• 한국농공학회논문집
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• 제57권1호
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• pp.89-97
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• 2015

This study is to assess the effect of non-point source pollution discharge loads between tillage and no-tillage applications for upland crop areas using SWAT (Soil and Water Assessment Tool) watershed modeling. For Byulmi-cheon small rural catchment ($1.17km^2$) located in upstream of Gyeongan-cheon watershed, the rainfall, discharge and stream water quality have been monitored in the catchment outlet since 2011. The SWAT model was calibrated and validated in hourly basis using 19 rainfall events during 2011-2013. The average Nash-Sutcliffe model efficiency and $R^2$ (determination coefficient) for streamflow were 0.67 and 0.79 respectively. Using the 10 % surface runoff reduction from experiment results for no-tillage condition in field plots of 3 % and 8 % slopes under sesami cultivation, the soil saturated hydraulic conductivity for upland crop areas was adjusted from 0.001 mm/hr to 0.0025 mm/hr in average. Under the condition, the catchment sediment, T-N (total nitrogen, TN), and T-P (total phosphorus, TP) discharge loads were reduced by 6.9 %, 7.4 %, and 7.7 % respectively.

• 상하수도학회지
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• 제26권3호
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• pp.479-486
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• 2012

Runoff characteristics of pollutant loads of the lower Han River was studied before full implementation of Total Pollution Load Management System(TPLMS). Magnitude of macroscopic(annual) fluctuation was in the order of Namhan River > Han River > Bukhan River, gross weight TP > gross weight TN > gross weight BOD, gross weight deviation > concentration deviation. Flux variation was higher than that of concentration. Microscopic(weekly) fluctuation showed similar pattern to macroscopic scale. TP showed the highest deviation resulting in the lowest reliability. 60% of annual flux passed during summer 3months resulting in 43-46% pass of gross weight at the lower Han River. Strong correlation was found between flux and gross weight especially in gross weight TN. Gross weight pollution increased as high as 400% while passing Seoul area due to the concentration. The deviation from moving average increased during summer season in the gross weight TP and BOD. Seasonal tendency was confirmed especially in gross weight TN and TP using autocorrelation function.

• 한국물환경학회지
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• 제25권2호
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• pp.193-204
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• 2009

The study was conducted investigation on land of D-dong in N city which is an urban area and D myeon of N city which is a suburban area, based on high resolution satellite image, to find out actual land usage. As for D-dong in N city, different rate between actual usage and official land information was 0.5~4.8% in terms of 5 major land types (paddy field, farm, ground, forest, and others). D myeon in N city posted 1.4~8.4%, which is higher than that of its counterpart. As for unit load, "land" which is large in terms of load presented a big difference between official information and actual usage. On the other hand, the levels of paddy, field, forest and others posted only small changes in load. In case of T-P, in particular, unit of each land type is lower than BOD and T-N, showing almost no changes in pollution loads.

• 한국농공학회논문집
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• 제55권5호
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• pp.1-7
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• 2013

The objective of this research was to experimentally test the effect of tillage methods on the reduction of runoff, non-point source (NPS) pollution load, sediment and discharge under a rainfall simulation. We used the runoff plots of $5m{\times}30m$ ($L{\times}W$) in size. Experimental treatments were conventional tillage (CT), CT-rice straw bundle (CT-RSB) and two no-till (NT) plots; slope of 3 % or 8 % ; and rainfall intensity of 30 mm/hr. The rainfall simulation was conducted to three times. The time to initial runoff from NT plots was less than that from CT plots regardless of the slope and it was delayed about 65~90 % compared to that of CT plot. And sediment discharge of 8 % slope reduced to 55 % compared to CT plot. But the sediment discharge was not occurred at 3 % slope. The NT and CT-RSB methods have a great possibility of reducing runoff and NPS pollution loads. Runoff rate of NT plots was significantly lower than those of CT plot. The average NPS pollution loads of the NT plots and CT-RSB plot reduced about 55~80 % and 2.1~40 % compared to those of the CT plots, respectively. It was also shown that runoff and NPS pollution loads reduction by NT method could be very significant and contribute to improve the water quality of streams in agricultural regions. It was concluded that the use of NT method on agricultural fields could reduce soil erosion and muddy runoff significantly and help improve the water quality and aquatic ecosystem.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2003년도 춘계학술발표회
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• pp.191-200
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• 2003

Gunsan coastal area is one of region increasing pollution problems. One of the most important factors that cause eutrophication is nutrient materials containing nitrogen and phosphorus which stem from excreation of terrestial sources. At this study, the three-dimensional numerical hydrodynamic and ecosystem model, which was developed by Institute for Resources and Environment of Japan, were applied to analyze the processes affecting the eutrophication. The residual currents, which were obtained by integrating the simulated tidal currents over 1 tidal cycle, showed the presence of a typical. Density driven currents were generated westward at surface and eastward at the bottom in Geum estuary area where the fresh waters are flowing into. The ecosystem model was calibrated with the data surveyed in the field of the study area in annual average. The simulated results of DIN were fairly good coincided with the observed values within relative error of 32.39%. correlation coefficient(r) of 0.99. In the case of DIP, the simulated results were fairly good coincided with the observed values within relative error of 24.26%, correlation coefficient (r) of 0.82. The simulations of DIN and DIP concentrations were performed using ecosystem model under the conditions of 20 ∼ 80% pollution load reductions from pollution sources. In study area, concentration of DIN and DIP were reduced to 20∼80% and under 10% in case of the 80% reduction of the input loads from fresh water respectively. But pollution loads from sediment had hardly affected DIN and DIP concentration. For the environment management of coastal areas, in case of Kunsan area, the most important pollution sources affecting eutrophication phenomenon were found to be the input loads from fresh water.

• 한국물환경학회지
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• 제28권6호
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• pp.859-865
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• 2012

It is necessary to evaluate performances hitherto carried out in the management of Total Maximum Daily Loads (TMDLs) and to set up direction so that this system can be improved continuously in the future. This study was investigated load allocation achievement ratio, water quality goal achievement ratio and interrelation between water quality goal and load allocation for the first period (2004~2010). Load allocation achievement and BOD water quality goal achievement ratio were 50% and 73% in Guem River Basin, respectively. The main reason for excess of load allocation and shortfall of water quality goal were unfulfilled reduction plan and pollution sources increment. Therefore, it is necessary to develop enhanced pollution sources prediction method and make a list realizable reduction plan. 63% of the unit watershed was not interrelation between water quality goal and load allocation. The reason why water quality goal and load allocation had not correlation were water quality of upper unit watershed, increment of inflow quantity, effluent water quality of wastewater treatment plant affected the unit watershed, increment of inner productivity by algae, water quality deterioration during the specific period, river management flow, etc.

• 한국농공학회논문집
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• 제56권6호
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• pp.11-18
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• 2014

Vulnerable areas by non-point source pollution and prioritizing control areas were researched using hydrological and geomorphological data, non-point source loads, and water quality data. Using overlay analysis, vulnerable areas were graded with various scenarios. Vulnerable areas were selected near the metro city with impermeable landuse because non-point source loads and water quality data had influence on overlay analysis to rank vulnerable area. Analysis scenarios and weighted values can be changed under regional characteristics and given conditions.

• 한국물환경학회지
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• 제35권6호
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• pp.497-509
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• 2019

After the Total Maximum Daily Loads(TMDLs) was applied, it became beyond the limit of concentration management. However, it does not adequately reflect the characteristics of various watersheds, and causes problems with local governments because of the standard flow set. Thus, in this study, the Han River system is organized into four groups in estimating the Pollution Contribution by applying the Flow Duration Curve(FDC) created by the daily flow of data from the HSPF. And the method of this study is expected to be valuable as basic data for the TMDLs. As a result, Group I contains the main watersheds with no large hydraulic structures and tributary watersheds. There is no specificity in the FDC and the Pollution Contribution is estimated as rainfall runoff. Group II contains watersheds near the city where the FDC is maintained above a certain level during the Low Flow Conditions and the Pollution Contribution is estimated as the discharge flow of large scale point pollution facilities. Group III contains the main watersheds in which the large hydraulic structures are installed and FDC is curved in the Low Flow Conditions. So the Pollution Contribution is estimated as the water quality of the large hydraulic structures. Group IV contains the upstream in mainstream watersheds in which the large hydraulic structures are installed and the FDC is disabled before the Low Flow Conditions. As the flow is concentrated in the High Flow Conditions, the non-point pollution sources are estimated as the Pollution Contribution.

• 한국수자원학회논문집
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• 제48권3호
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• pp.185-196
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• 2015

본 연구에서는 황룡강 유역에 유역모델 HSPF (Hydrological Simulation Program - Fortran)를 적용하여 기후변화에 따른 오염부하 유출 변화량을 분석하였다. 황룡강 유역을 7개 소유역으로 분할하고 2011년에 관측된 유량, SS, BOD, TN, TP 농도자료를 이용하여 모델 보정 및 검정을 실시하였다. 기후변화에 따른 황룡강 유역의 환경변화를 예측하기 위해 RCP 4.5와 8.5 시나리오를 이용하였으며, 과거 기간 동안의 강우와 기온에 대한 모의치와 관측치간 월별 평균을 비교하여 미래 기상 자료에 대한 편의 보정을 수행하였다. 기후변화 시나리오의 기상 자료 분석 결과, 21세기 전반기와 비교하여 중, 후반기에 상대적으로 많은 연강수량과 연평균기온을 보이는 것으로 분석되었다. 기후변화에 따른 황룡강 유역에서의 오염물질 유출량 분석 결과, RCP 4.5 시나리오에서는 2020년대 대비 2080년대에 평균 연간 강우, BOD, TN, TP 유출량이 각각 47%, 24%, 21%, 27% 증가율을 보여 21세기 후반기로 갈수록 연간 오염부하 유출량이 전반적으로 증가하는 것으로 분석되었다. RCP 8.5 시나리오에서는 2020년대 대비 2050년대에 평균 연간 강우, BOD, TN, TP 유출량이 각각 34%, 20%, 20%, 21% 증가율을 보이며 21세기 중반기에 연간 오염부하 유출량이 상대적으로 가장 많이 증가할 것으로 분석되었다. 이는 연강수량 변화와 동일한 패턴의 변화로서 기후변화에 따른 강우량 변화가 오염물질 유출량에 그대로 반영된 결과를 보여준다. 한편, 월별 오염물질 유출량은 RCP 4.5에서는 9월에, RCP 8.5에서는 2월에 상대적으로 크게 증가할 것으로 분석되었다.

• 한국해양환경ㆍ에너지학회지
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• 제3권1호
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• pp.52-61
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• 2000

제주도 남부연안해역을 대상으로 1997년 7월부터 1598년 6월 까지 매월 현장 조사와 수질 분석을 실시하였고, 생태계 모델을 이용한 시뮬레이션을 통하여 용존무기질소(DIP), 화학적 산소 요구량(COD) 및 용존산소(DO)의 수층별 분포를 재현하였다. 그리고 제주도 남부연안해역의 환경용량을 산정하기 위하여 해역수질 환경기준을 만족하지 못하는 환경악화 상태를 예측하는 수질 시뮬레이션이 실시되었으며, 이러한 예측 시뮬레이션은 생태계 모델을 이용하여 모델 해역으로 유입하는 주요 하천의 오염부하를 정량적으로 조절하면서 실시되었다. 그 결과 모델 해역으로 유입하는 4개 오염원으로부터의 오염부하가 증가할수록 오염원에 인접한 주변 해역에서 DIN, DIP 및 COD의 농도가 더욱 증가하는 것으로 나타났다. 하천을 포함한 4개 오염원 모두로부터의 오염부하가 현재 부하의 3배에 해당하는 경우, 오염원에 인접한 해역에서의 DIN 농도가 해역수질 환경기준의 3등급 기준인 0.20mg/ℓ까지 증가하는 것으로 예측되었다. 또한 오염원 모두로부터의 오염부하가 현재 부하의 10배에 해당하는 경우, 오염원에 인접한 해역에서의 COD농도가 해역수질 환경기준의 1등급 기준인 1.0mg/ℓ까지 증가하는 것으로 예측되었다. 그리고 오염원 모두로부터의 오염부하가 현재 부하의 20배에 해당하는 경우, 오염원에 인접한 해역에서의 DIP 농도가 해역수질 환경기준의 2등급 기준인 0.015mg/ℓ까지 증가하는 것으로 예측되었다.