• Journal of Korean Society on Water Environment
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• v.36 no.6
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• pp.592-610
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• 2020

In South Korea, the concept of water environment was expanded to include aquatic ecosystems with the Integrated Water Management implementation. Watershed-scale modeling is typically performed for hydrologic component analysis, however, there is a need to expand to include ecosystem variability such that the modeling corresponds to the social and political issues around the water environment. For this to be viable, the modeling must account for several distinct features in South Korean watersheds. The modeling must provide reasonable estimations for peak flow rate and apply to paddy areas as they represent 11% of land use area and greatly influence groundwater levels during irrigation. These facts indicate that the modeling time intervals should be sub-daily and the hydrologic model must have sufficient power to process surface flow, subsurface flow, and baseflow. Thus, the features required for watershed-scale modeling are suggested in this study by way of review of frequently used hydrologic models including: Agricultural Policy/Environmental eXtender(APEX), Catchment hydrologic cycle analysis tool(CAT), Hydrological Simulation Program-FORTRAN(HSPF), Spatio-Temporal River-basin Ecohydrology Analysis Model(STREAM), and Soil and Water Assessment Tool(SWAT).

• Journal of Environmental Impact Assessment
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• v.25 no.4
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• pp.248-260
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• 2016

This study was aimed to assess the effect of diverse pollutants control measures suggested in the Chuso basin and its upstream of So-oak stream watershed where are the most concerned areas on the control of algal bloom occurring in Daecheong Reservoir. The control measures were classified as watershed measures and in-reservoir measures, and their effects were simulated using a two-dimensional hydrodynamic and water quality model. The watershed measures were made up of 1) point sources control, non-point sources control, and their combinations. The in-reservoir measures were supposed to treat sediment at Chuso basin and to install a phosphorus elimination plant (PEP) at the end of So-oak stream. The results showed that the effect of each measure was influenced by the hydrological condition of the year. In wet year, as the contribution of non-point sources increased, the non-point source control measures (NPS1~NPS4) showed more effective compared to other measures, while, the PEP system to eliminate phosphorus from So-oak stream showed better performance in dry year. In particular, the scenario of NPS1, in which all livestock manures were collected and treated but only chemical fertilizers (NPS1) were used for agriculture fields, showed the best performance for the control of algal bloom in Chuso basin among the watershed measures.

• Journal of Korean Society on Water Environment
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• v.36 no.5
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• pp.445-452
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• 2020

Tributary is a part of life space for people and a very important place that accommodates rest recreation and other daily activities. absolutely insufficient basic data about water quality and flow rate are available for basin management. Efficient water and basin management systems, which are also supported by local residents can be established by securing such basic data of major tributaries in the Nakdong river system. In this study, the fluctuation characteristics of upstream and downstream water pollution levels were compared using the measurement results of the water environment measurement network and the tributary monitoring project for the gyeseong-stream and Hwapo-stream in the Nakdong-miryang watershed. In 2017, when water pollution is the highest, it was confirmed that the annual average rainfall was the lowest. Although the upstream and downstream water quality tendencies of the Gyeseong-stream are similar, the water quality concentrations of the Gyeseong-stream are relatively different. But although the Hwapo stream has various causes of pollution, there was not much difference in the level of pollution between the upper and lower streams. In addition, both rivers need the ability to purify rivers by securing sufficient water for river maintenance, and if the correlation between water quality items can be inferred through continuous monitoring of tributaries where the aspect of water quality change is unclear, water quality management Determined to be efficient operation.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.943-951
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• 2006

Spatial distribution of water pollution in the Gap Stream was investigated from October to November, 2005. Sampling was conducted three times including effluents discharged from a wastewater treatment plant (WWTP) and a dam reservoir during the low-flow period. As a typical urban stream, total nitrogen and inorganic nitrogen concentrations increased toward downstream. Ammonia concentration was the highest in the treated water of the wastewater treatment plant and the lowest nitrate concentration was found in the effluent of the dam reservoir. A part of soluble reactive phosphorous (SRP) in total phosphorous was 22~54% in the upstream reach of WWTP in the Gap Stream whereas 68~73% in the downstream reach. Mean chlorophyll-a concentration ranged from 1.6 to $11.0{\mu}g/L$ and it tends to increase toward downstream except for WWTP effluent. As expected, untreated wastewater and WWTP effluent were suggested as the major sources of water pollution in the Gap Stream. In this study, the water pollution of the Gap Stream is a significant undergoing typical eutrophication, caused by excessive phosphorus and nitrogen nutrients from WWTP located in the watershed. As a result, the critical factor for the water pollution was evaluated to dissolved inorganic nitrogen and phosphorus nutrients. Particularly, SRP is a most important for the eutrophication. It suggest that may occur in the most urban streams of Korean peninsula. Therefore, because the necessity of water pollution management in the urban stream, inorganic N and P nutrients should be included as an essential component of water quality criteria in the advanced water quality project of Korean Government by enforcing of water quality assessment and total maximum daily loads (TMDLs).

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.463-466
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• 2003

The physically based distributed modelling system, MIKE SHE, has been applied to the upper sub-watershed of the Gyeongancheon watershed. A horizontal grid square was constructed to represent the spatial variations in watershed characteristics, landuse, soil, and rainfall distributions. The hydraulic model MIKE 11 was also coupled with the MIKE SHE to simulate river flow in the main and tributaries of Gyeongancheon. The simulated daily stream flow at the outlet of the watershed was compared to the observed data for the period of 1988 to 1991. The results demonstrated the applicability of a comprehensive hydrological modelling system as management tool for watershed and floodplain.

• Journal of Environmental Science International
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• v.22 no.5
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• pp.515-522
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• 2013

To investigate groundwater variation characteristics in the Hancheon watershed, Jeju Island, an integrated hydrologic component analysis was carried out. For this purpose, SWAT-MODFLOW which is an integrated surface-groundwater model was applied to the watershed for continuous watershed hydrologic analysis as well as groundwater modeling. First, ephemeral stream characteristics of Hancheon watershed can be clearly simulated which is unlikely to be shown by a general watershed hydrologic model. Second, the temporally varied groundwater recharge can be properly obtained from SWAT and then spatially distributed groundwater recharge can be made by MODFLOW. Finally, the groundwater level variation was simulated with distributed groundwater pumping data. Since accurate recharge as well as abstraction can be reflected into the groundwater modeling, more realistic hydrologic component analysis and groundwater modeling could be possible.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2002.05a
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• pp.78-78
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• 2002

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2007.04a
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• pp.219-222
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• 2007

• The Journal of Engineering Geology
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• v.27 no.4
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• pp.383-392
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• 2017

Excessive abstraction of groundwater near streams for agricultural, domestic, or industrial use can significantly reduce the streamflow. Therefore, proper management of water resources must involve careful monitoring of groundwater use near streams. This study investigates the current status of groundwater intake plans in the Anseongcheon watershed, Korea, in order to understand the portion of groundwater wells according to distance from the stream and the distribution of wells near the stream. Among all the wells in the watershed, 20.5% were permitted and 31.3% were declared within 300m from the stream. In particular, among the wells located near streams, 11.4% were permitted and 88.6% were declared among the wells near streams. Therefore, the total amount of groundwater pumping rates from the declared wells is much higher than that from the permitted wells near the stream. Under current guidelines, investigations of the impact of groundwater use near a stream on streamflow depletion should only consider wells permitted by groundwater law. However, prudent management should also pay attention to declared wells, given their large number.

• Korean Journal of Ecology and Environment
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• v.54 no.2
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• pp.79-86
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• 2021

In this study, the distribution and habitat characteristics of Odontobutis obscura were investigated. It is a freshwater fish species which belongs to the Class I Endangered species as specified by the Ministry of Environment of South Korea. Sampling was conducted in the Sanyang Stream watershed between April and August of 2016. The Sanyang Stream watershed includes the Sanyang and Gucheon Streams, and their tributaries. Odontobutis obscura was caught at every sampling site, except sites 1~3, which are located in the lower part of the Sanyang Stream. Its habitat range extended from the headwaters to the lower parts of the stream that were not impacted by the South Sea. Salinity was the major factor limiting the distribution of O. obscura in the Sanyang Stream watershed. All individuals of O. obscura were caught in areas where the substrate composition was over 50% gravel. Furthermore, the substrate composition seems to be the most important habitat factor affecting spawning of O. obscura. Ecological studies of O. obscura are scarce, and this study is the first to report a detailed distribution for the species. Further studies on the physiology and ecology of O. obscura are essential for establishing preservation strategies for this endangered species.