• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.2
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• pp.102-114
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• 2013

The basin of Lake Shihwa is one of highly industrialized region of Korea and a current environmental issue of study area is the operation of tidal power plant (TPP) to improve water quality. The application of water quality index (WQI) which integrates five physiochemical parameters (transparency, DO, DIN, DIP and chlorophyll-a) of water quality in Lake Shihwa and outer sea during 2011~2012 were performed not only to evaluate the spatial and temporal distribution of the water quality but also to assess the effect of water quality improvement by the operation of tidal power plant. The higher WQI values were observed in monitored sites near the industrial complexes in Lake Shihwa and the outfall of wastewater treatment plants (WWTPs) in outer sea. This indicates that the quality of seawater is influenced by diffuse non-point sources from industrial, municipal and agricultural areas in Lake Shihwa and by point sources from the effluence of municipal and industrial wastewater throughout WWTPs in outer sea. Mean WQI value decreased from 53.0 in 2011 to 42.8 in 2012 of Lake Shihwa. Water quality has improved significantly after TPP operation because enhancement of seawater exchange between Lake Shihwa and outer sea leads to improve a hypoxic condition which is primarily a problem in Lake Shihwa. Mean WQI of outer sea showed similar values between 2011 and 2012. However, the results of hierarchical cluster analysis and the deterioration of water quality in summer season indicate that the operation of tidal power plant was not improved the water quality in the upper most area of Lake Shihwa. To successfully improve overall water quality of Lake Shihwa, it is urgently necessary to manage and reduce of non-point pollution sources of the basin of Lake Shihwa.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.94-96
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• 2003

Since 1995, MOCT(Ministry of Construction and Transportation) and KOWACO(Korea Water Resources Corporation) have established the National Groundwater Monitoring Network in South Korea and also MOE(Ministry of Environment) has operated Groundwater Quality Monitoring network. Until 2001, 202 monitoring stations by MOCT and 780 monitoring wells by MOE have been constructed, measured groundwater level and analyzed water samples. Groundwater quality analysis has been conducted two times a year during last 6 years for all monitoring wells. The quality data has about 15 components including pH, COD, Count of Coliform group, and etc.. Trend analysis has been peformed for 6 components(Coliform, pH, COD, NO$_3$-N, Cl and EC) of water quality which are analyzed more than 7 times for total monitoring wells. Two test methods have been used ; Sen's test and Mann-Kendall test. These trend tests have been done at the 0.05 significance level. By the result of Sen's test, Count of Coliform group has either upward or downward trends at 4.3 percent of the monitoring points. pH does at 5.6 percent, COD does at 8.6 percent, Nitrate-Nitrogen does at 13.2 percent, Chloride does at 13.4 percent, and. EC does at 11.6 percent of the monitoring points. The exact causes of the groundwater quality trends are difficult to specify. Notable downward trends in nitrate at many monitoring points may be the result of reduction on some contamination sources. Potential causes include diminished agricultural areas, improvements in sewage treatment and a decrease in atmospheric deposition. Increase in chloride at many monitoring points may be the result of increased non-point source pollution such as road salting and runoff from sprawling paved developments and suburbs.

• Journal of Environmental Impact Assessment
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• v.29 no.1
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• pp.8-25
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• 2020

Industrialization has increased the production of road-deposited sediments (RDS) and the level of heavy metals in those RDS, which can have a significant impact on the surrounding aquatic environments through non-point pollution. Although the relationship between contamination characteristics and particle size of RDS is important for pollution control, there is very little information on this. In this study, we investigated the characteristics of grain size distribution and heavy metal concentrations in the road-deposited sediments (RDS) collected from 25 stations in Shihwa Industrial Complex. The environmental impact of RDS with particle size is also studied. I_geo, the contamination assessment index of each metal concentration, represents the RDS from Shihwa Industrial Complex are very highly polluted with Cu, Zn, Pb and Sb, and the levels of those metals were 633~3605, 130~1483, 120~1997, 5.5~50 mg/kg, respectively. The concentrations of heavy metals in RDS increased with the decrease in particle size. The particle size fraction below 250 ㎛ was very dominant with mass and contamination loads, 78.6 and 70.4%, respectively. Particles less than 125 ㎛ of RDS were highly contaminated and toxic to benthic organisms in rivers. RDS particles larger than 250 ㎛ and smaller than 250 ㎛ were contaminated by the surrounding industrial facility and vehicle activities, respectively. As a result of this study, the clean-up of fine particles of RDS, smaller than 125-250 ㎛, is very important for the control and reduction of non-point pollution to nearby water in Shihwa Industrial Complex.

• The Korean Journal of Malacology
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• v.32 no.2
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• pp.83-93
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• 2016

For the continuous stable production of oyster, estimation of food availability (F) was carried out in Goseong Bay, south of coast Korea. Primary productivity ranged from 0.07 to $0.44gC/m^2/day$ (average $0.25gC/m^2/day$), lowest in July and highest in January. The distribution of primary productivity at Goseong Bay showed the pattern of "high in the south and low in the north." Food availability (F) was $F{\leq}0$, indicating insufficient food supply, from August to November and F > 0 from January to April. Continuous insufficient food supply was observed at 18 oyster farms in the southern part of the bay and 4 in its northern part. Mortality at the oyster farms was 56% on the average, and around 58% of death occurred during November when food supply was insufficient. The optimal population of cultured oyster per unit flow area was calculated to be $110-115indiv./m^2$ (198-201 indiv./string). When the sea area was divided into 3 regions (A, B, C) according to carrying capacity, the carrying capacity of (A) regions was $52-53indiv./m^2$ (93-95 indiv./string), (B) regions was $142-144indiv./m^2$ (255-259 indiv./string), and (C) regions was $198-202indiv./m^2$ (356-363 indiv./string). In particular, (A) regions showed extremely low productivity. For continuous stable oyster farming at Goseong Bay, it is necessary to control point and non-point source pollution through continuous environmental monitoring and to adjust harvest according to the base carrying capacity during the season of high water temperature.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.642-648
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• 2012

To evaluate the water quality in Juksancheon constructed wetlands for treating non-point source pollution, the removal rates of nutrients in water and the total amounts of T-N and T-P uptakes by water plants were investigated. Chemical characteristics of T-N and T-P in sediment were investigated. The concentrations of BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), SS (Suspended Solids), T-N and T-P in inflow were 0.07~1.47, 0.60~2.65, 0.50~4.60, 1.38~6.26 and $0.08{\sim}0.32mg\;L^{-1}$, respectively. The removal rates of BOD, COD, SS, T-N, and T-P were -10, 51, 66, -3 and 5%, respectively. The maximum amount of T-N uptake by water plants in August was $368.7mg\;plant^{-1}$ in the $2^{nd}$ treatment stage by Nymphoides peltata, $1314.6mg\;plant^{-1}$ in the $3^{rd}$ treatment stage by Iris pseudacorus, $1160.4mg\;plant^{-1}$ in the $4^{th}$ treatment stage by Nymphaea tetragona GEORGI, respectively. The maximum amount of T-P uptake by water plants in August was $121.7mg\;plant^{-1}$ by Nymphoides peltata in the $2^{nd}$ treatment stage, $268.7mg\;plant^{-1}$ by Iris pseudacorus in the $3^{rd}$ treatment stage and $212.0mg\;plant^{-1}$ by Nymphaea tetragona GEORGI in the $4^{th}$ treatment stage, respectively. Organic matter contents in sediments were not different. Contents of T-N and T-P in sediments were higher in spring. Microbial biomass C:N:P ratios in sediments in spring, summer, autumn and winter were 117~140:1~4:1, 86~126:5~6:1, 68~101:2~6:1 and 47~138:2~4:1, respectively. We could conclude that Juksancheon constructed wetlands show high removal efficiencies of COD and SS. However, improvements of management in winter season should be considered to improve the removal efficiencies of pollutants.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.142-148
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• 2011

This study was carried out to clarify the change characteristics of stream water quality by type of forest from June to August, 2009 in three stands (Castanea crenata, Pinus densiflora and Plantation Land) of Samgye-ri Naedong-myeon Jinju-si Gyeongsangnam-do. The pH of stream water in three stands was highest in Pinus densiflora (pH 7.18) followed by Castanea crenata (pH 6.90) and Plantation land (pH 6.90) while the electrical conductivity of stream water was highest in Plantation land followed by Castanea crenata stand and Pinus densiflora stand was the lowest. Cations contents of stream water in three stands were high in order of $Ca^{2+}$, $Na^{+}$, $Mg^{2+}$, $K^{+}$, and $NH_{4}{^{+}}$. But anions of stream water in Castanea crenata stand and Pinus densiflora stand were high in order of $SO_{4}{^{2-}}$, $Cl^{-}$ and $NO_{3}{^{-}}$ while those of stream water in Plantation land were high in order of $SO_{4}{^{2-}}$, $NO_{3}{^{-}}$ and $C\lambda^{-}$. The stream water in three stands was significant at pH, EC, $NO{^{3-}}$, $Ca^{2+}$, $Mg^{2+}$, $Na^{+}$, $Cl^{-}$, TNU and Color by duncan test. These results indicate that quality of stream water have a difference among three stands. The level of pH, $NH_{4}{^{+}}$, $Cl^{-}$, $SO_{4}{^{2-}}$ and $NO_{3}{^{-}}$ of stream water in three stands were within the domestic use standard for drinking water. but turbidity and color of stream water were more than that of domestic use standard for drinking water. Therefore, non-point sources like urban forest watersheds which are soil erosion and fertilizer application lands should be taken to the appropriate mitigation measures if they are to be used as source of drinking water.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.6
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• pp.111-119
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• 2011

The main objective of this study was to evaluate the effects of control-release fertilizer (CRF) on pollutant loadings from a small watershed. The Baran watershed, 386 ha in size, was selected as the study site, and the AGNPS (Agricultural Non-point Source Pollution) model was used to evaluate the effects of fertilizer types. Digital maps of digital elevation (DEM), slope distribution, channel, flow direction, landuse, soil, and curve number were extracted from the study watershed. Model parameters related to hydrology and water quality were calibrated and validated by comparing model predictions with the observed data collected for 2 years (1999 to 2000). Calibration and validation resulted in $R^2$ values of 0.75-0.91 for all the water quality parameters. All the paddy fields (21.2 %) of the study watershed were sprayed by either CRF or NPK (standard fertilizer). In CRF application, total nitrogen (TN) load was 4.9% less than NPK application, however total phosphorus (TP) load was 0.7 % more than NPK application. In CRF application, considering only paddy fields in the study area, TN load was 38.7 % less than NPK application. Using CRF in paddy fields could be one of the ways to reduce pollutant loadings from agricultural watersheds, however, in order to confirm it, more researches about effects of using CRF are necessary.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.505-509
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• 2008

우리나라의 최근에 개발된 신도시나 신시가지를 제외한 대부분이 합류식 하수관망으로 구성되어 있다. 이에 따른 초기강우시 도시 인접하천으로 유입되는 유출수가 수질오염을 가중시키고 있다. 분류식 하수관이 설치된 지역이라도 강우에 의해 도시지역 노면에서 우수관을 통해 하천으로 배출되며 유출수 자체도 오염물질 농도가 높고 유해물질까지 함유하고 있는 경우가 많다. 그러므로 도시하천에 대한 종합적인 수질관리를 위해서는 점오염원뿐만 아니라 초기강우시 도시 유출수의 수질 및 오탁부하량 등 비점오염원에 대한 기초조사 및 해석이 선행되어야 한다고 판단된다. 따라서, 이 연구에서는 도시하천의 초기강우에 의한 유출수의 수질특성을 분석하기 위하여 홍제천, 중랑천, 남가좌배수구역 및 군자배수구역 등 4개 도시유역에서 직접 시료를 채취하여 각 수질항목에 대하여 분석하였다. 수질분석은 환경오염공정시험법이나 표준시험법에 준하였고, 현장에서 실측이 가능한 항목들은 현장에서 측정하였으며, 나머지 항목은 시료를 즉시 실험실로 운반하여 분석하였다. 홍제천은 1996년 8월부터 1997년 9월까지 5개 강우사상의 자료를 분석하였고, 중랑천은 2001년 5월부터 2005년 4월까지 7개 강우사상, 남가좌배수구역은 1995년 7월에서 1997년 9월까지 5개 강우사상, 그리고 군자배수구역은 2005년 4월부터 2007년 9월까지 11개 강우사상에 걸쳐 수질분석을 실시하였다. 분석된 수질자료를 이용하여 도시지역의 초기강우에 의한 초기유출수와 수질의 관계를 분석 비교 하였으며, 또한, 초기유출수에 따른 비점오염원별 상관성을 분석하여 유량 측정을 통하여 보다 손쉽게 총 오염부하량을 산출 할 수 있도록 비유량과 SS, $BOD_5$, COD 등의 수질성분간의 상관계수와 회귀식을 도출하여 이들 상관식으로부터 유량변화에 따른 수질성분의 예측에 활용토록 하였다. 그러나, 외삽구간의 유량에 대한 수질 예측 결과에는 큰 오차가 있을 수 있으므로, 보다 다양한 유량에 대한 수질관측자료로 보완된 상관식의 개발로 극복되어질 수 있을 것으로 판단된다. 이 연구의 성과는 도시유출에서 수질과의 상관성과 도시하천의 유량 수질관리에 유용한 자료로 활용될 수 있을 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.465-469
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• 2008

수도권의 중요한 상수원인 팔당호 수질에 큰 영향을 주고 있는 경안천 유역의 오염배출량을 저감하기 위하여 많은 인공습지조성이 계획되었으나 이들의 위치선정의 적합성에 대한 분석이 부족한 실정이다. 또한 경안천은 상류에서 중류까지는 주변 농경지의 용수공급을 위해 많은 수중보가 설치되어 물의 흐름이 단절되어있어 수리적 요소에 인공요인으로 작용하고 있으며, 하류로 갈수록 하천이 곡선형태로 흐르고 하폭 또한 넓어져 자체적으로 유기물이 증가하기 좋은 환경을 가지고 있다. 본 연구에서는 유역의 자연적, 인공적 요소를 고려한 물리적 모델을 구축하고 각 오염원특성별 부하량 분석을 통한 속성정보를 반영하였으며 오염저감시설설치 시나리오의 타당성분석을 분석을 수행하였다. 연구과정을 좀더 상세히 살펴보면 첫째, 비점오염원의 주된 경로중 하나인 축산계부하량 저감을 위하여 지형적 인자를 고려한 인공습지조성 적지분석 결과를 HSPF모델에 반영하였다. 둘째, 기존 오염 총량제에서 수행해오던 오염부하량 산정방식을 통해 산정된 양을 유역단위로 재분배 하여 오염원 분포를 반영하였다. 주요 오염부하량인 축산계와 토지계의 오염부하량만을 적용하였으며 일부 오염원 항목들은 생략하거나 하수처리시설을 통해 처리되고 있는 것으로 모의하였다. 셋째, 각 시나리오별 시뮬레이션을 수행하여 경안천 인공습지조성가능성 및 수질개선 효과를 예측하였다. 기존의 점오염원 처리시설만으로는 하천에서의 목표수질을 만족시키는데 한계가 있기 때문에 점오염원 저감시설뿐 아니라 비점오염원 저감시설인 인공습지를 기존의 처리시설에 연계하여 시나리오를 구성하였다. 기존습지시설의 오염저감율은 각 시설들의 평균값을 적용하였으며 처리효율은 BOD, TN, TP 각각 40%, 25%, 12%로 적용하였다. 오염원분포를 고려한 모의결과 현재 인공습지 입지대상지역들 중 좀 더 효율적인 오염저감 효과를 보이는 지역이 분석되었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.79-79
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• 2011

도시지역에서 강우발생 시 우수는 대부분 도로를 통해 이동하고 배수된다. 도로의 배수시설은 도로면의 안전을 확보하기 위한 목적뿐만 아니라 도로 이외의 지역에 흐르는 유출수를 배수시키는 기능도 포함하고 있다. 현재 우리나라의 도로배수는 빗물받이와 횡유입부를 통해 대부분 이루어지고 있다. 이러한 배수시설이 제 기능을 충분히 발휘하지 못하면 노면수가 정체되고, 노면수가 인근 주택가로 유입되어 침수피해를 가중시키는 경우도 있고, 교통의 원활한 흐름을 저해하게 된다. 도로배수시설의 설계 시 설계빈도에 상위하도록 충분한 여유를 두고 설치하더라도 부유잡물 등에 의해 그 효율이 저하될 수도 있다. 또한 배수시설을 통해 배수되는 초기 유출수는 많은 비점오염원을 포함하고 있고, 이러한 오염원이 하천으로 유입되어 하천수 및 저수지를 오염시킬 수도 있다. 본 연구에서는 배수시설 중 빗물받이의 효율개선과 비점오염원을 처리할 수 있는 비노출배수로에 대하여 수리실험을 실시하고 효과를 검토하였다. 이를 위해 폭 2.4 m, 길이 10.0 m의 실험도로를 제작하였고, 유입유량을 증가시켜가며 배수효율을 확인하였다. 또한 흙탕물을 유입시켜 비노출 배수로를 통해 배수시킨 후 유입수와 유출수의 부유물질, BOD, $COD_{Mn}$, TN, TP의 량을 측정하고 변화를 확인하였다. 이때 비점오염원처리를 위한 여과재료로는 제오라이트를 이용하였다. 실험결과 실험도로의 측면에 비노출 배수로를 설치하였을 경우 도로위에 수심이 거의 발생하지 않으면서 배출할 수 있는 최대 유량은 2.29 l/s였고, 서울시를 기준으로 설계빈도 10년에 대하여 본 연구의 실험도로 규격에서의 유출량이 1.09 l/s임을 고려할 때 10년 빈도 강우강도 발생 시 비노출 배수로가 충분한 여유를 가지고 배수 시킬 수 있을 것으로 판단된다. 본 실험도로의 규격에서 2.29 l/s의 유출량이 발생하기 위한 강우강도는 서울시를 기준으로 100년 빈도에 상위하는 강우강도로 비노출 배수로에 막힘이 없는 경우 100년 빈도의 강우시에도 노면수 배출이 가능하였다. 쓰레기와 모래와 같은 부유잡물이 배수로를 막고 있다 하더라고 배수효율 저하는 크게 발생하지 않았다. 또한 BOD와 $COD_{Mn}$의 농도는 유입수와 비교하여 30%이상의 제거 효율을 보였다. 특히 부유물질의 경우 제거효율이 50 %인 것으로 검토되어 본 연구의 비노출 배수로가 초기우수의 오염원제거에 효과가 있을 것으로 판단된다.