• Journal of Korea Water Resources Association
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• v.54 no.5
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• pp.289-299
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• 2021

This study analyzes bifurcation characteristics of the Seolmacheon experimental catchment by extracting the shape variation of channel network due to variable scale of source basin or threshold area. As the area of source basin decreases, a bifurcation process of channel network occurs within the basin of interest, resulting in the elongation of channel network (increase of total channel length) as well as the expansion of channel network (increase of the source number). In the former case, the elongation of channel reaches overwhelms the generation of sources, whereas, in the latter case, the drainage path network tends to fulfill the inner space of the basin of interest reflecting the opposite trend. Therefore, scale invariance of natural channel network could be expressed to be a balanced geomorphologic feature between the elongation of channel network and the expansion of channel network due to decrease of source basin scale. The bifurcation structure of the Seolmacheon experimental catchment can be characterized by the coexistence of the elongation and scale invariance of channel network, and thus a further study is required to find out which factor is more crucial to rainfall transformation into runoff.

• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.178-188
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• 2024

The dynamics of suspended sediment (SS) in forested catchments vary depending upon human or natural disturbances, including land use change, forestry activity, forest fires, and landslides. Understanding the dynamics of SS originating from the potential sources within a forested catchment is crucial for establishing an effective water quality management strategy. Therefore, to suggest a systematic method for interpreting SS dynamics, we evaluated the performance and applicability of ten methods for calculating the hysteresis index based on observed hydrological data and two calculation models (Lawler's method and Lloyd's method) with five sampling intervals (50th, 25th, 10th, 5th, and 1st percentiles). Our results showed that Lloyd's method, which used a sampling interval at the 1st percentile, had the largest number of analyzable runoff events and exhibited the best performance. The results of this study can contribute to quantifying the hysteresis in the relationship between discharge and SS and provide useful information for interpreting SS dynamics.

• Journal of the Korean GEO-environmental Society
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• v.25 no.9
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• pp.5-14
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• 2024

In Korea, torrential rain frequency and intensity have surged over the past five years (2019-2023), breaking rainfall records. Due to insufficient observation facilities for rainfall and runoff data in small mountainous catchments, preparing for unexpected floods is challenging. This study examines the Bidogyo catchment in Goesan-gun, Chungcheongbuk-do, comparing design flood discharge calculated with optimized parameters versus standard guidelines. Using HEC-HMS and Q-GIS for model construction, five rainfall events were analyzed with data from the National Water Resources Management Information System. The time of concentration (Tc) and storage constant (K) were calculated using the Seokyeongdae formula and model optimization. Results showed that optimized parameters produced higher objective function values for flood events. The design flood discharge varied by -10.7% to 17.3% from the standard guidelines when using optimized parameters. Moreover, optimized parameters yielded flood discharges closer to observed values, highlighting limitations of the Seokyeongdae formula for all catchments. Further research aims to develop suitable parameter estimation methods for small mountainous catchments in Korea.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.325-330
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• 1998

Seawater desalination is the production of the water, suitable for human consumption, from seawater. Since the water supply produced by desalination is at least as good, in quality than that provided by traditional catchment, the decision as to whether or not desalination plant is to be installed should be made on technical, social, economic grounds. By analysis of these criteria, we selected some regions required seawater desalination.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.397-400
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• 2002

Discharge characteristics of pollutant loadings from sewage systems were estimated in the catchment area of a reclaimed area - Saemangeum -. Pollutant loadings were estismated according to the discharge pattern of small treatment facilities. BOD pollutant loadings produced by population were 84,380kg/day, which were composed of nightsoil 35% and sewage 65%.

• Proceedings of the IEEK Conference
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• 2002.06c
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• pp.59-62
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• 2002

Watershed Segmentation with Multiple Merging Conditions in Region Growing Process The watershed segmentation method holds the merits of edge-based and region-based methods together, but still shows some problems such as over segmentation and merging fault. We propose an algorithm which overcomes the problems of the watershed method and shows efficient performance for .general images, not for specific ones. The algorithm segments or merges regions by thresholding the depths of the catchment basins, the similarities and the sizes of the regions. The experimental results shows the reduction of the number of the segmented regions that are suitable to human visual system and consciousness.

• Journal of Environmental Health Sciences
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• v.12 no.2
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• pp.27-37
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• 1986

This study was carried out to investigate inflow stream of Chungju intake reservoir and in catchment area, run-off loading amount, distribution of Nitrogen and phosphorus, N/P ratio, correlationship between T-N and chlorophyll a, correlationship between T-P and chlorophyll a, and study of trophic state. Field survey was carried out from June to August, 1985, for the purpose of finding out the nitrogen and phosphorus concentration in Chungju intake reservoir.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2005.09a
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• pp.181-184
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• 2005

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.40-45
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• 2007

Water regulators in New Zealand have recognised the need to adapt water allocation regimes and water permit conditions to reflect the likelihood of lower catchment yield on the east coast from 2030 due to climate change. Water management mechanisms to protect the environment and maintain the reliability of other water users are currently being applied or assessed in Marlborough province. These include seasonal water quota based on spring aquifer status, linking water use to environmental triggers to avoid seawater intrusion or spring depletion; and redefining water permit entitlements to account for recharge variability.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.739-746
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• 1999

Discharge characteristics of organic materials and nutrients were estimated in the catchment area of relaimed area-Saemankeum-. Discharge load of BOD5 was high in the domestic system, while nitrogen and phosphorous were discharged mainly from the livestock system and the land . Load was so dependent on the precipitation that it increased in the rainy season, particulary in nitrogen and phosphorus. Loads from nonpoint sources in this area were higher compared with others.