• 한국환경과학회지
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• 제16권5호
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• pp.649-655
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• 2007

This study was focused on estimating instream flow, and its optimal alternative for securing the required total amount of instream flow was also researched in order to restore ecosystems and riverine aesthetics of the Mugeo Stream. the first tributary of the Taewha River flowing through the center of Ulsan. In this study the hydraulic and hydrologic conditions and water quality were investigated at specific channel reaches and representative stations of the Mugeo Stream to determine a proper estimate of instream flow. And riverine functions, such as the minimum flow, water duality conservation, fish habitat, and recreation, were considered to restore the environmental functions of the stream, As a result, the total amount of $11,500m^3/day$ was set as the target instream flow for the Mugeo Stream. It was chosen as the optimal alternative for securing the total external supply of $10,000m^3/day$ which have to be transfered from the riverbed flow diverted through the Taewha Main river at upstream of Samho bridge. The water duality throughout the Mugeo Stream channels will be improved considerably to 3-4 mg/l of BOD standard if the target instream flow is supplied and sewage is intercepted by the sanitary sewage system.

• 환경영향평가
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• 제14권1호
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• pp.37-46
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• 2005

In this study, field surveys were performed for 12 stations in main stream of Hongjechun and 3 stations in 2 tributaries, respectively, in order to find out dried reaches of the stream, and to examine the water quality of the stream, and to suggest methods to improve the stream concerned into eco-stream. In the results of water quality in stream, however distinct difference for seasonal variation of the water quality was not found, the water quality of winter was relatively better than that of other seasons. Annual mean concentration of BOD was 6.5mg/L in the upper reach, 11.8mg/L in the middle reach, 15.3mg/L in the lower reach of main stream, and total mean was 12.5mg/L, while the BOD concentration was 3.6mg/L in the upper reach, and was 9.6mg/L in the low reach of Gukichun, the tributary. Based on flow examination, the level of water depth was so low and the flow can not be traveled downstream in the reach between ST-9 and ST-10 for low water season, whereas it was observed that the flow was traveling except the dry season even the water level was lower than that of adjacent stations.

• Ecology and Resilient Infrastructure
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• 제2권3호
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• pp.247-254
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• 2015

Changes in land-use type can affect soil and water properties in stream ecosystems. This study examined the effects of different land-use types on biogeochemical properties and microbial activities of a stream. We collected water and sediment samples in a stream at three different sites surrounded by varying land-use types; a forest, a radish field and a rice paddy. Nitrogen contents, such as nitrate, nitrite and total nitrogen in the stream water body, showed significant differences among the sampling sites. The highest nitrogen values were recorded at the site surrounded by cropland, as fertilizer runoff impacted the stream. Soil organic matter content in the sediment showed significant differences among sites, with the highest content exhibited at the forest mouth site. These differences might be due to the organic matter in surrounding terrestrial ecosystems. Microbial activities determined by extracellular enzyme activities showed similar values throughout all sites in the water body; however, the activities in the sediments exhibited the highest values near the forest site and mirrored the soil organic matter content values. From these results, we conclude that different land-use types are important factors affecting water and sediment properties in stream ecosystems.

• 한국환경복원기술학회지
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• 제13권5호
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• pp.12-27
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• 2010

The purpose of this study is carried out to present the raw data for restoring and maintaining an urban stream by objective surveying and analysing about flora in Changwon stream and Nam stream, Changwon-si, Gyeongsangnam-do, Korea. The results are as follows. The numbers of vascular plants were summarized as 248 taxa; 71 families, 184 genera, 220 species, 26 varieties and 2 forma. The numbers of vascular plants by streams were 202 taxa in Changwon stream and 206 taxa in Nam stream. The endemic plant was Salix pseudolasiogyne. The rare plants designated by Korea Foret Service were 2 taxa; Aristolochia contorta and Koelreuteria paniculata. The specific plants by floristic region were 12 taxa; Aphananthe aspera, Artemisia selengensis, Indigofera pseudotinctoria and so forth. The naturalized plants were 37 taxa; Ailanthus altissima, Amaranthus patulus, Amorpha fruticosa and so forth. The invasive alien plants designated by Ministry of Environment were 4 taxa; Ambrosia artemisiifolia var. elatior, Aster pilosus, Rumex acetocella and Solanum carolinense. The UI (Urbanized Index) and NI (Naturalized Index) were 13.6% and 18.3% in Changwon stream and 13.6% and 17.9% in Nam stream.

• 한국환경과학회지
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• 제31권5호
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• pp.431-445
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• 2022

The Gwangju Stream is a major tributary of the Yeongsan River. To maintain environmental and ecological functions in the stream, the flow is secured by natural water from the Mudeung Mountain as well as waters discharged from Lake Juam and the Gwangju sewage treatment plants. A substantial amount of water is supplied into the upper reaches of Gwangju Stream from Lake Juam. To examine the ecological effects of the water input from Lake Juam on the Gwangju Stream, a field survey of phytoplankton community species and an evaluation of water properties was conducted at five stations, from station GJ1 before the inflow to station GJ5 in the lower region. Nutrient levels decreased in the vicinity of the Lake Juam inflow, suggesting that this water inflow can contribute to the reduction of eutrophication in the stream. The phytoplankton community was mainly composed of Bacillariophyceae, Chlorophyceae, and Cyanophyceae, and the community structure was similar to that of the other study sites located near the water inflow regions. The inflow of water from Lake Juam can affect water quality and the phytoplankton community over a limited area, reducing eutrophication and increasing water flow in the Gwangju Stream.

• 생태와환경
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• 제44권4호
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• pp.407-410
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• 2011

Aquatic Oligochaeta is a notable animal group in freshwater environment such as streams, rivers and lakes in view of its biomass and species richness. Taxonomic studies of this group, however, have hardly been performed in Korea. Here five naidid oligochaete species are reported - Slavina appendiculata, Pristina longiseta, Pristina biserrata, Chaetogaster diaphanus and Nais variabilis - from the Seokhyeoncheon Stream in Yangju and from the Changreungcheon Stream in Goyang, Gyeonggi-do. Aquatic oligochaetes attaching on aquatic vegetations were collected with a plankton hand net. An image and description on Nais variabilis new to Korea are provided.

• 한국물환경학회지
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• 제34권1호
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• pp.96-108
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• 2018

Large efforts have recently been made on research and development of sustainable and energy-efficient short-cut nitrogen removal processes owing to strong attention to the energy neutral/positive wastewater treatment system. Anaerobic ammonium oxidizing bacteria (anammox bacteria) have been highlighted since 1990's due to their unique advantages including 60% less energy consumption, nearly 100% reduction for carbon source requirement, and 80% less sludge production. Side-stream short-cut nitrogen removal using anammox bacteria and partial nitritation anammox (PN/A) has been well established, whereas substantial challenges remain to be addressed mainly due to undesired main-stream conditions for anammox bacteria. These include low temperature, low concentrations of ammonia, nitrite, free ammonia, free nitrous acid or a combination of those. In addition, an anammox side-stream nitrogen management is insufficient to reduce overall energy consumption for energy-neutral or energy positive water resource recovery facility (WRRF) and at the same time to comply with nitrogen discharge regulation. This implies the development of the successful main-stream anammox based technology will accelerate a conversion of current wastewater treatment plants to sustainable water and energy recovery facility. This study discusses the status of the research, key mechanisms & interactions of the protagonists in the main-stream PN/A, and control parameters and major challenges in process development.

• 한국물환경학회지
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• 제34권1호
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• pp.10-25
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• 2018

This study was conducted to estimate the habitat suitability of 17 benthic macroinvertebrate taxa in the Hwayang stream. Habitat Suitability Index (HSI) of benthic macroinvertebrates from the Hwayang stream was developed based on three physical habitat factors which include current velocity, water depth, and the substrate. The Weibull model was used as a probability density function to analyze the distribution of individual abundance by physical factors. The number of species and the total individual abundance increased along with the increase in current velocity. By means of Canonical Correspondence Analysis (CCA), the relative importance of each factor was determined in the following order: current velocity, water depth, and the mean diameter. The results depicted that, the most influential factor in the growth of benthic macroinvertebrates in the Hwavang system was current velocity. After comparing the analyzed results from the Hwayang stream with the resukts from the Gapyeong stream, the integrated HSI was drawn. The results indicated that current velocity and substrate had similar distributions of HSI in the two streams. This was due to the addition of unmeasured data from previous surveys, or the fact that benthic macroinvertebrates adapted to deeper waters in the Hwayang Stream. Most taxa showed a clear preference for a fast current velocity, deep water depth and coarse substrate except Baetiella, Epeorus, (mayflies), and Hydropsyche (caddisfly).

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.429-432
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• 2002

The purpose of this study was to get the change of stream water quality in upper stream of Dong-jin river stream, water samples were taken at samling site during 6 month with from march to August in 2002. The water temperature and pH of stream water were ranged $9.0{\sim}29.4^{\circ}C,\;6.48{\sim}9.33$, respectively. The COD values of stream water was ranged from 0.60 to 19.06. The content of T-N and T-P were $1.88{\sim}6.74mg/L$, $ND(not detcted){\sim}0.50mg/L$ by the livestock wastes and agricultural activity, respectively. Also, suspended solids of stream water was ranged $0.4mg/L{\sim}322.0mg/L$. The contents of heavy metal Zn, Cu, and Pb were $ND{\sim}0.070mg/L,\;ND{\sim}0.012mg/L,\;and\;ND{\sim}0.043mg/L$, respectively. Cd was not dected in all the samples.

• 한국물환경학회지
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• 제23권5호
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• pp.731-739
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• 2007

In this study, water quality monitoring focused on TOC was performed at 5 points in Mihocheon (Stream) from January to December 2006. And 10 parameters (water temperature, pH, DO, EC, turbidity, SS, BOD, $PO_4-P$, TOC, TN) were monitored every month for one year. According to this study, TOC increased towards the lower stream (#4~#5). Correlation coefficients between TOC and DO, EC, turbidity, SS, BOD, $PO_4-P$, TN were -0.126, 0.351, 0.320, 0.286, 0.711, 0.525, 0.666. TOC was highly related to BOD. As a result of linear regression analysis, regression equation between BOD and TOC was BOD=0.58TOC+1.90 ($R^2=0.506$). In Mihocheon (Stream), BOD/TOC ratio decreased towards the lower stream. This results show decrease of ratio of biodegradable organic material to total organic pollutants towards the lower stream. This study is significant since it has revealed the potential value of TOC as organic material indicator for inquiry of water quality characteristics in the natural water system.