• Korean Journal of Environment and Ecology
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• v.27 no.3
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• pp.381-395
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• 2013

In this study, we surveyed 6 times for the actual vegetation type and flora of Amgok wetland (Intermediate moor area, Alnus japonica community area) and it's watershed area in Tohamsan district, Gyeongju National Park from Apr. to Nov. in 2011. As a result of the actual vegetation type, most vegetation of watershed area was disturbed by human activity except wetland area. Even though the wetland is relatively broad compared with it's watershed, the wetland: watershed is around 1:10. The flora was surveyed 65 family, 184 species, 1 subspecies, 39 variety, 8 forma and totally 233 taxonomic group in the watershed. The wetland type was looked intermediate moor. Naturalized plants was surveyed 2taxonomic in the wetland area and total was17 taxonomic. This area has relatively broad wetland and soundly conserved. But several Salix koreensis and Acer ginnala are growing so needed the interest and monitoring.

• Journal of Korea Water Resources Association
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• v.36 no.6
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• pp.911-924
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• 2003

Many researches have been conducting on extracting geometry data and hydrologic parameters by using GIS technique. However, there is no clear standard on those methods yet. This study examines the changing pattern of runoff responses characteristics with applying lumped model on divided watershed. WMS is used in order to divide watershed and calculate hydrologic geometry data and parameters by GIS technique. HEC-1 is adopted as a hydrologic model to establish runoff responses. The basin is divided into small watersheds, which are approximately same size. This research conducted runoff response simulation of Pyoungchang River and Wichon River Basin. Especially, research was focused on what is the most appropriate level as a divined sub-basin, and tested the effect of size of sub-basin for the runoff response simulation. The results showed the size of sub-basin was not an important factor for the simulation results after a certain size. The results of this study can be applied as an appropriate guidance to select optimal simulation size of watershed for the lumped model in a specific watershed.

• Journal of Korea Water Resources Association
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• v.46 no.9
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• pp.885-896
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• 2013

SEMMA (Soil Erosion Model for Mountain Areas) should be revised to apply on mountain watershed of large scale. In this study, the basic structure of original SEMMA and methods to calculate main parameters are reviewed and the revised parameters are presented to expand a range of application. SEMMA-Ic is new model revised by a rate of vegetation cover which is substituted for index of vegetation structure to use specially NDVI for large scale areas. The correlation coefficient and the Nash-Sutcliffe simulation efficiency for the revised model decreased rather than those of original model. However the evaluation of the revised model on watershed showed the approximate simulation with measured sediment yield and the underestimated simulation when sediment yield is large. The additional research for channel erosion is needed so that soil erosion model for hillslopes is used to estimate sediment yield from a watershed.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.3
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• pp.68-80
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• 2013

The purpose of this study is to evaluate the applicability of UK design flood estimation model, FEH-ReFH through rainfall-runoff simulation of Korean watershed. For the Nam stream watershed($165.12km^2$), the model was calibrated using 6 storm events. The watershed and hydrological characteristics for the model requirements was prepared by developing input data pre-processors based on open GIS. The parameters of rainfall loss rate and unit hydrograph were calibrated from the observed data. The results can be used for improving and standardizing the Korean design flood estimation method.

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.397-408
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• 2004

Due to the growing impact of non-point source pollution and limitation of water treatment technology, a new policy of water quality management, called a source protection, is now becoming more important in drinking water supply. The source protection means that the public agency purchases the pollution sensitive area, such as riparian zone, and prohibit locations of point and non-point sources. Many studies have reported that this new policy is more economical in drinking water supply than the conventional one. However, it is very difficult to determine location and size of the pollution sensitive zone in the watershed. In this paper, we presented the scientific criteria for the priority of the pollution sensitive zone, along with a case study of the upstream watershed of the Paldang Reservoir, Han River. This study includes applications of the analytical hierarchy process(AHP) and a watershed-based land prioritization(WLP) model. After major criteria affecting water quality were selected, the AHP and geographic analysis were performed. The WLP model allowed us to include both quantity and quality criteria, using AHP as the multi-criteria method in making decision and reflecting local characteristics and various needs. By adding a travel-time function, which represents the prototype effectively, the results secured adaptability and scientific objectivity as well. As such, the WLP model appeared to provide reasonable criteria in determining the prioritization of land acquisition. If the tested data are used with a validated travel-time and AHP method is applied after further discussion among experts in such field, highly reliable results can be obtained.

• Journal of Korean Society on Water Environment
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• v.24 no.1
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• pp.7-18
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• 2008

The objective of this study was to develop and apply a water quality simulation model for the evaluation of ungaged watershed. The Modified WASP5 consisted of three sub-models, LOAD-M, DYN-M, and EUT-M. LOAD-M, an empirical model, estimates runoff loadings using point and non-point source data of villages. Daecheong Dam watershed was selected for the research to calibrate, verify and application of Modified-WASP5. LOAD-M model was established using field data collected from all items of water quality and water quantity gaging stations of the watersheds, and was applied to the ungauged watersheds, taking the watershed properties under consideration. The result of water quality simulation using ModifiedWASP5 shows that the observed BOD data of Yongpo and Daechong Dam in 1999 were 0.8 mg/L and 1.0 mg/L, and simulated data were 0.9 mg/L and 0.9 mg/L, respectively. In case of 1999, average BOD concentrations were 0.8 mg/L and 1.0 mg/L. Simulated concentration showed 1.1 mg/L and 1.5 mg/L, respectively. Generally, the simulation results were in good agreement with the observed data. This study was focused on formulating an integrated model for evaluating ungauged watersheds. Even though simulation results varied slightly due to limited availability of data, the model developed in this study would be a useful tool for the assessment and management of ungauged watersheds.

• Journal of Environmental Science International
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• v.21 no.10
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• pp.1235-1244
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• 2012

The objective of this study is to evaluate Flow-Pollutant load delivery ratio equations developed from rural watershed on main subwatersheds within Juam Lake. Two regression equations for BOD and three equations for T-P were evaluated on Bosung cheon, Dongbok cheon, Songgwang cheon, Naenam cheon, and Sinpyeon cheon. The results show that estimation of BOD delivery ratio using flow-delivery equation is reliable when relative composition of discharge load of pollutant sources of a watershed is similar to those of watershed where the equation developed. On the other hand, application of regression equation for T-P was feasible when the landuse pattern and relative composition of discharge load of pollutant sources of a watershed is similar to those of watershed where the equation developed.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.654-663
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• 2010

Attention has increasingly focused on the pollutant load discharged from rural area since the enforcement of total maximum daily loads (TMDLs) in korea. As one of the methods to control the inflow of pollutant load during wet weather events, local governments are attempting to apply non-point source control facility. To design those facilities appropriately, it is essential to understand the runoff characteristics of pollutants such as TSS, $BOD_5$, $COD_{Cr}$, TP and TN. In the paper, the quantitative analyses for pollutant runoff characteristics were examined in a small rural watershed with the area of about 53 hectares. For a dry weather day and wet weather events, variation patterns of dry weather flow and runoff characteristics of wet weather flows were monitored and investigated. The runoff model using XP-SWMM reflecting the landuse types of the watershed in detail was simulated to perform the sensitivity analyses for several factors influencing on their hydrograph and pollutographs. As a result, for the case of medium and small rainfall events (i. e. total rainfall of 35.8 and 17.5 mm), the impervious area including green house, roof and road which covers relatively low portion of total area (i. e. 16%) caused substantial first flush and the majority of total runoff load. Therefore, it has been concluded that the runoff characteristics of each pollutant and distribution of impervious area should be considered for the establishment of the control strategy of non-point pollutant runoff at a rural area.

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.214-222
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• 2007

This study was conducted to assay the relationship between the characteristics of watershed and water quality, and to evaluate water quality characteristics of the classified types by TSI deviation analysis with the collected data from 490 reservoir. Relatively shallow depth (<5m) reservoirs out of selected 490 appeared to be eutrophic. The mean TP concentration in reservoirs with the PFA+UFA/watershed area of above 30% was ${\geq}0.1$ mg $L^{-1}$. The mean TN concentration in reservoirs with the PFA/watershed area of above 25% was ${\geq}2.6$ mg $L^{-1}$. Based on the TSI deviation analysis, water quality parameters in TYPE III reservoirs were in high concentration compared to other reservoirs types. Characteristics of Type III generally showed eutrophic, small DA/RA ratio, shallow depth, and large paddy field and upland field to watershed ratio compared to other types of reservoirs. Both water quality and morpho-physical parameters, Type I and II reservoirs were similar with the exceptions of BOD and chi. ${\alpha}$ concentration. Phosphorus in Type I reservoirs was not the primary limiting factor on algal growth, but significant decrease chl. ${\alpha}$ concentration with the increasing TN/TP indicated that phosphorus was the possible secondary limiting factor. Overall results indicated that type of land use, such as PFA and UFA area in watershed, was important parameters for the assessment of water quality characteristics, and phosphorus was limiting nutrient on algal growth in 490 reservoirs.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.4
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• pp.247-259
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• 2007

In this study, we examined the flux of carbon and water using an eco-hydrological model, Regional Hydro-Ecologic Simulation System (RHESSys). Our purposes were to develop a set of parameters optimized for a well-designed experimental watershed (Gwangneung Research Watershed, GN) and then, to test suitability of the parameters for predicting carbon and water fluxes of other watershed with different regimes of climate, topography, and vegetation structure (i.e Gangseonry Watershed in Mt. Jumbong, GS). Field datasets of stream flow, soil water content (SWC), and wood biomass product (WBP) were utilized for model parameterization and validation. After laborious parameterization processes, RHESSys was validated with the field observations from the GN watershed. The parameter set identified at the GN watershed was then applied to the GS watershed in Mt. Jumbong, which resulted in good agreement for SWC but poor predictability for WBP. Our study showed that RHESSys simulated reliable SWC at the GS by adjusting site-specific porosity only. In contrast, vegetation productivity would require more rigorous site-specific parameterization and hence, further study is necessary to identify primary field ecophysiological variables for enhancing model parameterization and application to multiple watersheds.