-Llacer, Andrea Lami, Rebeca Martínez-Retureta, and Roberto Urrutia. "Machine Learning Algorithms for the Estimation of Water Quality Parameters in Lake Llanquihue in Southern Chile." Water 15, no. 11 (May 24, 2023): 1994. http://dx.doi.org/10.3390/w15111994.

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The world’s water ecosystems have been affected by various human activities. Artificial intelligence techniques, especially machine learning, have become an important tool for predicting the water quality of inland aquatic ecosystems. As an excellent biological indicator, chlorophyll-a was studied to determine the state of water quality in Lake Llanquihue, located in southern Chile. A 31-year time series (1989 to 2020) of data collected in situ was used to determine the evolution of limnological parameters at eight spaced stations covering all of the main points of the lake, and the year, month, day, and hour time intervals were selected. Using machine learning techniques, out of eight estimation algorithms that were applied with real data to estimate chlorophyll-a, three models showed better performance (XGBoost, LightGBM, and AdaBoost). The results for the best models show excellent performance, with a coefficient of determination between 0.81 and 0.99, a root-mean-square error of between 0.03 ug/L and 0.46 ug/L, and a mean bias error of between 0.01 and 0.27 ug/L. These models are scalable and applicable to other lake systems of interest that present similar conditions and can support decision making related to water resources.

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38

Sufyan, A., R. Akhwady, D. Mahabror, S. M. Permana, and R. Zulkarnain. "Analysis of Physical and Chemical Conditions in Sidakarya Coastal Waters, Bali." IOP Conference Series: Earth and Environmental Science 1118, no. 1 (December 1, 2022): 012049. http://dx.doi.org/10.1088/1755-1315/1118/1/012049.

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Abstract Sidakarya Coast is one of the developing ecotourism and fisheries areas in Denpasar City, Bali Province. This area has ecotourism and fishery potential that needs to be maintained so that ecotourism and fishery activities that depend on this area can enjoy economic prosperity. Activities around the coast of Sidakarya, such as ecotourism, housing areas, traditional fisheries, and agriculture, have indirectly affected the quality of coastal waters. This research was one of the efforts to identify the physical and chemical parameters of the coastal waters, including, salinity, temperature, DO (Dissolved oxygen), water transparency and pH. This research was conducted in April 2021 with five measurement points of water quality factors. Measurement location determination using the purposive sampling method. Water quality analysis was carried out by comparing the measurement results with values of water quality standards based on the State Minister Decree of the Environment Number 51 of 2004 for marine tourism and marine biotas and reffering to the State Minister Decree of the Environment Number 115 of 2003 concerning Rules for determining the situation with quality of water. The measurement results showed the value of Sidakarya water quality parameters ranging from 30.2-30.6 °C for temperature, 0.6-5 meter for water transparency, 29.7-33.7°/oo for salinity, 4.94-7.04 mg/l for DO and 6.9-7.4 for pH. The results obtained that the condition of Sidakarya waters in general still meets the water quality; only the water transparency parameter at the location near the estuary was below the quality standard. The after effects of the estimation of the pollution index (PI) on each sampling station show the PI value <1 or meets the quality standards for marine biota (stations 1 and 2) and meet the quality standards for marine tourism (stations 3,4 and 5). The results indicated that Sidakarya waters can still be developed for ecotourism areas and limited fisheries.

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Pivato, Mattia, Luca Carniello, Daniele Pietro Viero, Chiara Soranzo, Andrea Defina, and Sonia Silvestri. "Remote Sensing for Optimal Estimation of Water Temperature Dynamics in Shallow Tidal Environments." Remote Sensing 12, no. 1 (December 21, 2019): 51. http://dx.doi.org/10.3390/rs12010051.

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Given the increasing anthropogenic pressures on lagoons, estuaries, and lakes and considering the highly dynamic behavior of these systems, methods for the continuous and spatially distributed retrieval of water quality are becoming vital for their correct monitoring and management. Water temperature is certainly one of the most important drivers that influence the overall state of coastal systems. Traditionally, lake, estuarine, and lagoon temperatures are observed through point measurements carried out during field campaigns or through a network of sensors. However, sporadic measuring campaigns or probe networks rarely attain a density sufficient for process understanding, model development/validation, or integrated assessment. Here, we develop and apply an integrated approach for water temperature monitoring in a shallow lagoon which incorporates satellite and in-situ data into a mathematical model. Specifically, we use remote sensing information to constrain large-scale patterns of water temperature and high-frequency in situ observations to provide proper time constraints. A coupled hydrodynamic circulation-heat transport model is then used to propagate the state of the system forward in time between subsequent remote sensing observations. Exploiting the satellite data high spatial resolution and the in situ measurements high temporal resolution, the model may act a physical interpolator filling the gap intrinsically characterizing the two monitoring techniques.

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Mannina, Giorgio, and Gaspare Viviani. "A parsimonious dynamic model for river water quality assessment." Water Science and Technology 61, no. 3 (February 1, 2010): 607–18. http://dx.doi.org/10.2166/wst.2010.865.

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Water quality modelling is of crucial importance for the assessment of physical, chemical, and biological changes in water bodies. Mathematical approaches to water modelling have become more prevalent over recent years. Different model types ranging from detailed physical models to simplified conceptual models are available. Actually, a possible middle ground between detailed and simplified models may be parsimonious models that represent the simplest approach that fits the application. The appropriate modelling approach depends on the research goal as well as on data available for correct model application. When there is inadequate data, it is mandatory to focus on a simple river water quality model rather than detailed ones. The study presents a parsimonious river water quality model to evaluate the propagation of pollutants in natural rivers. The model is made up of two sub-models: a quantity one and a quality one. The model employs a river schematisation that considers different stretches according to the geometric characteristics and to the gradient of the river bed. Each stretch is represented with a conceptual model of a series of linear channels and reservoirs. The channels determine the delay in the pollution wave and the reservoirs cause its dispersion. To assess the river water quality, the model employs four state variables: DO, BOD, NH4, and NO. The model was applied to the Savena River (Italy), which is the focus of a European-financed project in which quantity and quality data were gathered. A sensitivity analysis of the model output to the model input or parameters was done based on the Generalised Likelihood Uncertainty Estimation methodology. The results demonstrate the suitability of such a model as a tool for river water quality management.

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41

Brdys, M. A., and K. Chen. "Joint Estimation of State and Parameters of Integrated Quantity and Quality Models of Dynamic Water Supply and Distribution Systems." IFAC Proceedings Volumes 29, no. 1 (June 1996): 4004–9. http://dx.doi.org/10.1016/s1474-6670(17)58306-8.

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42

Chen, K., and M. A. Brdys. "Set Membership Estimation of State and Parameters of Large Water Supply and Distribution Systems — Integrated Quantity and Quality Models." IFAC Proceedings Volumes 28, no. 10 (July 1995): 543–48. http://dx.doi.org/10.1016/s1474-6670(17)51575-x.

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Капранов, С. В. "Methodology for estimating the state of non-centralized sources of drinking water supply in an emergency socio-economic situation." Vodosnabzhenie i sanitarnaia tehnika, no. 10 (October 15, 2021): 56–64. http://dx.doi.org/10.35776/vst.2021.10.06.

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Целью работы явилось обоснование необходимости организации и проведения на конкурсной основе благоустройства нецентрализованных водоисточников с использованием разработанной методики комплексной гигиенической и экологической оценки состояния нецентрализованных источников питьевого водоснабжения в условиях чрезвычайной ситуации. В работе использованы результаты многолетнего санитарно-гигиенического обследования и лабораторных исследований воды коллективных источников нецентрализованного питьевого водоснабжения. Определены следующие основные показатели для комплексной гигиенической и экологической оценки состояния нецентрализованных водоисточников: степень соответствия водоисточника установленным санитарно-гигиеническим и санитарно-техническим нормам и требованиям; соблюдение зон санитарной охраны; санитарно-просветительное, эстетическое и художественное оформление водоисточников; уровень благоустройства территории, окружающей водоисточники; качество воды водоисточников по результатам лабораторных исследований за определенный период. По каждому из пяти показателей предусмотрена оценка по 12-балльной шкале с последующим суммированием баллов с целью получения итогового результата комплексной оценки. Учитывая успешное проведение конкурса по благоустройству нецентрализованных источников водоснабжения с использованием разработанной методики комплексной гигиенической и экологической оценки состояния нецентрализованных источников питьевого водоснабжения в районе с резким дефицитом питьевой водопроводной воды, рекомендовано опыт проведения данного мероприятия распространить на другие административные территории, находящиеся в подобной ситуации. The work objective was substantiating the need to arrange and conduct, on a competitive basis, the improvement of non-centralized water sources using the developed methodology for a comprehensive hygienic and environmental estimation of the state of non-centralized sources of drinking water supply in an emergency. The work uses the results of many years of sanitary and hygienic survey and laboratory studies of water from communal sources of non-centralized drinking water supply. The following main indicators have been determined for a comprehensive hygienic and environmental estimation of the state of non-centralized water sources: the degree of compliance of the water source with the established sanitary, hygienic and sanitary technical regulations and requirements; compliance with the sanitary protection zones; the sanitary and educational, aesthetic and artistic design of water sources; the level of improvement of the territory surrounding the water sources; the water quality of the water sources according to the results of laboratory tests for a certain period. Each of the five indicators was estimated according to the 12-point grading scale with the subsequent summation of points in order to provide for the final result of a comprehensive estimation. Considering the successful holding of a competitive tender for the improvement of non-centralized water supply sources using the developed methodology for a comprehensive hygienic and environmental estimation of the state of non-centralized drinking water supply sources in an area with severe shortages of drinking tap water, extending the experience of these measures to other administrative territories in a similar situation is recommended.

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Kang, Seongkyu, Sijung Choi, and Dongryul Lee. "Evaluation and Re-estimation of Instream Flow Considering the Water Quality and Aquatic Ecosystem of the Seomjingang River Watershed." Journal of the Korean Society of Hazard Mitigation 21, no. 6 (December 31, 2021): 347–55. http://dx.doi.org/10.9798/kosham.2021.21.6.347.

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In this study, the appropriateness of the current publicly announced and managed instream flow in the Seomjingang River watershed was evaluated based on the water quantity, water quality, and state of the aquatic ecosystem. The stream flow was evaluated based on the observed water flow rate at the Gurye-gun (Songjeong-ri) station that is the main point of the Seomjingang River flow management and located at the lowest downstream of the main stream of the Seomjingang River. Another important reason for choosing this station was that observational data from before the construction of the major dam to the present day were available. The water quality and aquatic ecosystem conditions were reviewed based on the data measured over the past 20 years, and the achievement ratio of instream flow was compared with that of stations in the other major river systems. Based on the evaluation result, the instream flow was re-estimated for the 11 important stations of the Seomjingang River and its two branches. Based on the currently permitted water use of the Seomjingang River, the amount of water required to supply for the instream flow deficit during dry seasons was predicted and presented as a reference for water management work.

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Caviglione, João H. "Pedotransfer functions of soil water properties to estimate the S-index." Revista Brasileira de Engenharia Agrícola e Ambiental 22, no. 7 (July 2018): 465–70. http://dx.doi.org/10.1590/1807-1929/agriambi.v22n7p465-470.

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ABSTRACT One big challenge for soil science is to translate existing data into data that is needed. Pedotransfer functions have been proposed for this purpose and they can be point or parametric when estimating the water retention characteristics. Many indicators of soil physical quality have been proposed, including the S-Index proposed by Dexter. The objective of this study was to assess the use of pedotransfer functions for soil water retention to estimate the S-index under field conditions in the diversity of soils of the Paraná state. Soil samples were collected from 36 sites with textures ranging from sandy to heavy clay in the layers of 0-0.10 and 0.10-0.20 m and under two conditions (native forest and cultivated soil). Water content at six matric potentials, bulk density and contents of clay, sand and silt were determined. Soil-water retention curve was fitted by the van Genuchten-Mualem model and the S-index was calculated. S-index was estimated from water retention curves obtained by the pedotransfer function of Tomasella (point and parametric). Although the coefficient of determination varied from 0.759 to 0.895, modeling efficiency was negative and the regression coefficient between observed and predicted data was different from 1 in all comparisons. Under field conditions in the soil diversity of the Paraná state, restrictions were found in S-index estimation using the evaluated pedotransfer functions.

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46

Kh Mukhtarov, F. "Analysis of ionic equilibria by water treatment stage and calculation of monitored parameters." IOP Conference Series: Earth and Environmental Science 1142, no. 1 (March 1, 2023): 012037. http://dx.doi.org/10.1088/1755-1315/1142/1/012037.

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Abstract The mathematical model of the unit of the water treatment scheme is based on the mathematical model of improvements in the consistency metrics by step of treatment and is the basis for the technical measurement of this element. The suggested step-by-stage estimation of the water quality indicators for the assembled water treatment unit system helps the final quality of the treated water to be calculated and the mathematical model of the quality indicators adjustment by treatment phase was developed in relation to the water used in the TPP water treatment. For circuit elements, the change in the input and output quality indicators occurs depending on the type of processing, which is conveniently represented by equivalent circuits. For circuit elements, input and output quality variation occurs depending on the type of processing, which is conveniently represented by equivalent circuits. Thus, an equivalent scheme for the change in quality indicators by treatment stage can be represented by the example of a one-stage chemical desalination scheme for natural water. It should be noted that the calculated concentration fractions of carbon dioxide dissociation forms and known carbonate hardness, for example, can be used to determine the concentrations themselves.

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47

Sun, Jian, and Guido D. Salvucci. "Performance Assessment of a New Stationarity-Based Parameter Estimation Method with a Simplified Land Surface Model Using In Situ and Remotely Sensed Surface States." Journal of Hydrometeorology 15, no. 1 (February 1, 2014): 340–58. http://dx.doi.org/10.1175/jhm-d-12-0118.1.

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Abstract This study evaluates the performance of a new stationarity-based method for parameter estimation of a simple coupled water and energy balance model using in situ and remotely sensed surface soil moisture [from Advanced Microwave Scanning Radiometer for Earth Observing System (EOS; AMSR-E)] and surface temperature [from a combined Moderate Resolution Imaging Spectroradiometer (MODIS) and AMSR-E product]. Parameter estimation is carried out using both direct calibration to measured surface fluxes (latent, sensible, and ground heat) and a recently published method based on enforcing stationarity of model-predicted surface state tendency terms. The latter stationarity-based method was developed for parameter estimation without knowledge of observed fluxes—that is, it requires only forcing terms (e.g., radiation, wind speed, air temperature) and surface states (moisture and temperature). In addition, the stationarity-based method can easily handle gaps in atmospheric forcing and surface state data, as it does not integrate over time to simulate fluxes. The evaluation is conducted at three AmeriFlux sites. Changing the data sources of surface states (in situ measured and remotely sensed data) leads to little degradation in estimating turbulent fluxes despite the relatively poor quality of satellite data at some sites. In all cases, direct calibration yields marginally better predictions than the stationarity-based method, with site-averaged root-mean-square errors for daily total energy fluxes approximately 5–6 W m−2 lower. However, direct calibration requires observed fluxes in the objective function, which imposes a strong limit on its application.

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Hartmann, Andreas, Juan Antonio Barberá, and Bartolomé Andreo. "On the value of water quality data and informative flow states in karst modelling." Hydrology and Earth System Sciences 21, no. 12 (November 30, 2017): 5971–85. http://dx.doi.org/10.5194/hess-21-5971-2017.

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Abstract. If properly applied, karst hydrological models are a valuable tool for karst water resource management. If they are able to reproduce the relevant flow and storage processes of a karst system, they can be used for prediction of water resource availability when climate or land use are expected to change. A common challenge to apply karst simulation models is the limited availability of observations to identify their model parameters. In this study, we quantify the value of information when water quality data (NO3− and SO42−) is used in addition to discharge observations to estimate the parameters of a process-based karst simulation model at a test site in southern Spain. We use a three-step procedure to (1) confine an initial sample of 500 000 model parameter sets by discharge and water quality observations, (2) identify alterations of model parameter distributions through the confinement, and (3) quantify the strength of the confinement for the model parameters. We repeat this procedure for flow states, for which the system discharge is controlled by the unsaturated zone, the saturated zone, and the entire time period including times when the spring is influenced by a nearby river. Our results indicate that NO3− provides the most information to identify the model parameters controlling soil and epikarst dynamics during the unsaturated flow state. During the saturated flow state, SO42− and discharge observations provide the best information to identify the model parameters related to groundwater processes. We found reduced parameter identifiability when the entire time period is used as the river influence disturbs parameter estimation. We finally show that most reliable simulations are obtained when a combination of discharge and water quality date is used for the combined unsaturated and saturated flow states.

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Chung, Yongjoo, Chunhyun Paik, and Young Jin Kim. "Estimation of Methane Emissions from Reservoirs Based on Country-Specific Trophic State Assessment in Korea." Water 14, no. 4 (February 12, 2022): 562. http://dx.doi.org/10.3390/w14040562.

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It has been reported that significant quantities of greenhouse gases are emitted from wetlands, from which emissions and their contributions to global warming have received much less attentions. Thus, a refinement to the previous published guidelines has recently been made to provide an updated and sound scientific basis for the purpose of supporting the preparation of national inventories. This study is aimed at demonstrating the applicability of the refinement for estimating methane emissions from reservoirs in the Republic of Korea. It is desirable to take the direct measurement of total methane fluxes across the reservoir surface, which may require a substantial amount of research efforts though. Alternatively, methane emissions from individual reservoirs may be estimated with relevant parameters accounting for the regional environmental characteristics. The assessment of trophic state has been employed to better represent the emissions behavior of reservoirs, based on which the methane emissions from local reservoirs in Korea are estimated. It is noted that the country has developed its own water quality index with the consideration of environmental characteristics. The seasonal variations in methane emissions are tested for their statistical significance and it is proposed that the emission estimates can be predicted from the trophic state assessment with the application of regression analysis. Following the guidelines prescribed by the refinement and procedures outlined in this study, the results from emissions estimation and prediction can be effectively used for the improvement of national inventories.

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Lehtonen, Aleksi, Tapio Linkosalo, Mikko Peltoniemi, Risto Sievänen, Raisa Mäkipää, Pekka Tamminen, Maija Salemaa, et al. "Forest soil carbon stock estimates in a nationwide inventory: evaluating performance of the ROMULv and Yasso07 models in Finland." Geoscientific Model Development 9, no. 11 (November 22, 2016): 4169–83. http://dx.doi.org/10.5194/gmd-9-4169-2016.

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Abstract. Dynamic soil models are needed for estimating impact of weather and climate change on soil carbon stocks and fluxes. Here, we evaluate performance of Yasso07 and ROMULv models against forest soil carbon stock measurements. More specifically, we ask if litter quantity, litter quality and weather data are sufficient drivers for soil carbon stock estimation. We also test whether inclusion of soil water holding capacity improves reliability of modelled soil carbon stock estimates. Litter input of trees was estimated from stem volume maps provided by the National Forest Inventory, while understorey vegetation was estimated using new biomass models. The litter production rates of trees were based on earlier research, while for understorey biomass they were estimated from measured data. We applied Yasso07 and ROMULv models across Finland and ran those models into steady state; thereafter, measured soil carbon stocks were compared with model estimates. We found that the role of understorey litter input was underestimated when the Yasso07 model was parameterised, especially in northern Finland. We also found that the inclusion of soil water holding capacity in the ROMULv model improved predictions, especially in southern Finland. Our simulations and measurements show that models using only litter quality, litter quantity and weather data underestimate soil carbon stock in southern Finland, and this underestimation is due to omission of the impact of droughts to the decomposition of organic layers. Our results also imply that the ecosystem modelling community and greenhouse gas inventories should improve understorey litter estimation in the northern latitudes.

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