• Korean Journal of Remote Sensing
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• v.30 no.2
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• pp.207-218
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• 2014

The information on the land cover along stream corridor is important for stream restoration and maintenance activities. This study aims to review the different classification methods for mapping the status of stream corridors in Seom River using airborne RGB and CIR digital ortho imagery with a ground pixel resolution of 0.2m. The maximum likelihood classification, minimum distance classification, parallelepiped classification, mahalanobis distance classification algorithms were performed with regard to the improvement methods, the skewed data for training classifiers and filtering technique. From these results follows that, in aerial image classification, Maximum likelihood classification gave results the highest classification accuracy and the CIR image showed comparatively high precision.

• Journal of Ecology and Environment
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• v.39 no.1
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• pp.71-80
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• 2016

The main goal of this study is to develop a multi-metric fishway assessment model (M_m-FA) and evaluate the efficiency of fishway. The M_m-FA model has three major fishway components with nine metrics: structural characteristics, hydraulic/hydrologic features, and biological attributes. The model was developed for diagnosing and assessing fishway efficiency and tested to Juksan Weir at the Yeongsan River Watershed. Structural characteristics of fishway included slope of the fishway (M₁), ratios of fishway width to stream width (M₂), and the proportion of orifice clogging and orifice size (M₃). Hydraulic/hydrologic characteristics included depth of fishway entrance head (M₄), depth of exit tail (M₅), and current velocity of inner fishway (M₆). Biological characteristics included fish species ratio of inner fishway to upper-lower weir (M₇), fish length distribution (M₈), and the proportion of migratory fish species to the total number of species (M₉). Overall, the assessment of fishway efficiency showed the total score of the M_m-FA model was 25 in the Juksan Weir, indicating "good condition" by the criteria of the five-level classification system. The M_m-FA model may be used as a key tool for the assessment of fishway efficiency, especially on the 16 weirs constructed for the "Four Rivers Restoration Project" after a partial calibration of M_m-FA model.

• Korean Journal of Environment and Ecology
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• v.15 no.2
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• pp.104-117
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• 2001

경상북도 낙동상 상류부에 위치한 하천변 식물군락에 대해 식물사회적 조사를 하였다. 그 결과 아래처럼 10군강에 속하는 30군락단위와 상급단위 미결정의 1군락단위를 식별하였다. 특히, 과거에 인위적 영향을 반영하여 쑥군강에 속하는 군집 군락이 가장 많이 출현하였다. A. 관목식물군락-A-1나도버들군장, 버드나무군단: 버드나무-왕버들군집, 버드나무군집, 시무나무군집, 갯버들군집, 눈갯버들군집, 선버들군집, A-2 찔레꽃 군강: 국수나무군락, 구기자나무군락: A-3 상급단위 미결정의 군락: 누리장나무군락; B, 초본식물군락 B-1 가래군강: 노랑어리연꽃군집, 마름군락, B-2 좀개구리밥군강: 좀 개구리밥-개구리밥군랍, B-3 가막사리군강: 고마리군집, 미꾸라지낚시-여뀌군집, 개기장-여뀌군집, B-4 갈대군강; 창포군집, 갈풀-미나리군집, 달뿌리풀군집, 물억새군집, 갈대군락, B-5 쑥군강:물쑥군집, 쑥군락, 물봉선군락, 왕고들빼기-환삼덩굴군집, 칡-환삼덩굴군집, 수크려군랑, B-6 명아주군강: 물피군락, 바랭이군란, 큰개여뀌군락, B-7 억새군강: 억새군락, B-8 질경이군강: 비노리-질경이군락, 이들 식생단위는 거의가 일본의 것과 공통하고 있어 한국에 고유한 하천변 식생은 매우 드물다는 사실을 나타내었다. 한편 하천에는 고유한 군강의 군집, 군락은 하류에서 상류로 감에 따라 양적으로 증가 하였으마, 귀화식물의 수는 그 반대였다. 또, 각 군락과 환경과의 관계, 하천변 식생의 복원생태 및 자연보호 등에 관해 상세히 논하였다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.5
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• pp.533-542
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• 2011

Numerous seagrass habitat restoration projects have been attempted recently due to the remarkable decline in seagrass coverage. Seagrass transplants tend to adapt to a new environment after experiencing transplanting stress during the early stages of transplantation. Once acclimated, the transplants grow into healthy seagrass beds via vegetative propagation. The establishment and growth dynamics of transplanted seagrasses in bays and coasts are widely reported, but few studies have been conducted on estuaries in Korea. We transplanted Zostera marina in November 2007 and November 2008 in the Nakdong estuary using the staple method, and monitored the survival, adaptation, and growth dynamics of the transplants as well as environmental factors every month for 1 year. Both transplants adapted well to the new environment without initial losses and showed rapid productivity during early summer. However, density of transplants increased 320% in 1 year from the previous year's transplants but that decreased to 59% during the following year. This significant reduction in density in the second year may have been caused by exposure to low salinity (10 psu) for 3 weeks during the unusually long monsoon season. While the survival and growth dynamics of seagrass transplants planted in bays and coasts are mainly controlled by underwater photon flux density and water temperature, salinity was the critical factor for those planted in Nakdong estuary.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.935-943
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• 2013

Man-heo-Jeong, which was located in the middle of the Sibri bamboo grove near by Tae-hwa river in Ulsan, was a Jeong-ja(a kind of pavilion) by Park Chui-moon, both a military officer and a nationwide town chief. Now we can presume the appearance of Man-heo-Jeong, referring to the old map describing old Ulsan districts and to old literatures of Park Chui-moon's family describing downtown of Ulsan of that times. It is estimated that the size of Manheo-Jung was constructed three-bay in front view, one point half-bay in side view and terrace in the fore front. Its space composition was designed likewise one-bay was both sides and in the middle there was one-bay Maru called joong-dang-hyeob-sil type. Such a structure made people to enter from the back entrance of gazabo and look the front view dramatically.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.218-218
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• 2011

낙동강은 4대강 살리기 사업에 의해 8개의 보(상주보, 낙단보, 칠곡보, 강정보, 달성보, 합천보, 함안보)가 하천 내에 건설되고 약 4억톤의 준설이 실시되면서 지형적으로 막대한 변화를 맞이하게 된다. 낙동강은 상류의 안동댐 및 임하댐에서 방류수, 중류의 구미 및 대구 등의 오염원 그리고 하류의 남강에 의한 영향 및 낙동강 하구언에 의한 정체에 의한 영향으로 지역적으로 수질 및 수리 특성이 서로 다르게 나타나고 있다. 낙동강에 건설되는 수중보들 또한 이러한 유입 및 경계 조건에 따라 서로 다른 수질특성을 나타낼 것으로 판단되며 이에 대한 영향을 미리 예측하고 발생 가능한 악영향에 대한 대안을 수립하는 것이 중요하다고 본다. 본 연구에서는 낙동강의 4대강 사업에 의한 지점별 및 시기적 영향을 정확하게 분석하기 위해 3차원 수리동역학 모델 EFDC와 수질모델 WASP을 연계하여 사용하였다. 연구대상지역은 안동댐 방류지점에서 낙동강 하구역까지의 총 334km의 지역을 포함하였으며 하천의 폭 방향, 수심방향 및 흐름방향에 대하여 3차원으로 격자를 구성하여 하천을 표현하였다. 수리 및 수질 보정에 필요 한 입력자료는 국토해양부 및 환경부 등에서 발표 된 자료를 이용하였으며 2007년을 기준으로 모의를 실시하였다. 4대강 살리기 사업에 의한 8개의 보 건설 및 낙동강 전역의 준설의 영향을 예측하여 사업 전 및 사업 후로 각각 구분하여 비교하였으며 사업 후 체류시간의 증가와 준설로 인한 수심증가에 따른 복합적인 원인에 의해 수질에 영향이 미치는 것으로 나타났다. 사업 후 낙동강의 각 수중보 출구 부근 지점에서 예측된 수질 특성은 사업전에 비하여 $BOD_5$는 전반적으로 감소하나, TN 및 TP 는 유사한 특성을 나타내었다. 그러나 Chl-a 농도는 상류와 중류에서는 체류시간의 증가로 증가하는 경향을 나타내었으며 이는 수질이 양호한 상류 지역에서 특히 큰 차이를 나타내는 경향으로 분석되었다. 그러나 낙동강 하구언 지역은 Chl-a 농도가 사업에 의해 약간 감소되는 경향을 나타내어 여타 구간과 다른 경향을 나타내었다. 이는 낙동강 하류의 Chl-a 농도가 이미 매우 높은 상태에서 체류시간에 의한 성장 촉진 보다는 수심증가로 인한 광량제한 효과가 더욱 지배적으로 나타난 것에 의한 영향으로 추정된다.

• Journal of Korea Water Resources Association
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• v.33 no.1
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• pp.3-14
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• 2000

The primary objective of this study is to estimate the suitable flow in need for conservation and restoration of the fish habitat in running water ecosystem, which has very important status in the instream flow for stream environment. Year, monthly low flows are estimated to properly maintain the fish habitat. Water depth and velocity are simulated, and also water temperature and Dissolved Oxygen(DO) are predicted at gradually varied flow using estimated low flows. These simulated conditions for each low flow are graphically compared with the requirements to maintain fish habitat at each life stage. These processes were applied to 3 riffle transects located at Dalcheon(Dal stream) in the South Han river. Pirami (Zacco platypus) was selected as a representative fish species in Dalcheon. It was shown that the suitable flow for maintaining the representative fish habitat at each life stage depends on hydraulic conditions rather than water quality conditions, and the flow ranges from the 10-year minimum low flow to consecutive 7-day 2.33-year low flow.w flow.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.373-373
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• 2011

Korean Government has been promoting Four River Restoration Project (i.e., Han, Geum, Nakdong, and Yeongsan rivers) since the second half of 2008. This project is expected to protect against floods and droughts by water resources management. Many researchers have study water resources management, but most studies were focused on direct runoff. However, in order to efficiently protect against floods and droughts, baseflow should be studied as well as direct runoff. Because baseflow has a great effect on streamflow, it needs to be correctly analyzed. For more accurate analysis of baseflow, direct runoff and baseflow from streamflow should be separated first. In this study, 12 flow gauging stations of four major rivers were selected, and flow data from them were obtained (2004-2010) through WAMIS and Web-based SWAT Bflow system (http://www.envsys.co.kr/~swatbflow) which was used to separate direct runoff and baseflow. Baseflow values of Pass 2 in SWAT Bflow system were used. As a result of this study, baseflow contribution was ranged from 23.4% to 68.6% and accounted for about 50% of streamflow. Through this study, it shows that in the case of the flow fluctuation, baseflow is more affected than direct runoff by changes in streamflow in a flood or dry season. Thus, baseflow estimation should not be overlooked for efficient water resources management. However, it has a limitation in this study that because this study used to select randomly 12 flow gauging stations, it did not show a common tendency on each watershed. It is important that flow gauging stations reflected on topographic characteristics of each watershed should be selected in a rigorous manner for further reliable and accurate baseflow estimation on four major rivers.

• Water for future
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• v.9 no.1
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• pp.55-69
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• 1976

The purpose of this paper is to provide basic data for construction methods of leakage pretaction for estuary barrien which is constructed to in take restoration water from irigative use and a river flow in its ultimate dsicharge to ward to sea, The water, accordingly, has reviewed the discrepancis between theories and experiments based on the hydraulic analysis of ground water through a series of sourveys on equi-patential line of seepage flow and a series of some experiments. apparently, however, the research results herein might reflect in some part not more than inference since those experiments are not conducted in a real foundation but from an indoor experiment or calculation, conclusion in brief are itemized here-under. 1. small-scale barrier require cut-off wall, which should reach the complete impereable layer, 2. Duplication barrier is provided effective in protection saline water seepage. 3. a barrier with broad crest might enable protection of massive seepage by fresh water lens formed from precipitation.

• Journal of Korea Water Resources Association
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• v.48 no.12
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• pp.1037-1049
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• 2015

The most of natural disasters that occur in North Korea are flood, typhoon and damage from heavy rain. The damage caused by those disasters since the mid-1990s is aggravating North Korea's economic difficulties every year. By recognizing the seriousness of the damages from the floods, the North Korean government has carried out the river maintenance, farmland restoration, land readjustment and afforestation projects since the last-1990s, but it has failed preventing the damages. In order to estimate the degree of flood risk regarding damage from chronic floods that occur inveterately in North Korea, this research conducted an additional simulation for rainfall-runoff analysis to reflect the characteristics of the ungauged area that make foreign countries hard to obtain the hydrological data and do not open the topographical data to public. In addition, this research estimates the degree of flood risk by selecting the factors of the hazard, exposure and vulnerability by following the standards of the Intergovernmental Panel on Climate Change (IPCC).