• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제2권4호
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• pp.259-273
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• 2021

We conducted a study to investigate the characteristics of the carbon cycle of two streams (located in Shig a Prefecture, Japan), having similar size, namely, the Adokawa stream (length: 52 km, area: 305 km², watershed population: 8,000) and the Yasukawa stream (length: 62 km, area: 380 km², watershed population: 120,000), but with different degree of human activity. Samples were collected from these two streams at 14 (Adokawa stream) and 23 (Yasukawa stream) stations in the flowing direction. The dissolved inorganic carbon (DIC) concentration and the stable carbon isotope ratio of DIC (δ¹³C-DIC) were measured in addition to the watershed features and the chemical variables of the stream water. The δ¹³C-DIC (-9.50 ± 2.54‰), DIC concentration (249 ± 76 µM), and electric conductivity (52 ± 13 µS/cm) in Adokawa stream showed small variations from upstream to downstream. However, the δ¹³C-DIC (-8.68 ± 2.3‰) upstream of Yasukawa stream was similar to that of Adokawa stream and decreased downstream (-12.13 ± 0.43‰). DIC concentration (upstream: 272 ± 89 µM, downstream: 690 ± 37 µM) and electric conductivity (upstream: 69 ± 17 µS/cm, downstream: 193 ± 37 µS/cm) were higher downstream than upstream of Yasukawa stream. The DIC concentration of Yasukawa stream was significantly correlated with watershed environmental variables, such as, watershed population density (r = 0.8581, p<0.0001, n = 23), and forest area percentage of the watershed (r = -0.9188, p<0.0001, n = 23). δ¹³C-DIC showed significant negative correlation with the DIC concentration (r = -0.7734, p<0.0001, n = 23), electric conductivity (r = -0.5396, p = 0.0079, n = 23), and watershed population density (r = -0.6836, p = 0.0003, n = 23). Our approach using a stable carbon isotope ratio suggests that DIC concentration and δ¹³C-DIC could be used as indicators for monitoring the health of stream ecosystems with different watershed characteristics.

• 한국물환경학회지
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• 제31권5호
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• pp.507-522
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• 2015

In this study, some of the model verification results of STREAM (Spatio-Temporal River-basin Ecohydrology Analysis Model), a newly-developed hybrid watershed model, are presented for the runoff processes of nonpoint source pollution. For verification study of STREAM, the model was applied to a test watershed and a sensitivity analysis was also carried out for selected parameters. STREAM was applied to the Mankyung River Watershed to review the applicability of the model in the course of model calibration and validation against the stream flow discharge, suspended sediment discharge and some water quality items (TOC, TN, TP) measured at the watershed outlet. The model setup, simulation and data I/O modules worked as designed and both of the calibration and validation results showed good agreement between the simulated and the measured data sets: NSE over 0.7 and $R^2$ greater than 0.8. The simulation results also include the spatial distribution of runoff processes and watershed mass balance at the watershed scale. Additionally, the irrigation process of the model was examined in detail at reservoirs and paddy fields.

• 한국물환경학회지
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• 제31권5호
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• pp.491-506
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• 2015

Distributed models represent watersheds using a network of numerous, uniform calculation units to provide spatially detailed and consistent evaluations across the watershed. However, these models have a disadvantage in general requiring a high computing cost. Semi-distributed models, on the other hand, delineate watersheds using a simplified network of non-uniform calculation units requiring a much lower computing cost than distributed models. Employing a simplified network of non-uniform units, however, semi-distributed models cannot but have limitations in spatially-consistent simulations of hydrogeochemical processes and are often not favoured for such a task as identifying critical source areas within a watershed. Aiming to overcome these shortcomings of both groups of models, a hybrid watershed model STREAM (Spatio-Temporal River-basin Ecohydrology Analysis Model) was developed in this study. Like a distributed model, STREAM divides a watershed into square grid cells of a same size each of which may have a different set of hydrogeochemical parameters reflecting the spatial heterogeneity. Like many semi-distributed models, STREAM groups individual cells of similar hydrogeochemical properties into representative cells for which real computations of the model are carried out. With this hybrid structure, STREAM requires a relatively small computational cost although it still keeps the critical advantage of distributed models.

• 농촌계획
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• 제2권2호
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• pp.109-117
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• 1996

The purpose of this study Is to develop water quality management system fort a farm village stream. The framework design of the system and the ecological monitoring of a test watershed were carried out, The system consists of GIS(Geographic Information System ), database, pollution source management, water quality and hydrologic analysis. Suri watershed located on Idong, Yongin city, Kyunggi Province, was selected as the test watershed for the application of the system. The fifteen's monitoring stations were chooses at up- and down-stream of the watershed. The results of an aquatic ecological monitoring were analyzed by the GPI(Group Pollution Index) method. The GPI revealed that water quality was varied within the stream. GPI and DO map for the watershed stream were developed, These maps facilitated to analyze the spatial distribution of the water quality.

• Spatial Information Research
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• 제10권3호
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• pp.439-453
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• 2002

수자원분야에서 DEM을 활용한 연구들이 활발히 진행되고 있으며, 특히 지형 및 수문분석의 기초가 되는 유역과 하천 추출은 GIS 분석에서 일반화되어 있다. 그러나 경사가 완만한 지형에서는 가늘고 긴 슬리버 폴리곤 형태의 유역이나 직선형태의 하천이 추출되므로, 활용측면에서 비 효율적이다 본 연구에서는 완경사지역에서 발생하는 비정상적인 유역과 하천을 효과적으로 추출하기 위해, 하천을 중심으로 완충구간을 설정한 후 점진적인 표고변화를 적용하였다. 특히 점진적인 표고변화를 부여하기 위해 보로노이 다이어그램(Voronoi Diagram)을 활용한 등거리 할당모형을 적용하였다. 또한 추출한 하천인식 DEM과 원시 DEM을 이용하여 유역 및 하천을 추출한 후, 완경사 지역에서의 유역 및 하천의 형태를 상호 비교함으로서 본 연구의 효용성을 평가하였다.

• 한국환경교육학회지:환경교육
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• 제21권4호
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• pp.25-39
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• 2008

The purpose of this study is to realize the teaching material, which develops the Model of Watershed Water Environment Education(EE) Textbook, by seeking for a method of the Inquiry with the Perspective of EE and by questing for the contents of watershed water environment necessary for Water EE with the Perspective of EE. First, the value of watershed EE was reilluminated through the literature analysis on the watershed. And 'Inquiry with the Perspective of EE' methodology was newly presented that quests for the contents necessary and proper for EE from the viewpoint of EE. Also, with suggesting it as concept and methodology of 'Inquiry with the Perspective of Watershed EE' by considering the value of EE in Water EE, it presented the content approach direction in the inquiry and the contents of the specific inquiry. Second, through the Inquiry with the Perspective of EE into water environment of the watershed Musim cheon (stream), which is a case region, it allowed the watershed water environment to be able to be synthetically understood. As for a sphere of the inquiry, 5 spheres were sought by taking into account a relation to a human being, as well as the water environment itself of the watershed Musim cheon (stream). Third, Based on the contents of the Inquiry with the Perspective of EE into the watershed Mlisim cheon (stream), 'the Model of Watershed Water EE Textbook' for middle-school students was developed. This model of textbook was selected largely four parts, and was organized with 10 learning objectives and 11 activities.

• 한국습지학회지
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• 제19권4호
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• pp.491-500
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• 2017

하천수량은 하천의 수질, 생태환경보전에 있어 가장 근원적이고 기본적인 사항으로 매우 중요한 요소이다. 본 연구의 목적은 경기도 도심하천의 불투수면적률에 따른 하천수량 변화 원인 및 영향을 분석하여, 경기도 도심하천의 하천수량 확보 방안 및 하천관리 정책에 반영할 있는 자료를 제시하는 것이다. 이를 위해 안양천유역, 탄천유역, 오산천유역을 표본 도심하천으로 선정하고, 불투수면적률(%ISA)에 따른 하천수량 및 수질의 변화와 직 간접적인 하천수 확보방안을 검토하였다. 그 결과를 정리하면 다음과 같다. 안양천유역, 탄천유역, 오산천유역의 불투수면적률은 2014년을 기준으로 약 10년전 보다 각각 5.32%, 6.32%, 7.22% 증가하였으며, 전반적으로 불투수면적률이 증가할수록 유출계수는 증가하는 경향을 보였다. 하천 재이용수량은 탄천유역에서 하천수 확보에 긍정적 효과가 나타났지만 안양천유역과 오산천유역은 하천수 확보 효과가 미흡하였다. 그러나 하천 재이용수량으로 인해 각 하천 수질등급이 개선되는 것으로 나타났다.

• 농촌계획
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• 제2권2호
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• pp.91-102
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• 1996

Monitoring techniques for afro-ecological environments were studied, Hydrologic and ecological components in conjunction with water quality were monitored in the Balkan watershed. The hydrologic monitoring program consists of four water level gauging stations along creeks and stream at the watershed having 26.5 km2. Stage - storage relationship of reservoir, rainfall amount of the watershed, and rating curve of the stream gauging stations were established. Soil type, land use, hydrologic soil group, population and economic activities within the watershed were surveyed. Water quality data from the streams were sampled weekly and chemical analysis was conducted. Temporal variations of water quality were investigated and water quality map of each reach of stream was made to identify spatial variations. Seasonal and spatial variations of vegetation densities along stream in the watershed were investigated using grid, Density variations of insect species such as arthropod, flying insect, spider spices, rice insects were also monitored to determine seansonal surveying density. These monitored data will be used to develop monitoring techi%ues and afro - ecological environment models.

• 한국농공학회지
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• 제45권7호
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• pp.49-56
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• 2003

Nonpoint source pollutant loading from watershed may cause a problem to the water quality of the reservoir and stream. The characteristics of stream flow and water quality were monitored to investigate the runoff loading of the Namdae-cheon watershed from May in 1999 to October in 2003. Stage-discharge rating curve at the stream gauging site was established, and annual stream runoff of the study watershed was estimated as 499.4∼1,330.8mm during four years. The concentrations of total-nitrogen and total-phosphorus of stream water quality ranged from 0.76 to 6.95mg/L and from 0.0010 to 0.2276 mg/L, respectively, where T-N was generally higher than the water quality standard 1.0 mg/L for agricultural water use. The loads by unit generation of pollutant mass with respect to population, livestock, land use in this watershed were calculated. The runoff pollutant loadings by concentrations of total-N and total-P were estimated during study period, where the annual runoff loading of total-P was much less than the load by pollutant mass unit generation. The relations between stream discharge and water quality were analysed, and there was a high correlation for total-N but low for total-P. These results will be used to develop the monitoring techniques and water quality management system of agricultural watershed.

• 한국농공학회논문집
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• 제52권4호
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• pp.53-61
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• 2010

An impervious cover in the watershed management has been used as effective indicators. It is a very useful barometer to measure the impacts of watershed development on aquatic systems. Hence, it is necessary to survey the impervious cover of a watershed and to develop an impervious cover model (ICM) for supporting best management practices. The main objectives of this study were to investigate the spatial patterns of the impervious cover, to calculate landscape indices using FRAGSTATS, and to develop an ICM in the Gap-stream watershed and its six sub-watersheds. The results showed that the impervious cover of the Gap-stream watershed increased from 4.9 % in 1975 to more than 11.2 % in 2000, the number of impervious cover fragments increased from 662 to 3,578, and the landscape shape index increased from 27.0796 to 91.1982. Fragmentation was severe within the Yudeungcheon downstream and the Gapcheon downstream of six sub-watersheds. This paper presented the results derived landscape indices to define landscape patterns and structure for the Gap-stream watershed. Our results indicate that altered land use might be influenced changes in landscape structure.