• Journal of Environmental Impact Assessment
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• v.13 no.6
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• pp.285-294
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• 2004

The purpose of this study is to understand the quantitative change of water resources using RMS(Remote Monitoring System) which takes real time data with high reliability. Also, the characteristic of stormwater runoff was understood by the application of the above system for three streams (Jiam, Yulmun, and Gongji stream) in Chuncheon City. The detailed results of these studies are as follows; RMS(Remote Monitoring System) was constructed by the combination of the automatic water-level meter, which measures water-level of streams at all times, and the wireless communication system sending real-time data from the meter. This system is used to evaluate the stormwater runoff in watersheds and the quantitative changes of streams. It is possible to overcome the limit of field investigations needed, which takes a lot of manpower and time, and it is very efficient to provide the reliable flowrate data. Also, it can be applied to the disaster prevention system for flood because the change of flowrate in stream is monitored at real-time. For 3 streams with different watershed characteristics, correlation equations induced from the relation analysis results. In terms of the relation between water-level and flowrate, flowrate was increased rapidly as the water-level rises in case of small watershed and steep slope. The application results of the proposed system for 3 streams (Jiam, Yulmun, Gongji) in Chuncheon city are as follows; The remote monitoring system was very useful for acquisition of the flow rate in stream that are basic data to understand pollutants runoff in watershed. In case of no-rainy day, the runoff ratio for pollutant loading rate was the highest level in Yulmun stream(BOD:2.3%, TN:20.2%, TP:1.2%). So, it shows the management of pollution source is needed such as rehabilitation of sewer line. Runoff ratio of total phosphorus by rainfall in Gongji watershed was increased about 19 times than no-rainy day, which is estimated as the influence of sewer overflow.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.233-233
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• 2015

Vu Gia - Thu Bon basin is located in central Vietnam between Truong Son mountain range on the border with Lao in the west and the East Sea in the east. The basin occupies about 10,350 km2 or roughly 90% of the Quang Nam Province and includes Da Nang, a very large city with about 876,000 inhabitants. Total annual rainfall ranges from about 2,000 mm in central and downstream areas to more than 4,000 mm in southern mountainous areas. Rainfall during the monsoon season accounts for 65 to 80% of total annual rainfall. The highest amount of rainfall occurs in October and November which accounts for 40 to 50% of the annual rainfall. Rainfall in the dry season represents about 20 to 35% of the total annual rainfall. The low rainfall season usually occurs from February to April, accounting for only 3 to 5% of the total annual rainfall. The mean annual flow volume in the basin is $19.1{\times}109m 3$. Similar to the distribution of rainfall, annual flows are distinguished by two distinct seasons (the flood season and the low-flow season). The flood season commonly starts in the mid-September and ends in early January. Flows during the flood season account for 62 to 69% of the total annual water volume, while flows in the dry season comprise 22 to 38% of total annual run-off. The water volume gauged in November, the highest flow month, accounts for 26 to 31% of the total annual run-off while the driest period is April with flows of 2 to 3% of the total annual run-off. There are some hydropower projects in the Vu Gia - Thu Bon basin as the cascade of Song Bung 2, Song Bung 4, and Song Bung 5, the A Vuong project currently under construction, the Dak Mi 1 and Dak Mi 4 projects on the Khai tributary, and the Song Con project on the Con River. Both the Khai tributary and the Song Con join the Bung River downstream of SB5, although the Dak Mi 4 project involves an inter-basin diversion to Thu Bon. Much attention has recently been focused on the effects that climate variability and human activities have had on runoff. In this study, data from the Vu Gia - Thu Bon River Basin in the central of Viet Nam were analyzed to investigate changes in annual runoff during the period of 1977-2010. The nonparametric Mann-Kendall test and the Mann-Kendall-Sneyers test were used to identify trend and step change point in the annual runoff. It was found that the basin had a significant increasing trend in annual runoff. The hydrologic sensitivity analysis method was employed to evaluate the effects of climate variability and human activities on mean annual runoff for the human-induced period based on precipitation and potential evapotranspiration. This study quantitatively distinguishes the effects between climate variability and human activities on runoff, which can do duty for a reference for regional water resources assessment and management.

• Journal of Korea Water Resources Association
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• v.56 no.12
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• pp.905-918
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• 2023

This study aimed to assess runoff reduction performance and determine installation priorities for Permeable Pavement (PP) and Rain Barrel (RB) within the Mokgam Stream basin. Optimal design parameters were determined to maximize the effectiveness of PP and RB in reducing runoff. Furthermore, the optimal parameters were incorporated to compare the runoff reduction performance of PP and RB. Analysis of the runoff curve at the basin outlet indicated that PP demonstrated superior performance in reducing runoff during the rising limb of the curve. At the same time, RB excelled within the falling limb. Comparisons of total runoff and peak runoff reduction by sub-catchment revealed that in larger sub-catchment areas, PP outperformed RB in runoff reduction. In contrast, RB exhibited higher performance in areas with a higher impervious ratio. Based on the evaluation of runoff reduction performance for PP and RB, installation priorities were determined within the Mokgam Stream basin. The results showed that PP and RB installations were prioritized for sub-catchments with larger areas and a higher impervious ratio. Furthermore, the correlation between the ranking of runoff reduction performance and sub-catchment characteristics showed a high correlation with both the impervious area ratio and sub-catchment geometrical properties in sub-watersheds exhibiting the top 25% runoff reduction performance. These results emphasize that when determining the priority for installing LID facilities in developed urban areas, it is necessary to consider not only the impervious area ratio but also the geometrical properties of the sub-catchment.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.342-349
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• 2016

Andong belongs to the Nakdong River Basin, Nakdong River is flowing through the city, including Andong dam and Imha dam. The runoff due to provincial transfer and impervious area has been increasing by urbanization increases and nonpoint source loads. In this study, we evaluate the runoff and nonpoint pollution loads in accordance with the development targeted at selected urban water cycle leading to Andong city. Andong city leading to the water cycle plan to evaluate the directly runoff and BOD, T-N and T-P nonpoint pollutant loads using the CN into account the temporal and spatial changes. Evaluation, direct runoff per year is 10.41 % if the green roof and a water permeable pavement replacement, water cycle parks and streets compositions, City impermeable layer improvements to be business including four kinds of scenario is applied to both the development and the BOD non-point pollutant loads 20.56%, T-N 9.55% and T-P pollution and nonpoint loads was investigated to be reduced 14.29%. Four kinds of low lapse rate of the development scenario of the highest thing urban impervious surface was investigated by improving business development prior year annual direct runoff is 6.25 %, BOD nonpoint pollution loads are 11.84%, T-N nonpoint pollution loads are 4.46 % and T-P was investigated by reducing pollutant loads to be 10.20%.

• Journal of Korean Society on Water Environment
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• v.26 no.2
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• pp.243-251
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• 2010

Evapotranspiration and rainfall-runoff are the major components of hydrological cycle and thereby the changes of them can directly affect the wetness/dryness or runoff characteristics of basins. In this study the wetness/dryness in Geum river basin are classified by dint of cumulative probability density function of monthly moisture index and the long term changes of them are analyzed based on climatic water balance concept. The drought events in Geum river basin are selected through evaluation of monthly moisture index and the various hydrological properties of them are investigated in detail. Also the trends of time-series of climatic water balance components are examined by Seasonal Kendall test and the variability of hydrological cycle in Geum river basin during the recent decade is inquired. It is judged that the results of this study can be contributed to establishment of the counter plan against the future drought events as the fundamental information.

• Journal of Korean Society on Water Environment
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• v.29 no.2
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• pp.247-258
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• 2013

A grid-based configuration of Land Surface Models (LSMs) coupled with a climate model can be advantageous in impact assessment of climate change for a large scale area. We assessed the applicability of Common Land Model (CoLM) to runoff and land surface temperature (LST) simulations at the domain that encompasses the Nakdong river basin. To establish a high resolution model configuration of a $1km{\times}1km$ grid size, both surface boundary condition and atmospheric inputs from the observed weather data in 2009 were adjusted to the same resolution. The Leaf Area Index (LAI) was collected from MODerate esolution Imaging Spectroradiometer (MODIS) and the downward short wave flux was produced by a nonstationary multi-site weather state model. Compared with the observed runoffs at the stations on Nakdong river, simulated runoffs properly responded to rainfall. The spatial features and the seasonal variations of the domain fairly well were captured in the simulated LSTs as well. The monthly and seasonal trend of LST were described well compared to the observations, however, the monthly averaged simulated LST exceeded the observed up to $2^{\circ}C$ at the 24 stations. From the results of our study, it is shown that high resolution LSMs can be used to evaluate not only quantity but also quality of water resources as it can capture the geographical features of the area of interest and its rainfall-runoff response.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.682-688
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• 2009

A plane field and a sloped field located at low-land plane and alpine areas, respectively, were monitored with respect to runoff, water quality and fertilizer uses from March to December, 2008. Runoff volume and Non-Point Source (NPS) loads were estimated and analyzed with respect to fertilizer uses. Total TN and TP loads from the sloped field were higher than those from plane field because of larger chemical uses in the alpine field than in the plane field. Organic matter load from plane field was higher than that from sloped field because more organic compost was applied to plane field than to sloped field. Event Mean Concentration (EMC) of measured water quality indices were relatively higher in both fields. Organic matter load per 1 mm rainfall were higher in plane field and TN and TP loads per 1 mm rainfall were higher in sloped field than those in respective comparing field. It was concluded that the type and application method of fertilizer could play an important role in the estimation of NPS pollution loads and the development of Best Management Practices (BMPs). However, it was recommended that long-term monitoring is necessary to better describe the relationship between fertilizer uses and water quality from agricultural fields because numerous natural and management factors other than fertilizer also affect runoff quality.

• Journal of Korea Water Resources Association
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• v.47 no.1
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• pp.1-10
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• 2014

This study aimed to analyze water cycle at Taehwa river, Dongcheon, Hoiya river and Cheongryang cheon in Ulsan city using CAT model developed by Korea Institute of construction technology. To apply CAT model, we separated Teahwa river into 25, Dongcheon into 11, Hoiya river into 17 and Cheongryangcheon into 5 subbasins and discriminated between contribution runoff basins and source basins. The results of water cycle analysis performed using rainfall datas measured from 1975 and 2008 and hydrologic datas of change of land use etc. were that surface runoff increase and interflow decrease, caused by the increase of impervious area. The increases of surface runoff at the basin of Taehwa river and Dongcheon which is a tributary of Taehwa river were small and similar to each other respectively as 1.7% and 2.4%, and increased high rate of 3.2% and 7.7% in Hoiya river and Cheongryangcheon including subbasins which are having high rate of urbanization.

• Journal of Korean Society on Water Environment
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• v.35 no.1
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• pp.9-18
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• 2019

Recently, it was realized that a significant portion of pollution from urban areas originates from non-point sources such as construction sites, washoff from impervious surfaces, and sewage input from unsewered areas and combined sewer overflows. Especially, Urban stormwater runoff is one of the most extensive cause of the deterioration of the water quality in streams located in urban area. The objective of this study was to investigate runoff characteristics of non-point pollutants source at the urban area in the Suyeong River. Water quality variations were investigated at two points of Suyeong River during a period of 10 rainfall events. Concentration difference of non-point pollution source appeared big by precedent number of days of no rainfall. In addition, Event mean Concentration (EMCs) that well represents runoff characteristics of storm water during rainfall, was calculated, and runoff pollutants loading was also examined. The probability distribution of EMCs of BOD, COD, TOC, T-N, T-P, and TSS were analyzed and the mean values of observed EMC and the median values of estimated EMCs compared through probability distribution. Other objectives of this study were the characterization of discharge from non-point source, the analysis of the pollutant loads and an establishment of a management plan for non-point source of Suyeong River. Also, It was established that the most important thing for the administration of non-point pollution source is to come up with the solution for the reduction of effluent at the beginning.

• Water Engineering Research
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• v.5 no.4
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• pp.185-193
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• 2004

Estimates of annual actual evapotranspiration are needed in water balance studies, water resources management projects, and many different types of hydrologic studies. This study validated a set of 5 empirical equations of estimating annual actual evapotranspiration with climate data on 11 watersheds, and evaluated the further applicability of these forms in estimating annual runoff on watershed level. Five empirical equations generally overestimated annual evapotranspiration, with relative errors ranging $3.3\%$ to $47.2\%$. The results show that Schreiber formula can be applicable in determining annual evapotranspiration in sub-humid region that is classified by aridity index, while Zhang equation gave better results than the remaining methods in humid region. The mean differences for annual evapotranspiration bias over 11 watersheds are Zhang, Schreiber, Budyko, Pike, and Ol'dekop formula from lowest to highest. The empirical equations provide a practical tool to help water resources managers in estimating regional water resources on ungauged large watershed.