• 한국물환경학회지
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• 제27권6호
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• pp.914-925
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• 2011

The variation of streamflow is regarded as one of the most influential factors on the fluctuation of water quality in the stream. The characteristics of the variation should be taken into account in the plans for the management of Total Maximum Daily Loads (TMDLs). This study analysed and characterized spatial distribution and temporal variation of streamflow at each unit watershed in Guem-river basin. For the analysis of the distribution of streamflow, the type and the extent of the distribution were investigated for the unit watershed. For the analysis of the variation, short and long term changes of streamflow were examined. The result showed that most of the distributions were not log-normalized and the extent of variation tends to be greater at the unit watershed placed on the tributaries in the basin. A kind of margin could be granted to the unit watershed involving high variations so as to establish the water quality goal and load allotment more reasonably and effectively in view of whole waterbody.

• 한국물환경학회지
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• 제29권3호
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• pp.393-399
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• 2013

To control organic matters, it needs to manage not only biodegradable organic matters but also refractory organic matters. Refractory organic matters from municipal wastewater, industrial wastewater, non-point sources and etc., have been continuously discharged to the near watersheds. It is estimated that the refractory organic matter ratios are continuously increased in waterbody. In watersheds of the Total Maximum Daily Loads (TMDLs), it was investigated that COD/BOD ratios increased in many unit watersheds of the 4 major river basins. The portions COD/BOD ratios increased were found to be a 97% of Geum River unit watersheds, a 81% of Yeongsan/Seumjin River unit watersheds, a 78% of Nakdong River unit watersheds, a 70% of Han River unit watersheds, respectively. Therefore, it has become important for establishment of effective management strategies to control refractory organic matter in watersheds of the Total Maximum Daily Loads (TMDLs). In order to properly manage organic matters including refractory organic matters, the present organic indicator (BOD) has to be converted to TOC (or COD). Compared to COD and BOD, TOC, as a organic matter indicator, is evaluated more appropriate.

• 한국농공학회논문집
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• 제55권2호
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• pp.29-36
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• 2013

The objective of the research was to describe the effect of straw mat cover and soil amendments on the reduction of runoff and non-point source load from steep sloped highland agricultural fields. Four $5{\times}30$ m plots on sandy loam soil with 28 % slope were prepared. Experimental treatments were bare (control), rice straw mat cover (3,000 kg/ha) (S), PAM (5 kg/ha)+Gypsum (1 ton/ha) (PG) and rice straw mat cover+PAM+Gypsum (SPG). A variety of lettuce was cultivated and runoff was monitored during a growing season in 2011. Natural monitoring was conducted to three times. Runoff rate of S, PG and SPG plots were significantly lower than those of control plot. Especially, the runoff rate is zero in SPG plot at a first rainfall events. The reduction rate of runoff from the S, PG and SPG plots was 30.8 %, 29.0 % and 81.8 % compared to control plots, respectively. The reduction rate of NPS pollution load of S, PG and SPG was ranged of 50~90 %, 30~70 % and 90~100 %, respectively. Yield of lettuce from S, PG and SPG plots was respectively 400 (567 kg/ha), 320 (453 kg/ha) and 760 (1,067 kg/ha) that of compared to control plots greater than that from control plots (140 kg/ha). We speculated that the experimental treated plots could hold more nutrients and moisture than the control and helped the crop grow healthier. When analyzing the above results, in terms of reduction of runoff and NPS pollution load and crop yields, SPG experimental treatment had the best effect. It was concluded that the use of rice straw mats cover and soil amendments on soil surface could not only reduce the NPS pollution loads in receiving waters but also help increase the crop yield.

• 한국물환경학회지
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• 제28권2호
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• pp.224-231
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• 2012

It is necessary to develop flow duration curve (FDC) on each unit watershed in order to analyze flow conditions in the stream for the management of Total Maximum Daily Loads (TMDLs). This study investigated a simple method to develop FDC for the general use of the curve. A simple equation for daily flow estimation was derived from the regression analysis between the 8-day interval flow data of a unit watershed and the daily flow monitoring data of an adjacent upstream region. FDC can be prepared with the calculation of daily flow by the equation for each unit watershed. An annual and a full-period FDC were drawn for each unit watershed in Guem river basin. Standard flow such as low and ordinary flow can be obtained from the annual FDC. Major percentile of flow such as 10, 25, 50, 75 or 90% can be obtained from the full-period FDC. It is considered that this simple method of developing FDC can be utilized more widely for the calculation of standard flow and the assessment of water quality in the process of TMDLs.

• 한국물환경학회지
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• 제29권5호
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• pp.630-640
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• 2013

It is one of the most critical steps identifying impaired waterbodies exactly in the selection of target water quality indicators for the management of Total Maximum Daily Loads (TMDLs). Excess ratio and excess level were applied and analyzed by the stream zone basis in order to evaluate water impairment for Nakdong, Geum, Youngsan and Seomjin rivers. Each river basin was divided into stream zones in the light of its watershed and waterbody characteristics. Selected water quality parameters discussed in this study were pH, DO, BOD, COD, SS, T-P, T-Coli and F-Coli. The excess ratios of the water quality parameters were used to discriminate water bodies that did not meet water quality standards. The excess levels were used to classify the degradation of water quality. The excess ratios and the excess levels to the water quality criteria of the medium influence areas were used for each stream zone. The results indicate that the excess ratios and the excess levels are varied on the stream zone in each river basin. Three parameters, pH, DO and SS, met water quality standards in all stream zones. The other five parameters indicated very high excess ratios in most waterbodies, and especially T-P and T-Coli revealed to be very high excess levels in some waterbodies. These parameters could be considered as major target indicators for the management of TMDLs.

• 한국수산과학회지
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• 제35권4호
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• pp.356-365
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• 2002

One of the most important factors that cause eutrophication is nutrient materials containing nitrogen and phosphorus which stem from excreation of terrestial sources and release from sediment. Therefore, to improve water quality, the reduction of these nutrients loads should be indispensible. 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 counterclockwise eddies between Gyewha and Garyuk island. Density driven currents were generated westward at surface and eastward at the bottom in Saemankeum 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 were fairly good coincided with the observed values within relative error of $30\%$. The simulations of DIN and DIP concentrations were performed using ecosystem model under the conditions of $40\~100\%$ pollution load reductions from pollution sources. In study area, concentration of DIN and DIP were reduced to $59\%$ and $28\%$ 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, The $95\%$ input load abatement is necessary to meet the DIN and DIP concentration of second grade of ocean water quality criteria.

• 한국환경복원기술학회지
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• 제17권1호
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• pp.173-184
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• 2014

Riparian areas are significant functional grounds for inhabiting ecological system on the river such as the self-regulation of the water quality and the foundation of important corridors. For such functional device to operate, consecutive land purchase scheme that prioritizes targeted areas with high pollutant load rate imposes sustainable development of the ecological riparian belt. The purpose of this study is focused on measuring the methodology for selecting land purchse order before establishing riparian belt in accordance with pollution loading estimation and the basin approach. The Yeongsan and Seomjin river which includes targeted areas of the land purchase have been classified into the large-medium-small(standard basin) influence areas based on their catchment rage, which than sub-divided the research area of Juam lake by 38 small basins and 223 units. Small basins with the high pollution load rates have been assessed as the first prioritized targets. For the second priority, the condition of the point pollutant sources, original area of the targets, original restored area were concerned. The final decision of the land purchase order targeted only those within 50 meter range from the basin. To validate the accumulated data, the on-site investigation went along the targeted zones, which the result shows that all prioritized areas included both point and non-point pollutant sources, and had not a small originally restored areas.

• 한국물환경학회지
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• 제27권5호
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• pp.572-579
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• 2011

We have examined the runoff characteristics of nonpoint source (NPS) in fields. Two monitoring sites were equipped with an automatic velocity meter and water sampler. Monitoring was conducted at fields 1 and field 2 during the rainfall event. Ten rainfall-runoff events were monitored and analyzed during the study period. The results show that runoff occurred if daily rainfall and intensity were higher than 40 mm and 1.6 mm/hr except a few extreme rainfall events with very high intensity. Runoff of field 1 was approximately twice of that of field 2. Event mean concentrations (EMC) and pollution load of analyzed water quality indices were also higher in field 2 than in field 1. Especially, TN load from field 2 was $75.4 mg/m^2$ and was about 5 times higher than that from field 1. Analysis of Pearson correlation coefficient of water quality parameter indicates that besides of TN all items in fields 1 have tight relationship respectively (p < 0.01). But those of fields 2 have a significant (p < 0.05). Estimating units loading of NPS, we suggested that variable such as soil texture, rainfall amount and intensity and slope were needed to be considered from agricultural landuses. The results of this study can be used as a basic data in the development and implementation of total maximum daily loads (TMDL) in Korea.

• 한국환경농학회지
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• 제24권1호
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• pp.17-23
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• 2005

한정된 수질자료를 이용 오염부하 산정시 집중적으로 많은 샘플을 채취한 경우에 비해 어느 정도 차이를 갖는지를 규명하는 것은 모니터링에 따른 오염부하량 산정결과의 신뢰범위 파악뿐만 아니라 경제적인 수질 샘플 채수빈도 수립에 곡 필요할 것으로 사료된다. 그 결과를 요약하면 다음과 같다. 논에서의 강-은유출시 채수 빈도가 오염부하 산정에 미치는 영향을 파악하기 위해 9개의 강우사상에 대해 2시간 간격으로 연속 수질샘플을 실시하여 분석한 결과 전체적으로 강우-유출과정 중 T-N, T-P, SS 농도는 시간별로 증 감변동을 하였으나 유량과의 상관성은 나타나지 않았다. 수질샘플 횟수에 의한 영향은 강우-유출과정 중 5회 정도 샘플을 실시하면 많은 수의 샘플을 채수한 경우에 비해 T-N ${\pm}15.2%$, T-P는 $-20.0{\sim}26.2%$, SS는 $-28.6{\sim}35.7%$ 범위안에서 오염부하를 추정할 수 있는 것으로 나타났으며, 차이범위가 ${\pm}10%$ 내에 들어가기 위한 샘플수는 일주기 조사시 T-N, T-P의 경우는 6회, SS의 경우는 단기유출시는 4회 정도 실시하면 되고, 장기 유출시에는 11회 정도 실시하면 되는 것으로 조사되었다. 유량-유하부하량 관계식에서 ${\pm}10%$내의 차이를 보일 샘플횟수는 T-N의 경우는 6회 이상, T-P와 SS는 9회 이상 정도 실시하면 되는 것으로 조사되었다.

• 유기물자원화
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• 제30권1호
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• pp.41-47
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• 2022

본 연구는 강우시 산업단지에서 발생하는 비점오염원 유출 특성을 평가하여 비점오염원 부하량 및 원단위 산정을 위한 기초자료로 활용하기 위하여 C 산업단지에 대하여 강우유출수 수질모니터링을 수행하였다. 강우 사상별 유출량에 따른 EMC 산정 결과, 1차 강우시 BOD, COD_Mn, SS, T-N, T-P의 EMCs 범위는 각각 1.32~48.76, 3.32~43.75, 2.89~199.43, 2.76~8.93, 0.08~068 mg/L로 나타났으며, 2차 강우시는 각각 0.5~2.9, 2.71~7.13, 2.82~174.94, 1.33~4.03, 0.01~1.28 mg/L로 나타났다. 누적 유출량과 누적 오염부하량 비율 산정 결과, 강우 초기 유출량이 적은 시간에는 대부분 오염부하량이 강우 유출량보다 적지만 시간이 지남에 따라 강우 누적 유출량과 누적 오염부하량의 비가 1보다 커지면서 초기세척 현상이 일어났다.