scholarly journals Study on the Impact of Tidal Effects on Water Quality Modelling of Juru River, Malaysia

2011 ◽  
Vol 4 (2) ◽  
pp. 129-138 ◽  
Author(s):  
Mohd Ekhwan Toriman ◽  
Norbaya Hashim ◽  
Abd. Jalil Hassan ◽  
Mazlin Mokhtar ◽  
Hafizan Juahir ◽  
...  
2010 ◽  
Vol 61 (9) ◽  
pp. 2381-2390 ◽  
Author(s):  
Gabriele Freni ◽  
Giorgio Mannina ◽  
Gaspare Viviani

The objective of this paper is the definition of a methodology to evaluate the impact of the temporal resolution of rainfall measurements in urban drainage modelling applications. More specifically the effect of the temporal resolution on urban water quality modelling is detected analysing the uncertainty of the response of rainfall–runoff modelling. Analyses have been carried out using historical rainfall–discharge data collected for the Fossolo catchment (Bologna, Italy). According to the methodology, the historical rainfall data are taken as a reference, and resampled data have been obtained through a rescaling procedure with variable temporal windows. The shape comparison between ‘true’ and rescaled rainfall data has been carried out using a non-dimensional accuracy index. Monte Carlo simulations have been carried out applying a parsimonious urban water quality model, using the recorded data and the resampled events. The results of the simulations were used to derive the cumulative probabilities of quantity and quality model outputs (peak discharges, flow volume, peak concentrations and pollutant mass) conditioned on the observation according to the GLUE (Generalized Likelihood Uncertainty Estimation) methodology. The results showed that when coarser rainfall information is available, the model calibration process is still efficient even if modelling uncertainty progressively increases especially with regards to water quality aspects.


2013 ◽  
Vol 68 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Bastian Johann Manz ◽  
Juan Pablo Rodríguez ◽  
Čedo Maksimović ◽  
Neil McIntyre

A key control on the response of an urban drainage model is how well the observed rainfall records represent the real rainfall variability. Particularly in urban catchments with fast response flow regimes, the selection of temporal resolution in rainfall data collection is critical. Furthermore, the impact of the rainfall variability on the model response is amplified for water quality estimates, as uncertainty in rainfall intensity affects both the rainfall-runoff and pollutant wash-off sub-models, thus compounding uncertainties. A modelling study was designed to investigate the impact of altering rainfall temporal resolution on the magnitude and behaviour of uncertainties associated with the hydrological modelling compared with water quality modelling. The case study was an 85-ha combined sewer sub-catchment in Bogotá (Colombia). Water quality estimates showed greater sensitivity to the inter-event variability in rainfall hyetograph characteristics than to changes in the rainfall input temporal resolution. Overall, uncertainties from the water quality model were two- to five-fold those of the hydrological model. However, owing to the intrinsic scarcity of observations in urban water quality modelling, total model output uncertainties, especially from the water quality model, were too large to make recommendations for particular model structures or parameter values with respect to rainfall temporal resolution.


Ekologija ◽  
2008 ◽  
Vol 54 (1) ◽  
pp. 22-28 ◽  
Author(s):  
Valentinas Šaulys ◽  
Nijolė Bastienė
Keyword(s):  

Author(s):  
I. Saakian ◽  
Aleksandr, Grigor’ev ◽  
E. Kravets ◽  
E. Rudakov ◽  
A. Faddeev ◽  
...  

Выполнен анализ действующей редакции Методики разработки нормативов допустимых сбросов веществ и микроорганизмов в водные объекты для водопользователей , утвержденной приказом Минприроды России от 17 декабря 2007 г. 333, на предмет непротиворечивости и соответствия нормам водоохранного законодательства. Выявлена неопределенность применения Методики в условиях воздействия на качество воды природных и антропогенных факторов, не зависящих от конкретного водопользователя. Положения Методики противоречат принципам нормирования воздействия на водные объекты на основе наилучших доступных технологий, что было показано на примерах утвержденных технологических показателей содержания загрязняющих веществ в сточных водах различных отраслей промышленности. Анализ системы нормирования допустимых воздействий на водные объекты и географической дифференциации нормативов качества воды в пределах Российской Федерации вместе с системой целевых показателей качества воды также показал несоответствие Методики основным принципам водоохранного законодательства.The analysis of the current edition of the Methods of developing standards for permissible discharges of substances and microorganisms into water bodies for water users , approved by the Order of the Ministry of Natural Resources of Russia dated December 17, 2007 No. 333 for consilience and compliance with the regulations of the water protection legislation, is carried out. Uncertainty of the application of the Methods in the conditions of the impact of natural and anthropogenic factors that are independent of a specific water user on the quality of water has been identified. The provisions of the Methods contradict the principles of regulating the impact on water bodies based on the best available technologies shown on the examples of approved process indicators of the concentrations of various industrial pollutants in wastewater. An analysis of the system of regulating the permissible impact on water bodies and the geographical differentiation of water quality standards within the boundaries of the Russian Federation, together with the system of water quality targets, also showed that the Methods do not comply with the basic principles of the water protection legislation.


2017 ◽  
Vol 68 (1) ◽  
pp. 175-179
Author(s):  
Oana Roxana Chivu ◽  
Augustin Semenescu ◽  
Claudiu Babis ◽  
Catalin Amza ◽  
Gabriel Iacobescu ◽  
...  

Rainfall is a major component of the environment and the main source of the air purification becouse of many pollutants increases who have the most varied sources: various human activities including industry and agriculture, and some household duties. Air purification by means of precipitation is achieved by numerous highly complex mechanisms. The final products of degradation of the pollutant in the air, which are generally harmless, can be reacted with each other in the presence of water, giving rise to the final compounds with a high toxicity. Thus, exhaust, mobile sources of noxious almost identical to those specific activities in the industrial processing of oil, contain lead which is the ideal catalyst for converting SO2 to sulfuric acid in the presence of rainwater, with all the disadvantages that they create. This paper will present an experimental research oabout how rainfall water quality is influenced by the activity of the industrial processing of oil, in a chemical plant in Constanta County.


2008 ◽  
Author(s):  
James M. Steichen ◽  
Stacy L. Hutchinson ◽  
Naiqian Zhang ◽  
J. M. Hutchinson ◽  
Charles Oviatt ◽  
...  

1998 ◽  
Vol 38 (10) ◽  
pp. 23-30
Author(s):  
Sarah Jubb ◽  
Philip Hulme ◽  
Ian Guymer ◽  
John Martin

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


2006 ◽  
Vol 33 (2) ◽  
pp. 55 ◽  
Author(s):  
MARIA LUCIA KOLOWSKI RODRIGUES ◽  
MILTON LUIZ LAQUINTINIE FORMOSO

This study evaluated the contamination of water samples from Cadeia and Feitoria rivers (Rio Grande do Sul State, Brazil), affected by tannery activities. From July 1999 to April 2000, four sampling campaigns were performed at ten sites in order to evaluate selected metals and ancillary physicochemical variables. Sample preservation and analyses followed recommendations of the Standard Methods. Factor analysis was used to obtain statistical indexes representing the contamination degree of waters evaluated. The information was summarized in two principal components. The first, which accounted for 50% of the total variance, was associated to a tannery contribution and generated a contamination index. Total, Suspended and Dissolved Solids, Dissolved Oxygen, Conductivity, Chromium, Manganese, Copper, Nickel, Sodium, Calcium, Potassium, and Magnesium were the well-correlated variables with this first component. The water quality decreased from headwaters up to mouth along both streams, but the most contaminated sites were located at the lower reach of Feitoria river (Ivoti and Lindolfo Collor cities), where tanneries are concentrated. After the entrainment of Feitoria waters (São Sebastião do Caí municipality), Cadeia river also presented an increased contamination degree. The application of statistical randomization tests highlighted these same sites as significantly distinct from the others. Water contamination also showed association to flow variations, and a poorer water quality was observed during the dry period (January). The second component, in which Iron, Aluminum, and Suspended Solids were the relevant variables, was loaded with 15% of the total variance. It was linked to natural events, since higher factor scores in this component were obtained during a period of increased water discharge (October), which caused resuspension and entrainment of solid material to the rivers bed. As a final result of the study, sampling stations were classified according to the contamination degree, and graphically represented on a basin map, which synthesized the environmental diagnosis.


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