• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.233-238
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• 2008

Recently, rainwater harvesting facilities have increasingly constructed mainly in elementary schools and government buildings. Nevertheless, few methods are available for efficient planning and design of rainwater harvesting facilities by considering the weather conditions and purpose of rainwater management in each site, which may lead to a construction of uneconomic facilities. The current method estimates the size of rainwater storage tank by multiplying the size of building or plottage with a certain ratio and has many limitations. In this study, we first developed a method for planning and design of rainwater storage facilities using $Rainstock^{TM}$ model, which is based on mass balance, and economic analysis. Then, the model was applied for the design of a rainwater harvesting facility in a building with the catchment area of $1,000m^2$. The model calculation indicated that the economic feasibility of rainwater harvesting depends on not only the size of storage tank but also the water usage rate. When the water usage rate is $1m^3/day$, the rainwater harvesting facility is not cost-effective regardless of the size of the storage tank. With increasing the water usage rate, the economical efficiency of the facility was improved for a specific size of the storage tank. Based on the model calculation, the optimum tank sizes for $5m^3/day$ and $10m^3/day$ of water usage rates were $24m^3$ and $57m^3$, respectively. It is expected that the model is useful for optimization of rainwater storage facilities in planning and designing steps.

• Clean Technology
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• v.17 no.4
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• pp.353-362
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• 2011

In our nature, the utilization of rainwater is essential for healthy water recirculation. This is one of the solutions of the increment of impermeability surface according to the development of new cities; this study of the improvement of rainwater quality has been carried on through the improvement of collecting and restoring system of rainwater. The southwestern region of Daejeon City, the rainwater coefficient of run off was 0.40 and this number had computed to 0.59 after the development. After filtration of rainwater, the heavy metal (Cu, As, Cr, Fe, Mn) contents level were lower than underground water. Moreover, collected rainwater showed better quality than underground water in following criteria; hardness, permanganate consumption quality, chloride, evaporation residue, sulfates and nitrate nitrogen. This water quality met the gray water quality standards. The rainwater quality was still suitable to use as bathroom flushing and gardening after 100 days of storage. This study proved that modification (installation of cover with gutter to existing rainwater collection system, proper filtering, and installation of underground storage tank) of collection system could improve quality of water and maintain this approximately 100 days.

• Journal of Soil and Groundwater Environment
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• v.25 no.1
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• pp.84-94
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• 2020

Jeju Island is seeking reliable ways to secure alternative water resources using rainwater in order to conserve and manage its groundwater as sustainable water resources. The purpose of this study is to investigate the rainwater storage capability of small-size storage facilities installed at farmhouses in Uigwi and Wimi of Namwon-eup region. The rainwater outflows from the storage facilities in rain events were analyzed. The appropriate size of rainwater utilizing facilities are suggested to be about 5,800 ㎥ in Uigwi area and 4,900 ㎥ in Wimi area based on the calculation from the rainfall frequency and runoff amounts. If those facilities are put into operation in Uigwi and Wimi area, it is estimated approximately 32.3 and 11.5% of total agricultural water can be supplied by the facilities. Wimi area showed low rainwater usage because of less number of facilities relative to the size of farm areas and less intensive underground water usage. It is analyzed that more than 55% of agricultural water can be supplied by rainwater if 70 facilities without the rainwater facilities are connected to the rainwater utilizing facilities.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.5
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• pp.461-468
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• 2010

This study investigated variation of rainwater quality by seasonal and storage duration of rainwater in Changwon city. Seasonally, the pollutants concentration of rainwater were higher in spring and winter. In the case of rainwater and storage rainwater quality, pH of rainwater was 4.3, storage rainwaters were 6.0 and Turbidity increased about 8 times from 1.82 NTU to 14.61 NTU. The changes of storage water quality during the storage period, initial KMnO4 consumption rainwater was exceeded drinking water standard. Total solid in rainwater was detected as 116 mg/L, it tended to stable at around 70∼80mg/L after storage period for a 6day.

• Environmental Engineering Research
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• v.18 no.2
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• pp.77-84
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• 2013

Recently, rainwater has come to the forefront as an alternative resource contributing to solving various environmental problems, especially those related to water. However, more or less biased perspectives on rainwater as a pollutant, mainly derived from acid rain, have still been pervasive in public as well as research communities. Considering the significance of rain harvesting in recent society, it is necessary to promote educational efforts to overcome such social prejudices and improve desired values towards rainwater. Thus, this research attempted to develop a teaching-learning program focusing on the theme of rainwater for high school students in Korea. To verify the effectiveness of the program, one group pre/post testing was conducted with 57 students participating in the courses. According to the survey, students show significant differences in both awareness and attitude towards rainwater as well as water after the courses. In conclusion, this study has an implication on developing an effective educational way to improve students' positive recognitions and attitudes regarding rainwater-related issues. Such an educational effort might contribute to sharing the worthiness of preserving rainwater with the future generation and promoting rainwater harvesting within wider public participation.

• KIEAE Journal
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• v.5 no.3
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• pp.17-24
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• 2005

Until today, rainwater management was processed without disposing the peak discharge, which was due to rainfall, to provide stability against flood damage. In this process, the natural hydrologic cycle changed quickly, and because of this, some problems that could harm human beings and the environment arose. These problems need to be addressed accordingly. One of the proposals was to carry out decentralized rainwater management through a natural hydrologic cycle on site, including utilization, infiltration, detention, and retention of rainwater. This study aims to set the direction of applicable decentralized rainwater management to housing complex in Korea. Therefore, spacial properties in urban housing complexes were analysed such as the impervious area-to-land ratio, the green area-to-land ratio, artificial land-to-land ratio etc. As the result of this study, when a housing complex was small and developed by reconstruction, the impervious area, artificial land, the green area in the artificial land-to-land ratio were high. So, direction of decentralized rainwater management of these housing complexes is available to utilize and detain rainwater. On the other hand, those of big housing complexes in land development district were low relatively. So, direction of decentralized rainwater management of these housing complexes is available to infiltrate and evaporate rainwater.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.485-485
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• 2018

Rainwater harvesting system (RWH) can provide a relief for the household and farmers especially in areas with intense water scarcity during the long lull of rainy season. However, much attention has not been given to this alternative water source in Nigeria. This paper estimates the per capita water demand for 1,950 inhabitants and rainwater potential in Ojonbodu Estate, Oyo State, Nigeria, using data from detailed questionnaires, water consumption calculator software, and 20-year rainfall data. The potential rainwater estimation was based on amount of precipitation, size of catchment and runoff coefficient. Consequently, using estimated values of $39420m^3$ and $6.5114{\times}10^7m^3$ for per capita consumption and potential rainwater respectively, the rainwater harvesting system was designed for rainwater collection, and storage. The harvested rainwater was $450, 000m^3$ with collection efficiency of 69.16 %, which exceeded the household water consumption requirement. Thus, the harvested rainwater was able to meet the estimated water demand of the Ojonbodu Estate households during the period of water scarcity.

• Journal of Korean Society on Water Environment
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• v.27 no.3
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• pp.300-305
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• 2011

This study aimed at analyzing the runoff quality by the layer thickness and material of soil roof to make best use of the rainwater falling on it in terms of safety and efficiency and resulted in the following assessments. It turned out that the concentrations decreased more in T-N, $NO_3$-N, $NH_4$-N, T-P and $PO_4$-P in roof rainwater except 30 cm for the RW1 soil roof after passing through it than those of first rainwater. On the other hand, the concentrations in rainwater passing through gravel roof turned out to be equal or same to those of the first rainwater. As a result of analysis of metallic stuff in runoff, there was no indication of Cd, Cr, Mn and Pb as well. The concentration of Cu, Fe and Zn in rainwater through soil roof became less than that of the first rainwater. In this research, the soil roof showed the good efficiency in lowering the concentration of such components as nitrogen, phosphorus and metals. Based on the results from this work, more practical study would be required further in the future in relation to soil roof when installing the rainwater-utilizing facilities.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.4
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• pp.361-368
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• 1998

Acid rainwater samples were collected during 4 years from 1992 in Pusan area nearby seaside. Ionic composition of early and succeeding rainwater were investigated to identify emission sources. pH and Electronic Conductivity of samples were measured immediately after sampling. Major ion concentrations of rain samples were Na+, Ca2+, Mg2+, K+, NH4+, SO42-, NO3-, Cl- which were analyzed by ion Chromatography. 55% of early rainwater and 90% of succeeding rainwater were identified below pH 5.6. Because, Na+, K+, Ca2+ were washed mostly in early rainwater, as a result, pH values were increased by increasing rainfall amounts. It was studied that pH value was varied from ambient ion component, rainfall, and rain intensity. From the principal component analysis result, the dominant components of acid rainwater were Na+, K2+, Mg2+, Ca2+, the elements were contributed soil and marine source, the second components nuts -SO42-, SO4a-, NO3-, nuts -Ca2+ originated from man - made source.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2003.11a
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• pp.195-200
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• 2003

The purpose of this study is to establish the rainwater Utilization for the housing complex through the using rainwater, infiltration and detention. This study focused on the following items. 1) Legal basic conditions for the rainwater utilization in Germany 2) Case study on the rainwater management with examples. As the results of this study, it is necessary to implement these rainwater management system in laws, legal norms and technical regulation.