• Journal of Korean Society of Coastal and Ocean Engineers
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• v.17 no.3
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• pp.149-157
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• 2005

Typical water quality (WQ) parameters defined in the governing equation of the WQ model are the pollutant loads from atmosphere and watersheds, pollutant release rates from sediment, diffusion coefficient and reaction coefficient etc. The direct measurement of these parameters is very difficult as well as requires high cost. In this study, the pollutant budget equation including these parameters was used to construct the linear simultaneous equations. Based on these equations, the inverse problems were constructed and WQ parameter estimation method minimizing the sum of squared errors between the computed and observed amounts of the mass changes was suggested. WQ parameters, i.e., the atmospheric pollutant loads, sediment release rates, diffusion coefficients and reaction coefficient, were estimated using .this method by utilizing the vertical concentration profile data which has been observed in Cheonsu Bay and Ulsan Port. Values of the estimated parameters show a large temporal variation. However, this technique is persuasive in that the RHS (root mean square) error was less than $5.0\%$ of the observed value ranges and the agreement index was greater than 0.95.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.1
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• pp.45-57
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• 2008

The purpose of this research is to select an appropriate location of water pollution prevention facilities(WPPF) through evaluating location decision factor using environmental geographic information system. To do that, this research reviewed the current location policies of WPPFs and its related researches. And this paper builds water pollutant statistical databases, integrated them with the geographic information system of the administrative areas where water pollutants are generated, and gears it with statistical programs such as correlation and regression analysis in order to figure out the pollution factors which influence on the location decision of WPPF on the real time base. The volume of discharge of industrial wastewater is one of the most important water pollutants on the location decision of WPPF. And the number of industrial facilities also was the most important location decision factor in constructing the WPPFs. In addition, this paper noted that the number of population in each area makes a role to restraint the construction of WPPF. It identified that the disposal facility in Nackdong river upper-middle watersheds was insufficient in treating the livestock pollutants. Therefore, Gyeongbuk should concentrate on the construction of disposal facilities of livestock pollutant in these areas. The results of this research will contribute to decide what kinds of WPPF should be constructed on which watershed in Nackdong River, and to forecast the future water quality of each watershed.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.1
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• pp.20-30
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• 2008

This study is to analyse the hydrological behavior of agricultural reservoir using SWAT model. For the upsteam watershed of Gongdo water level gauge station in Anseongcheon watershed, the streamflows at 2 reservoir (Gosam and Geumgwang) locations and Gongdo station were simulated with reservoir inclusion and exclusion. The daily water surface area and storage have been calculated considering the stage-storage curve function of the reservoir. Afterwards, the reservoir operation module in SWAT was modified from original module in SWAT for daily reservoir discharge simulated by water balance equation. Model validation results were Nash-Sutcliffe model efficiency coefficients value of 0.55, root mean square error value of 2.33 mm/day. On the other hand, the simulation results of two reservoir exclusion were Nash-Sutcliffe model efficiency coefficients value of 0.37, root mean square error value of 2.91 mm/day. The difference of Nash-Sutcliffe model efficiency coefficients between the simulation results of two reservoir inclusion and exclusion at Gongdo station was 0.18. This is caused by the storage and release operation of agricultural reservoirs for the runoff occurred at 2 reservoir watersheds.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.341-353
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• 2000

The purpose of this study is to investigate the characteristics of pollutants overflow on storm events and the first flush analysis in industrial complex. Eight sub-basins in the Chongju industrial complex were selected for sampling and study with different characteristics during the period from June 1997 to August 1998. Water quality parameters of stormwater runoff such as $BOD_5$, COD, SS, TKN, $NO_3-N$, $PO_4-P$, TP, n-Hexane extracts, Cr, Cu, Pb and Fe were analyzed. During the storm events, measured concentration ranges of $BOD_5$, COD, SS, $NO_3-N$, TKN, $PO_4-P$, TP, r-Hexane extracts, Cr, Cu, Pb and Fe were 2~324 mg/L, 5~810 mg/L, 1~1,110 mg/L, 0.01~10.89 mg/L, 0.1~59.8 mg/L, 0.08~7.02 mg/L, 0.1~7.8 mg/L, 0.1~1,723.6 mg/L, 0.001~0.363 mg/L, 0.001~0.488 mg/L, 0.001~1.28 mg/L, and 0.26~18.91 mg/L, respectively in the industrial complex watersheds. And a quantitative of first flush has been presented. First flush occurs more frequently as the ratio of impervious area increases.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.355-362
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• 2000

The objective of this paper is to estimate the pollutant load based on event mear concentrations(EMC) in industrial complex. Eight sub-basins in the Chongju industrial complex were selected for sampling and study with different characteristics during the period from June 1997 to August 1998. During the storm events, measured EMC ranges of $BOD_5$, COD, SS, TKN, TP, HEM, $NO_3-N$, $PO_4-P$, Cr, Pb, Cu and Fe in the industrial complex watersheds were 11~176mg/L, 40~502mg/L, 23~633mg/L, 104~20.9mg/L, 0.22~7.51mg/L, 12.7~548.7mg/L, 0.06~2.66mg/L, 0.12~3.39mg/L, 0.01~0.50mg/L. 0.02~0.42mg/L, 0.01~0.15mg/L and 1.29~11.51mg/L respectively. And the calculated annual average pollutant unit loadings of $BOD_5$ COD, SS, TKN, $NO_3-N$, $PO_4-P$, TP, HEM, Cr, Pb, Cu and Fe were 374.4kg/ha/yr 924.1kg/ha/yr, 983.6kg/ha/yr, 48.8kg/ha/yr, 8.1kg/ha/yr, 9.7kg/ha/yr, 17.8kg/ha/yr 943.0kg/ha/yr, 0.7kg/ha/yr, 0.9kg/ha/yr, 0.3kg/ha/yr and 28.9kg/ha/yr, respectively.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.6
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• pp.43-48
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• 2002

This study was carried out to clarify the change characteristics of stream water quality by land-use of forest from July to September, 2000 in three stands(Pinus densiflora, Castanea crenata (I), Castanea crenata (II) stand) of Jeongpyeong-ri, Jinju-si, Gyeongnam. The mean pH of rainfall results in acid rain of 5.3. The pH of stream water in three stands was high in order of Pinus densiflora (pH 6.59), Castanea crenata (II)(pH 6.53) and Castanea crenata (I) stand(pH 6.47). The electrical conductivity of stream water was high in order of Castanea crenata (I), Pinus densiflora and Castanea crenata (II) stand. Cations contents of three stands in stream water were high in order of $Ca^{2+}$, $Na^{2+}$, $Mg^{2+}$, $K^+$ and ${NH_4}^+$. But anions of stream water in Pinus densiflora stand and Castanea crenata (II) stand were high in order of ${SO_4}^{2-}$, $Cl^-$ and ${NO_3}^-$. In Castanea crenata (I) stand cations of stream water were high in order of ${NO_3}^-$, ${SO_4}^{2-}$ and $Cl^-$. The level of pH, ${NH_4}^+$, ${NO_3}^-$, $Cl^-$ and ${SO_4}^{2-}$ of stream water in Pinus densiflora stand and Castanea crenata (II) stand reached within the level of domestic use standard for drinking water But the level of ${NO_3}^-$ of stream water in Castanea crenata (I) stand was higher than that of domestic use standard. Therefore, non-point sources like forest watersheds which are fertilizer application lands should be taken to the appropriate mitigation measures.

• Korean Journal of Environment and Ecology
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• v.30 no.1
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• pp.71-80
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• 2016

The fauna of freshwater fish and water chemistry characteristics were investigated from June, 2014 to October, 2014 at 10 sites in Taebaeksan Provincial Park. A total of 7 species under three families were collected from the survey sites and among them one endangered species - Koreocobitis naktongensis - was identified. The endemic species of Korea were 2 species: Koreocobitis naktongensis, Iksookimia koreensis. Dominant species was Rhynchocypris oxycephalus(89%) and subdominant species was Orthrias nudus(8.9%). Water quality including conductivity, turbidity, pH and total dissolved solids(TDS) varied largely depending on the sampling locations. Values of ambient conductivity and TDS were greater in the upstream than in the downstream, and seasonal variabilities were also higher in the upstream. The pH decreased towards the downstream, and especially showed a sharp decrease in S5. This phenomenon was evident due to a dilution by the influx in the acid mine drainage(AMD) of S4. Physical habit conditions, based on qualitative habitat evaluation index(QHEI) model, indicated a "Sub-optimal" condition(mean: 157.3; range: 78 ~ 194) in the Sodo stream watersheds.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.6
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• pp.965-972
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• 2017

Assessment of vulnerability of water use to climate change include a variety of climate change scenarios. However, in most future vulnerability studies, only the climate change scenarios are used and not the future scenarios of social and economic indicators. Therefore, in this study, we applied the Representative Concentration Pathway (RCP) climate change scenario and Shared Socioeconomic reference Pathway (SSP) developed by IPCC to reflect the future. We selected indicators for estimating the vulnerability of water use, and indices were integrated with a multi-criteria decision making approach - Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The indicator data utilized national statistics and reports, social and economic scenarios, and simulated results from the Soil and Water Assessment Tool (SWAT) model which reflects climate change scenario. Finally, we derived the rankings of water use vulnerability for the short-term future (2020) and mid-term future (2050) within the Han River watershed. Generally, considering climate change alone and considering climate change plus social and economic changes showed a similar spatial distribution. In the future scenarios, the watershed rankings were similar, but showed differences with SSP scenario in some watersheds. Therefore, considering social and economic changes is expected to contribute to more effective responses to climate change.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.3
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• pp.12-26
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• 2017

The objective of this study was to develop a runoff analysis system of the Nakdong River watershed using the GRM (Grid-based Rainfall-runoff Model), a physically-based distributed rainfall-runoff model, and to assess the system run time performance according to Microsoft Azure VM (Virtual Machine) settings. Nakdong River watershed was divided into 20 sub-watersheds, and GRM model was constructed for each subwatershed. Runoff analysis of each watershed was calculated in separated CPU process that maintained the upstream and downstream topology. MoLIT (Ministry of Land, Infrastructure and Transport) real-time radar rainfall and dam discharge data were applied to the analysis. Runoff analysis system was run in Azure environment, and simulation results were displayed through web page. Based on this study, the Nakdong River real-time runoff analysis system, which consisted of a real-time data server, calculation node (Azure), and user PC, could be developed. The system performance was more dependent on the CPU than RAM. Disk I/O and calculation bottlenecks could be resolved by distributing disk I/O and calculation processes, respectively, and simulation runtime could thereby be decreased. The study results could be referenced to construct a large watershed runoff analysis system using a distributed model with high resolution spatial and hydrological data.

• International Journal of Highway Engineering
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• v.17 no.4
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• pp.11-18
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• 2015

PURPOSES: This study aims to evaluate the runoff reduction with permeable pavements using the SWMM analysis. METHODS: In this study, simulations were carried out using two different models, simple and complex, to evaluate the runoff reduction when an impermeable pavement is replaced with a permeable pavement. In the simple model, the target area for the analysis was grouped into four areas by the land use characteristics, using the statistical database. In the complex model, simulation was performed based on the data on the sewer and road network configuration of Yongsan-Gu Bogwang-Dong in Seoul, using the ArcGIS software. A scenario was created to investigate the hydro-performance of the permeable pavement based on the return period, runoff coefficient, and the area of permeable pavement that could be laid within one hour after rainfall. RESULTS : The simple modeling analysis results showed that, when an impervious pavement is replaced with a permeable pavement, the peak discharge reduced from $16.7m^3/s$ to $10.4m^3/s$. This represents a reduction of approximately 37.6%. The peak discharge from the whole basin showed a reduction of approximately 11.0%, and the quantity decreased from $52.9m^3/s$ to $47.2m^3/s$. The total flowoff reduced from $43,261m^3$ to $38,551m^3$, i.e., by approximately 10.9%. In the complex model, performed using the ArcGIS interpretation with fewer permeable pavements applicable, the return period and the runoff coefficient increased, and the total flowoff and peak discharge also increased. When the return period was set to 20 years, and a runoff coefficient of 0.05 was applied to all the roads, the total outflow reduced by $5195.7m^3$, and the ratio reduced to 11.7%. When the return period was increased from 20 years to 30 and 100 years, the total outflow reduction decreased from 11.7% to 8.0% and 5.1%, respectively. When a runoff coefficient of 0.5 was applied to all the roads under the return period of 20 years, the total outflow reduction was 10.8%; when the return period was increased to 30 and 100 years, the total outflow reduction decreased to 6.5% and 2.9%, respectively. However, unlike in the simple model, for all the cases in the complex model, the peak discharge reductions were less than 1%. CONCLUSIONS : Being one of the techniques for water circulation and runoff reduction, a high reduction for the small return period rainfall event of penetration was obtained by applying permeable pavements instead of impermeable pavement. With the SWMM analysis results, it was proved that changing to permeable pavement is one of the ways to effectively provide water circulation to various green infrastructure projects, and for stormwater management in urban watersheds.