• Advances in environmental research
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• v.6 no.3
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• pp.203-216
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• 2017

For survival of human beings clean water is an essential commodity whereas contamination in drinking water threatens to mankind. The main cause of water contamination is social and development activities of human being along with increasing population. The community in the study area has acute shortage of drinking water along with about 40 to 60% has no access to safe drinking water. This study indicates drinking water quality of two major sources of coastal belt of Karachi one is supplied by Karachi Water & Sewerage Board (KWSB) as tap water and the other through groundwater. The physicochemical analysis was carried out by following the standard methods for checking the quality of drinking water. The analyzed results showed that the quality of groundwater was unfit as potable water. The most critical situation was observed as high level of contamination followed by high turbidity and increased salinity levels. TDS in surface water were found 12% above and TDS in groundwater was 20% below the National Drinking Water Quality Standards (NDWQS) of Pakistan as well as the permissible WHO drinking water quality guidelines.

• Korean Journal of Ecology and Environment
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• v.42 no.4
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• pp.432-440
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• 2009

During the period of past fifteen years (1992~2006), variations of chlorophyll a in relation with water quality in freshwater reservoirs were investigated. This study compared total nitrogen (TN), total phosphorus (TP), chlorophyll a, Secchi depth (SD) and total suspended solids (TSS) between terrestrial freshwater reservoir and coastal freshwater reservoir systems based on their location. Regression analyses (linear and non-linear regressions) were applied for all study sites to examine relationship and interaction of these factors in the freshwater systems from in-land to coasts. The results demonstrated that chlorophyll a was significantly correlated to total phosphorus ($R^2=0.94$, P<0.0001) and was remarkably related to TSS increase ($R^2=0.63$, P<0.0001) in the selected reservoirs. The TN : TP ratio in the reservoir systems was higher than Redfield ratio (16 : 1) indicating that the reservoirs are potentially experiencing P limitation. Water quality of coastal freshwater reservoir system was more significantly decreased than the reservoirs located in in-land during the past fifteen years. The strict management of nutrient discharge into freshwater systems should implemented in the coastal reservoirs since the freshwater is introduced into coastal estuarine systems.

• Ocean and Polar Research
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• v.30 no.4
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• pp.379-399
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• 2008

Spatial-temporal variations in physiochemical water qualities (temperature, salinity, DO, SPM, POC and nutrients) of surface and bottom waters were investigated along the mid-western coastal area (Taean Peninsula to Gomso Bay) of Korea. Spatial distribution patterns of temperature and salinity were mostly controlled by the physical mixing process of freshwater from Geum River and/or Gyunggi Bay with nearby coastal water. A strong tidal front is formed off Taean Peninsula during spring and summer. Seasonal variations in nutrient concentrations, lower in spring and summer and higher in fall and winter, are primarily regulated by magnitude of phytoplankton occurrence rather than freshwater loadings into the bay. Based on seasonal and spatial variability of physicochemical parameters, water quality of the study area can be divided into four water masses; Gyunggi Bay-influenced Water Mass (GBWM), Geum River-influenced Water Mass (GRWM), Yellow Sea Bottom Cold Water Mass (YSBCWM) and Cheonsu Bay Water Mass (CBWM). Water quality of the GBWM (Taean Peninsula coastal area), which has relatively low salinity and high concentrations of nutrients, is strongly controlled by the Gyunggi Bay coastal water, which is under influence of the Han River freshwater. In this water mass, the mixed layer is always developed by strong tidal mixing. As a result, a tidal front is formed along the offshore boundary of the mixed layer. Such tidal fronts probably play an important role in the distribution of phytoplankton communities, SPM and nutrients. The GRWM, with low salinity and high nutrients, especially during the flood summer season, is closely related to physiochemical properties of the Geum River. During the flood season, nutrient-enriched Geum River water mass extends up to 60 km away from the river mouth, potentially causing serious environmental problems such as eutrophication and unusual and/or noxious algal blooms. Offshore (<$30{\sim}40m$ in water depth) of the study area, YSBCWM coupled with a strong thermocline can be identified in spring-summer periods, exhibiting abundant nutrients in association with low temperature and limited biological activity. During spring and summer, a tidal front is formed in a transition zone between the coastal water mass and bottom cold water mass in the Yellow Sea, resulting in intensified upwelling and thereby supplying abundant nutrients to the GBWM and GRWM. Such cold bottom water mass and tidal front formation seems to play an important role in controlling water quality and further regulating physical ecosystem processes along mid-western Korean coastal area.

• Ocean and Polar Research
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• v.33 no.1
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• pp.13-20
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• 2011

Comprehensive data collection was carried out between 2001-2006 to investigate the concentration levels of chlorophyll-a, nutrients (DIN and DIP), and COD for surface waters of Korean coastal areas. A statistical analysis of these parameters was carried out on the basis of the frequency distribution of their concentration. Furthermore, the numeric grading for chlorophyll-a, DIN, DIP, and COD concentrations were derived statistically from the normalized frequency distribution of log-transformed data. The statistical grading clearly reflects the water quality characteristics of three Korean coastal water bodies (Western, Southern and Eastern coastal zones), which indicate common environmental and ecological characteristics. So, this study could provide useful information to set up the guideline for water quality assessment of Korean coasts.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.43-51
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• 2005

This paper presents a waste load allocation study for the Incheon coastal environment, where a computer model, called AQUASEA, was applied. A finite element mesh was constructed and refined to cover the complicated geometry of Incheon coastal sea. The tidal height at 13 places of Incheon coastal boundary and flow of the Han River were given as an input condition to the tidal simulation. All pollution sources that discharge into Incheon coast were given as input data to the water quality simulation. The modeled parameters include tidal flow and COD(Chemical Oxygen Demand). The model was calibrated and verified with the field measurements. The model results showed reasonable agreements with field measurements in both tidal flow and water quality. Systems analysis showed that the pollution load from the Han River caused recognizable impacts on the water quality of Incheon coast from Yeomhwa waterway to northern area of Younghungdo. The loads from Incheon City affected water quality from the area below Youngjongdo to the area above Jawalldo. The discharge from the Sihwa Lake caused discernible impacts on the coastal zone from the dike outlet to the Incheon harbor, and pollution loads from Kyungkido affected the sea near the Oido. An effective water quality management plan was developed from the waste load allocation analysis of the validated model, that the maximum waste loads can be discharged without violating the water quality standard given in the Incheon coastal environment.

• Journal of Sensor Science and Technology
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• v.21 no.1
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• pp.46-52
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• 2012

The rapid water pollution in stream, river, lake and sea in recent years raises an urgent need for continuous monitoring and policymaking to conserve the global clean environment. In particular, the increasing water pollution in coastal marine areas adds to the importance of the environmental monitoring systems. In this paper, the mobile server is designed to gathers information of the water quality at coastal areas. The obtained data by the server is transmitted from field servers to the base station via multi-hop communication in wireless sensor network. The information collected includes dissolved oxygen(DO), hydrogen ion exponent(pH), temperature, etc. By the information provided the real-time monitoring of water quality at the coastal marine area. In addition, wireless sensor network-based flooding routing protocol was designed and used to transfer the measured water quality information efficiently. Telosb sensor node is programmed using nesC language in TinyOS platform for small scale wireless sensor network monitoring from a remote server.

• Journal of Korean Port Research
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• v.12 no.2
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• pp.303-312
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• 1998

It is necessary to quantitatively asses the influence of tidal currents to analysis the coastal current patterns before or after constructing offshore structures like as breakwaters. This assesment can be made through the use of simulation models designed to reproduce the water movements of the area. And it is very important to predict a phenomenon of pollutant dispersion in the area. In this study, in order to predict the changes of sea water quality for the port development plan, Ilgwang harbour, located at the east coast of Pusan, the numerical computations were carried out. The flow patterns were investigated before and after the development of the harbour bay and coastal area connected on it. The computational models are an extension of earlier work on the flow which used the ADI Method (Alternating Direction Implicit Method) in appling to Osaka Bay by KANEKO et al. The transport of pollutant constituents depends upon the currental characteristics of the water-transporting medium. In the currental flow model, water velocities and water levels are computed throughout the regions of it. These value are then used in the mass-balance equation to obtain the pollutant-constituent transport. As a result of this research, the present water quality of Ilgwang harbour and the coastal areas connected on it was proved out some good condition. The changes of sea water quality due to the port development plan of the Ilgwang habour bay and the coastal area were not large compared with the present condition, but it will be likely able to get worse by increasing the semi-enclosed areas in the harbour bay. In order to improve the water quality of the area after development, the method to activate tidal exchange in the area can be needed, as a mitigation technique.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1995.10a
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• pp.108-109
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• 1995

Hypoxia has persisted during summer in the bottom water of the lower portion of the Rappahannock Estuary, a western shore tributary of Chesapeake Bay. A laterally integrated two-dimensional, real-time model, consisting of linked hydrodynamic and water quality models, was developed to study the contributing processes for hypoxia. The hydrodynamic model gives the information of physical transport processes, both advective and diffusive, to the water quality model, which simulates the spatial and temporal distributions of eight water quality state variables. (omitted)

• Journal of Environmental Science International
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• v.16 no.4
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• pp.505-521
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• 2007

This study estimated response of water duality and pollutant behavior according to the discharge and reuse of treated wastewater by three-dimensional eco-hydrodynamic model, and suggest plan that water quality management and environmental restoration in the coastal area including urban stream of Yeosu, Korea. Dispersions of low-saline water and COD by treated wastewater loads (design facility capacity, about $110,000m^3/d$) were very limited in near of effluent site. Nutrients, however, increase compared to the other water quality factors, especially total nitrogen was very sensitive to input loads. When reuse some of treated wastewater to Yeondeung stream, nitrogen was big influence on estuarine water quality. Although current characteristics of treated wastewater such as discharge and water quality were negligible to the change of marine environment, effluent concentration of COD, TN and TP, especially 40% of TN, are reduced within the allowable pollutant loads for satisfy environmental capacity and recommended water duality criteria. Also, controls of input point/non-point sources to Yeondeung stream and base concentration of pollutants in coastal sea itself are very necessary.

• Journal of Korean Society on Water Environment
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• v.37 no.6
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• pp.425-432
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• 2021

A tidal power plant (TPP) has been in operation since the end of 2011 to improve the water quality of Shihwa Coastal Reservoir (SCR). Tidal mixing rate increased 5.6 times after the TPP operation so that in this study, its effects on water quality was assessed through statistical analysis of long-term water quality monitoring data. It was found that the increased tidal mixing contributed to solving the hypoxia problem in the bottom water by preventing the summer stratification. The analysis also showed that the increased tidal mixing had different effects depending on the relative concentration difference for each water quality substances between the SCR and the outside of SCR. The average concentrations of some substances (chemical oxygen demand, total phosphorus, chlorophyll-a) with higher concentrations than the outside of SCR decreased due to the dilution effect, but the other substances (total nitrogen, dissolved inorganic nitrogen, dissolved inorganic phosphorus) with lower concentrations compared to the outside ones increased on the contrary. Factor analysis also showed a consistent result that the first factor accounting for the water quality was changed from the organic-related substances to the nutrient-related substances after the increased tidal mixing. These results imply that the focus of future water quality management needs shifting from the organic substances to the nutrients, particularly dissolved inorganic nutrients. Considering the effect of inflow seawater on the nutrients, the management area should be extended to cover not only SCR but also a certain area outside of SCR.