• Journal of Wetlands Research
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• v.24 no.3
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• pp.161-169
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• 2022

In this study to estimate suitable size of rain tank in Suwon district, monthly rainfall, daily rainfall duration curve and daily rainy days have been analyzed. Annual rainwater consumption and daily average amount of storage with respect to size of rain tank have been calculated by applying continuity equations that take account of daily rainfall, daily consumptive use, storage of rain tank, It has been shown that above 50 mm of rainfall in the ordinance related to reclamation water may be inappropriate regulation if annual amount of rainfall captured, efficiency of utilized rainwater, number of days for utilized rain tank, daily average amount of storage and daily consumptive use have been considered. Thus, it has been shown that suitable size of rain tank should be determined considering reasonable daily consumptive use with respect to district, constructed cost of rain tank and benefit of rain tank constructed.

• Journal of Korea Water Resources Association
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• v.36 no.3 s.134
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• pp.455-464
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• 2003

In this paper, the experiments with installing a rainfall storage tank in the sub-surface were conducted and the reduction rates of the total runoff volume were investigated. The analysis were conducted based upon the variations of the rainfall intensity, surface coverage and surface slope. The reduction rate of the runoff volume was varied from 42.3% to 52.9% with the soil in the bank of the Seung Gi stream. In the experiments, the rainfall intensities were varied from 40mm/hr to 100mm/hr and the results indicate that the direct runoff reduction can be obtained with the installation of the rainfall storage tank in the sub-surface. The variation of the stored volume in the tank is very large in the mild slope but very small in the steep slope with over 3% slope. With this results, the reduction of the direct runoff volume for the longtime flood is expected with the installation of the rainfall storage tank in the region haying the steep slope such as the mountain area.

• Journal of Korean Society on Water Environment
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• v.27 no.5
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• pp.654-660
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• 2011

One of the best way to control Combined Sewer Overflow (CSO) is proposed to construct first flush storage tank. But there is little known parameters for optimum design of these facilities. This study was conducted to get optimum design parameters for a first flush storage tank construction. The optimization of the tank is generally based upon some measure of SS(Suspended Solid) mass holding efficiency. Water quality deterioration of receiving water body happened right after first time occurring rainfall in dry weather seasons. So, design rainfall intensity is used at 2 mm/hr for peak of monthly average intensities of dry seasons. The capacities for each evaluated catchment are designed from 14.4 min to 16.1 min HRT of CSOs flow at design rainfall intensity. Owing to all storage tanks are connected to interception sewer having a redundancy, the suggested volume could be cut down.

• Journal of Korean Society of Forest Science
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• v.98 no.3
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• pp.272-278
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• 2009

This study was conducted to develope calculation method of standard rainfall, which was used for predicting the outbreaking time of disaster by using Tank model, on warning and evacuation for soil sediment disaster. We investigate adeption possibility of developed method through comparing storage function method with Tank model. We calculated storage amount rainfall by storage function method and Tank model with 36 hillslope failures which have record on outbreaking time of disaster. The result in case of Sedimentary (quarternary period) showed that the difference of outbreaking time was 1.6 hour in case of tank model, but 3.2 hour in case of storage function method. In addition, the deviation of the peak storage were 7% in case of tank model, but 63% in case of storage function method. Total evacuation period was analyzed by using observed 5 years (1993-1997) rainfall data as well as each standard rainfalls which were determinated by two methods. The result showed that evacuation time by storage function method was about twice as many as that by tank model. Therefore, we concluded that calculation by tank model for predicting the outbreaking time of disaster was more useful and accurate than storage function method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.927-935
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• 2013

In this study, reservoir routings for 1 hour-50 year precipitation frequency were carried out at the Engineering Water Fall and the Amphitheater located at the downstream of Seoul National University Dam. Main analysis was focus on the following matters: (1) storage amount by the tank; (2) reduction of the outflow and the peak water surface elevation; (3) change of phase lag time; and (4) design of new boxes at the inlet and outlet of storage tank. As for the storage tank of $25,000m^3$ built in the Amphitheater area, the tank induced 49.43 % storage effect, 28 min. phase lag time, and reduced the peak outflow by 49.64 %. In addition, the peak water surface elevation was lowered by 35 cm compared with that of $15,000m^3$ storage tank. It is concluded that combined management of previous storage facility and new underground storage tank would control the excessive rainfall runoff efficiently.

• Journal of Environmental Science International
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• v.12 no.3
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• pp.359-366
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• 2003

Ecological society and energy conservative systems has become a subject of world wide attention. To examine the technologies of such systems as resource recycling society, this study is proposed for using rainwater as energy source and water resources in urban area. Useful informations for planning of utilizing rainfall as energy source, water resources, emergency water and controlling flood are discussed with model systems in urban area. It is calculated that the rate of utilizing rainwater, amounts of utilizing rainwater, substitution rate of supply water, amounts of overflow rainwater according to rain storage tank volume. By applying the past weather data, The optimum volume of rain water storage was calculated as 200m$^3$ which mean no benefits according to the increase of storage tank volumes. For optimum planing and control method at the model system, several running method of rainwater storage tank was calculated. The optimum operating method was the using weather data as 3hours weather forecast.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.3
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• pp.3-13
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• 2005

The conceptual rainfall-runoff models are used to predict complex hydrological effects of a basin. However, to obtain reliable results, there are some difficulties and problems in choosing optimum model, calibrating, and verifying the chosen model suitable for hydrological characteristics of the basin. In this study, Genetic Algorithm and SCE-UA method as global optimization methods were applied to compare the each optimization technique and to analyze the application for the rainfall-runoff models. Modified TANK model that is used to calculate outflow for watershed management and reservoir operation etc. was optimized as a long term rainfall-runoff model. And storage-function model that is used to predict real-time flood using historical data was optimized as a short term rainfall-runoff model. The optimized models were applied to simulate runoff on Pyeongchang-river watershed and Bocheong-stream watershed in 2001 and 2002. In the historical data study, the Genetic Algorithm and the SCE-UA method showed consistently good results considering statistical values compared with observed data.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.4
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• pp.76-86
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• 2000

The objective function of reservoir storage error was suggested to simulate daily reservoir inflow. DAWAST model, UMAX, LMAX, FC,CP, CE were calibrated. Daily reservoir inflow was imulated with calibrated parameters and reservoir storage was simulated on a daily basis. The simulated results were compared with the monthly results by Gajiyama equation and ten-day results by Tank rainfall-runoff model through equal value lines and hydrographs . DAWAST model showed the best results compared with Gajiymama equation and Tank model. Especially, DAWAST model showed a good agreement in dry periods. NEW concept using objective function of storage error was believed to be satisfactory and to be applied in estimating reservoir inflow.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.386-389
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• 2013

Under climate change and urbanization, rainwater harvesting (RWH) systems are emerging as an alternative source of water supply because of growing concern about water sustainability. RWH systems can satisfy the various watering needs and provide the environmental benefits of lessening the damages from flood, drought, and runoff. The economic success of a RWH system is vitally concerned with the determination of the design capacity of storage tank to be built in the system. The design capacity is determined by the factors of average annual rainfall, period of water scarcity, and water price during the whole life-cycles. Despite the high uncertainties inherent in these factors, the current engineering design of RWH system construction often assumes that storage tanks should be built all at once. This assumption implicitly ignores the managerial flexibility in responds to the future as new information comes out-the right to build storage tanks stage by stage depending on the evolution of demand. This study evaluates the value of a multistage storage tank construction using a real option approach. A case study involving a typical RWH system construction in Jeonju, the Republic of Korea is conducted. The managerial flexibility obtained from the real option perspective allows engineers to develop investment strategies to better cope with the issue of water sustainability.

• Journal of Korean Society on Water Environment
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• v.24 no.2
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• pp.221-229
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• 2008

This study revised a model for hydrologically analyzing rainwater harvesting facilities considering their rainfall-runoff properties and the data available. This model has only a few parameters, which can be estimated with rather poor measurements available. The model has a non-linear module for rainfall loss, and the remaining rainfall excess (effective rainfall) is assumed to be inflow to the storage tank. This model has been applied for the rainwater harvesting facilities in Seoul National University, Korea Institute of Construction Technology, and the Daejon World Cup Stadium. As a result, the runoff coefficients estimated were about 0.9 for the building roof as a rainwater collecting surface and about 0.18 for the playground. This result is coincident with that for designing the rainwater harvesting facilities to show the accuracy of model and the simulation results.