• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.5
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• pp.84-93
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• 2000

To provide the basic information for the water improvement and control of water resource in Boryung fresh water reservoir watershed, the characteristics of stream sediments and water quality of the watershed were investigated through 16 times totally, form November in 1998 to March in 2000. The COD values of stream water quality of the Boryung fresh-water reservoir watershed ranged from 0.75 to 6.38. Total -N concentration affected by the livestock wastes and agricultural activity ranged from 0.45 to 21.80mg/L and which was almost over the quality standard of agricultural water(1.0mg/L). Total-P concentration ranged from 0~0.176 mg/L and average value 0.031 mg/L . The contents of heavy metals from 138.4 to 3,457.3mg/kg and total-P were from 210.0 to 468.3 mg/kg. These were very high according to the influence by the livestock waste and sewage water partly.

• Journal of Korean Society on Water Environment
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• v.31 no.6
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• pp.680-692
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• 2015

A landcover map watershed of downstream reach in the Gyungan stream was made by using the existing land use map and interpreting satellite images and aerial photos. Based on the map, we analyzed land use patterns of this basin. Broad-leaved forest occupied the largest area among landscape elements established in this watershed. The total area of the zone designated as the waterside district by the central government was 4.7 km² , and broad-leaved forest occupied the largest area as 33.9% in this zone. Therefore, the area did not meet the qualifications of riparian zones. Riparian vegetation established in the Gyungan stream watershed was composed of Phragmites communis, Miscanthus sacchariflorus, Salix gracilistyla, Salix koreensis. But terrestrial vegetation elements such as Ambrosia trifida, Ailanthus altissima, Robinia pseudoacacia also appeared in this area. On the other hand, Phragmites japonica, Salix gracilistyla, Salix koreensis, Salix integra, Ulmus davidiana and so on appeared in the riparian zone the reference streams. Differently from the vegetation established on the reference streams, terrestrial vegetation elements appeared frequently in the Gyungan stream watershed. This result would be due to that the Gyungan stream watershed is exposed to excessive human interferences.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.3
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• pp.91-101
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• 2012

This study is to assess the runoff characteristics of nonpoint source pollution loads for Jecheon and Jangpyeong stream watersheds located in the upstream of Chungju lake. The SWAT (Soil and Water Assessment Tool), a physically based distributed hydrological model was calibrated and verified using 5 years (2006 to 2010) streamflow and water quality data. The Nash-Sutcliffe model efficiency for streamflow was 0.60~0.92 and the determination coefficients for sediment, Total Nitrogen (T-N), and Total Phosphorous (T-P) were 0.53~0.71, 0.51~0.91 and 0.38~0.85 respectively. The results showed that the Sediment, T-N, and T-P of Jangpyeong stream were 40.0~60.9 %, 34.8~64.1 % and 76.5~83.9 % higher than Jecheon stream watershed during wet days. The results evaluated high NPS loads at Jangpyeong stream because the percentage of urban and upland crop cultivation area Jangpyeong stream watershed was higher than Jecheon stream watershed.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.6
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• pp.39-48
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• 2010

Sediment yields from Imha watershed were simulated during 1993-2008 using Hydrologic Simulation Program-Fortran (HSPF). Using observed daily stream flow for 2004-2008 and hourly suspended solid concentration for three events during 2006, HSPF was calibrated and validated at the sites of Imha and Youngyang for stream flow and Dongchun and Jangpachun for sediment yield. The calibration and validation results represented high model efficiency for simulating daily stream flow and hourly suspended solid. The determination coefficients of calibration and validation were 0.90 and 0.81 for daily stream flow, and 0.91 and 0.86 for monthly stream flow, respectively. Based on model tolerances for calibration and validation of stream flow, HSPF performance for simulating stream flow represented 'very good'. The determination coefficients of calibration and validation were 0.94-0.96 and 0.95 for hourly sediment yields, respectively. The average yearly sediment yield during 1993-2008 was 122,290 ton/year and most of sediment yield (77 % of total yield) were generated from June to August. The calibrated HSPF simulated well the movement of water and eroded soil within Imha watershed.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.555-562
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• 2004

This paper presents the development and application of a riparian buffer zone design model(RBZDM). The model was developed as a decision-making tool for watershed management, by integrating geographic information system(GIS) and analytical hierarchy process(AHP) theory. Several factors for watershed management, such as pollution removal capacity, land aquisition cost, distribution of point and non-point pollution sources, and possibility of new pollution source location, were analyzed based on AHP theory. The vegetated buffer zone width was designed using GIS-based riparian buffer analysis. The developed model was applied to the Kyoungan Stream watershed, which is an important part of Paldang lake catchment area. The Kyoungan stream watershed was divided into sixteen subbasins. Six of them belong to the main stem, where the model was applied. Ten alternatives of buffer zone width and five hierarchial levels were designed. The relative importance and the relative preference were computed by pair-wise comparison of evaluation criteria given in hierarchial levels. The buffer zone width was determined by linear function of the given alternatives and relative preferences. From this study, it was determined that the six buffer zone widths of Kyoungan main stems would be 1,594, 1,744, 1,856, 1,782, 1,338, 1,780 meter, from upstream to downstream.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.3
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• pp.127-136
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• 1996

The purpose of this study is to provide with information for the water resources development and management in stream management planning, such as information on the sediment trensport, design of dam and water facilities, river improvement and flood plains management. The major results obtained from the field measurement and analysis of the watershed characteristics, hydraulic and sediment characteristics are as follows ; 1. The rating curve formulas obtained from the analysis of the hydraulic characteristics data collected are ; Q-=110.563 $(H-0.474)^2$ for 0.7m$(H-0.146)^2$ for 0.4m$Sr=aX{^2} {_1} X^{c}{_2}$, in the experimental watershed.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.4
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• pp.46-55
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• 2001

Analysis of fish farm influences on stream water quality may provide basic informations on watershed management to reduce environmental impact due to fish farm development and to conserve stream water quality in forested watershed area. In this research stream water qualities around Mt. Baegun area were monitored seasonally for three years. Due to the increase of pH in effluent water from the fish farm it was believed that alkalization of stream water can be accelerated by large scale development of fish farms in the forested watershed area. As a result of regression analyses, the linear equation of pH of influent and effluent water of fish farm was, pH of effluent water of fish farm = $0.6234{\times}pH$ of influent water of fish farm + 2.6263. Also, the linear equation of electrical conductivity of influent and effluent water of fish farm was electrical conductivity of effluent water of fish farm = $1.7275{\times}$electrical conductivity of influent water of fish farm - 14.007. Negative effects on stream water quality were observed by indications of increase in electrical conductivity and water temperature of effluent water from the fish farm. Decreases in physicochemical indices such as the amount of dissolved oxygen, total amount of cation and total amount of anion in effluent water from the fish farm were also negative aspects in downstream ecology. It is recommended that water purification system as well as environmentally-friendly fish farm design should be incorporated to large scale fish farm development plan in forested watershed area.

• Journal of Environmental Science International
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• v.22 no.5
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• pp.523-531
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• 2013

In this study, a method of simulating ephemeral stream runoff characteristics in Jeju watershed is newly suggested. The process based conceptual-physical scheme is established based on the SWAT-K and applied to Cheonmi-cheon watershed which shows the typical pattern of ephemeral stream runoff characteristics. For the proper simulation of this runoff, the intermediate flow and baseflow are controlled to make downward percolation should be dominant. The result showed that surface runoff simulated by using the modified scheme showed good agreement with observed runoff data. In addition, it was found that the estimated runoff directly affected the groundwater recharge rate. This conceptual model should be continuously progressed including rainfall interception, spatially estimated evapotranspiration and so forth for the reasonable simulation of the hydrologic characteristics in Jeju island.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1081-1083
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• 2007

The study in river basin has been performed for the identify water quality impaired stream segments, to create a priority ranking of those segments, and to calculate the heavy metal ion distribution for each impaired segment based on chemical and physical water quality standards. Two methods for modeling the potential area-specific heavy metal distribution are pursued in this study. First, a novel approach focuses on distance. Heavy metal distribution can be associated with a particular small geographic area. Based on the derived estimates an distribution map can be generated. Second, the approach is used the near watershed by means of kriging interpolation algorithm. These approaches provide an alternative distribution mapping of the area. The exposure estimates from both of these modeling methods are then compared with other environmental monitoring data. A GIS-based model will be used to mimic the hierarchical stream structure and processes found in natural watershed. Specifically, the relationship between landscape variables and reach scale habitat conditions most influential found in the Abandoned mine will be explored.

• Journal of Industrial Technology
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• v.18
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• pp.35-41
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• 1998

A watershed terrain factor is known to the very important in studies of a stream and a watershed. We have obtained the terrain factor in map directly or we have generated it in a digitalized map. In this study, DTED(Digital Terrain Elevation Data) offering in DMA(Defense Mapping Agency) was used to create a stream and a watershed and to extract the terrain factor. As comparison of the factors gererated in digitalized map the terrain factors extracted in DTED, DTED could be used to extract a terrain factor for a watershed management.