• Journal of Korean Society on Water Environment
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• v.29 no.6
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• pp.762-776
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• 2013

Load duration curve was applied to determine important water quality parameter control term for improvement of Paldang lake water quality. Load duration curve was analyzed with long term data from 1985 to 2012 including water quality, flow rate and climate state of Paldang water environment. From the result of flow rate patterns of paldang lake, differences between high and low flow rate of each year showed tendency of increase because rainfall characteristics of paldang lake watershed were changed by climate exchange. Both of land use state of upper Paldang lake watershed and number of limit excess from load duration curve indicated that seasonal action related with land use such as agricultural fertilizer distribution in upper watershed affected Paldang lake water quality. So focused BOD (biological oxygen demand) management during spring season from march to June is required to control organic materials in Paldand lake. The main affecting factor of TOC (total organic carbon) increase in Paldang lake was initial rainfall after march. T-N (total nitrogen) kept increasing during research period, so enhancement of T-N standard is needed to T-N control. Initial rainfall and increase of temperature during spring season from March to June showed a positive correlation with TP (total phosphorus) and Chl-a, respectively.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.135-140
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• 2012

In this study, the behavior of pollutant was calculated at Paldang reservior according to several scenarios of the accidental water pollution by means of the numerical models for forecasting water quality. Also managemental plans for situation of the accidental water pollution happening at Paldang watershed were simulated. According to the simulating results, a plan of increase of discharge at Cheongpyeong dam reduced the peak concentration of pollutants, whereas extended the time for stopping water intake. Another plan, drop of water elevation at Paldang dam, decreased seriously the time for stopping water intake although there were a little effect to decrease the peak concentration. Thus it was concluded that appropriate combinations of the plans for the increase discharge and the dropping water elevation should be used to deal with the accidental water pollution at Paldang watershed.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.1
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• pp.49-62
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• 2005

Lake Paldang is a main resource of drinking water for 20 million people in the greater Seoul area. Dry deposition amounts of nitrogen and sulfur were estimated for three typical days in each season over the watershed of Lake Paldang. Models- 3/CMAQ (Community Multiscale Air Quality) and MM5 (Mesoscale Model) were used to predict air quality and meteorology, respectively. Aerosols as well as gaseous pollutants were considered. Nitrogen was mainly deposited in the form of HNO, while most of sulfur was deposited in the form of SO$_2$. Contribution of secondary pollutants was the largest in fall since they were transported from the greater Seoul area. However, contribution of secondarily-formed particulate pollutants to the nitrogen deposition was the largest in winter because semi-volatile ammonium nitrate favors lower temperature. Annual deposition amounts of nitrogen and sulfur were 37% and 26% of their emission amounts, respectively, over the watershed of Lake Paldang. Higher value of the nitrogen deposition showed a more influence of pollutants emitted in the greater Seoul area.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.5
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• pp.367-377
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• 2014

Paldang lake which is the most important water resource in Korea is classified as a stream type reservoir and water quality of Paldang lake can be significantly influenced by external pollutant source. So this study was aimed to determine focused control BOD and TP sources of each unit watershed upper Paldang lake through analysis of pollutant source distribution and pollutant runoff characteristics. Generated load, discharge load, delivery load and each load density of 11 unit watersheds upper Paldang lake were calculated using data of water quality and flow rate from pollutant sources and 74 small streams. As a result of generated load, discharge load and delivery load of BOD and TP from pollutant sources, the most BOD generated load was taken by livestock with 66% of total BOD discharge load and domestic had the most BOD discharge load, 42.7%. The ratio of delivery load of livestock and domestic was 36.4% and 34.3%, respectively. Livestock occupied high ratio of TP generated load, discharge load and delivery load with 82.5%, 44.4% and 46.7%, respectively. Gyeongan watershed which had high population density showed the highest BOD delivery load density of $14.6kg/km^2/d$ and the highest TP delivery load density with $1.23kg/km^2/d$ was analyzed in Cheongmi watershed including the biggest number of livestock. From these results, management of domestic sewer and livestock excrement was determined as a focused control pollutant source. And intensive management about domestic sewer in Gyeongan stream and livestock excrement in Cheongmi stream is required for water quality improvement of Paldang lake.

• Journal of Korean Society on Water Environment
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• v.34 no.6
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• pp.688-702
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• 2018

Since the 1970s regulations against the pollution of drinking water have been introduced in Lake Paldang watershed area. To understand the effects of water environment management policies and the impacts of climate changes on Lake Paldang, a long-term comprehensive study of this watershed and the changes in its water environment is required. In this study, we analyzed changes in the weather, hydrology, sources of pollution, water quality, and algal development from 2000 to 2015 year based on the statistical data provided by several national information systems. While the population and amount of sewage in the Lake Paldang watershed increased by about 1.5 times, the amount of animal manure showed a decreasing trend during the same period. The wastewater also increased by about 1.5 times while the amount of water intakes rose by about 1.14 times. The water quality in front of the Paldang Dam, which is the representative monitoring site of the Lake Paldang, was stable. The annual average BOD concentration remained within 2 mg/L, which is a "Good (lb)" level according to the environment standards of Republic of Korea. The development of phytoplankton and harmful cyanobacteria were largely influenced by meteorological factors.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.504-511
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• 2007

Built-out issue of copper processing appearing recently in the Paldang watershed is a critical problem to deteriorate the basic framework of national water management policy as well as to be simply a copper-related problem. Up to now, Korea government has invested hard and relevant upstream areas have been victimized readily in a variety of field to comply its goal of 'Safe Water Supply'. Because of the reason, the desirable water quality level of the Paldang watershed has been maintained regardless of its dense population. Paldang drinking water management policy is based on residents' understanding which is considered as a 'social capital'. The issue raised in the aspect of water quality management policy should be reviewed on the basis of the 'social capital' concept. One regarding semiconductor industry as a potential industry to export many products in 10 years insists that the industry not be a simple private business but be a prominent part for national competitiveness. There is no doubt about this opinion. However, a nation should support environmental right-to-life of its people prior to any other tasks. In other words, it is really risky to give up people's right due to economic benefits. Therefore, it should not happen to trade 'life', the dignity of man, with national competitiveness which is likely to be preferred in these days. In addition, coherent policy not to destroy 'social capital' promoting Paldang drinking water resource management policy should be maintained.

• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.151-156
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• 2004

A decision support system, Watershed Analysis Risk Management Framework(WARMF), was applied to the Kyungan Stream watershed, a tributary of Lake Paldang, for calculation of total maximum daily loads(TMDL). The WARMF system was developed by Systech Engineering, USA, and has been successfully used in several watersheds, for TMDL studies. The study area was divided into 14 sub-basins, based on digital elevation model(DEM). The integrated watershed and stream model of WARMF was validated by flow and BOD data measured during the year of 1999. There were reasonable agreements between model results and field data, both in water flow and BOD. The validated Kyungan WARMF was extensively utilized to study the quantitative relationship between waste loads and receiving water quality. Based on TMDL guideline at Paldang Lake and Kyungan Stream, the water quality criterion were set to be 3.0mg/L, 3.5mg/L, and 4.0mg/L at the watershed outlet. The allowable waste loads of BOD, both from point and non-point sources, were determined at each water quality criterion. From this study, it was concluded that the WARMF provided several advantages over the conventional application of watershed and stream models for TMDL study, such as time variable simulations, multiple possible soutions, and reduction loads for goal water quality, etc.

• Journal of Korean Society on Water Environment
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• v.35 no.1
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• pp.43-54
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• 2019

The objective of this study was to assess the effect of policies on water quality management based on the changes in pollutants and water quality in Special Water Preservation Area (SWPA) of Lake Paldang watershed from 1990 to 2016. The population, total sewage and flow rate of wastewater in SWPA continuously increased from 1990 to 2016, while the location of new facilities for industrial and livestock facilities has been restricted. However, unlike the buffer zone in which industrial and livestock facilities were continuously reduced after implementing of TMDL, it was found that the effect of land-use regulations on industrial and livestock facilities in SWPA were mitigated by the increase in the size of large facilities. Since 1999 when the emission standard of public sewage treatment plants (STP) was changed, the water quality of Lake Paldang has increased despite the increase of pollutant source. Since emission standard of STP changed in 2012 (BOD 5 mg/L, TP 0.2 mg/L), BOD concentration in Lake Paldang has also improved to the level of water quality in the early 1990s where as TP concentration has remained at its lowest since 1990. BOD and TP average discharge concentration of 43 STP (${\geq}500m^3/day$) in 2016 have been maintained $1.7{\pm}0.7mg/L$ and $0.06{\pm}0.02mg/L$ respectively. While the discharged load of STP in SWPA was decreased by the concentration management, the contribution rate to the total discharged load of non-point pollutants increased to 70 % in 2015, and the contribution rate to the point discharged load of individual treatment facilities increased to 80 %.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.750-757
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• 2008

This study is conducted to characterize and evaluate delivered pollutant loads of point and nonpoint source on the upper watershed of lake paldang. The study area consists of 12 watersheds in Namhan-river and Kyungahcheon, which are approximately 80% of total area of Namhan-river and Kyungahcheon. Based on daily delivered loads from watersheds, 61% of $BOD_5$, 81% of T-N and 70% of T-P were from nonpoint sources, suggesting that delivered loads of nonpoint pollutants be crucial to water quality. On the other hand, 78% of $BOD_5$, 92% of T-N and 87% of T-P as delivered load were from nonpoint sources in an upper watershed of Namhan-river, while 48% of $BOD_5$, 70% of T-N and 57% of T-P as delivered load were from nonpoint sources in a lower watershed of Namhan-river, suggesting higher dependency of point sources than upper watershed of Namhan-river. In the characteristic of delivered loading pollutants from point and nonpoint pollution sources, delivered load of nonpoint pollutants differed significantly by seasonal flow, and as though discharged load of point pollutants were yearly uniform, delivered load of point pollutants was found to be flow-dependent because its delivery ratio was changed.

• Environmental and Resource Economics Review
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• v.17 no.4
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• pp.875-901
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• 2008

This article estimates the economic values of changes in water quality of the Paldang Watershed by using the Choice Experiment (CE). The conditional logit model estimation results show that a small improvement in water quality from the 'status quo' level to the level of 'very good' increases average household's monthly utility by 3,157 Won, whereas a water quality degradation down to the 'normal' level gives rise to an increase in the monthly average utility by 9,649 Won. The corresponding social gain and loss of water quality changes to the Metropolitan Area were thus estimated about 285 billion Won and 872 billion Won, respectively. This article seems meaningful in that it resorts to the new water ecosystem classification criteria and indices that are respondent-friendly. They help a CE study like this to overcome one of its critical weakness that the number and contents of attributes of a CE study can quickly add to the information overload problem, especially where the environmental good under investigation is hard for ordinary respondents to understand.