• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.6
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• pp.85-91
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• 2014

In this study, the water quality purification of new medias which were NPS media, hyugato, mineral stone, charcoal for applying soil media of Integrated Management Practices (IMPs) of Low Impact Development (LID) were evaluated. The influent concentrations of COD, T-N, and T-P were 117.8 mg/L, 17.1 mg/L, and 2.062 mg/L, respectively. The infiltration capacities of NPS media, hyugoto, mineral stone, charcoal, and gravel were $7.1{\times}10m/s$, $7.3{\times}10^{-5}m/s$, $7.9{\times}10^{-5}m/s$, $6.0{\times}10^{-5}m/s$, respectively. All media meet criteria of infiltration capacity as surface soil layer at IMPs which is over $1.0{\times}10^{-5}m/s$. Maximum removal rates of COD, T-N, and T-P occurred at Charcoal with 98 % of COD removal rate, NPS with 78 % of T-N removal rate, and hyugato with 75 % fo T-P removal rate, respectively. For more high removal efficiency of all water quality item, the mixed media which is 4.5(NPS media): 1(charcoal) : 4.5 (hyugato) as volume ratio was evaluated. The infiltration capacity of mixed media was $7.9{\times}10^{-5}m/s$ and met the criteria of infiltration as surface soil layer. The water quality removal efficiencies of mixed media were very high with showing 70 % for COD, 85 % for T-N, and 71 % for T-P. The mixed media could purify the water quality of surface runoff and was recommended to used at the LID site of ground water quality problem.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.5
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• pp.140-147
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• 2012

This study developed a flowerbed type infiltration system that could control the amount of runoff discharge under a certain level estimated its proper design infiltration rate, and analyzed the effects of its implementation. Analyzing the performance of infiltration system is the one of the essential processes that should be under review to predict its effects after implementation when a rainwater infiltration system is included in a district-based plan. To estimate the unit design infiltration rate of this system, the runoff decrease effect was analyzed by varying the unit infiltration rate of the system applied to the parking lot adjacent to the Korea Institute of Construction Technology laboratory building by using a water balance analysis program. After varying the unit design infiltration to $0.1{\sim}3m^3/m^2.day$ to analyze the variation in the rate of runoff, 80% of the runoff was infiltrated at $1.0m^3/m^2.day$, and the unit infiltration design rate at the time was 0.0416(m3/m2.hr). It was also found that the unit design infiltration rate obtained from a field infiltration test of the developed system was about $0.045m^3/hr$. Based on this study, it was possible that infiltration rate is estimated to consider the economic scale and environmental effect. It is significant to apply the spatial plan of rainwater infiltration system as green infrastructure.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.200-204
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• 2012

In engineering hydrology, an estimation of precipitation loss is one of the most important issues for successful modeling to forecast flooding or evaluate water resources for both surface and subsurface flows in a watershed. An accurate estimation of precipitation loss is required for successful implementation of rainfall-runoff models. Precipitation loss or hydrological abstraction may be defined as the portion of the precipitation that does not contribute to the direct runoff. It may consist of several loss elements or abstractions of precipitation such as infiltration, depression storage, evaporation or evapotranspiration, and interception. A composite loss rate model that combines four loss rates over time is derived as a lumped form of a continuous time function for a storm event. The composite loss rate model developed is an exponential model similar to Horton's infiltration model, but its parameters have different meanings. In this model, the initial loss rate is related to antecedent precipitation amounts prior to a storm event, and the decay factor of the loss rate is a composite decay of four losses.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.2
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• pp.59-68
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• 2001

A water balance analysis was performed for a paddy field neighboring the Dongchang stream, downstream of the Unmun reservoir, which is constructed for the urban water supply. Daily rainfall data were collected and irrigation water flow rate, drainage flow rate, evaportranspiration, infiltration, and piezometeric head were measured in the field. The flow rates were continuously observed by water level logger during the growing season. The evaportranspiration and the infiltration were measured by N-type depletion meter and cylindrical infiltrometer, respectively. PVC pipes with 12mm diameter were used for piezometric head measurement. Total Irrigation and drainage flows were 3,608mm and 1,170mm in 1999, and 3,971mm and 1,548mm in 2000, respectively. The mean and range of the daily infiltration rate were 4.4mm/d and 3.4mm/d to 5.5mm/d in 1999 and 5.1mm/d and 4.1mm/d to 6.5mm/d in 2000, respectively. The net ground water flow including the change of soil water storage was 2,855mm in 1999 and 2,540mm in 2000. The evapotranspiration was 458.3mm in 1999 and 553.5mm in 2000. The range of daily evapotranspiration rate was from 1.6 to 8.7mm/d. The return flow ratio was about 32% in 1999 and 39% in 2000 and three year average was 35% including previous study in 1997. The amount of irrigation water was much higher than design standards or references in this study, This was caused by the inadequate water management practice in the area where water was oversupplied on farmers’ request rather than following sound water management principles.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.4
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• pp.52-61
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• 2003

This study was carried out to analyze the effects of stormwater retention and infiltration pond on reduction of flood peak and volume in a experimentally developed ecological pond. The experimental site has 542$m^2$ watershed area, 1,310mm yearly-averaged rainfall. And the area of the retention pond is 60$m^2$, the maximum water depth is 0.5m, the maximum and average storage is 15$m^3$and 9.3$m^3$d. And the area of infiltration pond is 58$m^2$, and the water depth varies 0.2m~0.5m. The monitoring system consists of one rainfall gage, one Parshall flume and acoustic water level gage, two rectangular weirs and acoustic water level gage for discharge gaging, and one data recording unit. Data from ten storm events in total, three storm events in year 2000 and seven storm events in year 2001, were collected. From the data the evaporation rate was achieved with the water balance equation, and the result shows 5.0mm/day in average. The result from the analysis of the effects on reduction of flood peak and volume, is that 14% reduction of flood volume and 15% reduction of flood peak in retention pond and 49% reduction of flood volume in infiltration pond.

• Journal of Korea Water Resources Association
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• v.37 no.3
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• pp.249-255
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• 2004

To investigate the return flow ratio of irrigation water, lots of observations were made during the irrigation periods in 2003 crop year. This Area is a portion of Dae-Am pumping station basin which is located in Changryung-gun, Gyeongnam province. A water balance analysis was performed for a paddy field in Dae-Am pumping station in the Nakdong river basin, which is constructed for irrigation water supply. Daily rainfall data in the this area were collected and irrigation water flow rate, drainage water flow rate, infiltration and evaportranspiration were measured in field area. Irrigation water flow rate and drainage water flow rate were continuously observed by water level logger(GTDL-L10) during the growing season. The infiltration and evaportranspiration were measured by cylindrical 300mm depletion meter and cylindrical 200mm infiltrometer, respectively. Total irrigation and drainage flows were 654.7mm and 281.2mm in 2003. Total infiltration and evaportranspiration were 36.0mm and 160.0mm respectively. The mean of the daily evaportranspiration rate was 4.3mmm/d. The prompt return flow and retard return flow ratio were 43.0％ and 5.5％, respectively. Total return flow ratio was 48.5％. Therefore, it can be concluded that the amount of irrigation water was much higher than design standard or reference in this study. It means that this was caused by the inadequate water management practice in the area where water was oversupplied on farmers' request rather than following sound water management principles, and design standard should be changed in the future.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.362-369
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• 2003

A infiltration experiment of river water has been conducted to evaluate the applicability of electrical resistivity monitoring methods in an area containing gravelly deposits in Nagaoka, Japan. Apparent resistivity data, which are inverted to obtain the resistivity distribution, are measured with a newly developed system. This system can collect 490 data in an hour and be controlled with PC to store the data. Subsurface resistivity sections, which are obtained from two-dimensional nonlinear inversion of time-lapse apparent resistivity data, enable us to estimate the direction of the flow and the rate of infiltration. The infiltration rate is estimated to be $4.4{\times}10^4m/s$ in the early stage of the experiment when the infiltration process is dominant.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.1
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• pp.53-62
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• 2006

This study was carried out to obtain quantities of infiltration, inflow and exfiltration on sewer pipes of three areas at a small city. From the results, the most investigated sewer pipes should be infiltrated by underground water and undetermined water. Flowrate commonly showed two peak at 6 to 8 a.m. and 6 to 9 p.m. and which may be influenced by the sewer flowrate with washing or bathing time. BOD/TN ratio of below 4.0 were inferior as compared with proper criteria 5.1. Infiltration/inflow rates of three areas were 21.7% and $0.08m^3/km$ of A, 12.4% and $0.015m^3/km$ of B, 22.4% and $0.021m^3/km$ of C, respectively. This indicates that infiltration/inflow rate of A was obviously greater than that of B and C. Also, these results show that we can conduct sewer maintenance in good order as A, C and B zone.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.2
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• pp.185-192
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• 2011

Pearson's correlation was used to determine relations between infiltration and affecting factors using flow monitoring data measured in 24 areas with different characteristics. Factors showed relatively high correlations than others were indexed to determine infiltration rates of the study area. Among 8 factors(service area, sewer length, sewer diameter, multiplier of sewer length and diameter, number of manholes, population, number of properties, number of households) tested, the multiplier of sewer length and diameter, the number of population and the number of household in each service area indicated higher correlation coefficient(>0.8) than others. The goodness of fitness of linear regressions between infiltration and the factors followed the order: sewer length and diameter(0.68)> population(0.65)> number of household(0.60). Infiltration rates calculated by the multiplier of sewer length and diameter, the number of population and the number of household in each service area were 0.046~1.0396 $m^{3}/d{\cdot}mm-km$, 0.0917~1.7355 $m^{3}/capita{\cdot}d$, 0.196~4.529 $m^{3}/household {\cdot}d$ respectively. After sewerage rehabilitation work of the area, the infiltration rates calculated by above factors with high correlations are expected to be used for comparing effectiveness of the work once they are estimated under the same flow measuring conditions.

• Ecology and Resilient Infrastructure
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• v.3 no.2
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• pp.126-129
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• 2016

The risk of flooding and groundwater depletion is increasing due to the increase of impervious area in an urban area that reduces the volume of infiltration and increases the outflow of rainwater. The objective of this study is to examine the impact of installation of roadside tree protectors with infiltration pipes in terms of the change of the infiltration rate. Through this study, it has been attested that roadside tree protectors with infiltration pipes increased the infiltration rate and decreased water level on the ground, and could be applied in an urban area as the low impact development (LID) facilities.