• 한국물환경학회지
• /
• 제24권6호
• /
• pp.750-757
• /
• 2008

This study is conducted to characterize and evaluate delivered pollutant loads of point and nonpoint source on the upper watershed of lake paldang. The study area consists of 12 watersheds in Namhan-river and Kyungahcheon, which are approximately 80% of total area of Namhan-river and Kyungahcheon. Based on daily delivered loads from watersheds, 61% of $BOD_5$, 81% of T-N and 70% of T-P were from nonpoint sources, suggesting that delivered loads of nonpoint pollutants be crucial to water quality. On the other hand, 78% of $BOD_5$, 92% of T-N and 87% of T-P as delivered load were from nonpoint sources in an upper watershed of Namhan-river, while 48% of $BOD_5$, 70% of T-N and 57% of T-P as delivered load were from nonpoint sources in a lower watershed of Namhan-river, suggesting higher dependency of point sources than upper watershed of Namhan-river. In the characteristic of delivered loading pollutants from point and nonpoint pollution sources, delivered load of nonpoint pollutants differed significantly by seasonal flow, and as though discharged load of point pollutants were yearly uniform, delivered load of point pollutants was found to be flow-dependent because its delivery ratio was changed.

• 한국농공학회논문집
• /
• 제62권5호
• /
• pp.15-26
• /
• 2020

There are fifteen non-point pollution management areas in Korea and three of them (Doam lake, Daegi district and Golji-cheon) are located in the upstream of the Namhan river watershed. Many efforts to reduce non-point sources (NPS) pollution have been conducted, however, water quality pollution in the watershed is still serious. To solve these problems, it is a priority to grasp water quality using statistical techniques. In this study, a trend analysis was conducted to evaluate the effect of NPS management in the watershed. The long-term trends from 1996 to 2018 of water quality properties were analyzed using data collected from the water environment information system. Seventeen monitoring stations were selected along the main stream in Namhan river basin. Monthly water quality properties (BOD, COD, TN, TP, TN/TP ratio, Conductivity, SS and Chlorophyll-a) were collected and analyzed by Mann-Kendall test and LOWESS. The results showed that the Conductivity tended to increase in all regions and was the highest level in Jijangcheon. Organic pollution such as BOD and COD tended to increase in the Jungseon area. SS did not show a large tendency, but it showed high concentration in the Doam watershed. In all regions, 40% of water quality properties showed a tendency to 'UP', 15% of water quality properties tended to 'DOWN', and 46% indicated no tendency. In order to determine the cause of this, additional research and measures for improvement are necessary. This study will be used for the establishment of water quality policy in the future.

• 한국물환경학회지
• /
• 제23권6호
• /
• pp.889-896
• /
• 2007

From the direct outflow of Chungju Dam to the junction of water body and watershed in Paldang lake is the scope of this research. This study performed to investigate the main cause of water quality deterioration and the influenced region in the middle field range of the Namhan river Basin with the onsite measurement of water quality and flow rate simultaneously during spring dry season. The purpose of this study is to find out the time-spatial variation characteristics of water quality and flow rate. Following the flow direction $BOD_5$ and $COD_{Mn}$ concentration increased to the highest value of 3.7 mg/L, 5.9 mg/L at Wolgesa respectively. Chl.a concentration increased to $50mg/m^3$ or so at Kangsang, after that it decreased to $37mg/m^3$ at the junction of Paldang lake. Organic matter concentration variation trend showed similar than that of Chl.a. Also $BOD_5$ concentration tendency was similar to Chl.a in every measuring sites except Paldang lake mixing zone. The major factors of water quality deterioration in Namhan river and Paldang lake during dry season were algal bloom and followed internal production. High phosphorus load from Dalcheon and Seom river caused dry season algal bloom and internal production in transitional zone which was stagnant area in downstream of Namhan river.

• 한국물환경학회지
• /
• 제34권4호
• /
• pp.409-422
• /
• 2018

The purpose of this study is to find the characteristics of organic matters based on the distribution and oxidation rates, as noted according to the spatial and temporal variations from 2008 to 2016. Generally speaking, the Han River system is separated into one lower course and two upper courses which are the Namhan River and Bukhan River. The seasonal factor is one of the most important causes of water quality changing in both of the upper courses as a result of a few pollution sources. The concentration of organic matter was measured as higher in the lower course into which great streams with point and non-point sources were identified. According to seasonal variations, however, the change of the organic matter in the lower course is comparatively slighter than that of organic matters in the upper courses. The oxidation rates related to the BOD were 15 %, 17 % and 26 % in the Bukhan River, Namhan River and the lower course, respectively. These results could be explained that more biodegradable organic matter were seen to have existed in the lower courses comparing to the activity in the upper course. The oxidation rates of the BOD were noted as relatively higher in the eutrophicated places with phytoplankton. Therefore the BOD is one of the good index models to find the characteristic of the eutrophicated water. On the other hand BOD would not be enough to estimate concentration of refractory organic matters in the Bukhan and Namhan river. Consequently, both of the TOC and BOD are necessary indices to understand the identified refractory and/or biodegradable characteristics of organic matter.

• 한국환경과학회지
• /
• 제21권9호
• /
• pp.1115-1129
• /
• 2012

The objective of this study was to analyze long-term annual and seasonal trends of water chemistry on landuse patterns and seasonal precipitation using 72 sampling sites within Namhan River watershed during 2001-2010. Water quality, based on multi-parameters of water temperature(WT), dissolved oxygen(DO), biochemical oxygen demand(BOD), chemical oxygen demand(COD), suspended solids(SS), total nitrogen(TN), total phosphorus(TP), and electric conductivity(EC) varied largely depending on monsoon rain and landuse patterns such as forest, cropland, and residence. Concentrations of BOD and COD as an indicator for organic matter pollution, increased during summer monsoon season at the cropland and residential streams. Values of TN and TP were higher in residential streams than in the forest and cropland streams. In the meantime, DO values had weak relations to the landuse patterns of forest and cropland cover. Water quality was worst in cropland and residential streams, and also most degradated in 4th order streams. Overall, our results suggest that efficient water quality management is required in the cropland and residential landuse streams.

• 한국환경과학회지
• /
• 제24권8호
• /
• pp.1085-1099
• /
• 2015

The purposes of this study were to suggest the methodology to select prior areas in the environmental pollution survey for livestock excreta (EPSLE) as well as to elucidate the validity of the methodology. In this study, the prior areas in the EPSLE were determined by examining the number of compost facilities categorized according to the three levels of size including the basin, the sub-basin and the watershed, respectively, based on the data from "Annual Nation-wide Pollution Sources Survey (2012)". The results suggested that the list of prior basins were Nakdong, Geum, Youngsan and Han river basins in order. Also, it was examined that the prior sub-basins in the four river basins including Nakdong, Geum, Youngsan and Han rivers were Naesung Stream, Geumgang Gongju, Juam Dam and Namhan Downstream, respectively. The prior watersheds in the sub-basins of Naesung stream, Geumgang Gongju, Juam Dam and Namhan Downstream were Seocheon Downstream, Geum Stream, Gyeombaek Suwipyo and Yanghwa Stream, respectively. The validity of the methodology used in this study was elucidated by analyzing the correlation of the number of compost facilities with the concentrations of T-N and T-P observed in the end-points of sub-basins. The results of correlation analysis showed that the concentrations of T-N and T-P increased with the number of compost facilities. Specifically, there was the stronger correlation between the number of compost facilities and the concentrations of T-N than that for T-P. Consequently, it was proved that the methodology used in this work was valid and rational for the selection of prior areas in environmental pollution survey for EPSLE.

• 한국농공학회논문집
• /
• 제53권6호
• /
• pp.23-29
• /
• 2011

This study was conducted to identify the effect of lapse rate application according to elevation on the estimation of large scale watershed rainfall. For the Han river basin (26,018 $km^2$), the 11 years (2000-2010) daily rainfall data from 108 AWS (Automatic Weather Station) were collected. Especially, the 11 heavy rain and typhoon events from 2004 to 2009 were selected for trend analysis. The elevation effect by IDW (Inverse Distance Weights) interpolation showed the change up to +62.7 % for 1,200~1,600m elevation band. The effect based on 19 subbasins of WAMIS (Water Resources Management Information System) water resources unit map, the changes of IDW and Thiessen were -8.0 % (Downstream of Han river)~ +19.7 % (Upstream of Namhan river) and -5.7 %~+15.9 % respectively. It showed the increase trend as the elevation increases. For the 11 years rainfall data analysis, the lapse rate effect of IDW and Thiessen showed increase of 9.7 %~15.5 % and 6.6 %~9.6 % respectively.

• 대한환경공학회지
• /
• 제34권12호
• /
• pp.792-800
• /
• 2012

본 연구는 남한강과 북한강 유역 내 경작지 각 3개소(site A, B, C)를 대상으로 Web GIS-based VFSMOD System의 HUFF & SCS UH-based VFS Design Module을 적용하여 강우 시 경작지에서 유출되는 고형물질 유출저감을 모의하였다. 북한강 유역 내에 위치한 site A의 노지 밭의 토지경사도 5%, 강우 106.2 mm 조건에서 고추 및 옥수수를 재배할 경우, 70% 이상의 고형물질 유출저감 효율을 얻기 위해서는 초생대 폭이 최소 0.5 m 이상, 토지경사도 10%인 경우 70% 이상의 고형물질 유출저감 효율을 얻기 위해서는 초생대 폭이 최소 1.0~1.5 m 이상 유지해야 한다. 남한강 유역 내에 site B의 노지 밭의 토지경사도 5%, 강우량 95.1 mm 조건에서 토마토 및 땅콩을 재배할 경우, 70% 이상의 고형물질 유출저감을 위해서는 초생대의 폭이 최소 0.5 m, 토지경사도 10%인 경우 50% 이상의 고형물질 유출저감을 위해서는 최소 1.0 m 이상의 폭을 갖는 초생대를 설치해야 하는 것으로 나타났다. 남한강 유역 내에 site C의 노지 밭의 토지경사도 5%, 강우량 102.6 mm 조건에서 고구마 및 콩을 재배할 경우, 64.0% 이상의 고형물질 유출저감을 위해서는 초생대의 폭이 최소 1.0 m, 초생대를 설치해야 하는 것을 분석되었다. 또한, 동일한 조건에서 강우지속시간 2시간의 강우량을 151.2 mm로 증가시킬 경우, 62.0% 이상의 고형물질 유출저감을 위한 초생대의 최소 폭은 1.0 m 이상 설치해야 하는 것으로 분석되었다. 초생대 시설은 경작지와 같은 토지이용 시 친환경적인 고형물질 유출저감 방안으로 검토될 수 있으며, Web GIS-based VFSMOD System을 이용하여 다양한 토지특성과 강우 사상을 반영하여 적정한 규모의 초생대 설계가 가능할 것으로 분석되었다.

• Membrane and Water Treatment
• /
• 제15권3호
• /
• pp.99-106
• /
• 2024

This study developed an efficient management plan to improve the water quality by analyzing fluctuations in the ratio and amount of various organic substances in streams considering watershed characteristics and rainfall patterns. Monitoring was conducted on three streams and one lake over seven sessions during wet and dry seasons. Water quality indicators including total organic (TOC), refractory dissolved organic (RDOC), and particulate organic (POC) carbons were analyzed using high-temperature combustion oxidation. The three streams (Cheongmi, Yanghwa, and Bokha) displayed high TOC concentrations during the rainy season because the accumulated organic substances from the dry season were washed away by rainfall. By contrast, Paldang Lake exhibited a substantial decrease in TOC concentration due to dilution, which was influenced by watershed and rainfall characteristics. Across all streams and lakes, dissolved organic carbon (DOC) accounted for the highest proportion, at 77.5% of TOC, with RDOC making up 91% of DOC and 71% of TOC. Although POC contributed a small annual proportion to annual TOC, the concentration rapidly increased during late spring and early summer, with increases of 40.403%, 25.99%, and 27.388% in Cheongmi, Yanghwa, and Bokha, respectively. Continuous monitoring of RDOC is essential to identify seasonal fluctuations and changes due to rainfall events. Furthermore, intensive POC management during the rainy season, particularly in May and June, is potentially economical and efficient for water quality management.

• 한국환경생태학회지
• /
• 제22권1호
• /
• pp.43-58
• /
• 2008

하천식물의 자연환경조건을 규명하기 위하여 국내 중소규모의 10개 하천(한강수계의 문산천, 곡릉천, 낙동강 수계의 미천, 쌍계천, 남천, 북한강 수계의 가평천, 조종천, 남한강 수계의 청미천, 양화천, 복하천)을 선별한 다음에 각 하천의 전 유로연장에서 가장 자연성이 높은 구간 1km를 중점조사구로 결정하였다. 그리고 그 구간에 대하여 $2004\sim2007$년 여름에 식물조사를 belt transect 방법으로 실시하였다. 그 결과 총 296종이 출현하였는데, 그 중에서 출현빈도가 높은 121종과 대상지의 환경인자(저수로 물로 부터의 거리, 하상재료의 크기, 사주의 개수, 대상지의 고도, 하상경사, 저수로의 폭, 하천수질측정값)간의 RDA (Redundancy analysis) 및 피어슨의 상관성 분석을 실시하였다. 그 결과 대입된 식물종들은 대상지의 고도, 하상경사, 사주의 개수의 인자와는 유의성이 없었으나, 하상재료의 크기, 저수로의 폭, 전기전도도와 인산염인$(PO_4-P)$의 농도와는 상관성이 “매우 높은$\sim$보통”으로 분석되었다. 그리고 이 식물들은 현재의 그들의 수환경 조건을 그대로 반영하고 있기 때문에 분석방법의 신뢰성에 큰 무리가 없으나, 사례의 다양성 부족으로 다른 사례하천으로의 확대해석은 어려울 것이다. 그러나 본 자료는 앞으로 하천특성에 따른 식물연구나 하천식물 선정을 위한 기초 자료로는 이용할 수 있을 것이다.