• Journal of Korean Society on Water Environment
• /
• v.22 no.1
• /
• pp.128-133
• /
• 2006

The paved areas in nonpoint source are highly polluted landuses because of high imperviousness and high pollutant mass emissions from vehicle activities. Particularly, the metal pollutants are a big issue in the paved area. It is usually washed-off during storms by adsorbing on sediments or soluble status. Therefore, this research was achieved for understanding the characteristics of metal pollutants in stormwater runoff in highways. Five monitoring sites were equipped with an automatic rainfall gage and an automatic flow meter. This manuscripts will summarize the washoff characteristics of metal pollutants and its concentration changes during storms. Usually first flush phenomenon was observed for all of the storm events and visibly confirmed with hydro- and polluto-graphs. Also it was coincided with the tendency of particulates and organic matters. The decrease rate per total reduced amount for metals during initial 30-min storm duration was obtained on 80%. The result may be able to use for determining the economical treatment criteria for stormwater runoff in highways.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2015.05a
• /
• pp.445-445
• /
• 2015

비점오염의 특성에 대해 지속적으로 연구 중이지만 수문특성과 연관성이 크다 보니 그 일관성에 대해 확실한 기법이 개발되지 않았다. 기법 개발과 효과적인 오염원 관리를 위해 SWMM 등의 모형을 활용하고 있지만 투입된 노력과 시간에 비해 그 효율성이 매우 적은 편이다. 이런 부분을 보완하고자 본 논문에서는 기존의 비점오염량 산정방법이 아니라 낙동강유역의 도시화 특성 및 수문/기상자료와 처리장 운영자료를 활용한 차별화된 원단위법을 통해 비점 배출 부하량 산정방법을 제시하려고 한다. 배수구역 내 관거 시스템을 합류식으로 가정하였고 배수구역별 비점 발생형태는 하수처리장의 강우 유입량, 하수처리장의 우회유량(Bypass 유량), 하수처리구역의 CSO 유량 3가지로 구분 지었다. 유입 방류자료와 강우자료를 활용하여 임계강우량을 3mm로 설정하여 3mm이상일 경우에 우회유량이 발생한다고 가정하였고 우회유량 발생시 오염부하량 산정은 건기평균유량에 유량변동부하율을 곱하여 시간최대유량으로 전환한 후 강우 지속기간 동안만 우회유량이 발생하는 것으로 가정하였다. CSO 유량은 처리구역/배수구역 면적비에 따라 3개의 그룹으로 구분한 뒤 검증된 SWMM-온천천 모형의 각 소유역별 불투수면적비와 비교하여 유사한 소유역을 각 그룹의 대표유역으로 선정하였다. 선정된 소유역의 CSO 유량과 수문현상의 비선형적인 관계를 고려할 수 있는 신경망 기법을 적용하여 강우특성에 따른 CSO 오염부하량 산정을 실시하였다. 산정결과를 바탕으로 각 하수처리장별 비점저감 기여율을 산정한 결과 대구북부 처리장에서 21.56%로 가장 높은 효율을 보여줬으며 거창가조 지점에서 0.11%로 가장 낮은 효율을 보여주는 것을 확인 할 수 있었다. 이러한 결과를 바탕으로 낙동강유역 내 위치한 하수처리장의 효율성에 대해 알 수 있으며 개선되어야 할 처리장들을 알 수 있었다. 또한 획일화된 방법이 아닌 차별화된 원단위법을 통한 오염부하량 산정은 앞으로의 연구방향에 있어서 좋은 사례가 될 것으로 사료된다.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.61 no.3
• /
• pp.15-22
• /
• 2019

In order to preserve water environment, Total Maximum Daily Load(TMDL) is used to manage the total amount of pollutant from various sources, and the annual average load of source is calculated by the unit load method. Determination of the unit load requires reliable data accumulation and analysis based on a reasonable estimation method. In this study, we propose a revised unit load estimation method by analyzing the unit load calculation procedure of National Institute of Environment Research(NIER) method. Both methods were tested using observed runoff ratio and water quality data of rice paddy fields. The estimated values with the respective NIER and revised NIER methods were highly correlated each other. However, the Event Mean Concentration(EMC) and the runoff ratio considered in the NIER method appeared to be influenced by rainfall classes, and the difference in unit load increases as the runoff and EMC increase. The error can be further increased when the EMC and runoff ratio are changed according to changes in rainfall patterns by climate change and change of agricultural activities. Therefore, it is recommended to calculate unit load by applying the revised NIER method reflecting the non point pollution runoff characteristics for different rainfall classes.

• Journal of Korean Society on Water Environment
• /
• v.29 no.3
• /
• pp.309-316
• /
• 2013

The Non-Point Sources shows different characteristics over a wide area depending on basin situation and rainfall events etc. In addition, Among various land uses in the urban areas, runoff appears high in the paved area, though small in its size, during a heavy rain than in other land use owing to its high impervious rate, and pollutants become severly accumulated owing to continual transportation of vehicles, characteristically showing high concentrations of runoff in the early stage. As a result, several advanced countries including USA give a special emphasis on the paved area as a target for supervision. In view of these aspects, the research is not only required to consider separated sub-basins which are distributed according to land uses, but also needed to develop a suitable monitoring which is reflected rainfall-runoff relation. The on-site monitoring has been performed to collect data in object watershed as well.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.54 no.1
• /
• pp.55-62
• /
• 2012

This study is to assess the reduction of nonpoint source pollution by applying Best Management Practice (BMP) in Chungju-dam watershed (6,585.1 $km^2$) using Soil and Water Assessment Tool (SWAT). The model was calibrated using 3 years (1998-2000) daily streamflow at 3 locations and monthly water quality of sediment (SS), total nitrogen (T-N) and total phosphorus (T-P) data at 2 locations and validated for another 3 years (2001-2003) data. The 5 BMPs of streambank stabilization, porous gully plugs, recharge structures, terrace, and contour farming were applied to stream and area with the specific criteria of previous researches. Through the parameter sensitivity analysis, the farming practice P-factor and Manning's roughness of stream were sensitive. Overall, the NPS reduction effect was high for streambank stabilization, terrace, and contour farming. At the watershed outlet, the SS, T-P, and T-N were reduced by 64.4 %, 62.8 % and 17.6 % respectively.

• Journal of Korean Society of Water and Wastewater
• /
• v.23 no.5
• /
• pp.631-636
• /
• 2009

This study has its intention to investigate the water quality of non-point source which is runoff from roads. We have classified and selected twelve sites as city road, industrial road, national road and mountain road by considering their traffic volume and surroundings. Water quality was analyzed based on BOD, COD, SS, T-N and T-P and the concentrations were measured by sampling after rainfall with the interval of 10 minutes, 20 minutes, and 30 minutes. BOD was the highest in city road with 57.6 mg/L and the lowest in mountain road with 45.0 mg/L. For COD, the highest concentration in industrial road was 146.5 mg/L and the lowest was in mountain road with 98.0 mg/L. The run off concentration of SS was up to maximum 630.0 mg/L (average 280.4 mg/L) which was remarkable compared to other types of road. It showed its lowest concentration in national road with 76.0 mg/L. T-N and T-P were the highest in industrial road and the lowest in mountain road. We found out that the runoff concentration was high with large amount of traffic volume and it seemed to be high in city road and industrial road where they were largely affected by their surroundings. Relatively, national road and mountain road seemed to show low concentration as they have less traffic volume and less affected by their surroundings.

• Journal of Korean Society on Water Environment
• /
• v.31 no.5
• /
• pp.491-506
• /
• 2015

Distributed models represent watersheds using a network of numerous, uniform calculation units to provide spatially detailed and consistent evaluations across the watershed. However, these models have a disadvantage in general requiring a high computing cost. Semi-distributed models, on the other hand, delineate watersheds using a simplified network of non-uniform calculation units requiring a much lower computing cost than distributed models. Employing a simplified network of non-uniform units, however, semi-distributed models cannot but have limitations in spatially-consistent simulations of hydrogeochemical processes and are often not favoured for such a task as identifying critical source areas within a watershed. Aiming to overcome these shortcomings of both groups of models, a hybrid watershed model STREAM (Spatio-Temporal River-basin Ecohydrology Analysis Model) was developed in this study. Like a distributed model, STREAM divides a watershed into square grid cells of a same size each of which may have a different set of hydrogeochemical parameters reflecting the spatial heterogeneity. Like many semi-distributed models, STREAM groups individual cells of similar hydrogeochemical properties into representative cells for which real computations of the model are carried out. With this hybrid structure, STREAM requires a relatively small computational cost although it still keeps the critical advantage of distributed models.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2000.10a
• /
• pp.490-499
• /
• 2000

Several studies on development of water quality treatment systems by wetlands are on going because of their benefits of low construction cost and high efficiency of waste water treatment. The objectives of this study were to review the necessary contents of survey and design factors for constructing constructed wetlands and to examine the required wetland area to treat non-point source pollution through case studies. The measurement of water quality and quantity in precipitation period is needed to analyse the inflow characteristics of the non-point pollution and to determine the amount of design flow. The design inflow for constructing constructed wetland was determined to the total runoff from 30mm of daily rainfall in the AMC(III) condition of the SCS method and is similar 70% of the annual mean runoff. The natural type wetland system with 0.1m of water depth and 5 hours of detention time was applied. From the results of the case studies, 70% of inflow could be treated and 1∼3% of wetland area of the total basin is needed.

• Journal of Environmental Science International
• /
• v.19 no.7
• /
• pp.819-827
• /
• 2010

This study was conducted to investigate runoff characteristics of non-point pollutants source at the urban area in boeun area, Chungbuk Province. The monitoring site covering the watershed of $2.11\;km^2$ contains about 40.3 % of total watershed with the urban area. The monitoring was conducted with six events for five months and Event Mean Concentration(EMC) and Site Mean Concentration(SMC) of SS, BOD, CODMn, T-N, T-P were calculated on the result of the water quality parameters. As a result of the comparion between Arithmetic Mean Concentration and Event Mean Concentration, it showed that over all Event Mean Concentration was higher than Arithmetic Mean Concentration. And it showed that SS, BOD, T-P featured the first-flushing effect, showing relatively high concentration in early-stage storm event.

• Journal of Wetlands Research
• /
• v.14 no.1
• /
• pp.89-99
• /
• 2012

This study aims to develop the Masan bay special management system of the point and nonpoint sources of pollution using GIS as part of the Integrated Management System of the Masan Bay Special Management Area and utilize Total Pollution Loads Management System in Masan Bay more systematically and scientifically. The result of the pollution sources management at the Masan bay in conjunction with GIS was made possible the comparison of the source of pollution and the pollutant load among each administration area. It also developed Arc-GIS watershed management program which enables to estimate the population for discharge facilities, the water use of domestic population and commercial population, and pollutant load and discharge load of COD, TN and TP by the administration areas, years, and usages. In addition, this study anticipated minimizing temporal, economical efforts in utilizing large amounts of property and space utilization data and expediting the decision making process of policies in relation to the systematic and effective management system of pollutant loads at the Masan bay area. Further studies are required to plan the systematic management of the point and nonpoint sources of pollution and complement the watershed management system using GIS program for pollutant load which enables to predict the current and future state of point and nonpoint sources.