• 대한토목학회논문집
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• 제28권6B호
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• pp.615-625
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• 2008

본 연구에서는 금강유역의 제1지류인 지천과 섬진강유역의 제1지류인 요천에 대해서 하천분류를 실시하고 하도진화모형의 적용성을 검토하였다. Rosgen과 한국건설기술연구원에서 제안된 하천분류방법을 적용하여 하천분류를 수행하였고, Schumm 등 (1984)에 의해서 연구 제안된 하도진화모형 결과를 바탕으로 지천과 요천 연구구간의 하도진화단계를 비교 검토하였다. Rosgen 하천분류 적용결과에 따르면 지천과 요천의 경우, 전체적으로 자갈이 혼재하는 산지하천의 특성을 보이고 있다. 하도진화모형 적용결과 지천 및 요천의 현재 하천상태는 Schumm 등 (1984)에 의해서 제시된 하도진화과정에 따르면 유사공급과 유사이송능력 사이에 평형이 발생하여 동적 평형상태가 이루어지고 있다. 본 연구의 결과는 치수사업의 계획, 하천복원 사업, 바람직한 하도계획 등에 필요한 기초자료를 제공할 것으로 생각된다.

• Ecology and Resilient Infrastructure
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• 제3권4호
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• pp.285-293
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• 2016

본 연구는 원주천을 대상으로 하천시설물의 최적 설계를 위한 안정하도 평가와 물리적 교란개선 평가를 수행하였다. 안정하도 설계를 위한 구간별 안정경사를 분석하였으며, 안정경사를 만족하기 위한 하천시설물의 개선 시나리오를 도출하였다. 그에 따라 각 시나리오에 대한 물리적 교란개선 평가를 통해 안정하도 설계와 물리적 교란개선을 위한 최적의 시나리오를 선정하였다. 아울러 안정하도 설계와 물리적 교란개선을 위한 하천시설물의 개선 시 물리 서식처의 변화를 분석하였다. 원주천의 하천 환경조사와 어류의 군집특성을 이용하여 수중 생태계를 대표할 수 있는 복원 목표어종으로 참갈겨니를 선택하였다. 참갈겨니의 서식적합지수를 사용한 서식적합도 분석은 PHABSIM 모형을 이용하였다. 예측 평가를 수행한 결과 서식적합도와 가중가용면적은 소폭 감소하는 것으로 나타났으나, 하천시설물의 개선에 따른 영향은 아닌 것으로 나타났다. 따라서 원주천의 물리적 건전성과 안정성을 제고할 수 있는 하천시설물의 배치 방안을 제시하였으며, 그에 따른 물리 서식처의 변화는 영향이 없는 것을 확인하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.237-237
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• 2015

The district of Marlborough has had more than its share of river management projects over the past 150 years, each one uniquely affecting the geomorphology and flood hazard of the Wairau Plains. A major early project was to block the Opawa distributary channel at Conders Bend. The Opawa distributary channel took a third and more of Wairau River floodwaters and was a major increasing threat to Blenheim. The blocking of the Opawa required the Wairau and Lower Wairau rivers to carry greater flood flows more often. Consequently the Lower Wairau River was breaking out of its stopbanks approximately every seven years. The idea of diverting flood waters at Tuamarina by providing a direct diversion to the sea through the beach ridges was conceptualised back around the 1920s however, limits on resources and machinery meant the mission of excavating this diversion didn't become feasible until the 1960s. In 1964 a 10 m wide pilot channel was cut from the sea to Tuamarina with an initial capacity of $700m^3/s$. It was expected that floods would eventually scour this 'Wairau Diversion' to its design channel width of 150 m. This did take many more years than initially thought but after approximately 50 years with a little mechanical assistance the Wairau Diversion reached an adequate capacity. Using the power of the river to erode the channel out to its design width and depth was a brilliant idea that saved many thousands of dollars in construction costs and it is somewhat ironic that it is that very same concept that is now being used to deal with the aggradation problem that the Wairau Diversion has caused. The introduction of the Wairau Diversion did provide some flood relief to the lower reaches of the river but unfortunately as the Diversion channel was eroding and enlarging the Lower Wairau River was aggrading and reducing in capacity due to its inability to pass its sediment load with reduced flood flows. It is estimated that approximately $2,000,000m^3$ of sediment was deposited on the bed of the Lower Wairau River in the time between the Diversion's introduction in 1964 and 2010, raising the Lower Wairau's bed upwards of 1.5m in some locations. A numerical morphological model (MIKE-11 ST) was used to assess a number of options which led to the decision and resource consent to construct an erodible (fuse plug) bank at the head of the Wairau Diversion to divert more frequent scouring-flows ($+400m^3/s$)down the Lower Wairau River. Full control gates were ruled out on the grounds of expense. The initial construction of the erodible bank followed in late 2009 with the bank's level at the fuse location set to overtop and begin washing out at a combined Wairau flow of $1,400m^3/s$ which avoids berm flooding in the Lower Wairau. In the three years since the erodible bank was first constructed the Wairau River has sustained 14 events with recorded flows at Tuamarina above $1,000m^3/s$ and three of events in excess of $2,500m^3/s$. These freshes and floods have resulted in washout and rebuild of the erodible bank eight times with a combined rebuild expenditure of $80,000. Marlborough District Council's Rivers & Drainage Department maintains a regular monitoring program for the bed of the Lower Wairau River, which consists of recurrently surveying a series of standard cross sections and estimating the mean bed level (MBL) at each section as well as an overall MBL change over time. A survey was carried out just prior to the installation of the erodible bank and another survey was carried out earlier this year. The results from this latest survey show for the first time since construction of the Wairau Diversion the Lower Wairau River is enlarging. It is estimated that the entire bed of the Lower Wairau has eroded down by an overall average of 60 mm since the introduction of the erodible bank which equates to a total volume of $260,000m^3$. At a cost of $$0.30/m^3$ this represents excellent value compared to mechanical dredging which would likely be in excess of $$10/m^3$. This confirms that the idea of using the river to enlarge the channel is again working for the Wairau River system and that in time nature's "excavator" will provide a channel capacity that will continue to meet design requirements.

• Journal of Forest and Environmental Science
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• 제13권1호
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• pp.81-89
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• 1997

도시하천(都市河川)은 인간활동(人間活動)에 의해 주변 환경이 민감하게 변화하므로 지속적인 관찰이 필요하다. 이 연구에서는 인간활동이 도시하천(都市河川)에 미치는 영향을 파악하고자 춘천시(春川市) 태백천(太白川)을 대상으로 1993년 6월 부터 1996년 6월까지, 4개년간 5회에 걸쳐 구간별 하상(河床)의 횡단형상(橫斷形狀), 변동량(變動量) 및 편의도(偏倚度)를 분석하였다. 연구결과, 1. 횡단형상(橫斷形狀) 변화(變化)는 조사시기 별로는 1996년 6월이 가장 크게 나타났으며, 구간별로는 측선 19~20구간에서 최대(最大) 퇴적량(堆積量) $1.247m^3$, 측선 6~7구간에서 최대(最大) 세굴량(洗掘量) $340m^34가 각각 발생하였고, 2. 1993년 6월 하상면(河床面)을 기준으로 하면 1996년 6월에는 하상(河床)이 전체적으로 상승하여 약 $4.660m^3$이 퇴적(堆積)되었으며, 3. 유로편의도(流路偏倚度)는 시기별로는 1996년, 측선별로는 6, 7, 15, 16, 17, 18, 19, 20을 중심으로 발생하였다.

• 한국수자원학회논문집
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• 제45권5호
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• pp.445-454
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• 2012

본 연구는 상류역에 댐이 존재하지 않는 충적하천에서 과거 이치수 위주의 하천정비사업이 하도지형의 장기적인 변화에 미치는 영향과 그원인을 유사계의 관점에서 파악하는 것을 목적으로 하였다. 영산강 유역의 지석천 중하류역을 대상으로 하도선형, 사주형태와 식생활착율 등의 하도의 평면형상 변화를 분석하고, 하상재료 및 하상변동 조사를 실시하였다. 자연적인 충적하천 당시(1966년)와 제방과 저수로, 취수보 건설 등의 하천정비사업으로 변모된 최근(2002년)의 항공사진의 비교분석결과, 유로형태의 변화(단일사행에서 다지형화), 하도선형의 만곡도 감소(9.2%), 지천사주의 확장, 그리고 사주의 식생활착(97%) 현상이 발견되었다. 이와 같은 하도의 주수로 고정화와 사주내 식생이입은 댐하류 조절하천에서 나타나는 대표적인 평면 하도특성으로, 대상구간에서도 댐하류역과 유사한 유황의 변화 또는 유사량 감소가 영향을 미치고 있음을 추정할 수 있다. 유황변동 조사결과, 비록 댐하류 하천에서 나타나는 연간 수위변동의 균일성은 보이지 않았지만, 과거에 비해 홍수빈도와 규모가 감소하였다. 하상재료의 입경은 4~5배정도 조립화 되었고, 하상변동 조사결과 전체적으로 하상저하가 발생하였으나 지천합류부에서 국부적인 하상상승을 보였다. 이러한 결과들은 비록 댐으로 조절되지 않는 충적하천에서도, 하도내의 하천정비사업으로 인하여 유사 공급량의 감소, 지천과 본류간의 유사이동능력의 불균형, 그리고 하도내 지형형성 과정의 저하 등과 같은 유사계의 인위적인 교란이, 장기적으로 댐하류 조절하천과 유사한 하도의 평면하도 형상의 변화를 유발하고 있음을 의미한다.

• 한국지형학회지
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• 제27권1호
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• pp.1-19
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• 2020

A river bed which is submerged in water at high flow and becomes part of the river at low flow, serves as a bridge between the river and the land. The channel bar creates a unique ecosystem with vegetation adapted to the particular environment and the water pool forms a wetland that plays a very important role in the environment. To evaluate anthropogenic impacts on the river bed in the Middle Yeongsangang River, the fluvial landforms in the stream channel were analyzed using multi-temporal remotely-sensed images. In the aerial photograph of 2005 taken before the construction of the large weirs, oxbow lakes, mid-channel bars, point bars, and natural wetlands between the artificial levees were identified. Multiple bars divided the flow of stream water to cause the braided pattern in a particular section. After the construction of the Seungchon weir, aerial photographs of 2013 and 2015 revealed that most of the fluvial landforms disappeared due to the dredging of its riverbed and water level control(maintenance at 7.5El.m). Sentinel-2 images were analyzed to identify differences between before and after the opening of weir gate. Change detection was performed with the near infrared and shortwave infrared spectral bands to effectively distinguish water surfaces from land. As a result, water surface area of the main stream of the Yeongsangang River decreased by 40% from 1.144km² to 0.692km². A large mid-channel bar that has been deposited upstream of the weir was exposed during low water levels, which shows the obvious influence of weir on the river bed. Newly formed unvegetated point bars that were deposited on the inside of a meander bend were identified from the remotely sensed images. As the maintenance period of the weir gate opening was extended, various habitats were created by creating pools and riffles around the channel bars. Considering the ecological and hydrological functions of the river bed, it is expected that the increase in bar areas through weir gate opening will reduce the artificial interference effect of the weir.

• 대한공간정보학회지
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• 제16권3호
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• pp.105-110
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• 2008

하천의 수리/수문 모델링에 활용하는 하천 지형자료는 하천정비기본계획을 위한 횡단측량을 통하여 취득된 하천단면 자료를 활용하고 있으나 취득되는 단면간의 거리가 다소 커 모델링 과정 중 보다 조밀한 간격의 단면형상을 필요로 하는 경우에도 단면자료를 취득할 수 없을 뿐만 아니라 관측점간의 직선거리를 고려하는 보간기법들의 특성에 의하여 현실적인 하천의 형상을 반영하지 못하는 문제점이 있다. 본 연구에서는 대표적인 수체부 하천 지형자료라 할 수 있는 하천정비기본계획상의 하천단면자료를 이용하여 하천의 형상을 효율적으로 추정하고자 하였으며 관측된 하천단면자료들 사이의 임의 단면을 생성하는 알고리즘을 제시함으로써 GIS 자료를 이용한 수리/수문 모델링에서 쉽게 활용이 가능하도록 하였다.

• 자원환경지질
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• 제27권6호
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• pp.579-592
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• 1994

A case study is presented where a fluvial system is modeled in three dimensions and compared to data gathered from a study of the Arkansas River. The data is unique in that it documents changes that affected a straight channel that was excavated within the river by the U.S. Army Corps of Engineers. Excavation plan maps and sequential aerial photographs show that the channel underwent massive deposition and channel migration as it returned to a more natural, meandering path. These records illustrate that stability of fluvial system can be disrupted either by catastrophic events such as floods or by subtle events such as the altering of a stream's equilibrium base level or sediment load. SEDSIM, Stanford's Sedimentary Basin Simulation Model, is modified and used to model the Arkansas River and the geologic processes that changed in response to changing hydraulic and geologic parameters resulting from the excavation of the channel. Geologic parameters such as fluid and sediment discharge, velocity, transport capacity, and sediment load are input into the model. These parameters regulate the frequency distribution and sizes of sediment grains that are eroded, transported and deposited. The experiments compare favorably with field data, recreating similar patterns of fluid flow and sedimentation. Therefore, simulations provide insight for understanding and spatial distribution of sediment bodies in fluvial deposits and the internal sedimentary structure of fluvial reservoirs. These techniques of graphic simulation can be contributed to support the development of the new design criteria compatible with natural stream processes, espacially drainage problem to minimize environmental disruption.

• 한국환경과학회지
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• 제16권4호
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• pp.495-503
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• 2007

In this study, we took the geometrical character of the river channel junction and hydrologic conditions as independent variables, and hydraulic behavior characteristics as an independent variable. The result, after multiple analysis was carried out, proved that, except for the generating area of the accelerating zone of velocity the accelerating zone and both the main channel and the tributary zone of stagnation the stagnation zone, there was correlation of over 90%. Also, derived presumed expression of the hydraulic characteristics of the junction was applied to the real natural channel - the river channel of the Guem-ho main channel(the A-yang bridge to the Guem-ho bridge). As the result, it proved that it represented hydraulic characteristics relatively well.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.354-355
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• 2005