• Journal of Korean Society on Water Environment
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• v.27 no.5
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• pp.689-698
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• 2011

In South Korea, Total Maximum Daily Load (TMDL) has been enforced since 2004 to restore and manage water quality in the watersheds. However, the appraisal of TMDL in South Korea has lots of weaknesses to establish the plan for recovery of water quality because it just evaluates the target water quality during the particular flow duration interval. In the United States, Load Duration Curve (LDC) method bas been widely used in the TMDL to evaluate the water quality and pollutant loads considering variation of stream flow. In a recent study, web-based Load Duration Curve system was developed to create the LDC automatically and provide the convenience of use. In this study, web-based Load Duration Curve system was applied in the Gapyeongcheon watershed using the daily flow and 8-day interval water quality data, and Q-L Rating Curve was used to evaluate the water quality and pollutant load in the watershed, also. As a result of study, water quality and pollutant load in Gapyeongcheon watershed were met with water quality standard and allocated load in the all flow durations. Web-based Load Duration Curve system could be applied to the appraisal of South Korean TMDL because it can be used to judge the impaired flow duration and build up the plan of load reduction, and it could enhance the publicity. But, web-based Load Duration Curve system should be enhanced through addition of load assessment tools such as Q-L rating curve to evaluate water quality and pollutant load objectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.899-905
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• 2022

Seawater management via Total Pollutant Load Management System (TPLMS) is crucial because it enables local governments to optimally allocate pollutant loads in order to best reduce pollutant load burden while supporting reasonable development. This study analyzed the feasibility of introducing a TPLMS on Gwangyang Bay, a specially managed sea area. We researched the inflow of pollutants and analyzed the present state of seawater quality in Gwangyang Bay and then discussed our findings and reviewed other specially managed sea area with the Gwangyang Bay Advisory Committee. We conclude that TPLMS on Gwangyang Bay is needed and suggest checking economic feasibility, ef iciency, and conducting continuous monitoring of seawater quality indicators such as chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), heavy metals and polcyclic aromatic hydrocarbons (PAHs) prior to introducing a TPLMS in Gwangyang Bay.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.340-345
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• 2003

This study, as a basic study for establishing a influence forecasting/estimating model when drain the deep sea water to the ocean after using it, carried out studies as follows; 1) estimating the amount of river discharge and pollutant loads inflowing into the developing region of deep sea water in East Sea, Korea 2) a field observation of tidal current, vertical distribution of water temperature and salinity, and 3-D numerical experiment of tidal current to analysis physical oceanographic status. The amount of river discharge flowing into the study area was estimated about $462.6{times}10^{3}m^{3}/day$ of daily mean in 2002 year. annual mean pollutant load of COD, TN and TP were estimated 7.02 ton-COD/day, 4.06 ton-TN/day and 0.39 ton/day, respectively. Field observation of tidal current results usually show about $20{\sim}40cm/sec$ of current velocity at the surface layer, it indicated a tendency that the current velocity decreases under 20cm/sec as the water depth increases. We could find a stratification within approximately the depth of 30m in field observation area, and the depth increases. We could find a stratification within approximately the depth of 30m in field observation area, and the differences of water temperature and salinity between the surface layer and bottom layer were about $18^{\circ}C$ and 0.8 psu, respectively. On the other hand, we found that there was a definite as the water mass of deep sea water about 34 psu of salinity.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.99-104
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• 2003

This study investigated the yearly variation of pollutant loads outflowing from six watershed of Yeong-il Bay and compared the relationship of pollutant load and water quality, and estimated the Inner productivity of Yeong-Il Bay by using ${\Delta}COD$ method which analysis nonlinear process of water quality. As the estimated results for the pollutant loads of Yeong-Il Bay, total COD load outflowing from Hyeong-san river in flood season(summer) of 2001 year was 2275.0 kg/hr and in dry(low water) season(winter) 852.8 kg/hr, respectively. Load quantity in flood season was about 2.67 times than that in dry season. And as the calculated results of the net-flux of water for seven divisions, it showed that the net-flux of water increased for the divisions of the north coast and inner sea of Yeong-Il Bay but decreased for the south coast. On the contrary, for the cases which water quantity increase from land, the net-flux of water in estuary front of Hyeong-san river decreased but outflowing quantity of that though division of the south coast of Homi-got increased. Finally, this study compared the Inner productions for flood and dry season of Yeong-il Bay by using ${\Delta}COD$ method.

• Journal of Ocean Engineering and Technology
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• v.19 no.1 s.62
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• pp.14-19
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• 2005

As a basic study for establishing the input conditions of a forecasting/estimating model, used for deep-sea water drainage to the ocean, this study was carried out as follows: 1) estimating the amount of river discharge and pollutant loads into the developing region of deep sea water in the East Sea, Korea, 2) a field observation of tidal current, vertical water temperature, and salinity distribution, 3) 3-D numerical experiment of tidal current to analyze the physical oceanographic status. The amount of river discharge flowing into this study area was estimated at about $462.7{\times}103 m\^3/day$ of daily mean in 2002. Annual mean pollutant load of COD, TN, and TP were estimated at 7.02 ton-COD/day, 4.06 ton-TN/day, and 0.39 ton/day, respectively. Field observation of tidal current normally shows 20-40cm/sec of current velocity at the surface layer, and it decreases under 20cm/sec as the water depth increases. We also found a stratification condition at around 30m water depth in the observation area. The differences in water temperature and salinity, between the surface layer and the bottom layer, were about 18 C and 0.8 psu, respectively. On the other hand, we found a definite trend of 34 psu salinity water mass in the deep sea region.

• Korean Journal of Environmental Agriculture
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• v.27 no.2
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• pp.111-119
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• 2008

This study was conducted to evaluate water quality and pollutant loads on small agricultural watershed in Jeonbuk province. The EC level of investigated watershed ranged from 0.07 to 0.52 dS/m, BOD level ranged from 0.1 to 5.0 mg/L, and $COD_{Cr}$ level ranged from 0.6 to 17.7 mg/L. As above, contents of water quality indicators covered wide range, but each indicator was alike in mean content every other year. The contents of EC, $Ca^{2+},\;Mg^{2+},\;K^+\;and\;Na^+$ were decreased in rainy season, but the contents of BOD, $COD_{Cr},\;COD_{Mn}$, T-N and T-P were not greatly different as compared to dry season. And high content of SS showed substantial sediments near the surface flow out and influence on water system in rainy season. The pollutant loads measured in terminal of watershed were $9.6{\sim}757.9$ kg/day for BOD, $51.2{\sim}1418.5$ kg/day for T-N and $0.3{\sim}44.7$ kg/day for T-P. The pollutant loads of BOD, T-N and T-P in rainy season increased several times as compared to dry season. In rainy season, watershed with more than 30% in the proportion of paddy field to land showed relatively low discharge and pollutant loads in comparison to watershed with less than 30%. The discharge of watershed in rainy season increased 5.7times compared with the dry season in watershed with less than 30% in the proportion of paddy field to land, whereas was only 2.3times in watershed with more than 30%. The correlation coefficient($R^2$) of regression between discharge and pollutant loads of T-N were higher than those of BOD and T-P.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.17 no.3
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• pp.149-157
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• 2005

Typical water quality (WQ) parameters defined in the governing equation of the WQ model are the pollutant loads from atmosphere and watersheds, pollutant release rates from sediment, diffusion coefficient and reaction coefficient etc. The direct measurement of these parameters is very difficult as well as requires high cost. In this study, the pollutant budget equation including these parameters was used to construct the linear simultaneous equations. Based on these equations, the inverse problems were constructed and WQ parameter estimation method minimizing the sum of squared errors between the computed and observed amounts of the mass changes was suggested. WQ parameters, i.e., the atmospheric pollutant loads, sediment release rates, diffusion coefficients and reaction coefficient, were estimated using .this method by utilizing the vertical concentration profile data which has been observed in Cheonsu Bay and Ulsan Port. Values of the estimated parameters show a large temporal variation. However, this technique is persuasive in that the RHS (root mean square) error was less than $5.0\%$ of the observed value ranges and the agreement index was greater than 0.95.

• Journal of Environmental Impact Assessment
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• v.18 no.2
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• pp.59-67
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• 2009

Water quality of the Lake Youngrang in the Sokcho City is eutrophic. Jangcheon is the largest inflow source to the lake. Major pollutant sources are stormwater runoff from resort areas and various land uses in the Jangcheon watershed. A storm sewer on the southern end of the lake is also an important pollution source. In this study, water quality modelling for Lake Youngrang was carried out considering the rainfall-runoff pollution loads from the watershed. The rainfall-runoff curves and the rainfall-runoff pollutant load curves were derived from the rainfall-runoff survey data during the recent 4 years. The rainfall-runoff pollution loads and flow from the Jangcheon watershed and the storm sewer were estimated using the two kinds of curves, and they were used as the flow and the boundary data of the WASP model. With the measured water quality data of the year 2005 and 2006, WASP model was calibrated. Non-point pollution control measures such as wet pond and infiltration trench were considered as the alternative for water quality management of the lake. The predicted water quality were compared with those under the present condition, and the improvement effect of the lake water quality were analyzed.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.2
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• pp.65-71
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• 2008

A monsoon season monitoring data from June to September, 2005 of a small forested watershed located at the upstream of the North Han River system in Korea was conducted to analyze the flow variations, the NPS pollutant concentrations, and the pollution load characteristics with respect to sampling frequencies. During the 4-month period, 1,423 mm or 79.2% of annual rainfall(1,797 mm) were occurred and more than 77%, 54% and 68% of annual T-N, $NO_3$-N and T-P loads discharged. Flow rate was continuously measured with automatic velocity and water level meters and 58 water quality samples were taken and analyzed. It was analyzed that the flow volume by random measurement varied very widely and ranged from 79% to 218% of that of continuous measurement. It was recommended that flow measurement of small forested watersheds should be continuously measured with automated flow meters to precisely measure flow rates. Flow-weighted mean concentrations of T-N, $NO_3$-N and T-P during the period were 2.114 mg/L, 0.836 mg/L, and 0.136 mg/L, respectively. T-N, $NO_3$-N and T-P loads were sensitive to the number of samples. And it was analyzed that in order to measure the pollution load within the error of 10% to the true load, the rate of sampling frequency should be higher than 89.7% of the sample numbers that were required to compute the true pollution load. If it is compared to selected foreign research results, about 10 water samples for each rainfall event were needed to compute the pollution load within 10% error. It is unlikely in Korea and recommended that thorough NPS pollution monitoring studies are required to develop the standard monitoring procedures for reliable NPS pollution quantification.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.342-349
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• 2016

Andong belongs to the Nakdong River Basin, Nakdong River is flowing through the city, including Andong dam and Imha dam. The runoff due to provincial transfer and impervious area has been increasing by urbanization increases and nonpoint source loads. In this study, we evaluate the runoff and nonpoint pollution loads in accordance with the development targeted at selected urban water cycle leading to Andong city. Andong city leading to the water cycle plan to evaluate the directly runoff and BOD, T-N and T-P nonpoint pollutant loads using the CN into account the temporal and spatial changes. Evaluation, direct runoff per year is 10.41 % if the green roof and a water permeable pavement replacement, water cycle parks and streets compositions, City impermeable layer improvements to be business including four kinds of scenario is applied to both the development and the BOD non-point pollutant loads 20.56%, T-N 9.55% and T-P pollution and nonpoint loads was investigated to be reduced 14.29%. Four kinds of low lapse rate of the development scenario of the highest thing urban impervious surface was investigated by improving business development prior year annual direct runoff is 6.25 %, BOD nonpoint pollution loads are 11.84%, T-N nonpoint pollution loads are 4.46 % and T-P was investigated by reducing pollutant loads to be 10.20%.