• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.5
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• pp.69-79
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• 2011

This study assessed the subsurface runoff and peak flow reduction in rain gardens. The results showed that the highest water retention was found in rain garden mesocosms in which Rhododendron lateritium and Zoysia japonica were planted, followed by mesocosms in which either R. lateritium or Z. japonica was planted, and the lowest water retention rate was found in non-vegetated control treatment mesocosms(${\alpha}$ < 0.05). Although higher rainfall intensity caused a decrease of peak flow reduction in both vegetated and non-vegetated treatments, peak flow reduction was the greatest in mesocosms with mixed plants. A rain garden can be an effective tool for environment-friendly stormwater management and improving ecological functions in urban areas. Depending on the purpose such as delaying runoff or increasing infiltration, various plant types should be considered for rain garden designing.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.6
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• pp.64-72
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• 2004

This study analyses influences on partial work rates under whole work rates on landscape constructions in Ulsan Grand Park. The schedule management is one of the factors that are very important to the process management of landscape construction. The time process of the whole construction is supposed to be affected by several kinds of work that organize the whole construction. First, this study divides the construction of Ulsan Grand Park into 10 kinds of works: earth work, rain and sanitary sewage water work, water-supplying work, planting work, paving work, water proofing work, fountain work, instituting work and temporary work. Then the time-process curves of all kinds of work are statistically compared to that of the whole construction. The trial methods of statistics are lineal regression, non-lineal regression, and principal analysis. In the result of the non-lineal regression, the rain and sanitary sewage water work, the water-supplying work and the earth work strongly affected the whole construction. The principal analysis results show that the whole construction is affected strongly by the water-supplying work, the rain and sanitary sewage water work and the earth work. However the lineal regression is shown to be senseless because of its high collinearity.

• KDI Journal of Economic Policy
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• v.44 no.4
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• pp.1-24
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• 2022

We investigate how reforestation contributed to stabilization of riverine water levels in South Korea. For the purpose, we estimate an equation capturing dynamic relationships among rainfall, upstream-area tree stock, and downstream water levels in three river systems of Hongcheon, Mangyeong, and Hyeongsan, using daily observations of precipitation and water levels for the period from 1985 to 2005. Simulation based on estimation results shows that increase in the tree stock in a river basin leads to a significantly suppressed peaking in riverine water levels in response to an abrupt and concentrated rain in the upstream area. For instance, an hour-long concentration of 100mm rain results in 0.7m rise in water level if the volume of growing stock is 1 million m³, whereas the rise in water level stays below 0.27m with 5 million m³ in the growing-stock volume.

• Journal of recreation and landscape
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• v.11 no.2
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• pp.1-11
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• 2017

Recently, growing emphasis has been placed on the installation of rain gardens. However, previous rain garden studies have mainly focused on physicochemical effects such as rainfall runoff management and water quality improvement. Therefore, this study aims to investigate general perceptions of rain gardens and landscape aesthetics among rain garden visitors. To achieve this goal, a survey of 100 rain garden visitors was conducted, gathering information about their general perceptions of rain gardens and landscape aesthetics at three pre-selected rain garden locations. Results showed that rain garden recognition was limited to 34% of the respondents, indicating that most people were not aware of rain gardens and were unable to notice differences between rain gardens and traditional gardens. However, stronger support for rain gardens was observed among those who were aware of the concept, those who recognized that rain garden planting types are differentiated from traditional gardens, and those who rated positively the landscape aesthetic value of rain gardens. The main findings are expected to encourage further studies of quantitative indicators by conducting a correlation analysis between aesthetics and functionality of rain gardens.

• Journal of Korean Society on Water Environment
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• v.34 no.6
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• pp.669-677
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• 2018

Torrential rain and drought are repeated due to the increase in the unpredictable fluctuating of rainfall patterns. It is time for stabilize water resource management in terms of disaster prevention. Distributed control from sources is needed to minimize damages caused by torrential rains and droughts. Rain barrel can be used to reduce the runoff as they collect and store rainwater. In response to this situation, Seoul Metropolitan Government and other local governments implemented a project to support the installation of rain barrel and provided 90% of the cost of installing it in private areas. However, with limited budget, it is difficult to distribute rainwater to the city which is mostly covered by private areas. In this study, Samho-dong, Ulsan, where pilot projects of water cycle leading city are underway, analyzed the effects of reducing the runoff with respect to the amount of rainwater that can be used, and analyzed the economics of recoverable investment cost when installed. From the analysis, it was established that it is possible to show sufficient efficiency with a small capacity without the need to install large rain barrel effectively in the private sector, and to support the installation cost of less than 70 percent of the rainwater can be recovered.

• Journal of Korean Society on Water Environment
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• v.28 no.5
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• pp.676-685
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• 2012

As impermeable layer continues to increase with the urbanization process, direct input of nonpoint source pollutants into water bodies via stormwater has caused serious effects on the aquatic ecosystem. Potential applications of rain gardens are increasing not only as best management practices (BMP) for reducing the level of nonpoint source pollutants but also as an ecological engineering alternative for low impact development (LID). In this study, remediation performance of various planting types, such as a mixed planting system with shrubs and herbaceous plants, was assessed quantitatively to effectively manage stormwater and increase landscape applicability. The mixed planting system with Rhododendron lateritium and Zoysia japonica showed the highest removal performance of $76.9{\pm}7.6%$ and $58.4{\pm}5.0%$ for total nitrogen and $89.9{\pm}7.9%$ and $82.4{\pm}5.2%$ for total phosphorus at rainfall intensities of 2.5 mm/h and 5.0 mm/h, respectively. The mixed planting system also showed the highest removal performance for heavy metals. The results suggest that a rain garden with the mixed planting system has high potential applicability as a natural reduction system for nonpoint source pollutants in order to manage stormwater with low concentrations of pollutants and will increase water recycling in urban areas.

• Journal of Korea Water Resources Association
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• v.55 no.6
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• pp.393-404
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• 2022

Reliable terrestrial rainfall observations from satellites at finer spatial resolution are essential for urban hydrological and microscale agricultural demands. Although various traditional "top-down" approach-based satellite rainfall products were widely used, they are limited in spatial resolution. This study aims to assess the potential of a novel "bottom-up" approach for rainfall estimation, the parameterized SM2RAIN model, applied to the C-band SAR Sentinel-1 satellite data (SM2RAIN-S1), to generate high-spatial-resolution terrestrial rainfall estimates (0.01° grid/6-day) over Central South Korea. Its performance was evaluated for both spatial and temporal variability using the respective rainfall data from a conventional reanalysis product and rain gauge network for a 1-year period over two different sub-regions in Central South Korea-the mixed forest-dominated, middle sub-region and cropland-dominated, west coast sub-region. Evaluation results indicated that the SM2RAIN-S1 product can capture general rainfall patterns in Central South Korea, and hold potential for high-spatial-resolution rainfall measurement over the local scale with different land covers, while less biased rainfall estimates against rain gauge observations were provided. Moreover, the SM2RAIN-S1 rainfall product was better in mixed forests considering the Pearson's correlation coefficient (R = 0.69), implying the suitability of 6-day SM2RAIN-S1 data in capturing the temporal dynamics of soil moisture and rainfall in mixed forests. However, in terms of RMSE and Bias, better performance was obtained with the SM2RAIN-S1 rainfall product over croplands rather than mixed forests, indicating that larger errors induced by high evapotranspiration losses (especially in mixed forests) need to be included in further improvement of the SM2RAIN.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.54-55
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• 2015

Increase of impervious areas due to expansion of housing area, commercial and business building of urban is resulting in property change of stormwater runoff. Also, rapid urbanization and heavy rain due to climate change lead to urban flood and debris flow damage. In 2010 and 2011, Seoul had experienced shocking flooding damages by heavy rain. All these have led to increased interest in applying LID and decentralized rainwater management as a means of urban hydrologic cycle restoration and Natural Disaster Prevention such as flooding and so on. Urban development is a cause of expansion of impervious area. It reduces infiltration of rain water and may increase runoff volume from storms. Low Impact Development (LID) methods is to mimic the predevelopment site hydrology by using site design techniques that store, infiltrate, evaporate, detain runoff, and reduction flooding. Use of these techniques helps to reduce off-site runoff and ensure adequate groundwater recharge. The contents of this paper include a hydrologic analysis on a site and an evaluation of flooding reduction effect of LID practice facilities planned on the site. The region of this Case study is LID Rainwater Management Demonstration District in A-new town and P-new town, Korea. LID Practice facilities were designed on the area of rainwater management demonstration district in new town. We performed analysis of reduction effect about flood discharge. SWMM5 has been developed as a model to analyze the hydrologic impacts of LID facilities. For this study, we used weather data for around 38 years from January 1973 to August 2014 collected from the new town City Observatory near the district. Using the weather data, we performed continuous simulation of urban runoff in order to analyze impacts on the Stream from the development of the district and the installation of LID facilities. This is a new approach to stormwater management system which is different from existing end-of-pipe type management system. We suggest that LID should be discussed as a efficient method of urban disasters and climate change control in future land use, sewer and stormwater management planning.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.648-653
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• 2010

Discharged pollution load for the management of Total Maximum Daily Loads (TMDLs) is calculated on the basis of rainfall data for reference year. Rainfall has an influence on discharged pollution load in unit watershed with combined sewer system. This study reviewed the status of discharged pollution load and rainfall conditions. We also investigated rainfall effects on discharged pollution load by analyzing change of the load in accordance with increase of rainfall. The change ratio of discharged pollution load was 18.6% while inflow load only 5.8% for 5 years from 2004 to 2008 in Daejeon district. The greatest rainfall and rain days were over 2 times than the least during the period. This change in rainfall could have great effect on discharged pollution load. The analysis showed that discharged pollution load increased 2.1 times in case rainfall increased 2 times and 1.2 times in case rain days increased 2 times. Rainfall effects, therefore, should be considered to make resonable evaluation of discharged pollution load in the assessment of annual performances.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.3
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• pp.49-58
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• 2009

This study was done to provide a case model with a concept of environmental integration based on the water circulation system. Area of interest (AOI) is the Eastern Pangyo New Town area, which has several advantages in adaptation of a water circulation system. The AOI has a potential of maintaining water resources, and has a good condition to construct the water circulation system. Research done for the purpose of the establishment of the water circulation system in the Eastern Pangyo New Town shows the following. The main sources of water supply in the water circulation system in the Eastern Pangyo New Town is from two subway stations and runoff water, along with the natural water flowing from the mountains, rain water, and stream water. It was determined that more than 35,000 tons of water would be needed for the creation of water circulation system at the Eastern Pangyo. If the creation of infrastructure for the use of runoff and rain water as well as the periodic management can be provided, it can serve as the new model for a new city with water circulation system. In addition, since the Eastern Pangyo New Town water circulation system can secure enough amount of water resources, natural drainage system (NDS) in which it can be in dry condition in non-rainy days, is applied and connected to the typical waterways. Such water circulation system has many positive aspects including the wise use of water resources, and providing wild Life animals corridors and habitats. Also, the water circulation system can lead to the environmental education to the residents and visitors on environmental awareness of the water circulation system and their environment.