• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.582-582
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• 2015

최근 하천에서 발생하는 침수피해는 대규모 하천보다는 중소규모의 하천이 전체의 약 50%이상 발생하고 있으며, 기후변화에 따른 강우량의 증가와 도시화에 따른 불투수층의증가로 인하여 도시유역을 통과하는 중소규모 하천에서의 침수피해는 증가하고 있다. 특히, 도시를 통과하는 중소하천의 경우 강우발생시 짧은 도달시간으로 갑작스런 침수피해가 발생하며, 최근 급격한 인구의 증가, 산업화 및 도시화로 인한 불투수면적의 증가로 도시유역의 유출특성이 변화되고 있다. 기존의 선행된 하천 연구는 주로 유역단위의 연구가 진행되었지만 하천이 통과하는 도시유역의 경우 대부분 합류지점에 도시지역이 밀집되어 있어 하천유역을 기반으로 하는 도시지역의 구분은 어려움이 있다. 따라서 본 연구에서는 기존 하천분류인 국가하천, 지방하천, 소하천에서 침수피해가 발생하는 지방하천과 소하천사이의 중소하천에 대한 구분 기준을 제시하고 중소하천의 유역의 불투수면적뿐만 아니라 하천 선을 중심으로 하천폭에 대한 불투수면적에 대하여 비교 분석하고자 한다.

• Journal of Wetlands Research
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• v.3 no.2
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• pp.119-131
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• 2001

This study uses HEC-RAS for the quantitative aspects and the QUAL2E model for the qualitative aspects of the flow of urban streams, where the natural recovery system is applied. The instream flow of the small streams is estimated using the numerical model by verifying the existing data with the acquired data. The characteristics of the model reach place more weight on the drought discharge around the ordinary discharge, and this is caused by the natural recovery system that maintains the existing bank. The data of direct discharge to the sewage treatment plant through the inception pipe, BOD, DO, temperature, and so forth, are the official data from the department of environment. Considering the characteristics of small streams, the factors for the QUAL2E model are estimated with the focus on the hydraulic conditions and the stream view. This study proposes the future improvements for the natural recovery system by investigating the practical use of the waterfront and the application of the proper instream flow. Also, the hydraulic and hydrological investigation of the covering rate by the natural vegetation and the meandering by the varying river way is performed.

• Water for future
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• v.27 no.4
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• pp.85-94
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• 1994

A Sensitivity analysis on the model parameters involved in the Clark watershed routing method is made to demonstrate the effect of each parameter on the magnitude of 50-year design flood for small urban streams. As for the rainfall parameter the time distribution pattern of design storm was selected. For short duration storms Huff, Yen & Chow and Japanese Central type distributions were selected and the Mononobe distribution of 24-hour design storm was also selected and tested for Clark method application. The effect of SCS runoff curve number for effective rainfall and the methods of subbasin division for time-area curve were also tested. The routing parameter, i.e. the storage constant(K), was found to be the dominating parameter once design storm is selected. A multiple regression formula for K correlated with the drainage area and main channel slope of the basin is proposed for the use in urban stream practice for the determination of design flood by Clark method.

• Spatial Information Research
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• v.4 no.1
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• pp.21-42
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• 1996

The Anyang-cheon is one of the Han River tributaries in Seoul Metropolitan area. It is 35.1km long, has a basin area of 287km2 and touches seven cities of Kyounggi Province and part of Seoul. The purpose of this study were 1) to reconstruct the ancient stream network and to investigate the change of landuse in Anyang-cheon watershed between 1957 and 1991,2) to measure the change of the hydrologic ¬acteristics with urbanization, 3) to suggest the institutional solutions to reduce natural hazard as the area has urbanizedThe main results are as follows: 1.Anyang-cheon river basin has experienced the rapid urbanization and industrialization since 1957. Anyang-cheon stream network was oversimplified in the watershed. The total stream length decreased atributaries in the upper part of river basin have eliminated or buried undergrolmd in pipes. 2.Urbanization impacted to all of the area of Anyang-cht'On watershed. Urbanization in Anyang-cheon watershed corresponds to the large portion of flat area, especially flood - prone zone of river side, and the small portion of Greenbelt to constrain urban expantion in cities. 3.The urbanization of Anyang-cheon watershed produces fundamental changes in watershed hydrology. As infiltration is reduced by the creation of extensive pavement, concrete surface, and sewer pipe, runoff moves more quickly from upland to stream. As a result, runoff from the watershed is flashier, increasing flood hazardAs urban area continue to grow we will need to better utilize stream by protecting and enhancing stream systems.otecting and enhancing stream systems.tems.

• Spatial Information Research
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• v.6 no.1
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• pp.91-102
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• 1998

The objectives of this research were to develop fish-habitat relationship models which can be used to estimate fish species riclmess of small and medium rivers in Korea, and test the accuracy of the models. The models are based on the Aquatic GAP Analysis model in the New York Cooperative Fish & Wildlife Research Unit (19%), and they employ three habitat factors; river size, physical habitat, and water quality of each river segment. Model 1 and model II are based on the water quality standard for life support of EP A and the water quality class of Korea, respectively. Test sites for this study include one urban stream and three less spoiled tributaries of the Han River. The results of this research can be summarized as follows. First, the number of habitat types identified by model I and model II are nine and 14, respectively. Second, the average accuracy of the three distribution maps of rare or endangered fish species are 80.6% (model 1) and 81.2% (model II). Third, the accuracy of fish species richness are 94% (model 1) and 95% (model II), and the water quality is the most important factor affecting fish species richness. Fourth, the accuracy of fish species list are 50.5% (model 1) and 68.7% (model II), but the accuracy of less spoiled stream segments and that of polluted stream segments are 67.1% and 86.5%, respectively. Finally, it can be concluded that the overall performance of model II is better than that of model I at our test sites.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.3 no.1
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• pp.54-65
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• 2022

Species distribution models are a useful tool for predicting future distribution and establishing a preemptive response of invasive species. However, few studies considered the possibility of habitat for the aquatic organism and the number of target sites was relatively small compared to the area. Environmental DNA (eDNA) is the emerging tool as the methodology obtaining the bulk of species presence data with high detectability. Thus, this study applied eDNA survey results of Micropterus salmoides and Lepomis macrochirus to species distribution modeling by seasons in the Anyang stream network. Maximum Entropy (MaxEnt) model evaluated that both species extended potential distribution area in October compared to July from 89.1% (12,110,675 m²) to 99.3% (13,625,525 m²) for M. salmoides and 76.6% (10,407,350 m²) to 100% (13,724,225 m²) for L. macrochirus. The prediction value by streams was varied according to species and seasons. Also, models elucidate the significant environmental variables which affect the distribution by seasons and species. Our results identified the potential of eDNA methodology as a way to retrieve species data effectively and use data for building a model.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.432-436
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• 2009

Recently, damage of flood is increased because of a short of time of concentration by development and a rise in runoff discharge by frequently heavy rain. The increase of runoff discharge is resulted in not only rise of water level but also damage of lives and property around river. Therefore, it is should be the first to estimate the exact runoff discharge. And based on the estimated flood discharge, flood damage is prevented by estimating inundated area of flood. In this study, flood stage is forecasted using HEC-HMS and HEC-RAS for Namdae-stream. The peak discharges were determinated by probability rainfall with the return period. The peak discharges obtained from HEC-HMS were inputted boundary conditions for the channel routing. Flood stages were evaluated using HEC-RAS.

• Journal of Environmental Science International
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• v.23 no.7
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• pp.1349-1358
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• 2014

This study suggests plan of green space management based on the result of research apprehending the characteristic through sorting types of city thermal environment targeting summer which thermal pollution is the most serious. Considering anthropogenic heat, development level of wind road, thermal environment, as a result of types of thermal environment process, it is appeared 36 types, and 10 types is relevant of this research subject. Type I-1, size of building is large, artificial covering area is wide, and thermal load of anthropogenic heat is high, type II-1, development condition of wind road is incomplete as IIlevel, entering cold air is difficult and thermal management and improvement is needed area. Type III-1, scale is large and it is area of origin of cold air, development level of wind road is mostly favorable, type III-2 is revealed as smaller scale than III-1, and small area of origin of cold air. Type IV, anthropogenic heat is $81{\sim}150W/m^2$, average, but development function of wind road is very favorable. Type V, large area of thermal load and the origin of cold air are distributed as similar ratio, and level of development function of wind road is revealed as II level. According to standard of type classification of thermal environment, as a result of suggesting plan of green space management and biotops area ratio, type I-1 is buffer green space and waterway creation, goal biotops area ratio 35%, type II-1 afforestation in site and goal biotops area ratio 40%, type III-1, preservation plan to display the current function continuously is requested. Type IV suggests afforestation of stream current, and type V suggests quantitative increase of green space and goal biotops area ratio 45%.

• Korean Journal of Environmental Biology
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• v.25 no.4
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• pp.385-393
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• 2007

Benthic macroinvertebrate communities were studied after a small dam removal from the mid-section of the Gyeongan stream in Gyeonggi-do, Korea. Quantitative sampling was conducted at immediately upstream (upper) and downstream (lower) sites from the dam as well as at the site where the dam was located (dam site: middle) using a Surber sampler (50$\times$50 cm, mesh 0.25 mm), four times (November 2004, May 2005, January 2006, and May 2006) after the dam removal. As a result, 46 species of benthic macroinvertebtates, belonged in 35 genera, 27 families, 11 orders, 5 classes, and 4 phyla, were sampled from the stream sites, but the number of species that occurred at each sampling trial was different (ranged 3$\sim$17 spp.) according to the seasons and sites. Approximately one year after the dam removal, the species number has in-creased and taxa composition has changed as the microhabitat became more heterogeneously due to a riffle formation in the upstream site. Chironomid larvae and tubificid worms, which are common in Korean urban streams, were the dominant species, while Hydropsyche kozhantschikovi was the 2nd dominant species at some sampling trials. In general, McNaughton's dominance indices decreased and Shannon species diversity indices increased approximately one year after the dam removal. Compositions of collector-filterers, clingers, and swimmers increased as hydropsychid caddisflies, heptageniid mayflies, and baetid mayflies increased, respectively, in the upstream site. The group pollution index and the ecological score using benthic macroinvertebrates both indicated that water environment has been improved in the upstream site after the dam removal.

• Journal of Korea Water Resources Association
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• v.52 no.3
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• pp.207-217
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• 2019

This study aims at development and application of a facility that is capable of reducing pollution in water quality by reducing nonpoint source pollutants (NPSP). NPSP originated from the initial rainfall caused not only large catchment of urban area pass a river but also small watershed pass a stream. For this purpose, the performance tests carried out with the field models from the facility based on the preceding study. And the tests induced reduction efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (T-N) and suspended solid (SS), respectively. The average reduction efficiency obtained by time interval, and the result showed an excellent reduction performance. As a result, the facility satisfied reduction efficiency of NPSP of the proposed standard by the National Institute of Environmental Research, and thus it can be used in practical applications.