• 한국농공학회논문집
• /
• 제51권5호
• /
• pp.69-78
• /
• 2009

In order to improve water quality of upper watershed of Paldang reservoir, it is necessary to evaluate non-point source pollution loads and identify critical watershed pollution sources. A GIS based Soil and Water Assessment Tool was applied to evaluate model application and reliability, estimate NPS pollution load, identify critical watershed by NPS pollution sources, and suggest various best management practices for Kyongan Stream watershed. Yearly NPS pollution loads were estimated 30.0% SS, 60.1% TN and 35.4% TP, respectably. The watershed pollution load is mainly decided by precipitation condition and SS and nutrients load have a significant regression relationship. Based on 10-year average yearly NPS pollution load, critical sub-watersheds were identified. The No. 5 and 17 which have lots of relatively intensive agricultural fields and scattered industrial area were vary critical sub-watersheds and under more intensive pollution load. In order to control critical watershed, watershed best management practices such as scientific fertilizer, contour farming and parallel terrace, transferring the sloppy farmland to grass or forest and constructing a buffer zone, and constructing wetlands and retention ponds will be applied. Overall the SWAT model can be efficiently used for identification of critical sub-watersheds in order to develop a priority watershed management plan to reduce water pollutions.

• 환경영향평가
• /
• 제16권1호
• /
• pp.79-87
• /
• 2007

The performance of a stream water quality analysis model depends upon many factors attributed to the geological characteristics of a watershed as well as the distribution behaviors of pollutant itself on a surface of watershed. Because the model run has to import the pollution load from the watershed as a boundary condition along an interface between a stream water body and a watershed, it has been used to introduce a pollution delivery coefficient to behalf of the boundary condition of load importation. Although a nonlinear regression model (NRM) was developed to cope with the limitation of a conventional empirical way, this an up-to-date study has also a limitation that it can't be applied where the pollution load washed off (assumed at a source) is less than that delivered (observed) in a stream. The objective of this study is to identify what causes the limitation of NRM and to suggest how we can purify the process to evaluate a pollution delivery coefficient using many field observed cases. As a major result, it was found what causes the pollution load delivered to becomes bigger than that assumed at the source. In addition, the pollution load discharged to a stream water body from a specific watershed was calculated more accurately.

• 환경영향평가
• /
• 제12권5호
• /
• pp.359-367
• /
• 2003

The total pollution load management system of watershed has been implemented upon Special Law pertaining to the Han River Watershed Water Quality Improvement and Residents Support, Special Law pertaining to the Nakdong River Watershed Water Management and Residents Support, Special Law pertaining to the Youngsan River Watershed Water Management and Residents Support, and Special Law pertaining to the Seomjin River Watershed Water Management and Residents Support in Korea since 2002. But many other similar systems with total pollution load management system of watershed are being operated separately or independently, even though its purpose is nearly same with those of the total maximum pollutants load management in Law on Water Quality Environmental Protection, environmental impact assessment(EIA) in Law of Impact Assessment on Environment, Transportation and Disaster and Pre-environmental assessment of Environmental Policy Act. Therefore the contents of total pollution load management system of watershed and many other related systems could be overlapped and at some times have inconsistency among them. This study suggests first the integrated operation of total pollution load management system of watershed, EIA, pre-environmental assessment, urban planning, and sewage planning and secondly EIA system development by integration of EIA and pre-environmental assessment and strategic environmental assessment(SEA).

• 한국물환경학회지
• /
• 제28권6호
• /
• pp.786-795
• /
• 2012

Water quality management should be focused on the pollution concentrated area so that the improvement of water quality can be achieved effectively for the management of Total Maximum Daily Loads (TMDLs). It is necessary to consider discharge characteristics in the TMDL plan. This study analysed discharge characteristics such as pollution generation and discharge load density, and reduction potential by each unit watershed, and categorized the unit watershed into four groups according to its discharge load characteristics. This analysis can be used as helpful information for the prioritization of pollution reduction area and selection of pollution reduction measures in the development of TMDL plans.

• 한국환경과학회지
• /
• 제15권4호
• /
• pp.349-357
• /
• 2006

The purpose of this study is to evaluate the water pollution degree in the Mid-Nakdong River watershed regarding to landcover types using GIS method. As a result of landcover classification, rate of urban appeared highly on Daegu Metropolitan city. Also, rate of agriculture showed highly in the riparian zones of the Nakdong and Guemho River and rate of forest appeared highly in the borders of the study area. To identify the groups of watershed with similar landcover patterns using the Cluster Analysis. According to the cluster analysis, the fifty sub-watersheds were grouped in three clusters, 'Urban watershed', 'Agriculture watershed', 'Forest watershed'. The proportion of urban area in each cluster had a positive correlation with water pollution degree. Otherwise, the proportion of agriculture in the Agriculture watershed had a high positive correlation with water pollution degree. Therefore, it is necessary to estimate environmental capacity of water duality considering ecological and environmental characteristics of watershed ecosystem and expand water duality monitoring systems to small stream.

• 환경영향평가
• /
• 제20권4호
• /
• pp.489-496
• /
• 2011

The water pollution such as oil spill from stream and river because of car accidents have been frequent cases in the watershed of Dam. However we don't have any simulation methods about flow modeling on the watershed and stream tree. In this study aims to analyze water pollution accidents area on impact range for ANDONG-Dam. The focused watershed and the risk range of path analysis model was designed by GIS database. The frequency of transportation accidents which may occur from road accidents in the level of quantitative and qualitative analysis to map flow analysis using ArcHydro Model and Open Geospatial Consortium(OGC) API. and the path way from the accident point to the reservoir stayed on the path was simulated. The area of risk accessment index was displayed with cell and grid of dam area.

• 한국습지학회지
• /
• 제14권4호
• /
• pp.607-628
• /
• 2012

고현천 유역을 10개의 소유역으로 나누고 지류에 19개 조사지점을 정하고 풍수기(장마시기)와 갈수기로 나누어 지류의 수질오염과 오염부하량 변동 특성을 조사하였다. 수질분석결과로부터 고현천 유역은 상류지역(T1~T8)은 전원지대의 특성을 나타내었고, 하류지역(T9~T19)은 도심지대의 특성을 나타내었다. 고현천 지류의 비점오염부하량은 SS가 연간 총 2,063ton/yr, COD가 601ton/yr, DIN이 365ton/yr, DIP가 45ton/yr으로 산정되었고, DIP를 제외하고 약 60%가 풍수기 때 발생하여 비점오염원의 유출에는 강우의 영향이 매우 컸다. 한편 DIP 비점오염부하량은 평수기와 갈수기를 합쳐서 약 60%가 나타나 이 기간 동안 인 오염원의 관리가 중요함을 나타내었다. Pearson 상관관계 분석을 통하여 상류지역과 하류지역의 SS 발생원에 분명한 차이를 나타냈으며, 상류지역은 장마시 농경지와 임야지대로부터 부유토사의 유출에 의하여 주로 오염부하가 발생하고 하류지역은 생활하수와 도심유출수(municipal run-off)에 의하여 발생하는 것으로 나타났다.

• 한국공간정보시스템학회:학술대회논문집
• /
• 한국공간정보시스템학회 2007년도 GIS 공동춘계학술대회 논문집
• /
• pp.246-251
• /
• 2007

The purpose of this study is to develop a grid based model for calculating the critical nonpoint source (NPS) pollution load (BOD, TN, TP) in Nak-dong area in South Korea. In the last two decades, NPS pollution has become a topic for research that resulted in the development of numerous modeling techniques. Watershed researchers need to be able to emphasis on the characterization of water quality, including NPS pollution loads estimates. Geographic Information System (GIS) has been designed for the assessment of NPS pollution in a watershed. It uses different data such as DEM, precipitation, stream network, discharge, and land use data sets and utilizes a grid representation of a watershed for the approximation of average annual pollution loads and concentrations. The difficulty in traditional NPS modeling is the problem of identifying sources and quantifying the loads. This research is intended to investigate the correlation of NPS pollution concentrations with land uses in a watershed by calculating Expected Mean Concentrations (EMC). This work was accomplished using a grid based modelling technique that encompasses three stages. The first step includes estimating runoff grid by means of the precipitation grid and runoff coefficient. The second step is deriving the gird based model for calculating NPS pollution loads. The last step is validating the gird based model with traditional pollution loads calculation by applying statistical t-test method. The results on real data, illustrate the merits of the grid based modelling approach. Therefore, this model investigates a method of estimating and simulating point loads along with the spatially distributed NPS pollution loads. The pollutant concentration from local runoff is supposed to be directly related to land use in the region and is not considered to vary from event to event or within areas of similar land uses. By consideration of this point, it is anticipated that a single mean estimated pollutant concentration is assigned to all land uses rather than taking into account unique concentrations for different soil types, crops, and so on.

• 한국관개배수논문집
• /
• 제13권2호
• /
• pp.283-292
• /
• 2006

The characteristics of nonpoint source pollutant loads in upstream of Nakdong River were studied through analysis of pollutant loads of 10 sub-watersheds divided based on administrative district. The discharge and pollutant concentration of each sub-watershed were collected from Nakdong-River Water Research Institute and Daegu Regional Environmental office, respectively. Pollution items analysed in this study were BOD, T-N and T-P. The delivery loads of the nonpoint source pollutions of each sub-watershed were calculated after analysing the concentration of the pollution of each site. Several points were found from the results. Firstly, in general, city areas including Sangju, Andong showed higher degree of nonpoint pollution than country areas including Cheongsong, Yeongyang. The sub-watersheds located upstream side, such as Yeongju, Bonghwa, Necessarily show better water quality than the sub-watersheds located downstream side, such as Mungyeong, Uiseong. This result indicates that a given pollution condition within the watershed can be more sensitive than location factor to the level of water quality. Secondly, the delivery load and area of watershed were not necessarily correlated in the sense of water quality, while the discharge was shown to be highly correlated to the delively load of pollution. Lastly, sewage and waste caused from population and livestock, as well as landuse factor, were found to significantly contribute to the water pollution. Alternative solutions for controlling pollution source, therefore, should be provided to meet target levels of water quality in these regions.

• 한국물환경학회지
• /
• 제31권6호
• /
• pp.732-738
• /
• 2015

Water quality in four major river basin in Korea was managed with Total Maximum Daily Load (TMDL) System. The unit watershed in TMDL system has been evaluated with Target Water Quality (TWQ) assessment using average water quality, without considering its volume of water quantity. As results, although unit watershed are obtained its TWQ, its allocated loads were not satisfied and vice versa. To solve these problems, a number of TWQ assessments with using Load Duration Curve (LDC) have been studied at other watersheds. The purpose of this study was to evaluate achievement of TWQ with Flow Duration Curve (FDC) and Load Duration Curve(LDC) at 26 unit watersheds in Han river basin. The results showed that achievement rates in TWQ assessment with current method and with LDC were 50~56 % and 69~73%, respectively. Because of increasing about 20% of achievement rates with using LDC, the number of exceeded unit watershed at Han river Basin was decreased about 4~6 unit watersheds.