• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.2
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• pp.35-45
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• 2023

The DOR (Drainage outlet raising) in the paddy field has been suggested as one of the most important best management practices for the TMDL (Total maximum daily load) management in the technical guidelines by the NIER (National institute of environmental research). However, this method is underestimated and is not well adopted by local governments for the TMDL. The purpose of this study is to evaluate the unit load reduction equation according to the application of DOR in order to expand this equation. The original equation in the guideline was derived using the HSPF (Hydrological Simulation Program-Fortran) model for 1 year in Changnyeong. We analyzed the reduction effect of the original equation application by collecting additional long-term monitoring data from the Buan, Icheon, Iksan, and Jeonju. When comparing the reduction loads between the original equation and monitoring results, the evaluation results of the original equation were 11% of the monitoring analysis results, which was underestimated. This means that the original equation needs to be improved. For assessing the equation, the HSPF Paddy-RCH model was established according to the NI ER guideline and evaluated for applicability. The performance results of the model showed a reasonable range by the statistical criteria. Modified equations 1 and 2 were proposed based on the monitoring and modeling results. Modified equation 1 was the method of modifying the original equation's main factors, and modified equation 2 was the method of applying the non-point pollution reduction efficiency according to the rainfall class using the long-term modeling results. At the level of 58.6~64.6% of monitoring data, the difference between them could be further reduced compared to the original equation. The suggested approach will be more reasonable and practicable for decision-makers and will contribute to the TMDL management plans.

• KCID journal
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• v.17 no.2
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• pp.35-41
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• 2010

For efficient water quality management of Saemangeum lake, it is very important to accurately analyze discharged load characteristics using investigated pollution sources data from Saemangeum watershed. Investigation of pollution sources was conducted from 2003 to 2007. In this study, pollution sources are largely classified into human population, livestock, industry, and land use. Discharged loads of BOD, T-N and T-P from classified pollution sources were calculated by Korea TMDL (Total Maximum Daily Load) technical guideline. The calculated results showed that the major sources of BOD and T-N were land use, human population, livestock, and industry in order. However, the major sources of T-P were livestock, land use, human population, and industry in order. Our results clearly show that pollution sources of the priority management for water quality enhancement in the Saemangeum lake has represented land use and livestock.

• Journal of Korean Society on Water Environment
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• v.33 no.5
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• pp.531-537
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• 2017

The biologic Oxygen Demand (BOD) is a reliable and generally accepted indicator of water pollution by organic pollutants. Accordingly, estimation of BOD export from paddies carries important implications fwith regard to water management in rural areas. In this study, hydrology and BOD concentration were monitored during the period 2008 through 2012, in an effort to understand the characteristics of BOD export from paddy fields. The findings demonstrated that BOD load by rainfall above 50 mm. occupied about 50 % of total load, whereas the load by less than ten mm. rainfall occupied about 29 % of the total load during periods of stormy activity. It therefore seems that it could be possible to reduce the BOD load up to 29 % during storm periods, when drainage control conducted for rainfall less than ten mm.(an amount which is relatively easy to manage). The documented mean loads of storm and non-storm were $17.1kg\;ha^{-1}\;yr^{-1}$ and $11.2kg\;ha^{-1}\;yr^{-1}$, respectively. The BOD load during the significant rainfall period was similar to the renewed unit load by NIER (2014). However, there were substantial differences between unit load and actual load when the non-storm load was incorporated into the BOD load estimation from paddy fields. In view of the foregoing, it is felt that, the non-storm load needs to be further considered and managed for the successful implementation of Total Maximum Daily Load (TMDL) program.

• Journal of agriculture & life science
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• v.44 no.5
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• pp.117-127
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• 2010

The purpose of this study is to analyze the temporal and spatial characteristics of water quality data of Nakdonggang watershed which is second largest watershed in South Korea. The correlation between the water quality items for rainy and non-rainy seasons were also analyzed for two TMDL sites which are Gumi and Namji. BOD data of two Total Maximum Daily Loads (TMDL) target sites were compared with TMDL criteria, 3-year arithmetic mean BOD concentration of the target sites should not exceed the target concentration for 2 consecutive years, to figure out current water quality status. Spatial analysis results showed that the correlation coefficient between Goryeong and Hyunpung was highest with the value of 0.978 followed by Hapcheon and Namji with the value of 0.874. The observed BOD data of Gumi station fluctuated around the TMDL criterion, 1.8mg/L while Namji station mostly exceed the criterion, 2.6mg/L. The criteria values for each target sites are defined by Ministry of Environment. The major factor of correlation coefficient was the distance between the stations. The correlation between the water quality items for non-rainy season showed no relation while the correlation between COD and SS was high followed by COD and TP for Gumi and Namji.

• Journal of Environmental Impact Assessment
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• v.22 no.4
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• pp.319-327
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• 2013

This study was conducted to identify runoff characteristics of pollutants using flow duration curve(FDC) and load duration curve(LDC) in Youngbon A watershed during 2009~2011. A flow rate and pollutant load in the study watershed were estimated by equation of stage-discharge and discharge-loads rating curve. From these methods, BOD, T-N, and T-P have evaluated whether water quality standards would have attained. Results showed that BOD loads of about 50% plotted above the LDC, while T-N and T-P loads of about 50% plotted below the curve. It means that BOD of about 50% have exceeded the water quality criteria, while T-N and T-P of about 50% have complied with the water quality standards. Meanwhile, BOD, TN and T-P loads plotted above the LDC of low flows, implying that they were more affected by point pollution sources than nonpoint pollution sources in the study watershed.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1079-1083
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• 2010

Due to summer rainfall is concentrated in the construction of the reservoir and the dam was inevitable. The character of these structures are different from the common rivers have been characterized. According to this problem, we need to adopt to this area with three dimensional model. Construction of dams for preservation of land, utilization of water resources, and exploitation of energy potential, which is a basic element of countries' development, is regarded as indispensable for peoples. In addtion, the development of the Nakdong River nutrient and pathogen Total Maximum Daily Loads (TMDL) required that the full range of pollutants, sources, and flow conditions, typical of heavily urbanized areas, be addressed for a single water body with 1-D simulation model (river) and 3-D simulation model (reservoir). The objective of this study is to simulate the applicability of reservoir with the coupling of 3-D hydrodynamic and water quality models to estimate water balance and pollutant loading in Namgang Dam(Jinyang reservoir).

• Journal of Environmental Impact Assessment
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• v.16 no.6
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• pp.525-532
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• 2007

In order to establish and implement the total maximum daily load (TMDL) management plan in Korea, it is necessary to set the source units and calculate discharge loads for non-point source pollutants such as BOD, COD, SS, TN and TP. This study analysed the corelation between stormwater runoff characteristics and event mean concentrations (EMCs) of non-point source pollutants. As the result of the corelation analysis, we knew that all the antecedent dry days (ADD) and the rainfall correlated lowly with non-point source pollutants in the urban areas such as resident area, industrial area, business area, road area and parking area. Therefore, it is necessary to get all samples from stormwater starting point to stormwater ending point and standardize the sampling method of stormwater in order to obtain more accurate EMCs for landuse.

• Journal of Wetlands Research
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• v.18 no.3
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• pp.232-243
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• 2016

In order to establish the watershed water quality management strategy of Total Maximum Daily Load(TMDL), it is necessary to understand the relationship between water quality component impacts, and to identify the impacts on downstream target point of watershed water quality management of waste treatment plant(WTP) discharge and upstream/tributary loads. In this study, we determined the impacts between the water quality contaminants, and traced water pollution sources using monitoring data of ministry of environment in tributaries and main stream and WTP monitoring data. Test area is set to Geumho river basin which has characteristics of urban and rural area and composes of GeumhoA, GeumhoB, GeumhoC watershed units in TMDL. The clustering with five grades of discharge data and the correlation analysis were performed through the FDC(Flow duration curve) analysis, which more clearly identified the points and water contaminants deteriorating target water quality of downstream point. This can be used as a tool for tracing pollutants with FDC analysis, and will help us establish the watershed water quality management strategy for TMDL target point in watershed more effectively.

• Spatial Information Research
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• v.21 no.6
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• pp.91-98
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• 2013

Government introduces a Total Maximum Daily Loads(TMDL) which can be implemented for total pollutant amounts in 2004. Normally, the local governments have been calculated the amounts of pollutant discharge of each watershed using a water quality model. However, among the input data to use the water quality model, creating a schematic diagram of the stream or the modeling usually requires considerable amount of time and efforts due to the manual work. Therefore, this study tried to develop an algorithm which automates the creation of a schematic diagram for water quality modeling using the Korean Reach File capable of river network analysis. Further, this study creates a schematic diagram with the shape of a stream utilizing GIS capabilities. The diagram can be easily analyzed with overlapping various spatial information such as pollution sources and discharge points. This study mainly has automated element segmentation algorithm to divide streamflows into equal distance using line graphic data of Koran Reach File. Also, automated attribute input algorithm has also been developed to enable to insert element order and type into elements using point graphic data of Korean Reach File. For the verification of the developed algorithm, the algorithm was applied to kyungan stream basin to see the acceptable results. To conclude, it was possible to automate generating of schematic diagram of water quality model and it is expected to be able to save time and cost required for the water modeling. In future study, it is necessary to develop an automatic creation system of various types of input data for water quality modeling and this will lead to relatively easier and simple water quality modeling.

• Journal of Korean Society on Water Environment
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• v.35 no.6
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• pp.481-496
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• 2019

The Ministry of Environment has measured streamflow at eight-day intervals for the estimation of standard flow of the Total Maximum Daily Loads (TMDL) system. This study identified the availability of the partially measured the eight-day interval data for estimating standard flow and found the optimal extension techniques of standard flow. The study area was selected for the Nakbon-A watershed in the Nakdong River, and four streamflow record extension techniques of standard flow were considered: extension, percentile, drainagearea, and regional regression methods. The flow duration curve (FDC) using the eight-day interval streamflow data indicated very high Nash and Sutcliffe Efficiency (NSE) values above 90 % from FDC-II to FDC-VII compared to FDC-VIII, the standard FDC. This result demonstrates that FDC using daily data of three-six cumulative years could represent standard FDC fairly well. For the streamflow record extension techniques of standard flow, the percentile method was selected as the optimal alternative, showing the minimal difference from FDC-VIII. These results validate the availability of the eight-day interval streamflow data in the standard flow estimation and the application of extension techniques. It seems that these results could reduce the uncertainty of partially measured streamflow data for water quantity and quality management.