• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.3
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• pp.141-152
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• 2017

This paper presents a technical method for flood estimation based on satellite rainfall and satellite rainfall correction method for watersheds lacking measurement data. The study area was the Sebou Watershed, Morocco. The Integrated Flood Analysis System(IFAS) and Grid-based Rainfall-Runoff Model(GRM) were applied to estimate watershed runoff. Daily rainfall from ground gauges and satellite-derived hourly data were used. In the runoff simulation using satellite rainfall data, the composites of the daily gauge rainfall and the hourly satellite data were applied. The Shuttle Radar Topographic Mission Digital Elevation Model(SRTM DEM) with a 90m spatial resolution and 1km resolution data from Global map land cover and United States Food and Agriculture Organization(US FAO) Harmonized World Soil Database(HWSD) were used. Underestimated satellite rainfall data were calibrated using ground gauge data. The simulation results using the revised satellite rainfall data were $5,878{\sim}7,434m^3/s$ and $6,140{\sim}7,437m^3/s$ based on the IFAS and GRM, respectively. The peak discharge during flooding of Sebou River Watershed in 2009~2010 was estimated to range from $5,800m^3/s$ to $7,500m^3/s$. The flood estimations from the two hydrologic models using satellite-derived rainfall data were similar. Therefore, the calibration method using satellite rainfall suggested in this study can be applied to estimate the flood discharge of watersheds lacking observational data.

• Journal of the Korean earth science society
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• v.33 no.7
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• pp.596-607
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• 2012

The R-Z relationship is one of important error factors to determine the accuracy of radar rainfall estimation. In this study, we have explored the effect of the R-Z relationships derived from disdrometer data in estimating the radar rainfall. The heavy rain event that produced flooding in St-Remi, Quebec, Canada has been occurred. We have tried to investigate the severity of rain for this event using high temporal (2.5 min) and spatial resolution ($1^{\circ}$ by 250 m) radar data obtained from the McGill S-band radar. Radar data revealed that the heavy rain cells pass directly over St-Remi while the coarse raingauge network was not sufficient to detect this rain event. The maximum 30 min (1 h) accumulation reaches about 39 (42) mm in St-Remi. During the rain event, the two disdrometers (POSS; Precipitation Occurrence Sensor System) were available: One used for the reflectivity calibration by comparing disdrometer Z and radar Z and the other for deriving disdrometric R-Z relationships. The result shows the significant improvement with the disdrometric reflectivity-dependent R-Z relationships against the climatological R-Z relationship. The bias in radar rain estimation is reduced from +12% to -2% and the root-mean squared error from 16 to 10% for daily accumulation. Using the estimated radar rainfall rate with disdrometric R-Z relationships, the flood event was well captured with proper timing and amount.

• Journal of Korea Water Resources Association
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• v.50 no.2
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• pp.111-119
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• 2017

The underflow type movable weirs were arranged in a multi-stage way along a reach at the Chiseong River, where flooding has been observed frequently. With management water level of the movable weirs the control effects of storage and flood were suggested and the control effects were compared with those of existed weir system. The water level for the targeted storage and flood elevation was suggested by building the artificial neural network model. When the underflow type of movable weirs were arranged in a multi-stage way, the peak flood elevation decreased by 68.28% in the downstream compared with the existed weir system, and the total storage of the target section of multi-stage movable weirs increased by 216%. As a result of numerical simulation to build the artificial neural network model, 60%, 20%, and 20% among 216 data were used for the training, validation, and test, respectively. The training result of mean square error was $0.1681m^2$ and the high coefficients of determination were 0.9961, 0.9967, and 0.9943 in the training, validation, and test, respectively. As a result the water level management of each movable weir for the controls of flood elevation in the targeted downstream and targeted storage was suggested by using the artificial neural network.

• Korean Journal of Weed Science
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• v.15 no.3
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• pp.175-182
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• 1995

The experiment was conducted to obtain basic information on weed ecology and effective weed control in direct-seeded rice Gelds at National Yeongnam Agricultural Experiment Station in 1994. Double cropping system of rice-barley reduced weed occurrence about 30% as compared with rice single cropping due to allelopathic effect of barley residue or stubble. Occurrences of red rice (weedy rice), barnyard grass and water foxtail were closely related with tillage method; the greatest occurred in no tillage plot followed by rotavation only and plow plus rotavation. Period of seed germination of barnyard grass and carbgrass varied with temperature and soil depth. In the same environmental condition, the germination period of barnyard grass shortened 3 to 5 days as compared with that of carbgrass. Two systematic applications of herbicides, that is, the first application at 10 to 15 days after seeding and the second at just after flooding, were the most recommendable system in dry-seeded rice field in terms of weed suppression and yield capacity.

• Journal of Korea Water Resources Association
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• v.39 no.5 s.166
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• pp.405-415
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• 2006

The deposition of sewer solids during dry weather in combined sewer systems results in a loss of flow capacity that may restrict flow and cause a local flooding and enhanced solids deposition. Sewer solid accumulations in drainage systems also create the 'first-flush' phenomena during wet weather runoff periods. In order to solve these problems, measurement of these loadings for a given sewer system for extended period is needed but this task is very difficult and extremely expensive. In this study, generalized procedures for estimating sewer sediment solid during dry weather in combined sewer systems developed by the U. S. Environmental Protection Agency were applied in a drainage system in Korea. As result, the appropriate equation can be selected and applied according to the available data. However, the estimated solid sediment shows considerable difference between methods which classified by model and estimation methods of variable. The estimated values using equations (1) $\sim$ (4) are greater than that of equations (5) $\sim$ (9) and intermediate models show greater values than elaborate or simplest models. The comparison between simulated and measured solid deposition is difficult due to the absent of measurement data, but this estimation method can be used usefully for the management of sewer solid with reduction of cost and effort if the measurement is carried out and the equation is adjusted according to the actual drainage systems in Korea.

• Korean Journal of Weed Science
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• v.18 no.2
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• pp.116-121
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• 1998

Field experiment were carried out to elucidate the changes of weed occurrence according to the sowing time and to establish the efficient weed control system in dry seeded rice cultivation. E crus-galli and D. sanguinalis are tow major weeds at the earlier sowings, but C. difformis was dominating at the later sowing. In the case of E. crus-galli, there was a tendency of gaining its dominance values as the rice growth stage advances. The later the sowing time was, the more weeds occurred at the early rice growth stages: However, when measured at heading, total dry weight was greater at the earlier sowings. Yield loss due to weeds were also greater at the earlier sowings. Community diversity of weeds was greater at the later sowings, while specific weed was gradually dominating as rice growth stage advances, regardless of sowing time. When herbicides were applied before 15 DAS, weeds were effectively controlled only upto 35 DAS. So systemic herbicide application, one on 0 to 10 DAS and the other on just after flooding, appeared to be recommendable in direct seeded rice cultivation.

• 한국해양학회지
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• v.26 no.3
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• pp.181-192
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• 1991

Zooplankton were sampled horizontally with a standard net from the surface layer of the estuarine system of Mankyong River and Dongjin River in October, 1989, March, May, and July, 1990. Among dominant taxa of the zooplankton community, copepods were predominant in October, 1989 and March, 1990 and Noctiluca scintillans in May and July, 1990. Abundance of zooplankton showed considerable spatial and temporal fluctuations with a range of $12~9,256ind./m^3$ in wet weight. In the copepod community, Pseudodiaptomus inopinus and Paracalanus inducus were predominant in October, 1989: Acartia hudosonica and P. inducus in March, 1990; A. hudosonica and Centropages abdoinalis in May, 1990; A. pacifica, P. indicus and Tortanus spinicaudatus in July. 1990. In summer (July),there were large seasonal changes in salinity ($0.7~28.9\textperthousand$), due to monsoonal flooding, and associated changes in community structured of copepods. There were eight species of copepods in the mixo-mesohaline zone ($5.0~28.8\textperthousand$), namely Acartia pacifica, A. hudosonica, Centropages tenuiremis, C. abdominalis, Labidocera Euchaeta, Tortanus spinicaudatus, corycaeus affinis and Paracalanus indicus. On the other hand, Thermocouple hyalinus, Pseudodiaptomus inopinus and Sinocalanus tenellus occurred in the mixo-oligohaline zone ($0.5~5.0\textperthousand$), showing more tolerant of low salinity than any of the other species. In the mixoeuhaline zone ($>28.0\textperthousand$), Labidocera bipinnata, Oithona similes, Calanus sinicus, Acartia omorii and Tortanus forcipatus were founded.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.646-659
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• 2018

This study proposed "Reservoir Park", which added disaster prevention function to urban green spaces such as city parks through domestic and overseas related laws review, case studies, field trips. This is a combination of urban parks and reservoirs as urban planning facilities, which can provide both space for daily use by urban residents and disaster mitigation functions in case of emergency. In order to prevent flooding in urban areas due to climate change, facilities should be installed in the form of parks, etc., as the reservoir facility should be systematically reviewed together with urban planning facilities. However it was found that the reservoir park was not clear as a theme park. In this study, the types of storage facilities in urban areas were reclassified into five types of storage parks reflecting the characteristics of urban green spaces through domestic case studies and field trips. The classification of the reservoir parks is classified into 5 kinds such as ecological type, vegetation cover type, exercise facility type, underground burial type and hybrid type based on groundwater level, human use, and reservoir size. This classification system can be used to determine the types of facilities to be built after designating the location of future storage facilities.

• Korean Journal of Heritage: History & Science
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• v.45 no.4
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• pp.22-37
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• 2012

Storage facility of the pre-historic Korea is classified into the subterranean, ground and overground types. The rectangular-shaped subterranean Storage facilities have been identified in the Pungnaptoseong, the Gong mountain fortress site and the Gwanbukri site. Feature no. 196 at Gyeongdang District in Pungnaptoseong yielded a large quantity of glazed potteries, and a wooden storage at the Gwanbukri site contained a large amount of fruit seeds. These storage facilities might be functioned as the warehouse for the highest group rather than the storage for the emergency such as war and flooding and stipend of government officials. This article subdivided into "state storage" on the concept of the former that "royal storage" on the concept of the latter. If it look on the state storage at large, this include the royal storage too. But it subdivided to help article understand because Baekjae changed from state storage to royal storage by change and specialization of system after 4th. The reason why the diversification of storage pits was closely related to the unification of local polities and the concentration of political power in the state-level. Therefore, it might reflect the political circumstances the ruling elites attempted to heighten their authority in terms of the organizing tax collecting system. And divided the time of storage is confirmed separative storage pits in the suburbs of capital city. There is hight probability of top local polities or nation that have possessional a role. This is to cover on frequent war in the Three States. On the other hand, state storage is located around ancent road that linked castle gate that is divided into center and periphery depending on function and position of storage. Center is located royal storage focusing in the presumed royal palace that periphery is located state storage to provide service to the public. It is presumed that located with the government office.

• Korean Journal of Remote Sensing
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• v.38 no.5_3
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• pp.901-912
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• 2022

The frequency of disasters is increasing due to global climate change, and unusual heavy rains and rainy seasons are occurring in Korea. Periodic monitoring and rapid detection are important because these weather conditions can lead to drought and flooding, causing secondary damage. Although research using optical images is continuously being conducted to determine the waterbody, there is a limitation in that it is difficult to detect due to the influence of clouds in order to detect floods that accompany heavy rain. Therefore, there is a need for research using synthetic aperture radar (SAR) that can be observed regardless of day or night in all weather. In this study, using Sentinel-1 SAR images that can be collected in near-real time as open data, the UNet model among deep learning algorithms that have recently been used in various fields was applied. In previous studies, waterbody detection studies using SAR images and deep learning algorithms are being conducted, but only a small number of studies have been conducted in Korea. In this study, to determine the applicability of deep learning of SAR images, UNet and the existing algorithm thresholding method were compared, and five indices and Sentinel-2 normalized difference water index (NDWI) were evaluated. As a result of evaluating the accuracy with intersect of union (IoU), it was confirmed that UNet has high accuracy with 0.894 for UNet and 0.699 for threshold method. Through this study, the applicability of deep learning-based SAR images was confirmed, and if high-resolution SAR images and deep learning algorithms are applied, it is expected that periodic and accurate waterbody change detection will be possible in Korea.