• Journal of Korean Society of Forest Science
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• v.110 no.3
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• pp.419-430
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• 2021

This study investigated spatiotemporal trends of sediment-related disasters in North Korea from 1960 to 2019 and post-disaster recovery cases based on a literature review and satellite images. Results showed that occurrence status of sediment-related disasters was initially externally reported in 1995 (during the Kim Jongil era); their main triggering factor was heavy summer rainfall. Furthermore, forest degradation rate was positively correlated with population density (R² = 0.4347, p = 0.02) and occurrence number of sediment-related disasters was relatively high on the west coast region, where both variables showed high values. This indicates that human activity was a major cause of forest degradation and thus, significantly affected sediment-related disasters in mountain regions. Finally, sediment- related disasters due to shallow landslides, debris flow, and slow-moving landslides were observed in undisturbed forest regions and human-impacted forest regions, including terraced fields, opencast mines, forest roads, and post-wildfire areas, via satellite image analysis. These disaster-hit areas remained mostly abandoned without any recovery works, whereas hillside erosion control work (e.g., treeplanting with terracing) or torrent erosion control work (e.g., check dam, debris flow guide bank) were implemented in certain areas. These findings can provide reference information to expand inter-Korean exchange and cooperation in forest rehabilitation and erosion control works of North Korea.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.1
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• pp.21-30
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• 2017

Soil erosion has been issued in many countries since it causes negative impacts on ecosystem at the receiving water bodies. Therefore best management practices to resolve the problem in a watershed have been developed and implemented. As a prior process, there is a need to define soil erosion level and to identify the area of concern regarding soil erosion so that the practices are effective as they are designed. Universal Soil Loss Equation (USLE) were developed to estimate potential soil erosion and many Geographic Information System (GIS) models employ USLE to estimate soil erosion. Sediment Assessment Tool for Effective Erosion Control (SATEEC) is one of the models, the model provided several opportunities to consider various watershed peculiarities such as breaking of slope length, monthly variation of rainfall, crop growth at agricultural fields, etc. SATEEC is useful to estimate soil erosion, however the model can be implemented with ArcView software that is no longer used or hard to use currently. Therefore SATEEC based on ArcView was rebuild for the ArcGIS software with all modules provided at the previous version. The rebuilt SATEEC, ArcSATEEC, was programmed in ArcPy and works as ArcGIS Toolset and allows considering monthly variations of rainfall and crop growth at any watershed in South-Korea. ArcSATEEC was applied in Daecheong-dam watershed in this study, monthly soil erosion was estimated with monthly rainfall and crop growth variation. Annual soil erosion was computed by summing monthly soil erosion and was compared to the conventional approach to estimate annual soil erosion. The annual soil erosion estimated by the conventional approach and by summing monthly approach did not display much differences, however, ArcSATEEC was capable to provide monthly variation of soil erosion.

• Journal of Korean Society of Forest Science
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• v.108 no.4
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• pp.469-483
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• 2019

North Korea has experienced floods and sediment-related disasters annually since the 1970s due to deforestation. It is of paramount importance that technologies and trends related to forest restoration and soil erosion control engineering be properly understood in a bid to reduce damage from sediment-related disasters in North Korea, and to effect national territorial management following unification. This paper presents a literature review and bibliometric analysis including 146 related articles published in North Korea. First, we analyzed the textual characteristics of the articles. We then employed the VOSviewer software package to classify the research topic and analyzed this topic based on the time change. The results showed that articles on the topic have consistently increased since the 1990s. In addition, research related to soil erosion control engineering has been classified into four subjects in North Korea: (i) assessment of hazard area on soil erosion and soil loss, sediment related-disasters; (ii) hydraulic and hydrologic understanding of forests; (iii) reasonable construction of soil erosion control structures; and (iv) effects and management plan of soil erosion control works. The proportion of research related to the (ii) hydraulic and hydrologic understanding of forests had been significant during the reign of Kim Ilsung. However, the proportion of research related to the (i) assessment of hazard area on soil erosion and soil loss, sediment-related disasters, increased during the reign of Kim Jongil and Kim Jongun. Using these results, our analysis indicated that an interest in and need for soil erosion control engineering in North Korea has continually increased. The results of this study are expected to serve as a basis for preparing forestry cooperation between North and South Korea, and to serve as essential data for better understanding soil erosion control engineering in North Korea.

• Journal of Korean Society of Forest Science
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• v.94 no.4 s.161
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• pp.252-257
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• 2005

The study on long-term change of natural and sediment disasters such as landslides and debris flows is not thoroughgoing enough in spite of increasing of concern for disaster. Therefore, the change of natural and sediment disasters was investigated with the number of victims caused by both disasters and the ratio of sediment disasters for natural disasters was compared. The number of victims by sediment and natural disasters has apparently been decreasing despite of the change of rainfall pattern. The number of victims was changed to 140 persons/year in the late 1990s from 250 persons/year in the 1970s of natural disaster and that of sediment disaster to 20 persons/year in the late 1990s from 60 persons/year in the late 1970s. Furthermore, the ratio of sediment disaster victims to natural disaster victims has decreased from 2/7 in the 1970s to 2/15 after 1980s. But, the system of sediment disaster management and new soil erosion control works tough introduction of watershed management concept are requested because of increased landslide area in recent years (206ha in 1981 $\rightarrow$ 688ha in 1999).

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.238-241
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• 2007

The forest seemed apparently to die on the forest fire area in Honjima, Kagawa Prefecture, Japan. However, the soil that became growing basic of vegetation hardly suffered damage, and the forest recovery was started by the sprout, etc. in the next year. For restoration of forest fire area, the fascine mulching works and log barrier works using the damaged trees were used for the upper-stream, and chack dam and erosion control dam were set up in the downstream. Also, the forest restoration was tried with the plants and the microorganism that inhabit in Honjima to preserve a peculiar forest ecosystem.

• Journal of Wetlands Research
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• v.18 no.1
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• pp.45-57
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• 2016

Levee safety is being evaluated using one of the several failure causes including overtopping, infiltration and erosion or 1D hydraulic analysis considering physical characteristics of levee in practical engineering works. However, mentioned evaluation methods are not able to consider various failure causes of levee at the same time and to get reliable results where requires the accurate topographic information. This study proposed the flood hazard index which is able to consider several hazard factors involving overtopping, infiltration and erosion risk simultaneously. The index was generated from results of 2D hydraulic analysis reflecting accurate topographic information. The study areas are the confluences of the Nakdong River and two streams(Gamcheon and Hoecheon). Levee safety was evaluated using results based on 2D hydraulic analysis considering riverbed changes of before and after dredging work in the study area. This study will contribute to estimate the reliable safety evaluation of levee where may have hazards during extreme flood events.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.483-493
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• 2011

Erosion control dams play a primary role in preventing or controlling natural disasters (landslide and debris flow etc.) and also conserve ecosystem in forested watersheds. This study examines structural characteristics of the dams such as the height of ecosystem control and the ecosystem permeability of the erosion control dams under standard drawings and the existing construction works. The objective of this study was to characterize the type classification of erosion control dams as ecosystem. Average permeability was highest on eco-piller dam (63.0%), followed in increasing order by wire rope (13.9%), silt dam (10.9%), multifunctional dam (7.2%), and gravity dam (0.4%). The height of ecosystem control was highest on gravity dam (3.2 m), followed in increasing order by multifunctional dam (1.7 m), wire rope dam (1.2 m), silt dam (0.6 m), and eco-piller dam (0.0 m). Criteria for defining the height of ecosystem control was indefinite. We grouped erosion control dams into three functional types (eco-connection, eco-semi connection, and eco-disconnection) by considering physical and structural characteristics such as the ecosystem permeability and the height of ecosystem control. The type of eco-connection (permeability > 20%) had connection areas from streambed to adjacent riparian areas, and these connection areas serve as ecosystem corridors for fauna and flora. Typical wildlife species includes mammals, reptiles, amphibians, and fishes. The type of eco-semi connection (5% < permeability < 20%) had < 2 m in the eco-barrier height from streambed, however, this type of dams partially serve as wildlife corridors and often provide fish ways. The type of eco-disconnection (permeability < 5%) had > 2 m in the eco-barrier height from streambed, thereby preventing wildlife movement.

• Journal of Korean Society of Forest Science
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• v.84 no.2
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• pp.239-246
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• 1995

This research aimed at the contribution to obtaining the scientifical data which were required for planning she environmentally sound and sustainable management, particularly in the field of the logging road construction. Main natural environmental variables including natural vegetation, rainfall, soil runoff were measured in the logging road on-sites and analysed. This project was carried out at the (mt.)Paekunsan Research sorest of Seoul National University, located in Gwangyang, Chollanam-do in southern part of Korea, from 1993 to 1994. 1. The explanatory variables for erosion and sedimentation on logging road surface were accumulated rainfall, erosion distance, cross-sectional gradient, and soil hardness. The erosion and sedimentation on logging road was increasing positively in proportion to the accumulated rainfall, soil distance from starting point of the logging road, and cross-sectional gradient. 2. On cut-slope of logging road, cut-slope shape, part of the slope, plant coverage, soil hardness, sand content, accumulated rainfall, clay content, and silt content were effective factors. Cut-slope erosion and sedimentation on logging roam increased as with the lower plant coverage, the lower accumulated rainfall, the high sand content in the soil. 3. On fill-slope of logging road, there were three significant variables such as total rainfall and number of rainfall-storm. Fill-slope erosion and sedimentation had a positive correlation with the amount of rainfall, the number of rainfall, the soil hardness. 4. The total erosion and sedimentation on logging road were $5.04{\times}10^{-2}m^2/m^2$ in logging road construction year, $7.37{\times}10^{-2}m^2/m^2$ in next year. The erosion and sedimentation on logging road surface were 32.7% of total erosion and sedimentation on Logging road in construction year, and 57.1% in next year, respectively. The erosion and sedimentation on cut-slopes were 30.4% on logging road in construction year, fill-slopes of total erosion and sedimentation and 21.0% in next year, respectively. The erosion and sedimentation on fill-slopes were 36.9% on logging road in construction year, 21.9 in next year. To decrease the erosion and sedimentation at the logging road from the beginning stage of construction, the effective revegetation works should be implemented on the cut-slope and fill slopes, and erosion control measures such as optima. road design must be constructed on read surface.

• Journal of Korean Society of Forest Science
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• v.77 no.3
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• pp.276-282
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• 1988

Many landslides occurred at the western part of Gyeongnam province by the typhoon No. 875. Their conditions and causes were investigated and were summarized as follows : The total number of landslide occurred was 2,490 and its area was 156.53ha. In about 94% of landslides and about 97% of landslides area occurred in 3 counties, Sancheong, Hamyang and Geochang. The landslides smaller than 0.01ha was 49% of the total indicating that about half of them were the small landslides. Considering homogenous topography amount of precipitation and forest type landslides appeared to be mainly has a high affected by the geological factor because the landslides mainly occurred in the deep weathered soil of igneous rock. The landslides occured on concave slopes of 31 to $35^{\circ}$ in steepness with low crown density. In the area of the deep weathered soil, landslide likely occur repeatedly. Therefore, regular erosion control works are recommended in the area of pos for disaster prevention and counter-measures.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.2
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• pp.24-34
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• 2000

The project for rehabilitation and revegetation of the abandoned coal-mine lands is a very important national environmental restoration project in the view point of rehabilitation and revegetation of denuded forest-lands caused by coal mining as well as restoration of disturbed natural environment and control of the variable pollutions. In Korea, because a large number of coal mines had been developed in order to fill up abundantly consumption of coal as a major energy source in the developing period, a lot of denuded forest-lands caused by coal mining had distributed in the whole country. And, due to the absence of effective rehabilitation and revegetation works on the denuded forestlands caused by coal-mining, most of them had been remained with being damaged. In 1990, area of the abandoned coal-mine lands, requiring the rehabilitation and revegetation works, was about 1,437.1 ha. For the past ten years ('90~'99), about 1,081.8 ha out of them had been rehabilitated and revegetated, and the rehabilitation planning area was about 33.0 ha in 2000. So, remaining area out of abandoned coal-mine lands will be about 322.3 ha after 2000. In principle, after abandoning coal-mine, mine owners must carry out the rehabilitation and revegetation works on the abandoned mine lands by themselves. But, most of mine owners were in financial difficulty after abandoning coal-mine, so that principle couldn't have obtained the desired effects. To solve this problem, from 1995, Coal Industry Promotion Board (CIPB) have carried out the rehabilitation and revegetation works on the abandoned coal-mine lands at government budgets, and they have obtained good results in the construction area. However, due to application of the "conventional erosion control measures and techniques" to the rehabilitation and revegetation measures on the abandoned coal-mine lands, the results and effects of the works excuted have not been successful. Therefore, unique measures and techniques for rehabilitation and revegetation of the abandoned coal-mine lands will have to be developed, especially including development of new techniques on the soil-dressing and soil-covering, seed spray and hydro-seeding measures with seed-fertilizer-soil materials as the mechanized measures, and using of new materials for the tree planting and seedling measures.