• Journal of Forest and Environmental Science
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• v.7 no.1
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• pp.23-34
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• 1990

Based on the topographical and vegetational indicators on sediment movement of Yongcheon River, the movement occurence years were estimated. 1. The cross sectional shapes of deposits in torrential stream are stepped and even-aged forests tend to be established on each step. 2. Generally the older the forest age is, the higher the height of step from the lowest base tend to become. 3. The ages of trees indicate the year when deposition occured, and so may be useful as plant indicator to get chronological information.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1822-1826
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• 2010

본 연구의 지리정보시스템(GIS)을 이용한 야계의 입지해석모델 개발은 사방댐 하류 야계에 대한 야계사방사업의 위치 선정, 하도계획 및 구조물 계획 등을 기 구축되어 있는 국가 DB와 강우 강도 산정, 홍수유출해석 및 수리계산 소프트웨어를 연계하여 체계적으로 표준화된 시스템을 구축하는 것이 목표이다. 따라서, 본 연구에서는 강우, 지형 지질 토지이용 자료를 이용하여 홍수유출해석을 통해 기본 홍수량을 산정하고, 홍수량과 수치지형도 및 항공사진으로부터 추출한 야계의 종단, 평면 및 횡단지형정보를 기본자료로 HEC-RAS의 지형자료(geometry data) 및 흐름자료(flow data)를 구축하여 수리계산을 수행하였다. 수리계산 결과를 토대로 종단, 평면, 횡단의 하도계획과 호안, 수제 및 하상유지공 등 구조물 계획 등에 필요한 야계입지해석모델을 개발하고자 하였다. 연구결과 강우, 지형 지질 토지이용, 항공사진 자료 등 국가 DB자료만을 이용하여 야계입지를 해석할 수 있는 시스템을 개발하였으며, 1 : 5000의 수치지형도 및 항공사진으로부터 야계부분에 대한 지형도를 분리하여 1m 간격의 등고선으로 된 수치지형도에서 야계의 종단, 평면 및 횡단지형정보를 기본자료로 수리계산을 위한 HEC-RAS의 지형자료(geometry data)를 구축할 수 있음을 제시하였다. 또한 수리계산 결과를 토대로 최심하상고, 수위, 수심, 유속, 소류력, Froude수 등 종단, 평면, 횡단의 하도계획과 호안, 수제 및 하상유지공 등 야계 구조물 계획 등에 필요한 수리학적 인자를 추출할 수 있었으며, 시험유역에 대한 적용 가능성을 검토한 결과 야계사방사업의 입지선정을 위한 수단으로 활용할 수 있음를 제시하였다.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.280-287
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• 1996

This study was carried out to investigate the export rate of suspended sediment by different precipitation intensity after forest road construction for torrential streams on three different watersheds with various forest road density(Watershed A : 6.67m/ha, Watershed B : 5.52m/ha, and Watershed C : control) in the Experimental Forest of Kangwon National University. The results were as follows. 1. Closely related to the the amount of rainfall in both 1994 and 1995, the average streanfkiw rate was less than $0.25{\times}10^4m^3/day$ during May and June and $5.0{\times}10^4m^3/day$ during July and August. More than $25{\times}10^4m^3/day$ of streanflow rate was occurred twice in 1994 and seven times in 1995. 2. The amount of suspended sediment in three watersheds was less than standard of drinking water(25mg/l) before road construction with daily rainfall of 74mm, 92mm, and 120mm in 1994, also after road construction with daily rainfall of 21mm and 47mm in 1995. But, under the 192mm of daily rainfall, Watershed C did not show the difference in the amount of suspended sediment, however, Watershed A and B produced 1,525mg/l and 775mg/l, respectively, which is 61 and 31 fold of stabdard of drinking water, and construction to export for 35 hours after rainfall. 3. The maximum amount of suspended sediment was less than the standard of drinking water with light rainfall before and after road construction. Under the 192mm of daily rainfall, the maximum amounts of suspended sediment in Watershed A and B were 13,150mg/l and 2,690mg/l, of 526 and 108 fold of standard of drinking water, respectively, showing obvious water pollution by sedimentation. Results of the study indicated that the forest road construction had great influence on the sedimentation, and getting increased by higher road density and heavier rainfall. Therefore such practices as vegetation covering and soil erosion control facility should be established accompanying with forest road construction to prevent from sedimentation.

• Journal of Korean Society of Forest Science
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• v.103 no.3
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• pp.392-401
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• 2014

This research was carried out to understand the impact of mountainous torrent on topographical change of slope and sediment volume within a deposit line by dredging of soil erosion control dam. Terrestrial LiDAR surveys were conducted at dredged and non-dredged sites. Terrestrial LiDAR has an advantage on detecting topographical changes easily without demanding workmanship and technical skill for users. The distribution of erodible slope ($20^{\circ}-40^{\circ}$) was higher in non-dredged site than that of dredged site. However, the distribution was higher in dredged site than that of non-dredged site after rainy season. Erosion and deposition appeared regularly in a dredged site, but those occurred irregularly in the non-dredged site. The inflow of soil per square meter was 1.7 times higher in dredged site than that of non-dredged site after rainy season. The difference of rainfall in each site did not affect to soil erosion. The distribution of erodible slope was increased in dredged site than that of non-dredged site after rainy season due to inflow of soil from upper stream caused by dredging.

• Journal of Korean Society of Forest Science
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• v.101 no.4
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• pp.686-694
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• 2012

This study was conducted to investigate that affect benthic macroinvertebrates for installed erosion control works at a mountain torrential stream. The survey was carried out six times from April 2007 to October 2008 at two points where erosion control works were installed and at a control point in the upstream with no such works. Variations in the community structure and cluster of benthic macroinvertebrates and ecological water quality were analyzed in the survey. From the six times survey, the identified benthic macroinvertebrates were 6,922 individuals belonged to 27 species, 24 families, 13 orders, 6 classes and 4 phyla. As the average results of three surveyed sites, the dominant species was Gammarus sobaegensis of Amphipoda. The species diversity index(H') showed the highest as 1.47 at Site 2 of the fourth survey and the lowest as 0.24 at Site 2 of the sixth survey. The evenness Index(EI) showed the highest as 0.823 at Site 2 of the fourth survey and the lowest as 0.194 at Site 1 of the fifth survey. The richness index(RI) showed the highest as 2.794 at Site 1 of the first survey and the lowest as 0.291 at Site 2 of the sixth survey. The ecological score of benthic macroinvertebrate community(ESB) and individual of EPT-group were declined during the survey period. The functional feeding group(FFG) showed the highest SH types during the survey period.

• Journal of Korea Water Resources Association
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• v.54 no.12
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• pp.1285-1294
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• 2021

In recent years, as rainfall is concentrated and rainfall intensity increases worldwide due to climate change, the scale of flood damage is increasing. Rainfall of a previously unobserved magnitude falls, and the rainy season lasts for a long time on record. In particular, these damages are concentrated in ASEAN countries, and at least 20 million people among ASEAN countries are affected by frequent flooding due to recent sea level rise, typhoons and torrential rain. Korea supports the domestic flood warning system to ASEAN countries through various ODA projects, but the communication network is unstable, so there is a limit to the central control method alone. Therefore, in this study, an artificial intelligence-based flood prediction model was developed to develop an observation station that can observe water level and rainfall, and even predict and warn floods at once at one observation station. Training, validation and testing were carried out for 0.5, 1, 2, 3, and 6 hours of lead time using the rainfall and water level observation data in 10-minute units from 2009 to 2020 at Junjukbi-bridge station of Seolma stream. LSTM was applied to artificial intelligence algorithm. As a result of the study, it showed excellent results in model fit and error for all lead time. In the case of a short arrival time due to a small watershed and a large watershed slope such as Seolma stream, a lead time of 1 hour will show very good prediction results. In addition, it is expected that a longer lead time is possible depending on the size and slope of the watershed.

• Journal of Korea Water Resources Association
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• v.49 no.6
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• pp.519-528
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• 2016

Frequently torrential rain is occurred by climate change and urbanization. Urban is formed with road, residential and underground area. Without detailed topographic flooded analysis consideration can take a result which are wrong flooded depth and flooded area. Especially, flood analysis error of population and assets in dense downtown is causing a big problem for establishments and disaster response of flood measures. It can lead to casualties and property damage. Urban flood analysis is divided into sewer flow analysis and surface inundation analysis. Accuracy is very important point of these analysis. In this study, to confirm the effects of the elevation data precision in the process of flooded analysis were studied using 10m DEM, LiDAR data and 1:1,000 digital map. Study area is Dorim-stream basin in the Darim drainage basin, Sinrim 3 drainage basin, Sinrim 4 drainage basin. Flooding simulation through 2010's heavy rain by using XP-SWMM. Result, from 10m DEM, shows wrong flood depth which is more than 1m. In particular, some of the overflow manhole is not seen occurrence. Accordingly, detailed surface data is very important factor and it should be very careful when using the 10m DEM.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.101-109
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• 2008

Automated rainfall warning system is a facility to prevent casualties who were recreating in the down stream region with operating lead broadcasting or signaling warning automatically when torrential rainfall occurs in mountainous area. But standard of conventional warning does not consider the characteristics of basin, and warning signal. Evacuation signal 1 and evacuation signal 2 are uniformly signaled when the 10minute moving total of observed rainfall is higher than 4 mm, 6 mm, and 8 mm respectively. therefore, local governments and relative agencies had re-established the standard of warning by analyzing the risk water level, critical discharge and reference rainfall, which are considering the characteristics of basin. In this study the standard of conventional and re-established warning of weolseong basin, which is available to acquire a real rainfall. There are analyzed by considering the risk water level, critcal discharge and reference rainfall. Also this study compares rainfall of conventional and re-established warning standard and indentifies problems by analyzing adequacy of rainfall estimation for warning and proposes alternative. The standard of conventional warning which investigates with the converted rainfall(unit of a minute) issued too many alarm. The re-established standard upward has the necessity which will be regulated about the alarm announcement number of times. Considers the safety, upward regulation of alarm standard rainfall is a necessity which will be prudent.

• Korean Journal of Environment and Ecology
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• v.2 no.1
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• pp.19-36
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• 1988

To investigate edge vegetation structure and edge species in Chiak Mountain National Park, field survey was executed from July to September, 1988. Canonpy drip-line type, cantilevered type and advancing type of edge vegetation were observed on site. The relative importance values of major species in each crown layer were changed along distance from edge to forest interior differently by aspect and present tree layer vegetation. Especially light-oriented edge species as codominant species were observed in Pinus densiflora forest interior at south slope and moisture - oriented species as codominant species were observed with light-oriented species in north edge beside torrential stream. No. of species and individuals by crown layer, species diversities and dissimilarities were decreased according to the distance from edge to forest interior, and edge depth was estimated as 15-20m. Dominant species of edge in shrub and ground layer were different by altitude and topographic locations; valley, ridge, summit and edge species at summit were not observed at other area. Floristic similarities between edge vegetations at different environments were affected by altitude, aspect and topographic location. Frequency classes of edge species were different by aspect, altitude and topographic location. Weigela subscssilis showed high frequency class in all environment conditions and Quercus mongolica, Lindera obtusiloba, Symplocos chinensis for, pilosa, weigela subscssilis, Fraxinus rhynchophylla, Actinidia arguta, Rubus crategifolius. Pinus densiflora, Aralia elata etc, were observed as edge species at all environmental conditions, respectively.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.412-425
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• 2012

Concrete Soil Erosion Control Dam, which blocks flow of debris flow in torrential stream, are reported to lose expected functions due to structural failure and collapses, caused by poor construction, material deterioration and external impacts. In this paper, an integrity assessment technique for debris barriers was proposed, which allows preliminary detection of problems inherent in debris barriers. The proposed integrity assessment technique is a non-destructive method based on SASW method, one of surface-wave tests. In this paper, a practical procedure and analysis guidelines in applying the SASW technique to debris barrier was proposed and its validity was verified using five decrepit debris barriers older than 20-year old. As a result, the SASW method was validated for the reliable grade evaluation method for concrete soil erosion control dam, and the resulting grades turned out to agree with the results determined by Sabang Associations.