• 대한토목학회논문집
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• 제39권1호
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• pp.25-32
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• 2019

도시지역 샛강은 생물이 서식하기 어려운 도심지에 다양한 수변공간을 제공하여 생물다양성에 중요한 역할을 하며, 시민들에게는 휴식 및 체험 공간으로 활용되고 있다. 특히, 여의도 샛강은 국내 최초의 생태공원으로 조성되었으며, 서울 도심 중심에 흐르고 있어 장소적 희소성이 크고 생태적 가치가 매우 높다. 그러나 여의도 샛강은 조성 당시부터 수질 문제가 지속적으로 제기되어 오고 있어, 샛강 환경에 영향을 미치는 요소들과 그 원인에 대한 분석이 필요하다. 이에 본 연구에서는 여의도 샛강 흐름 정체와 수질 악화 원인을 분석하였다. 이를 위해 하천 측량 및 항공사진 분석을 통해 자연적인 물 순환이 어려운 원인에 대해 분석하고 고찰하였다. 한편, 여의도 샛강의 수질 모니터링 결과, 비가 오지 않는 평상시에는 BOD, T-P는 평균 III등급과 IV 등급 수준으로 나타났으며, 강우 시에는 BOD, T-P 모두 V~VI 등급인 것으로 나타났다. 또한 배수분구 분석을 통해 샛강 수질에 영향을 미치는 소유역을 선정하였으며, 결과에 대해 고찰하였다.

• 한국물환경학회지
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• 제26권2호
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• pp.208-214
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• 2010

This study aimed at the introduction of desktop method for assessment of environmental flows developed by International Water Management Institute (IWMI) recently and its application to Geum river basin. This scheme simulated the influence on aquatic ecosystem caused by watershed development and in turn the decrease of water quantity keeping the river's own flow regime. It was found to be as very effective method although it had simple structure. Flow duration curves for different environmental classes at Sutong and Gongjoo sites were estimated according to the natural conditional scenario of Geum river basin and the results were relatively compared well with the previous studies. The behaviors of monthly average runoff time series of both sites showed the level of A class. The results of this study would provide the fundamental data to establish the future plans of monitoring or management for aquatic ecosystem of Geum river basin.

• 한국물환경학회지
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• 제25권2호
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• pp.212-220
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• 2009

In many studies, the Numeric Integration (NI) method has been widely used to calculate pollutant loads from the watershed because it is easy to apply. However, there have been many needs for more accurate pollutant loads estimation method with the restricted number of water quality samples. However, the ESTIMATOR model does not allow the users to define the regression model to explain the measured flow and water quality relationship, indicating the ESTIMATOR model is not flexible. The LOADEST model allows the user to choose the model type from 11 predefined general forms of regression equations. Annual loads of T-N and T-P with the LOADEST model were 0.70 times and 0.84 times of those by NI method, respectively. The coefficient of determination ($R^2$) of the LOADEST regression for the T-N and T-P were 0.92 and 0.72, respectively. This indicates that the load estimation regression model with the LOADEST for the study watershed explains the relationship between the observed flow and water quality data well reasonably well. Based on these findings, we suggest that the LOADEST model estimated regression equation could be used to estimate pollutant loads using the measured flow data for the study watershed.

• 한국물환경학회지
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• 제23권6호
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• pp.837-842
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• 2007

This study was conducted to test the effect of residual Al on plankton community after dissolved air flotation (DAF) application. Growth rate of phytoplankton after DAF application ($0.37day^{-1}$) was about 2 times lower than that before DAF application ($0.70day^{-1}$). Under the condition of addition of nitrogen and phosphorus without light, growth rate phytoplankton in treatment without residual Al increased in difference with showing the negative growth rate in treatment with residual Al. Under the condition of light without addition of nutrient, growth rate of phytoplankton was no noticeable difference between the before and after DAF application. The relatively high settling rate (0.47 m/day) was observed in treatment after DAF application. Although the abundance of rotifer decreased, the abundance of copepod and cladoceran such as Daphnia galeata, Diaphanosoma sp. and Bosmina longirostris with relative higher grazing was no noticeable difference between the before and after DAF application. In the treatments before and after DAF application with zooplankton, growth rate of phytoplankton was $0.41{\pm}0.08day^{-1}$, $0.20{\pm}0.03day^{-1}$, respectively. This difference was in treatment after DAF application similar with those in treatments before and after DAF application without zooplankton. Those indicate that the filter-feeding effect of zooplankton on phytoplankton community may be not changed by residual Al after the DAF application. These results suggest that residual Al after DAF application be to improve water quality by inhibition of growth rate as well as increasing settling rate of phytoplankton.

• 한국물환경학회지
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• 제29권5호
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• pp.648-655
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• 2013

Nonpoint source pollution characteristics of recreation park was investigated. Runoff ratio of recreation park ranged 23-57%, which was lower than other urban area since impervious area was less than 37%. The average BOD, COD, TOC, SS, T-N, T-P, were 14.09, 32.86, 12.19, 121.51, 7.78 and 0.72 mg/L, respectively. First flush of recreation park was analyzed by normalized cumulative load - volume curve and mass first flush ratio(MFFn), MFF10 for BOD, COD, SS, T-P, T-N, TOC were 2.90, 1.59, 2.15, 2.74, 2.60, and 1.59, respectively. Observed data showed that 62% of pollutant could be removed by storaging 5 mm rainfall-runoff and even 3 mm depth could store up to 50% of pollutant in runoff.

• 한국물환경학회지
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• 제36권1호
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• pp.1-13
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• 2020

The purpose of this study was to investigate the thermal and chemical stratification in Lake Paldang 2013-2018 weekly using Schmidt's stability index (SSI) and the index of chemical stratification (IC-i). The annual average for SSI was 19.1 g cm/㎠ with the maximum value of 45.3 g cm/㎠ in the summer and the minimum value of 4.8 g cm/㎠ in fall-winter showing seasonal differences as well as increased vertical mixing in the summer. The lake stability increased higher in 2016 as compared with the other period. The most influential factors of thermal stratification were temperature and heavy rainfall. Especially, high water temperature and a prolonged residence duration caused by reduced rainfall and inflows could result in an increase of the stratification period. While decreasing inflow and outflow at the end of the rainfall, the thermal stratification was restrengthened within 7-14 days, and then stabilized rapidly before the rainfall. IC-DO increased with high air temperature in the spring and fall-winter. However increasing sunshine duration and residence time and decreasing rate of outflow caused an increase of IC-DO in the summer. Rainfall (less than 800 mm/year) and discharge (less than 200 CMS) significantly declined in 2015 resulting in IC-DO (0.77) increased more than three times over the other years and bottom water hypoxia occurred. The SSI and IC-i used in this study could be applied to other lakes to understand changes in stratification and mixing dynamics.

• 한국물환경학회지
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• 제26권5호
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• pp.850-859
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• 2010

Structure and succession of zooplankton community studied by hydraulic and ecological characteristics targeting the five lakes in the Han river system from March to December 2008. Results separated by river-type lake and lake-type lake depending on the type of hydraulic, Paldang lake and Cheongpyeong lake were river-type lake, while Chungju lake, Hoengseong lake and Doam lake was lake-type lake. The Paldang lake was a eutrophic lake, zooplankton community density and species number were the most among the five lakes. Relative dominance of the rotifera was the largest and the yearly first dominant species was a small cladocera Bosmina longirostris. The Cheongpyeong lake was a mesotrophic-eutrophic lake, hydraulic characteristics and zooplankton community changes were similar the Paldang lake. Relative dominance of the cladocera was the largest and the yearly first dominant species was a small cladocera Bosmina longirostris. The Chungju lake was a oligotrophic-mesotrophic lake, zooplankton community density was the least among the five lakes. Relative dominance of the copepoda was the largest and the yearly first dominant species was a large cladocera Daphnia galeata. The Hoengseong lake was a oligotrophic-mesotrophic lake, relative dominance of the rotifera was the largest and the yearly first dominant species was a small cladocera Bosmina longirostris. The Doam lake was a mesotrophic-eutrophic lake, zooplankton community density showed dramatic difference at the investigation time. Relative dominance of the rotifera was the largest and the yearly first dominant species was the copepoda Nauplius.

• 한국물환경학회지
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• 제36권2호
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• pp.89-97
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• 2020

North Han River is a very unique type of water system, where Hwacheon, Chuncheon, Soyanggang, Euiam and Cheongpyeong Dams are located consecutively. These dams are operated differently in the amount of discharge and release schedule according to their structure and purpose of use. They have different water quality characteristics depending on external pollutant inflow and internal mixing condition. Therefore, this study investigated the relationship between the upper dam and down stream river with respect to water quality indicators, such as water temperature, electrical conductivity, BOD, COD, TN and TP of the North Han River. The similarities and correlations representing the relationship were analyzed by Pearson's correlation r and t-test. The data was taken from the Ministry of Environment's water quality monitoring from 1999 to 2018. The results show that water temperature and electrical conductivity of the dam and river are similar and correlated. However, it turned out that there was no similarities and correlations in BOD, COD, TN and TP that are significantly affected by subaqueous reaction mechanism. The results of this study present the impact of the dam on the water quality of North Han River, which can be used as useful data for management of water quality.

• International journal of advanced smart convergence
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• 제9권3호
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• pp.1-8
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• 2020

Water consumption has grown at more than 2.5 times, comparing the past century. About 2.8 billion people live in river basins with some form of water deficit, because more than 75 % of the river flows are withdrawn for agriculture and other needs. Challenges faced by more and more countries in their struggle for economic and social development are increasingly related to water. This paper proposes a test of an effective local river field environment management solution. And describing a part of a pilot project for the ministry of water resources of Uzbekistan. Current work focused on direct action items of the existing project and describe an IoT routing based solution for local river field environment management solutions. Suggested technological decisions provided by needs and on-site testing results. The paper describes the backbone of IoT routing based river water resources management system.

• 환경영향평가
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• 제22권6호
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• pp.557-568
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• 2013

In this study, Calculated the nonpoint sources(NPS) load per unit area about various rainy events in vineyard of Nakdong River basin. NPS monitoring and calculation for NPS load per unit area were estimated from 'Investigation method of precipitation discharge(National Institute of Environmental Research, 2007)'. The evaluation of applicability for NPS load per unit by compared with prior research data and Total Maximum Daily Load(TMDL) data. Five target areas were each $2000m^2$, $1800m^2$, $1943m^2$, $2484m^2$, $864m^2$ and located in Gyeongsangbukdo Gyeongju, Gyeongsangbukdo Sangju, Gyeongsangnamdo Hapcheon in Korea. Since fruits were the only crop on the target area, the characteristics of stormwater discharge at survey sites could be evaluated independently. A total of 115 rainfall events in the Orchard area during five years(2008-2012) was surveyed, and 38 of them became stormwater discharge. In the Nakdong River watershed, average of event mean concentrations(EMCs) in Orchard area for biochemical oxyzen demand(BOD), Chemical oxyzen demand(COD), total nitrogen(T-N), total phosphorus(T-P) were 2.0mg/L, 10.1mg/L, 3.195mg/L, 0.578mg/L, respectively. NPS load per unit area in Orchard area showed BOD : $2.0kg/km^2{\cdot}day$, COD : $10.2kg/km^2{\cdot}day$, T-N : $3.220kg/km^2{\cdot}day$, T-P : $0.606kg/km^2{\cdot}day$.