• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.617-621
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• 2007

최근 관심을 받고 있는 지속가능한 하천관리는 과거에 이루어졌던 이수 및 치수중심의 하천관리와 90년대 고조된 자연형 하천관리에서 진일보된 하천관리로써, 전체적인 하천시스템을 고려하여 자연과 인간이 함께 하천을 공유할 수 있도록 하기 위한 것이다. 환경유량은 이를 위한 필수적인 요소이며 하천 시스템에 절대적인 영향을 미치게 된다. 따라서 환경유량 산정시에는 하천의 특정 분야만 고려했던 과거와는 달리, 이 치수, 어류, 식생, 저서생물 등 하천의 전체시스템을 고려하여야 한다. 이를 위해 대상 지역의 전체적인 개황을 조사하고 환경유량 산정시 우선적으로 고려되어야 하는 영향인자를 결정하게 되는데 이때 각 분야의 전문가적 견해가 요구되어진다. 하천에 대한 전체적인 시스템 분석은 매우 다양한 방법으로 수행 될 수 있는데 하천의 유황변화, 하도의 변화, 하천을 중심으로 하는 수생 동식물의 변화, 하천에 설치된 수공구조물의 변화 등 여러 분야에 걸쳐 다양한 자료의 수집과 연계분석이 이루어져야 한다. 하천 생태계를 구성하는 가장 기본적인 환경유량의 파악은 이러한 다양한 분야의 연계 분석을 통해 이루어지며, 하천특성에 맞는 적절한 환경유량은 손상된 하천 생태계를 회복하는 근간이 될 수 있다. 환경유량의 영향인자를 결정하기 위해 현장답사를 통한 조사 분석이 수행되는데, 지금까지는 특정분야의 특정 전문가가 현장답사를 실시하고 특정 전문가의 견해에서 결과분석이 이루어져 왔다. 그러나 최근 선진국에서는 다학제간 전문가 그룹(Multi-disciplinary Expert Team, MET)을 통해 하천의 전체 생태시스템을 고려하여 환경유량을 산정하고 이를 유지할 수 있는 방안을 마련하고 있다. 본 연구에서는 금강유역의 환경유량을 산정하기 위하여 다학제간 전문가그룹의 접근방법을 구축하고 하천, 수질, 식생, 어류, 저서생물 등 각 분야별로 국내외의 전문가가 참여하는 MET를 구성하였다. 환경유량 산정을 위한 금강유역의 현장답사에 있어 MET의 기능과 역할을 분석하였으며 현장답사를 통해 금강유역의 전반적인 하천환경을 조사 분석하고 상호간 의견 교환을 통해 도출한 답사결과를 환경유량 산정에 적용하는데 있어 구성된 MET의 기능 및 역할을 현장답사 내용을 중심으로 분석하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.99-99
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• 2015

본 연구에서는 금강 유역을 대상으로 토양저류함수모형기반의 개념적 강우유출모형의 장기 유출모의를 평가하였다. 연구유역인 금강 22개 계측유역을 주요 유역특성인자(면적, 경사도, SCS-CN등)을 수문학적 거리 산정방법을 활용하여 3개의 유역그룹을 선정하였다. 적용모형인 개념적 강우유출모형은 3개의 토양저류함수모형[확률분포모형(PDM: Probability Distributed Moisture), 유역습윤지수모형(CWI: Catchment Wetness Index), 수정펜맨타입모형(MP: Modified Penman type model)]과 3개의 유역추적모형[병렬2선형 저류지 유출 모형(2PAR: 2-conceptual reservoirs in parallel), 빠른 지표하 흐름을 고려한 병렬 2선형 저류지 유출모형(2PMP: 2Macro-pre Approach parallel structure), 병렬 3선형 저류지 유출모형(3PAR: 3-conceptual reservoirs in parallel)]의 조합인 9개의 모형을 사용하였으며, 2006년부터 2012년의 일자료를 바탕으로 검정(Calibration), 2001년부터 2005년의 일자료를 검증(Validation)을 Monte carlo method(Uniform Random Sampling)로 수행 후, 모형의 성능은 NSE(Nash sutcliffe Efficiency)로 평가하였다. 분석결과 유역그룹에 대한 모형성능의 편차는 작아서 유역그룹에 대한 토양저류 함수모형의 뚜렷한 상관성을 확인할 수 없었다. 이는 금강 유역을 단일 유역 그룹으로 적용할 수 있음을 제시하고 있다. 검정 검증성능 및 검정매개변수의 개수를 바탕으로 적용성 평가를 실시한 결과에서 토양저류함수모형인 확률분포모형(PDM)과 유역추적모형의 병렬2선형 저류지 유출모형(2PAR)와 빠른 지표하 흐름을 고려한 병렬2선형 저류지 유출모형(2PMP)의 조합이 금강 22개 유역에서 적용성이 우수함을 확인하였다. 향후 이 모형을 바탕으로 금강유역의 대표적인 강우유출모형을 개발하고자 한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.622-627
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• 2007

최근 하천의 모습은 이수 및 치수를 위해 설치된 수공구조물과 각종 오염원으로 인한 수질악화, 산업화 및 도시화에 따른 물순환시스템의 변화로 하천의 물순환 시스템이 바뀌게 되고 하천을 찾는 시민들의 환경의식 미성숙으로 인한 직간접적인 하천오염 활동이 이루어지고 있다. 하천에 대한 이러한 변화는 수질, 수량 및 하천의 구조적 측면에서 하천 생태계에 많은 영향을 끼치고 있다. 따라서 하천의 정상적인 기능을 회복시켜 하천 생태계 보전과 환경적으로 안정된 하천 조성이 이루어지도록 하기 위해서는 하천을 보다 자연스럽고 지속적으로 관리하기 위한 효율적인 환경유량의 관리가 필요하다. 하천의 전체적인 생태시스템을 고려한 환경유량의 관리를 위해서는 기존 환경유량의 개념, 산정방법 등 현황을 분석하고 하천 생태계에 영향을 미치는 인자들에 대한 관리방안을 마련하는 것이 중요하다. 본 연구의 목표는 하천생태계에 대한 영향인자의 장단점을 분석하고 이들이 어느 정도의 영향을 미치고 있는지를 정량적으로 파악함으로써 사회적으로 요구되는 환경유량을 산정할 때 어류 및 식생 등 하천의 생태계와 하천의 수량 및 수질, 하천의 수리구조물 등 하천의 구조적인 변화를 고려할 수 있는 방안을 마련하는 것이다. 이를 위하여 우선적으로 국외 선진국에서 활용되고 있는 다학제간 전문가 그룹(Multi-disciplinary Expert Team, MET)을 통해 하천 생태시스템을 분석하고 환경유량 산정 모형을 활용하여 저수지 댐과 연계 운영함으로써 어류 및 식생 등 생태서식처와 사회환경 개선에 필요한 유량을 유지할 수 있는 방안을 적용하고자 한다. 본 연구에서는 대상유역인 금강유역에 대해 환경유량을 산정하기 위한 개념모형을 구축하였다. 개념모형은 대청댐 건설 이전, 대청댐 건설이후${\sim}$용담댐 건설 이전, 대청댐과 용담댐 건설 이후 등 3개의 시나리오를 통해 하도 및 수변공간과 유량변화에 따른 유황분석 등을 통해 손실된 생태시스템을 정량화하여 궁극적으로는 복원을 위한 대응방안을 마련하도록 할 수 있도록 구축되었다. 또한 댐으로 인한 하류지역의 영향범위 및 하천생태계에 미친 영향을 감소하기 위하여 적절한 환경유량을 산정하기 위한 것이다. 구축된 개념모형을 바탕으로, 금강유역에 대한 기초적인 수문, 하천특성, 현장조사 등을 실시하였다. 향후에는 본 연구결과를 기초로 하여 환경유량을 산정하기 위한 모형을 개발하고 산정된 환경유량을 확보 및 관리하기 위한 방안과 친환경적인 댐 운영방안을 마련하게 될 것이다.

• Korean Journal of Ecology and Environment
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• v.54 no.1
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• pp.24-38
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• 2021

Microhabitat In the upper stream is created by various environment variables such as the bottom substrate and the physicochemical factors, and may influence the distribution of benthic macroinvertebrates. We investigated the bottom substrate and environmental variables influencing the distribution of benthic macroinvertebrate in 26 stream-type waterways established at upper reaches of Geum River. During study period, total 85 families, 160 species, 9305 individuals of benthic macroinvertebrates were recorded. The stream-type waterways, where the bottom substrates consist mainly of pebble (16~64 mm) and cobble (64~256 mm) or with rapid water velocity (more than 0.2 m/s) and high dissolved oxygen (more than 120%), were supported by high species diversity of benthic macroinvertebrate. Hierological cluster analysis and the nonparametric multidimensional scale (NMDS) divided 26 stream-type waterways into a total of three clusters. In Cluster 1, the invertebrate species, such as Branchiura sowerbyi, Cloeon dipterum, Ischnura asiatica, Paracercion calamorum, and Radix auricularia, closely related to aquatic macrophytes, and Chironomidae spp., Limnodrilus gotoi, and Tanypodinae sp. were abundant in waterways, with high coverage of silt and clay as well as high turbidity and total nitrogen. The benthic macroinvertebrate species (Cheumatopsyche brevilineata, Drunella ishiyamana, Dugesia japonica, Ephemera orientalis, Gumaga KUa, Macrostemum radiatum, Potamanthus formosus, Semisulcospira libertine, Stenelmis vulgaris, and Teloganopsis punctisetae) included in Cluster 2 were dominated in sites with high cover rates of pebble and gravel. Cluster 3 was predominantly covered by the Cobbles, was supported by Simulium sp. Such a clear distinction in the study sites means that each stream-type waterways is governed by a clear habitat environment. In the case of some sites with low species diversity, improvement measures are required to restore nature, such as improving the function of inflows and outflows, creating meandering channel, and inducing the settlement of littoral vegetation.

• Korean Journal of Environment and Ecology
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• v.37 no.4
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• pp.289-301
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• 2023

Forests within watersheds are essential in maintaining ecosystems and are the central infrastructure for constructing an ecological network system. However, due to indiscriminate development projects carried out over past decades, forest fragmentation and land use changes have accelerated, and their original functions have been lost. Since a forest's structural pattern directly impacts ecological processes and functions in understanding forest ecosystems, identifying and analyzing change patterns is essential. Therefore, this study analyzed structural changes in the forest landscape according to the time-series land cover changes using the FRAGSTATS model for the dam watershed of the Geum River upstream. Land cover changes in the dam watershed of the Geum River upstream through land cover change detection showed an increase of 33.12 square kilometers (0.62%) of forests and 67.26 square kilometers (1.26%) of urbanized dry areas and a decrease of 148.25 square kilometers (2.79%) in agricultural areas from the 1980s to the 2010s. The results of no-sampling forest landscape analysis within the watershed indicated landscape percentage (PLAND), area-weighted proximity index (CONTIG_AM), average central area (CORE_MN), and adjacency index (PLADJ) increased, and the number of patches (NP), landscape shape index (LSI), and cohesion index (COHESION) decreased. Identification of structural change patterns through a moving window analysis showed the forest landscape in Sangju City, Gyeongsangbuk Province, Boeun County in Chungcheongbuk Province, and Jinan Province in Jeollabuk Province was relatively well preserved, but fragmentation was ongoing at the border between Okcheon County in Chungcheongbuk Province, Yeongdong and Geumsan Counties in Chungcheongnam Province, and the forest landscape in areas adjacent to Muju and Jangsu Counties in Jeollabuk Province. The results indicate that it is necessary to establish afforestation projects for fragmented areas when preparing a future regional forest management strategy. This study derived areas where fragmentation of forest landscapes is expected and the results may be used as basic data for assessing the health of watershed forests and establishing management plans.

• Korean Journal of Ecology and Environment
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• v.39 no.3 s.117
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• pp.310-319
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• 2006

The objective of study was to evaluate ecological health from seven sampling locations of Yoogu Stream, one of the tributaries of Guem River, July and September 2005. The research approach was based on the Index of Biological Integrity (IBI) using fish assemblage and Qualitative Habitat Evaluation Index (QHEI) using fish assemblage. The models of IBI and QHEI were modified as 10 metric model and 11 metric model, respectively, for the regional applications. In Yoogu Stream, value of IBI were averaged 29.5 (n=7) which is judged as a 'fair condition'. The IBI model scores, at the site 3 and 7, were estimated as 23 and 24, indicating a 'poor${\sim}$fair condition' while, site 5 was estimated as 28, 'fair condition'. The remaining sites were between 31 and 34, indicating 'fair${\sim}$good condition'. According to the analysis of QHEI, the average was estimated as 136, 'fair${\sim}$good condition'. Spatial variation the QHEI were evident; site 1 and site 4 were 186 and 120 respectively, indicating an 'excellent and fair${\sim}$good conditions'. Site 3 was 69, fair condition while the other sites were 128${\sim}$156, good condition.

• Journal of Korea Water Resources Association
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• v.33 no.4
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• pp.471-482
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• 2000

Surface energy balance components were evaluated by Landsat TM data and GIS with meteorological data. Calibration and validation for the applicability of this methodology were made through the estimating of the large-scale evapotranspiration (ET). In addition, sensitivity and error analysis was conducted to see the effects of the surface energy balance components on ET and the accuracy of each components. Bochong-chon located on the upper part of Guem River basin was selected as the case study area. Spatial distribution map of ET were produced for five dates: Jan. 1, Apr. 3, May. 10, and Nov. 27, 1995. The study results showed tat ET was greatly varied with the aspect and theland use type on the surface. In the case of having northeast and southeast in the aspect, ET was linearly increased depending on growing net radiation. While surface temperature has a high value, NDVI(Normalized Difference Vegetation Index) has a low value in the vegetated area. Therefore, ground heat flux was increased but ET was relatively decreased. The results of sensitivity and error analysis showed that net radiation is most sensitive and effective, ranging from 12.5% to 23.6% of sensitivity. Furthermore, the surface temperature, air temperature, and wind speed have the significant effects on ET estimation using remotely sensed data.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.4
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• pp.357-365
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• 2011

The variation of the dissolved inorganic nutrients were investigated four times per year in the costal area of Gunsan, Yellow Sea from 2001 to 2010. Water samples were collected at 10 stations and phsico-chemical parameters were analyzed including water temperature, salinity, suspended solids, dissolved oxygen, chemical oxygen demand, chlorophyll a and dissolved inorganic nutrients. The average of dissolved inorganic nitrogen(DIN) for ten years at Gunsan area showed similar concentration between surface and bottom. The average of DIN at surface was 0.421mg/L (0.198~0.846mg/L) and bottom was 0.344mg/L(0.148~0.717mg/L). The highest value of annual average of DIN at surface was 0.846mg/L in 2002 and the lowest value was 0.198mg/L in 2010. The percentage of ammonia, nitrite and nitrate for the average DIN of 10 years showed 27%, 3% and 70% which showed most of DIN was nitrate. Dissolved inorganic phosphate(DIP) for ten years at Gunsan area showed similar concentration between surface and bottom and DIP was decreasing from 2003 to 2010. The average of DIP of 10 years was 0.024mg/L and annual average 0.021mg/L in 2008, 0.007mg/L in 2009 and 0.008mg/L in 2010 which showed decreasing pattern from 2007 to 2010. The average of DIN/DIP ratio from 2002 to 2010 was 6.0(3.2~10.1) at surface and 4.6(2.6~7.0) at bottom. The average value of dissolved inorganic silicate from 2004 to 2010 showed 0.372mg/L at surface layer and 0.352mg/L at bottom layer and was on decreased from 2006 to 2010. The Spearman's correlation analysis was carried out to knowrelation among the salinity and dissolved inorganic nutrients at the surface and bottom layer. The correlation factor of DIN was -0.72, DIP was -0.46 and dissolved inorganic silicate was -0.63 at surface layer and DIN was -0.70, DIP was -0.44 and dissolved inorganic silicate was -0.57 at bottom layer. The dissolved inorganic nutrients at the nearshore of Gunsan was affected from the freshwater discharge of Geum river. Especially, a lot of DIN flowed into the nearshore of Gunsan from Guem river. The concentration of dissolved inorganic nutrients at Gunsan showed high at station 1, 2 and 3 and there was a little concentration differences according to the cruise time. The concentration of dissolved inorganic nutrients showed high value at the station 1, 2, 3 which exist nearshore of Gunsan city and it means these stations mainly affected by Geum river and Gunsan city. The annual average of dissolved inorganic nutrients showed gradually decreased from 2003 to 2010 and we need more research on this conditions.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.361-371
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• 2005

The objective of study was to diagnose integrative ecological health of Daejeon Stream, one of the tributaries of Guem River, during May 2004 ${\sim}$ April 2005. The research approach was primarily based on a Qualitative Habitat Evaluation Index (QHEI) and the Index of Biological Integrity (IBI) using fish assemblage. These outcomes were compared with conventional chemical dataset. For the experiment, four sampling sites were chosen from Daejeon Stream and long-term water quality data during 1995 ${\sim}$ 2004 (obtained from the Ministry of Environment) were analyzed in the spatial and temporal aspects. For the biological health assessment, we developed a stream health assessment model (SHA model) far regional applications. We found that current water quality conditions, based on the COD, BOD, TN and TP, were enhanced by 1.6 ${\sim}$ 5.3 fold over the period of 1995 ${\sim}$ 2004 and that the parameters showed a typical longitudinal decline from the upstream to downstream reach. The differences of water quality between the two reaches were more than 4.4 times, indicating a large spatial variations within the stream. The health conditions, based on the SHA model, averaged 23 and varied from 20 to 26 depending on the sampling stations. Values of the QHEI varied from 39 (Poor condition) to 124 (Cood condition)and values of QHEI in the reach of S2 ${\sim}$ S4 had significantly lower than in the headwater site (S1). Also, biological stream health, based on the criteria of US EPA (1993), was judged as 'Poor condition', in the S4 where TN, TP, BOD and COD were highest. In the meantime, maximum value of SHA (26) was found in the upstream reach (S1) where the water quality and QHEI were best. We also found that compositions of sensitive species showed a linear function with water quality conditions and this pattern was evident in the tolerant species. Thus, the biological stream health, based on the SHA model, matched well water chemistry. Overall outcomes suggest that the biological health impact was a function of chemical degradation and physical habitat quality in the stream.

• Journal of Wetlands Research
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• v.16 no.4
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• pp.303-318
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• 2014

Baseflow gives a significant contribution to stream function in the regions where climatic characteristics are seasonally distinct. In this regard, variable baseflow can make it difficult to maintain a stable water supply, as well as causing disruption to the stream ecosystem. Changes in land use can affect both the direct flow and baseflow of a stream, and consequently, most other components of the hydrologic cycle. Baseflow estimation depends on the observed streamflow in gauge watersheds, but accurate predictions of streamflow through modeling can be useful in determining baseflow data for ungauged watersheds. Accordingly, the objectives of this study are to 1) improve predictions of SWAT by applying the alpha factor estimated using RECESS for calibration; 2) estimate baseflow in an ungauged watershed using the WHAT system; and 3) evaluate the effects of changes in land use on baseflow characteristics. These objectives were implemented in the Gapcheon watershed, as an ungauged watershed in South Korea. The results show that the alpha factor estimated using RECESS in SWAT calibration improves the prediction for streamflow, and, in particular, recessions in the baseflow. Also, the changes in land use in the Gapcheon watershed leads to no significant difference in annual baseflow between comparable periods, regardless of precipitation, but does lead to differences in the seasonal characteristics observed for the temporal distribution of baseflow. Therefore, the Guem River, into which the stream from the Gapcheon watershed flows, requires strategic seasonal variability predictions of baseflow due to changes in land use within the region.