Fluctuations In Water Quality Research Articles

INVESTIGATIONS OF WATER QUALITY FLUCTUATION OF THE INNERMOST PART OF THE ARIAKE SEA BY FIELD OBSERVATION

The Ariake Project II was operated in July 2003 to grasp the whole features of water movement and water quality change in the Ariake Sea. This study reports the results obtained from a part of the project. Especially, the features at an innermost part of the Ariake Sea are described in detail. Observation along vertical measure lines at fixed points and a long-term observation at observation tower are combined to consider the mechanism of water movement and water quality fluctuation. As a result, the project can be effective to study the summer feature of the Ariake Sea with meteorological conditions, such as rain, wind, and other watershed conditions.

Disturbance, Herbivory, and Propagule Dispersal Control Dominance of an Invasive Grass

Despite the dramatic changes invasive plants cause to ecosystems and communities, factors that control dominance of invasive species after establishment in a community are poorly understood. Most active management relies on catastrophic disturbances of invasive-dominated communities to increase richness and diversity of plant communities. This study examines the importance of propagule dispersal and deer herbivory on continued dominance of Phalaris arundinacea after a non-catastrophic, short-term disturbance to monotypic stands of this invasive grass. The disturbance caused no change in P. arundinacea cover among treatments during any year of the study and, thus, simulates disturbance intensity more likely to be encountered in unmanaged settings. Despite the small disturbance, the combinations of disturbance + seeding and disturbance + seeding + deer exclusion caused greater species richness than controls even three years after disturbance. Increased invasion of P. arundinacea stands caused few effects on the dominant, as P. arundinacea biomass was unaffected after the first year. Selective herbivory by deer of species other than P. arundinacea increased the effects of disturbance and seeding, and aided in continued dominance of the grass. The tolerance of P. arundinacea for direct anthropogenic effects, including poor water quality and hydroperiod fluctuations, and indirect effects, such as increased herbivory by historically high deer populations, indicates the complexity of determining persistence of invasive species.

Runoff water quality characteristics in a small agriculture watershed

I have observed the water quality in the Ohwada District of Kasumigaura Town near Lake Kasumigaura for a period of over seven years (1993–1999). During this observation period, sampling was performed for 3 years at 4-h intervals using an automatic sampler, and the water quality was subsequently analyzed. As a result of this long-term precision study of water quality fluctuation, important new information was obtained. First, the quantity of nitrogen found to have been removed was great, especially in the paddy fields, and this contributed to water quality purification. Secondly, the paddy fields produced algae and this algae supported denitrification in the paddy fields. However, the paddy fields increased the COD runoff. Thirdly, for determining the average water quality by monitoring, monthly sampling is sufficient, though for understanding the fluctuation pattern of the water quality, weekly sampling is necessary.

Pelicans at risk in Salton Sea—an eco-epidemiological model-II

The Salton Sea which is located in the Southeast desert of California is becoming a dangerous habitat for birds. It is supposed that elevated salinity, accelerated eutrophication, blooms of Avian botulism and dramatic water quality fluctuation are the key factors for massive die-off of Tilapia (prey) and Pelican (predator) in the Salton sea. Chattopadhyay and Bairagi [Ecol. Model. 136 (2001) 103] proposed and analyzed a three-component eco-epidemiological model consisting of susceptible fish population, infected fish population and their predator, the Pelican population. We modify their model from more biologically realistic point of view and then analyze it. The main objective of the work is to find out conditions for which the modified system becomes disease free. Numerical simulations for a hypothetical set of parameter values are presented to illustrate the analytical findings. It is observed that if the initial value of the system is contained in the invariant set which contain the disease-free equilibrium, the solution will approach the disease-free equilibrium under suitable parametric conditions. If the initial value of the system is not in the invariant set, impulsive harvesting strategies can be used to change the initial state to the desired disease-free equilibrium state.

Inter-Annual Fluctuation of Water Quality in Seto Inland Sea: Relationship with Sea Levels at the Entrances of the Inland Sea

The comprehensive water quality survey in the Seto Inland Sea has been operated by the Ministry of Land, Infrastructure and Transport (MLIT), Japan. The water quality survey Program was established for the purpose of making data sets available to know actual conditions of water pollution, and to generate products that would be valuable for scientific analysis of climate-related processes. The program started in May 1981. Water qualities (salinity, water temperature, DO, pH, turbidity and clearness) were observed in February, May, August and October. The observations were carried out at 200 points (142 points in 1989–1999) located on 8 km × 8 km grid. We examined the physical factors affecting inter-annual and seasonal changes in water quality of the Seto Inland Sea by using the data (salinity, temperature, sea level etc.) measured/collected by several institutions, mainly MLIT and JMA (Japan Meteorological Agency). From the present study, it is revealed that the water mass inside the Inland Sea is strongly related to the sea level along the Japanese coast facing the Pacific Ocean. High salinity water that is a part of the Kuroshio intrudes into the Inland Sea. In the past twenty years, the Kuroshio path moved periodically. The Kuroshio was often observed to take a large meandering path in the 1980s and to take a northerly path in the 1990s. Because of this change in the Kuroshio path, the salinity distribution in the Inland Sea has dramatically changed. Geographical and inter-annual fluctuation of primary production was studied in relation to currents of the Inland Sea.

Pelican at Risk in Salton Sea – a Delay-Induced Eco-Epidemiological Model

Elevated salinity, accelerated eutrophication, blooms of Avian botulism and dramatic water quality fluctuation are supposed to be the key factors for massive die-off of Tilapia (prey) and Pelican (predator) in the Salton sea. We modify the model of Chattopadhyay and Bairagi [Ecological Modelling 136 (2001), pp. 103-112] with an assumption that the growth rate of susceptible fish population is very high and study the dynamics of the system by introducing a delay factor in the predator response function. It is observed that the otherwise stable system exhibit a stable limit cycle solution when the lag factor attains its critical value. It is also observed that there is a high possibility of an epidemic out break in the fish as well as in the Pelican population if the predation process is delayed by a considerable amount of time. Numerical simulations for a hypothetical set of parameter values are presented to illustrate the analytical findings.

Application of an automatic sampling and measurement system to a mountainous stream investigation during rain events

An automatic sampling and measurement system was developed to take water samples efficiently during rain events. The system consisted of an automatic sampler, a rain gauge and a data logger as well as sensors for pH, electrical conductivity (EC), and both water and air temperature. The system was tested in a stream in a forested watershed (5.8 km2) located in the middle of Hyogo prefecture, Japan. The sampling program has been improved gradually. For several rain events of 30 to 157 mm, most water samples were in agreement with the hydrograph from the beginning of each rainfall until the rain had stopped and the water level had begun to fall. The fluctuations in water quality in the samples taken by the automatic sampler during those rain events showed patterns similar to those of water samples taken by hand. There were also no problems with the water level or the EC sensor during the investigation periods, but the pH values were lower than those in the laboratory. The results showed that the system is suitable for taking water samples from mountainous streams during rain events.

CONSEQUENCES OF THE KUROSHIO PATH FOR HYDRAULIC PHENOMENA AROUND SETO INLAND SEA

We examined the physical factors affecting annual and seasonal changes in water quality of the Seto Inland Sea, Japan by using the data measured by several institutions. The observed sea level height (SLH) and sea surface temperature (SST) at Cape Shiono and Cape Ashizuri were influenced by the Kuroshio path. This result suggests that an open boundary condition is sensitive to the annual/seasonal fluctuation of water quality in inland seas.The water quality in Seto Inland Sea is greatly related with the Kuroshio path. In the recent twenty years, the Kuroshio path changed periodically. The Kuroshio current often takes a meanderings path over 1980's and it tends to come alongside Kii peninsula over 1990's. Also, the salinity distribution in the inland sea changed periodically with the shifts of the Kuroshio path.

Effects of environmental fluctuation on an eco‐epidemiological model of the Salton sea

AbstractElevated salinity, accelerated eutrophication, blooms of Avian botulism and dramatic water quality fluctuation are the key factors for massive die‐offs of Tilapias and pelicans in the Salton Sea. A stochastic model for infected Tilapias and their predator pelicans is proposed. The environmental parameters are perturbed by color noise characterized by Ornstein–Uhlenbeck process. The dynamical behavior of the system is studied by using the spectral density analysis and the solutions of the stochastic differential equations (SDE). A simple and transparent technique is given for finding the safe region in which the chance of pelican extinction is minimized. To substantiate the analytical results computer simulation is also performed for a hypothetical set of parameter values. Copyright © 2001 John Wiley & Sons, Ltd.

A decade of large scale experience in dissolved air flotation

In April 1990 Antwerpse Waterwerken brought a new DAF-plant into operation at the production centre Notmeir-Walem. The flotation unit, which has a capacity of 200,000 m3/d, was integrated in one of the two existing treatment lines. Its main objective was to eliminate the important raw water quality fluctuations caused by increasing algal growths. During the past ten years several optimisation studies were carried out which resulted in a further simplification of operation and mechanical design. This paper will focus mainly on the integration of dissolved air flotation in the entire treatment line, the consequences on the dual layer filtration and the operational experience and information gathered during the past decade.

Long-term Trends and Temporal Heterogeneity of Water Quality in Tidally Mixed Estuarine Waters

Dynamics of water quality in the Keonggi Bay, a shallow macrotidal temperate estuary of Yellow Sea, Korea were identified using the major water quality parameters such as dissolved oxygen (DO), ammonia, nitrate, phosphate, and chemical oxygen demand (COD). The study area during the last 18 years was in eutrophic and mesotrophic water in terms of the nutrient eutrophication index even with a slight decrease in DIN and COD concentrations during recent years. Monthly values of nitrate and ammonia significantly correlated with SS and salinity, respectively, indicating that re-suspension of sediment by vertical mixing and freshwater input are critical factors of monthly fluctuation in water quality. The lack of significant autocorrelation in water quality parameters suggested a significant tidal effect on temporal water quality fluctuation in the tidally mixed estuarine system. Principal component analysis (PCA) revealed a clear pattern of long-term trends of water quality. The early 1980s were the periods of best water quality, with worst conditions during the late 1980s and early 1990s. These long-term trends of water quality were well discriminated by PCA which can be further applied for the whole ecosystem interpretation with biological variables.

Characteristics of fluctuations in salinity and water quality in brackish Lake Obuchi

Fluctuations in the salinity and physicochemical characteristics of water quality were surveyed in brackish Lake Obuchi on the Shimokita Peninsula in Aomori, Japan. The mean salinity in the surface layer in all regions of Lake Obuchi was about 10 psu, whereas in the basin region at depths of greater than 3 m it was 20 psu. Furthermore, all the year round the halocline was formed at depths of 1–4 m. The maximum density gradient along a vertical axis in the center of the lake was observed at depths of 1–2 m in summer and 2–4 m in spring and fall. The depth of the maximum density gradient fluctuated with the seasons. In summer the water in the bottom layer was anoxic, and Fe, Mn, PO43−-P, and NH4+-N supplied from the bottom sediment accumulated at high concentrations below the halocline. Thus, it was observed that the transfer of substances between the layers above and below the barrier formed by the halocline is suppressed. Although Lake Obuchi is small and shallow, the inflowing seawater easily resides, and a stable halocline readily forms because of the shape of its basin, which suddenly deepens on the Pacific Ocean side.

Simulation of lead compliance data

Lead in drinking water principally arises from contact between municipally supplied water and lead service pipes. Compliance sampling which is used to assess lead levels on a routine basis usually incurs a wide variability. This is due to the large number of random factors which effect it. A simulation programme has been written to mimic the sampling process, the variability in water quality, differences in the housing stock, and customer characteristics. Comparison is made in one case between the predicted and observed distribution of lead levels and found to be in good agreement. The analysis shows that for water with low alkalinity, fluctuations in water quality are a significant contributor to variability. The simulation programme is used to assess the significance of different performance measures, the impact of different measurement methods, and different lead strategies on lead exposure. The impact of sample size and the number of leaded properties in a compliance zone is analysed and discussed.

TOWARDS QUANTIFYING THE ECONOMIC EFFECTS OF POOR AND FLUCTUATING WATER QUALITY ON IRRIGATION AGRICULTURE: A CASE STUDY OF THE LOWER VAAL AND RIET RIVERS

Irrigation farmers in the lower reaches of the Vaal and Riet Rivers are experiencing substantial yield reductions in certain crops and more profitable crops have been withdrawn from production, hypothesised, as a result of generally poor but especially fluctuating water quality. In this paper secondary data is used in a linear programming model to test this hypothesis by calculating the potential loss in farm level optimal returns. The model is static with a time frame of two production seasons. Linear crop-water quality production functions (Ayers & Westcot, 1983; adapted from Maas & Hoffmann, 1977) are used to calculate net returns for the eight most common crops grown. Results show optimal enterprise composition under various water quality situations. Leaching is justified financially and there is a strong motivation for a change in the current water pricing system. SALMOD (Salinity and Leaching Model for Optimal irrigation Development) is the Excel Solver model used to derive the preliminary results, but is currently being developed further in GAMS (General Algebraic Modelling System). Useful results have already been obtained on which this paper is based. The ultimate aim for SALMOD is a mathematical model using dynamic optimisation, simulation and risk modelling techniques to aid in whole farm and system level management decisions to ensure sustainable irrigation agriculture under stochastic river water quality conditions.

Determination of optimal coagulant dosing rate using an artificial neural network

Determining coagulant dosing rates currently depends on Jar-test results and the experience of the operators in many cases. The nature of these practices makes it difficult to cope quickly with the rapid fluctuation of raw water quality, mainly because it takes a relatively long time to obtain Jar-test results. For promptly predicting required coagulant doses in response to water quality changes, a number of researchers have attempted to use the multi-variable regression (MVR) approach. However, the prediction capability of the MVR approach has not been satisfactory. An artificial neural network (ANN) is an excellent estimator of the nonlinear relationship between the accumulated input and output numerical data. Using this characteristic of the ANN, this study has attempted to predict the optimal coagulant dosing rate accurately and quickly. To train the ANN and deduce the MVR equation, a set of 142 units of data chosen from the 2-year operation of a water treatment plant was used. Another set of 72 units of data, not used in training, was also used to check the prediction capability of the trained ANN and MVR equation. Root-mean-square normalized error (RMSE) was used as a quantitative indicator of prediction capability. For the training data set and the raw data set, the RMSEs of the MVR equation were, respectively, 0.0143 and 0.0193 while those of the ANN were 0.0058 and 0.0092, respectively. These results indicate that the ANN reduced the prediction error for the training data by about 59%, and for the raw data by about 52%. Thus, our study demonstrates that the prediction capability of the ANN for raw data is enhanced by twice that of MVR. As the advancement of on-line monitoring techniques enables the ANN to update the weights periodically, its prediction capability can be also continuously enhanced.

Patterns in groundwater chemistry resulting from groundwater flow

Groundwater flow influences hydrochemical patterns because flow reduces mixing by diffusion, carries the chemical imprints of biological and anthropogenic changes in the recharge area, and leaches the aquifer system. Global patterns are mainly dictated by differences in the flux of meteoric water passing through the subsoil. Within individual hydrosomes (water bodies with a specific origin), the following prograde evolution lines (facies sequence) normally develop in the direction of groundwater flow: from strong to no fluctuations in water quality, from polluted to unpolluted, from acidic to basic, from oxic to anoxic–methanogenic, from no to significant base exchange, and from fresh to brackish. This is demonstrated for fresh coastal-dune groundwater in the Netherlands. In this hydrosome, the leaching of calcium carbonate as much as 15 m and of adsorbed marine cations (Na+, K+, and Mg2+) as much as 2500 m in the flow direction is shown to correspond with about 5000 yr of flushing since the beach barrier with dunes developed. Recharge focus areas in the dunes are evidenced by groundwater displaying a lower prograde quality evolution than the surrounding dune groundwater. Artificially recharged Rhine River water in the dunes provides distinct hydrochemical patterns, which display groundwater flow, mixing, and groundwater ages.

CHARACTERIZATION OF TOXIC CONDITIONS ABOVE WILSON'S CREEK NATIONAL BATTLEFIELD PARK, MISSOUR1

ABSTRACT: Wilson's Creek has an extensive history of toxicity from both point and nonpoint sources. Seven‐day chronic daphnid (Ceriodaphnia dubia) bioassays identified one toxic site in the Wilson's Creek watershed. Procedures for the characterization phase of a Toxicity Identification Evaluation (TIE) were modified for chronic assessment and performed on four water samples from the toxic site. The characterization involved chemical/physical alterations of samples, combined with bioassays, to help in identification of the class(es) of toxicants; followed by chemical analyses. To help understand the additivity of mixtures, toxic units were derived. Successive samples contained concentrations of copper, cadmium, nickel and zinc that literature values describe as being chronically toxic to daphnids. Summed chronic toxic units for these values greatly exceeded ambient toxic units, and more than accounted for observed toxicity.Substantial fluctuations in water quality occurred over the five sampling periods of the characterization studies and a Test of Methods, June through August, 1991. This variability illustrates the difficulty in detecting and documenting nonpoint sources of pollution. Tests using living organisms, in conjunction with toxicity identification methods, on samples taken over time appear to be appropriate for detecting acute and chronic toxicity in areas impacted by intermittent point and nonpoint‐source toxicity.

Removal of particles, bacteria and parasites with ultrafiltration for drinking water treatment

After more than 2 years operation of four pilot plants, with five modules of micro- and ultrafiltration, it was proved that at correct operation, in spite of fluctuations in raw water quality, the complete and safe removal of bacteria, parasites and particles with running costs including membrane replacement of <0.1 DM/m 3 treated water can be achieved. Due to the modular construction of the membrane plants, as constructed by WABAG, in reverse osmosis and other membrane plants for more than 20 years, problem-free expansion is possible. The first large installation for drinking water treatment in Germany will be finished in June 1998 with a treatment capacity of 140m 3/h. Furthermore, the combination of UF/PAC-dosage and the treatment of filter backwashing water are reported.

Water quality fluctuations in a closed recirculating system for the intensive culture of the guppy, Poecilia reticulata (Peters)

Water quality fluctuations in a closed recirculating system for the intensive culture of the guppy, <i>Poecilia reticulata</i> (Peters)

Water quality fluctuations in a closed recirculating system for the intensive culture of the guppy, Poecilia reticulata (Peters)

Water quality fluctuations in a closed recirculating system for the intensive culture of the guppy, Poecilia reticulata (Peters)