• Journal of The Korean Society of Agricultural Engineers
• /
• v.49 no.2
• /
• pp.17-24
• /
• 2007

This study analyzes the flood inundation in low agricultural area caused by rainfall during typhoon periods and how flood inundation areas should be affected. GIS techniques, HEC-HMS and HEC-GeoHMS were used for flood runoff, HEC-RAS was applied in water surface elevation analysis at each cross-section. RMA2, SED2D were applied for runoff characteristics of inundation areas and river bed change and distribution of sediment. As a result, velocity distribution was analyzed 2.6 m/s-3.4 m/s in flood inundation by water level increase. In the case of bed elevation change, most sediments were deposited to the parts that adjoin bank.

• Journal of Korea Water Resources Association
• /
• v.51 no.4
• /
• pp.293-299
• /
• 2018

In this study, a new technique for evaluating the flood vulnerability of river banks is proposed. For this purpose, flood quantities of the basin were estimated based on the future climate change scenarios and the infiltration stability was evaluated by analyzing the infiltration behavior using SEEP/W which is a 2D groundwater infiltration model of the levee. The size of the river levee was investigated. The size of river levee was investigated by selecting the target area. The safety factor of the levee was analyzed considering the current flood level of the levee and the flood level considering the climate change. The factor needed to analyze the levee vulnerability was derived. We analyzed the vulnerability of the levee considering the change of the levee level according to the climate change scenarios. Levee Flood Vulnerability Index (LFVI) were used to evaluate the vulnerability of the levee.

• Water for future
• /
• v.27 no.4
• /
• pp.115-121
• /
• 1994

In tidal rivers, the water level is affected by a tidal wave. The latter creates higher flood stages that enlarge the flood plain areas and increase potential damages. In such rivers, the water level is not solely a function of the flow discharge but rather a joint function of both the discharge and tidal phenomena. This paper attempts at formulating a relation between tital water level and river flow discharge that can be used for the predictions of water level in coastal rivers. Numerical applications were performed on the HaDong and the SongJung Station in Sumjin river with satisfactory results. The correlation coefficients between the tide(M) and the water stage(Z) at the HaDong Station is 0.558, and SongJung is 0.016. From this result, the water level at HaDong Station is greatly affected by a tide, whereas songJung is not.

• Journal of Korea Water Resources Association
• /
• v.51 no.spc
• /
• pp.1161-1169
• /
• 2018

In this study, a new methodology was proposed to evaluate the flood vulnerability of river levee and to investigate the effect on the levee where the water level changes according to climate change. The stability of levee against seepage was evaluated using SEEP/W model which is two-dimensional groundwater infiltration model. In addition to the infiltration behavior, it is necessary to analyze the vulnerability of the embankment considering the environmental conditions of the river due to climate change. In this study, the levee flood vulnerability index (LFVI) was newly developed by deriving the factors necessary for the analysis of the levee vulnerability. The size of river levee was investigated by selecting the target area. The selected levees were classified into upstream part, midstream part and downstream part at the nearside of Seoul in the Han river, and the safety factor of the levee was analyzed by applying the design flood level of the levee. The safety ratio of the levee was analyzed by applying the design flood level considering the current flood level and the scenario of climate change RCP8.5. The degree of change resulting from climate change was identified for each factor that forms the levee flood vulnerability index. By using the levee flood vulnerability index value utilizing these factors comprehensively, it was finally possible to estimate the vulnerability of levee due to climate change.

• Journal of Korea Water Resources Association
• /
• v.38 no.5 s.154
• /
• pp.401-413
• /
• 2005

This study analyzed the hydraulic effects of Singok submerged weir in the lower Han River. 1-D hydraulic flood routing model was used and calibration and verification were performed using 8 flood or nonflood events. Flow characteristics were analyzed using various outflows of Paldang Dam and tidal data of the Yellow Sea. Water level increase effects by establishment of Singok submerged weir were as following, when maximum flood tidal was 2.4m, highest water level increased about 0.65m, and lowest water level increased about 1.25m in the downstream of Jamsil submerged weir. In Hangang Bridge, due to the Singok submerged weir, when maximum flood tidal was 2.4m, tidal range was 0.07m and decrement of tidal range was about $90\%$. And when maximum flood tidal was 5.5m, tidal range was 1.6m and decrement of tidal range was about $35\%$. When the outflow of Paldang Dam was over 20,000cms, tidal range was below about 0.06m, and tidal effect did not appear hardly.

• Journal of Korea Water Resources Association
• /
• v.48 no.5
• /
• pp.379-391
• /
• 2015

Multi-functional weirs has been installed in four rivers are hydraulic structures across the river. The structures were divided into movable and fixed weirs. Hence, riverbed-level variation and sediment transport can be varied due to water gate operation. In this study, the long-term riverbed-level variation of Geum river basin due to water gate operation of multi-functional weirs was studied. Result of this study shows that the variation of thalweg elevation was greater than the variation of annual average riverbed elevation due to multi-functional weirs construction and water gate operation. Maximum riverbed degradation of thalweg elevation that occurred was 2.79m and riverbed aggradation was 1.90m. Maximum riverbed degradation of the annual average riverbed elevation that occurred was 2.16m and riverbed aggradation was 1.24m. Analysis result of flood stage by the variation of riverbed-level shows that flood stages were increased in majorities area. The maximum increase in the value of flood stage was 2.23m. For this reason, flood stages can be greater than the freeboard of the levees. Therefore, we should consider the water gate operation of multi-functional weirs when planning and managing sediment in the river. We are expecting to use the result of this study in river planning for river management and selecting the river regime.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2004.05b
• /
• pp.790-793
• /
• 2004

TM/TC system is composed of control center, reservoirs, pumping stations and twelve canal systems. For this system we developed water management program which includes flood forecast program, drought reduction program, irrigation scheduling program and database program. With these program we expect that operators improve the irrigation efficiencies of the irrigation systems due to the timely irrigation on a right place, in a proper quantity and refute tile cost of maintenance and reduce flood and drought damages. In agricultural engineering respect, the databases including water level, rainfall, the amount of flowing can be useful to the researcher who make a study of hydrology and hydraulics in . rural area. Water management program records all of the TM/TC data to MDB format file per 10 minutes.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.15 no.4
• /
• pp.15-25
• /
• 2012

This study is to develop a web-based real-time agricultural flood management system(RAFMS) for 378 agricultural reservoirs equipped with auto water level gauge stations. The RAFMS was designed to operate linking with Rural Agricultural Water Resource Information System(RAWRIS) which supports data viz. real-time rainfall and water level necessary for RAFMS. The system was constituted to monitor the floods simultaneously at each reservoir by calculating the real-time reservoir inflow from watersheds, water level, and release to downstream. In addition, the system has the prediction function for the flood by applying weather forecasting data from Korea Meteorological Administration(KMA).

• Journal of the Korean Society of Hazard Mitigation
• /
• v.7 no.5
• /
• pp.179-186
• /
• 2007

This paper has investigated a rise of water level in upstream and downstream of bridge, which is caused by accumulation of debris in a bridge. The debris has been classified into several types in terms of size. The rise of water level which has been caused by installation and removal of sheet pile that is used to block water in a bridge has been analyzed using HEC-RAS model. According to the analysis, it has turned out that the debris has no influence on the rise of water level in ordinary water flow. In addition, sheet pile has little impact on the rise of water as well. Even though the impact of sheet file has turned out trivial in flood flow just like the ordinary water flow, it's been simulated that the maximum water level difference between upstream and downstream of bridge turned out more than 1.0meter because of debris in 80-year or more flood frequency. When the rise of water level in upstream from the cross section of the bridge was investigated based on 100-year flood frequency, besides, it has turned out that it had an influence up to 17.84km distance because of the effect of debris.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.4
• /
• pp.25-36
• /
• 2021

This study analyzed the causes of flood accidents, such as isolation and lost footing accidents in Dorimcheon, to provide legal and institutional improvements. For cause analysis, Field Investigation, Stakeholder Interview, Report, manual, Law et al. Review, Analysis of water level change characteristics, automatic alarm issuance standard level analysis, and evacuation time according to river control were evaluated. Dorimcheon has the characteristics of a typical urban river, which is disadvantageous in terms of water control. In addition, the risk of flood accidents is high because the section where fatal accidents occur forms sharply curved channels. Tripping and isolation accidents occur in the floodplain watch and evacuation stage, which is the stage before the flood watch and warning is issued. Because floodplain evacuation is issued only when the water level rises to the floodplain, an immediate response according to the rainfall forecast is essential. Furthermore, considering that the rate of water level rise is up to 2.62 cm/min in Sillimgyo 3 and Gwanakdorimgyo, sufficient evacuation time is not secured after the floodplain watch is issued. Considering that fatal accidents occurred 0.46 m below the standard water level for the flood watch, complete control is very important, such as blocking the entry of rivers to prevent accidents. Based on these results, four improvement measures were suggested, and it is expected to contribute to the prevention of Tripping and Isolation Accidents occurring in rivers.