• Journal of Environmental Impact Assessment
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• v.15 no.6
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• pp.357-372
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• 2006

The excessive land activities in farming can cause soil erosion, inundation by a flood, and fallow. So far land evaluation has been analyzed using the land use limitation derived from the excessive land activities. This study was done for evaluating the agricultural fields by using 3 land use limitations, inundation potential, soil erodibility potential, and fallow potential. The study area is Ibang-myeon, Changnyeong-gun, Gyeongnam-province, Korea. A logistic regression model was applied to recognize the inundation potential by a flood in the Nakdong river basin. And potential soil erodibility index (PSEI) was derived from USLE model to analyze the soil erodibility potential. And a probability model from a logistic regression model was applied to detect the fallow potential. Therefore, we found 220.7ha for the 4th grade and 86.1ha for the 5th grade was analyzed as water damage potential. Large area near Nakdong river have problem to grow the rice due to the damage by water inundation. And 213.6ha for the 3rd grade and 103.3ha for 4th grade was detected as a result of the analysis of soil erosion potential. The soil erosion potential was high when within-field integrity of soil was not stable, or the kinetic energy was high or the slope length was long due to a steep slope of a specific land. And 869.1ha for 3rd grade, 174.9ha for 4th grade, and 110.6ha for 5th grade was detected to be distributed having the fallow potential. Especially, a village, having a steep mountain, had 249.5ha for the 3rd grade, which was 28.7% of total area showing the 3rd grade. Finally, Three villages, including An-ri, Geonam-ri, Songgok-ri, showed they had largest area of the suitable land in the study area. These villages had similar topographic condition where they were far from Nakdong river, and they had relatively higher elevation and flat lands.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.5
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• pp.55-63
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• 1996

The situation and cause of bund collapse in steep sloping paddy area by a heavy rainfall of Chungbuk Province were investigated by field surveys. Shapes of paddy plots are irregular and average size of them is 12.6a. Surface, groundwater and plot-to-plot irrigations are being carried out in the study plots. The type of bund collapse can be divided as follows: overflow type and inundation type. The overflow type generally occurs at the bund with slope lacking the design standard. The inundation type damages paddy plots more seriously than the overflow type. It induces continuous bund collapse from a inflow-plot to a outflow-plot and includes lots of type (inside paddy) collapse, which results in much subsoil erosion. The installation of mountain stream weir and maintenance of mountain stream are proposed to prevent the inundation type collapse.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.6
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• pp.45-52
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• 2012

Along with global warming, ever intensifying weather events have increased damages to agricultural farms and facilities. The objective of this study was to investigate the spatial distribution and regional characteristics of agricultural damages by extreme weather events. Agricultural disaster statistics provided by the National Emergency Management Agency were summed over for a 13-year period from 1998 to 2010 and used for the spatial analysis. Two indices of damage area ration and property damage per unit area were introduced to quantify regional agricultural damages. As the results, farm inundation accounted for the largest area primarily damaged by typhoons with heavy rainfalls. Most property damages to farm lands originated from farm erosion in the alpine regions by localized guerrilla rains. The two major causes of damages to greenhouse and livestock facilities were typhoon with strong wind and winter blizzards. Gangwon was the province of the largest property loss mostly from farm land erosion losses, followed by Gyeongnam, Jeonnam, and Chungnam where losses to greenhouse and livestock facilities were relatively greater. Property loss per unit area was also the greatest for the Gangwon province (4.91 M\/ha), followed by Gyongnam and Chungnam of 2.20 and 1.50 M\/ha, respectively. Unit loss for greenhouse and livestock facilities was 13.3 M\/ha, approximately 13 times greater than that for farm land (1.06 M\/ha). The study findings indicated the importance of reducing highland farm erosion and reinforcing farming facilities structures for agricultural disaster management.

• Proceedings of the KSRS Conference
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• v.1
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• pp.455-458
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• 2006

Stretching on the coastline of 70 km, the Tam Giang - Cau Hai Lagoon plays a very important role for the coastal ecology and socio-economic development of Hue region where was Vietnam's Ancient Kingdom Capital and recognized as a World's Cultural Heritage. Recently, coastal hazard in the lagoon have occurred seriously such as inlet movement and fill up, coastal erosion, flood and inundation, etc. These hazards have impacted on lagoon environment, resources, ecosystems, socio-economic and sustainable development of this coastal area. This paper present a case study using remote sensing data in combination with ground survey for monitoring the coastal hazards in Tam Giang - Cau Hai lagoon in recent decades. Analysis results find that during its natural evolution, the lagoon has been being in three situations of only one, two and three inlets. When inlets opened or displaced, coastal erosion have occurred seriously toward new balance condition. Flood and inundation occurs every rainy season in lowland plain around lagoon. The historical flood happened in early of November 1999 with six days long, created very terrible damages for Thua Thien Hue province. Remote sensing data with capability of regular update, large area coverage is effective provide real-time and continuous information for coastal hazards monitoring.

• Journal of Korea Water Resources Association
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• v.42 no.7
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• pp.571-578
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• 2009

Levee-break Analysis model is developed to predict the variation of breach width according to time and to estimate inundation area and depth in protected lowland. This Model calculate flood depth using 4 point implicit finite difference method in river channel and analyze breach flow based on physical theory introducing soil transport equation and erosion process. Breach analysis model and channel flood model are combined into Levee-Break Model and this model is applied to actual levee break case. Then, this model can simulate reasonably many levee-break parameters such as river stage, breach width, breach formation and so on. If the applicability of this model is proved through applications to more various actual levee-break cases, the suggested model is expected to do more accurate flood analyses on levee break site.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.1
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• pp.56-65
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• 2006

In the past, flooding is commonly occurred in the Bockha stream watershed area with inundation by the water and eroded sediments. The purpose of this study is to find the relationship between area under cultivation and amount of soil erosion in each watershed areas using geographic information system(GIS) for decreasing the damages of flooding. The soil erosion amounts were computed on GIS using by universal soil loss equation(USLE). Small catchment areas was divided by topography and computed soil erosion amounts. The mean amount of soil erosion is 0.03 $ton/ha{\cdot}yr$ on the condition of the 1,329 mm/yr annual precipitation. The high erosion area(0.05 $ton/ha{\cdot}yr$) is shown in farm areas of the Sangyong-ri in Baeksa-myeon. The high erosion watershed area is related on the slopes of the farm lands and bare soil areas adjoining between the mountain slope and fluvial streams show much amount of soil erosion.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.211-211
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• 2015

Mekong River is the world's $10^{th}$ longest river and runs through China's Yunnan province, Burma, Thailand, Laos, Cambodia and Vietnam. And Tonle Sap Lake, the largest fresh water body in Southeast Asia and the heart of Mekong River system, covers an area $2,500-3,000Km^2$ in dry season and $10,000-16,000Km^2$ in wet season. As previously noted, the water within Sap river flows from the Mekong River to Tonle Sap Lake in flood season (between June and October) and backward to Mekong River in dry season. Recently the flow regime of Sap River might be significantly affected by the development of large dams in upstream region of Mekong River. This paper aims at basic study about the large scale flood inundation of Cambodia using by CAESAR-Lisflood. CAESAR-Lisflood is a geomorphologic / Landscape evolution model that combines the Lisflood-FP 2d hydrodynamic flow model (Bates et al, 2010) with the CAESAR geomorphic model to simulate flow hydrograph and erosion/deposition in river catchments and reaches over time scales from hours to 1000's of years. This model is based on the simplified full Saint-Venant Equation so that it can simulate the interacted flow of between Mekong River and Tonle Sap Lake especially focusing on the flow direction change of Sap River by season.

• Journal of the Korean Geosynthetics Society
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• v.14 no.2
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• pp.11-21
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• 2015

According to the damage investigation in 2002, the failures of river levee were caused by overflow, erosion, and unstable body conditions due to piping, inappropriate embanking materials, and poor compaction. Especially, overflow was identified as a main reason that induces levee failure by 39.5% from the distribution of failure types. The major parameters, such as levee collapsing angle (${\theta}$), levee collapsing rate (k) affect inundation velocity and area size during the analysis of inundation modeling, however, domestic research effort on this area is still insufficient. In this paper authors conducted levee failure experiments of 4 levee height types, 0.20 m, 0.25 m, 0.30 m, and 0.40 m based on theassumption of Froude Similarity (${\lambda}_{Fr}=1$). As a result, the authors suggested a levee failure mechanism according to the levee heights (H), a collapse extension lengthwhich is around, levee collapse angle (${\theta}$), levee collapse rate (k).

• Journal of Wetlands Research
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• v.16 no.1
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• pp.93-102
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• 2014

In the flood plain, river facilities such as sports facilities and ecological park are builded up since the late 2000s. The recent increase of rainfall intensity and flood frequency results in the immersions of parks and river facilities located in the flood plain. Therefore it is necessary to perform the numerical analysis for the extreme rain storm in the flood plain. In this study, to analyze the hydraulic impact by lowering and rising of the water level at flood plain, Both the FaSTMECH, which is a quasi-unsteady flow analysis model to be used for simulating the wet and dry, and the Nays2D, which is unsteady flow analysis model, are used in this study. Also, the flow velocity distribution and the inundation are compared over a period of the typhoon. As a result, the flow velocity distribution at flood plain showed very low values compared to the flow rate in the main channel. This means that the problem of sedimentation is more important than that of erosion in the flood plain.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.3
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• pp.53-63
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• 2010

The global sea level rise has an effect on eco-environmental change by the inundation and erosion in the coastal area. Forecasting model on the change of morpho-ecological environments by the sea level change will give us information for coastal area management by predicting environmental changes of the up-coming future. This research aimed to foresee eco-environmental changes by the sea level rise in coastal area. Prediction model used SLAMM model developed to forecast coastal changes by IPCC scenario. The model predicted centennial environmental changes in the mouth of Han river and Nakdong river, Suncheon and Hampyeung bay as case areas. To sum up the research findings, in the estuary of the Han river, tidal flat was gradually disappeared from the year 2075, scrubmarsh and saltmarsh belts were developed. In the Nakdong River estuary, scrubmarsh was decreased from the year 2025, tidal flat was deposited from the year 2050, and also, the Gimhae plain was partially inundated, and wetlands were formed. In the Hampyeung bay, saltmarsh was deposited in the year 2025, tidal flat expanded until 2050 was partially submerged after that time. Tidal flat of Suncheon bay was disappeared by the inundation after 2025, and saltmarsh was developed in the embayment.