• Title/Summary/Keyword: WATERSHED

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Measurement and Analysis of Low Flow in the Cheonggecheon Watershed (청계천 유역 갈수량 측정 및 분석)

  • Noh, Seong Jin;Kim, Hyeon Jun;Jang, Cheol Hee;Kim, Dong Pil;Hong, Il Pyo
    • Proceedings of the Korea Water Resources Association Conference
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    • 2004.05b
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    • pp.1067-1071
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    • 2004
  • 도시 유역의 물순환 특성을 종합적으로 이해하기 위해서는 갈수량 자료의 구축이 필수적이다. 하지만 지금까지의 인구는 주로 치수분야에 한정되어 대부분의 자료 또한 홍수기에 대해서만 자료가 구축되어 있으며 상대적으로 갈수기에 내한 자료와 관련 연구는 부족한 편이다. 본 연구에서는 청계천 유역의 기존 수문자료를 이용하여 유역의 유출 특성을 분석하고 갈수량을 측정하여 청계천 유역의 물순환 특성을 파악하기 위한 기초자료를 구축하였다. 청계천은 서울의 서북쪽에 위치한 인왕산과 북한산의 남쪽 기슭, 남산의 북쪽 기슭에서 시작하여 서에서 동으로 종로, 세운상가, 동대문 등 서울의 도심부를 흐르는 유로연장 13.75 km, 유역 면적 $50.96 km^2$의 도시하천으로 중량천의 제1지류인 지방2급 하천이며, 정릉친, 성북천을 제1지류, 월곡천을 제2지류로 포함한다. 청계천은 도시화로 인해 1950년대부터 1970년대까지 점차 복개되었다가 2003년 7월부터 5.9 km의 본류구간에 대한 복원공사가 진행 중이다. 청계천은 홍수기 이후 유량이 급격히 줄어 11월 이후에는 다음 홍수기까지 강바닥이 완전히 들어나는 일종의 간헐천으로 홍수기를 제외한 시기의 자료는 전무한 실정이다. 본 연구에서는 유역내 8개의 모니터링 지점을 선정하여 2003년 9월 이후, 월 2회 이상 갈수량 자료를 현장 측정${\cdot}$분석하였다. 청계천 유역은 복원공사 완공 후에는 유역의 물순환 특성이 대폭 바뀔 것이 예상되는 지역으로 본 연구에서 구축된 갈수량 자료는 청계천 유역의 물순환계 변화를 분석하고 건전한 물순환 체계의 유지${\cdot}$관리를 위한 기본 자료가 될 것으로 판단된다., 바늘꽃과, 속새과, 십자화과, 장미과, 사초과, 삼과, 현삼과, 닭의장풀과가 각 1종씩 조사되었으며, 조사지점(II)인 1km지점에서는 15과 26종으로, 벼과가 4종, 마디풀과, 국화과가 3종, 버드나무과, 십자화과, 콩과가 2종씩, 바늘꽃과, 속새과, 자라풀과, 장미과, 사초과, 백합과, 현삼과, 골풀과, 닭의장풀과가 각 1종씩으로, 조사지점( I )보다 좀 더 많은 종이 분포하는 것으로 조사되었다. 또한 어류는 조사지점( I )에서 3회에 걸쳐 총 396개체가 채집되어 3목 8과 21종이었다. 이 중 한국 고유종은 11종이었고, 외래 어종은 검정우럭과 2종이 조사되었으며, Zacco platypus(피라미), Zacco temmincki(갈겨니), Acheilongnathus koreanus(칼납자루), Odontobutis platycephala(동사리), Coreoleuciscus splendidus(쉬리) 순으로 분포하고 있었고, Acheilognathus signifer(묵납자루)는 댐 건설 전에는 많이 분포하였으나 현장조사에서 서식을 확인 할 수 언어 개체수의 큰 감소내지 멸종된 것으로 추정되었다.에서 동시에 시행하였다. 수술 후 1년 내 시행한 심초음파에서 모든 환아에서 단지 경등도 이하의 승모판 폐쇄 부전 소견을 보였다. 수술 후 조기 사망은 없었으며, 합병증으로는 유미흉이 한 명에서 있었다. 술 후 10개월째 허혈성 확장성 심근증이 호전되지 않아 Dor 술식을 시행한 후 사망한 예를 제외한 나머지 6명은 특이 증상 없이 정상 생활 중이다 결론: 좌관상동맥 페동맥이상 기시증은 드물기는 하나, 영유아기에 심근경색 및 허혈성 심근증 또는 선천성 승모판 폐쇄 부전등을 초래하는 심각한 선천성 심질환이다

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A Study on the Simulation of Runoff Hydograph by Using Artificial Neural Network (신경회로망을 이용한 유출수문곡선 모의에 관한 연구)

  • An, Gyeong-Su;Kim, Ju-Hwan
    • Journal of Korea Water Resources Association
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    • v.31 no.1
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    • pp.13-25
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    • 1998
  • It is necessary to develop methodologies for the application of artificial neural network into hydrologic rainfall-runoff process, although there is so much applicability by using the functions of associative memory based on recognition for the relationships between causes and effects and the excellent fitting capacity for the nonlinear phenomenon. In this study, some problems are presented in the application procedures of artificial neural networks and the simulation of runoff hydrograph experiences are reviewed with nonlinear functional approximator by artificial neural network for rainfall-runoff relationships in a watershed. which is regarded as hydrdologic black box model. The neural network models are constructed by organizing input and output patterns with the deserved rainfall and runoff data in Pyoungchang river basin under the assumption that the rainfall data is the input pattern and runoff hydrograph is the output patterns. Analyzed with the results. it is possible to simulate the runoff hydrograph with processing element of artificial neural network with any hydrologic concepts and the weight among processing elements are well-adapted as model parameters with the assumed model structure during learning process. Based upon these results. it is expected that neural network theory can be utilized as an efficient approach to simulate runoff hydrograph and identify the relationship between rainfall and runoff as hydrosystems which is necessary to develop and manage water resources.

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Flood Simulation with the Variation of Runoff Coefficient in Tank Model (탱크모형의 流出孔 乘數 변화를 고려한 홍수모의)

  • Lee, Sang-Ho
    • Journal of Korea Water Resources Association
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    • v.31 no.1
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    • pp.3-12
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    • 1998
  • Rainfall intensity under storms affects peak discharge or its time of occurrence in watershed runoff. Thus, it is reasonable to reflect the effect on the parameters of rainfall-runoff models or the governing equations of the models. This paper relates the change of the runoff coefficient of the first tank in tank model to rainfall intensity under storms. The standard four tanks have made the basic structure of the flood event model. and its modifications are as follows: it has two equal runoff coefficients in the first tank: the runoffs from first and second tanks produce delayed response through a simple delaying parameter. Applying the event simulation model to flood data from Naerinchon. runoff coefficients were estimated and their relation to rainfall intensity was analyzed. The results showed the Weak relation of the two factors. The trend of the two was fitted with the equation a1=kI$. where a1is the runoff coefficient of the first tank: I is rainfall intensity; k and m are fitting coefficients. In the verification. the model used moving averages for the calculation of I(t). If the value I(t) gave more greater value of a1(t) than that of previous time(t-1). the flood simulation was performed again from the beginning with the updated greater value of a1. The reflection of rainfall intensity on the runoff coefficient showed far better results than that of a fixed parameter.

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Characteristics of stormwater runoff from urbanized areas (도시화된 토지이용에서 유출되는 강우유출수의 유출특성분석)

  • Mercado, Jean Margaret R.;Geronimo, Franz Kevin F.;Choi, Jiyeon;Song, Young-Sun;Kim, Lee-Hyung
    • Journal of Wetlands Research
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    • v.14 no.2
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    • pp.159-168
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    • 2012
  • Stormwater runoff affects the quality of surface water and groundwater due to the nonpoint sources (NPSs) of pollutants that it carries during storm events. Typically, urbanized areas experience high pollutant mass emission because of paved roads and other areas which are all highly impervious. For this reason, proper identification of the levels of pollutants from the watershed area is important to pass the Ministry of Environment of the Republic of Korea's water quality standards in rivers and streams. This research was conducted in order to determine and quantify the different constituents present in stormwater runoff generated from highly impervious areas in Cheonan City, Korea. Also, the average event mean concentration (EMC) of stormwater runoff from paved areas was compared with EMCs of other countries to determine the possible causes of its occurrence. In addition, the occurrence of first flush phenomenon was studied in order to find the first flush criteria to be used on the design of best management practices. The results show the pollutant concentration of stormwater runoff was higher than other countries due its landuse and relatively small size of catchment area. During the first 30 minutes of the rainfall events, occurrence of first flush phenomenon was highly evident. Several factors affected the pollutant concentrations in the stormwater such as landuse type, geographic and topographic characteristics,catchment area and amount of rainfall. This research can provide guidance in achieving an effective NPS pollution management applicable to highly urbanized areas in the future.

Development of small constructed wetland for urban and roadside areas (도시 및 도로 조경공간을 활용한 소규모 인공습지 조성 기술)

  • Kang, Chang-Guk;Maniquiz, Marla C.;Son, Young-Gyu;Cho, Hye-Jin;Kim, Lee-Hyung
    • Journal of Wetlands Research
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    • v.13 no.2
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    • pp.231-242
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    • 2011
  • Recently, the green spaces in the urban areas were greatly reduced due to urbanization and industrialization. As urban structures such as roads and buildings are built, the amount of impervious area within a watershed increases. High impervious surfaces are the common causes of high runoff volumes as the soil infiltration capacity decreases and the volume and rate of runoff increase thereby decreasing the groundwater recharge. These effects are causing many environmental problems, such as floods and droughts, climate change, heat island phenomenon, drying streams, etc. Most cities attempted to reduce sewer overflows by separating combined sewers, expanding treatment capacity or storage within the sewer system, or by replacing broken or decaying pipes. However, these practices can be enormously expensive than combined sewer overflows. Therefore, in order to improve these practices, alternative methods should be undertaken. A new approach termed as "Low Impact Development (LID)" technology is currently applied in developed countries around the world. The purpose of this study was to effectively manage runoff by adopting the LID techniques. Small Constructed Wetland(Horizontal Subsurface Flow, HSSF) Pilot-scale reactors were made in which monitoring and experiments were performed to investigate the efficiency of the system in removing pollutants from runoff. Based on the results of the Pilot-plant experiments, TSS, $COD_{Cr}$, TN, TP, Total Pb removal efficiency were 95, 82, 35, 91 and 57%, respectively. Most of the pollutants were reduced after passing the settling tank and the vertical filter media. The results of this study can contribute to the conservation of aquatic ecosystems and restoration of natural water cycle in the urban areas.

Sediments and Design Considerations in the Forebay of Stormwater Wetland (강우유출수 처리목적 인공습지 침강지의 퇴적물 특성 및 설계 적정성에 관한연구)

  • Park, Kisoo;Cheng, Jing;Kim, Youngchul
    • Journal of Wetlands Research
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    • v.14 no.2
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    • pp.223-235
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    • 2012
  • In this paper, field study results about accumulation of sediments and its property in the forebay of wetland aiming at stormwater from rural area wherein intensive cow feeding lots are operated are provided. In addition, some design aspects are discussed. Amount of sediment generation in the longitudinal direction of forebay was found to be affected by hydrological factors such as rainfall depth and intensity. Nutrient contents in the sediments of this wetland were 10 times higher than those in stormwater wetland in rural area without animal-feeding lot. Total-Pb and As contents show similar level to values from the soils of surrounding watershed, but Total-Cu content was higher due to the animal feeding lots. Yearly amount of sediment generation, its depth and volume were estimated to 13tons, 23cm, and $65m^3$. Based on these results and recommended guideline by Korean Ministry of Environment, dredging frequency was found to be about 2.7years. The shape of forebay has to be carefully designed to deal with a great change in flow rate. According to the results of sediment depth analysis, instead of the present rectangular, wedge-shape forebay is more desirable in handling scouring caused by high flows.

Key factors causing the Euryale ferox endangered hydrophyte in Korea and management strategies for conservation (멸종위기 부엽식물 가시연꽃 개체군의 분포, 멸종 원인 key factor에 대한 실험과 보전을 위한 관리전략)

  • You, Young-Han;Kim, Hae-Ran
    • Journal of Wetlands Research
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    • v.12 no.3
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    • pp.49-56
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    • 2010
  • Euryale ferox is only annual hydrophyte among endangered plants in Korea and its seed is high valuable medicinal material. This studies were carried to find out key factors that made E. ferox endanger in Korea and to apply the results for effective management of the natural wetlands inhabited by E. ferox. We investigated the distributed sites reported by previous studies and classified the distribution-affected factors into three categories, eutrophication(hypothesis 1), soil accumulation(hypothesis 2) and increasing of water level(hypothesis 3) in the habitat. These three hypotheses were tested in the field and explained the results with the morphological characteristics of seed germination stages of E. ferox. The geographical distribution ranges of E. ferox diminished at a rate of $1^{\circ}$ latitude with about 10 natural wetlands for last 30 years. Water eutrophication in the wetland had a positive effect on the establishment of E. ferox. But higher in soil accumulation and water depth, then lower in the establishment rate of E. ferox. These results indicate that water depth in the wetland must be below 50cm during the germination season, especially in May and emergent hydrophytes filter zone is need to protect soil accumulation from soil erosion within its watershed for the effective management of wetland with E. ferox.

Characteristics of Stormwater Runoff discharged from vinyl greenhouse growing area in farming area (농촌의 비닐하우스 재배지역에서 배출되는 강우유출수의 특성)

  • Jeon, Je Chan;Lee, Sang Hyeub;Kwon, Koo Ho;Lee, Jea Woon;Kwon, Heun Gag;Min, Kyung Sok
    • Journal of Wetlands Research
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    • v.16 no.4
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    • pp.413-422
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    • 2014
  • In national water quality policy, it changed previous regulation method that focuses on concentration of pollutants in effluent water to the way that regulates total amount of pollutants. The target of water quality in watershed of each river was set up, as the government instituted Total Maximum Daily Loads(TMDL). In order to accomplish successfully TMDL, it requires that the amount of pollutant loads discharged from point and nonpoint pollutant source should be investigated. This study, therefore, conducted the monitoring of the stormwater runoff at field region in farming area. And pollutants loads and unit loads discharged from field region results is calculated. As a result, the concentration of pollutants were calculated as follows: 10.5 BOD mg/L, 19.6 $COD_{Mn}$ mg/L, 4.5 TN mg/L and 2.4 TP mg/L. The unit load of BOD, $COD_{Mn}$, TOC, TSS, TN and TP discharged from field region, also, were determined to $31.8kg/km^2/yr$, $56.7kg/km^2/yr$, $8.5kg/km^2/yr$, $560.9kg/km^2/yr$, $8.3kg/km^2/yr$ and $5.1kg/km^2/yr$, respectively. It was identified that there were some differences of unit loads between the results obtained from this study and previous one. To calculate exact unit loads, therefore, long term monitoring should be conducted.

Development and Cost-effective Evaluation of Grass Blocks Minimizing Construction Waste (건설폐기물을 최소화한 비용 효율적 잔디 블록 기법 개발 및 평가)

  • Jeon, Minsu;Hong, Jungsun;Jeon, Jechan;Kim, Lee-Hyung
    • Journal of Wetlands Research
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    • v.19 no.3
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    • pp.359-365
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    • 2017
  • Impermeable surfaces such as transportation land uses including roads and parking lots accumulate high heavy metals and particulate matters concentration especially during dry season which worsens the river water quality and distort the water circulation system during rainfall events. Recently, the government has been promoting policies to install Low Impact Development (LID) facilities such as permeable pavements or grass blocks in parking lots or pavements. However, transition of asphalt-paved surfaces to permeable pavement generated asphalt wastes which are detrimental to the environment and has cost implications due to its removal and disposal. Therefore this study was conducted to provide a method of constructing a cost-effective permeable pavement to reduce waste generation and cost. In this study, comparative analysis of the water circulation capacity and economic efficiency of the traditional construction method and new method proposed in this study through the lab-scale experiment. The proposed method was to make holes in existing asphalt pavements, layout geotextile fabric and permeable base media such as sand before compaction. After compaction, layout grass blocks on the compacted base media then layout sand in between each grass blocks before compaction. Apparently, there was no significant difference between the traditional installation method of permeable pavement and the proposed method in this study considering surface runoff, infiltrated volume, stored volume, and rainfall-runoff delay time. The proposed method in this study generated 86% less wastes compared to the traditional installation method and has 70% cost reduction considering asphalt removal and disposal. The construction method proposed in this study yielded similar performance compared to the traditional installation method and water circulation effect, but was proven to be less complicated and economical.

Estimation of Distributed Groundwater Recharge in Mihocheon Watershed (미호천 유역의 분포형 지하수 함양량 산정)

  • Chung, Il-Moon;Kim, Nam-Won;Lee, Jeong-Woo;Won, Yoo-Seung
    • Proceedings of the Korea Water Resources Association Conference
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    • 2007.05a
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    • pp.698-701
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    • 2007
  • 지하수 개발가능량 산정을 위한 함양량의 평가는 수문계의 물리적인 형태나 함수층의 수리성 분석 및 수직인 지질분포를 파악하여 어떤 조건하에서 물이 유입 유출되는가를 파악한 후에만 가능하다. 또한 지하수계의 물리적인 형태를 이해함으로써 조사지역의 지표수계나 지하수계의 양계를 통해서 흐르는 물의 양을 결정짓는 물수지 분석이 수행되어야 한다. 이에 따라 강수량, 증발산량, 지하수 유출량, 지표유출량 그리고 하천유출량 등을 수문학적으로 고려해야만 한다. 본 연구는 지표수-지하수 결합모형을 도입하여 분포형 지하수 함양량의 시공간적인 변동성을 파악하는 데 그 목적이 있다. 이를 위해 지표수-지하수 결합모형인 SWAT-K모형을 미호천 유역에 적용하였으며, 지표수의 총유출량과 지하수위의 공간분포자료를 이용하여 검정과 검증을 수행하였다. 전체유역에 대한 연평균 함양량은 수문총량의 약 19%인 것으로 나타났다. 1999년${\sim}$2004년까지의 소유역별 연간 함양량 결과를 월별로 나타냈으며, HRU(Hydrologic Response Unit)별 함양량의 공간분포를 통해 월별, 계절별 특성을 살펴볼 수 있었다. 소유역 모두 강수가 집중하는 7-9월에 걸쳐 많은 함양이 이루어지며 $1{\sim}3$월에는 상대적으로 함양이 적은 것을 볼 수 있다. 월함양량의 경우 최대 약200mm범위내에서 유역의 토지이용 및 토양특성, 경사등에 따라 매우 비균질하게 분포하는 것을 확인할 수 있었다. 이와같은 함양량의 시공간적 불균일성으로 인해 지하수 관리방안은 소유역별 함양특성을 반영해야 할 것으로 판단된다.의 종분산지수가 일반적인 자연대수층에 비해 9.1배 정도 높다는 것을 의미한다. 이는 시험대수층의 투수성이 매우 높아 염소이온의 용질이송이 매우 빠르게 발생되었기 때문이다. 본 연구에서 추정된 종분산지수를 Gelhar et al.(1992)의 연구 결과와 비교 분석한 결과에서도 시험규모에 비해 매우 높은 수리분산이 발생된 것으로 나타났다. 그리고 염소이온의 확산면적을 추정하기 위해, 수렴흐름 추적자시험에 의한 종분산지수와 시험대수층의 평균선형유속을 이용하여 종분산계수를 구하였다. 현장에서 수행된 양수시험에 의한 평균선형유속 22.44 m/day와 평균 종분산지수 0.4155 m를 적용하여 산정된 종분산계수는 $9.32\;m^2/day$이었다. 따라서, 시험부지 내 충적층에서 일정한 양수율$(2,500\;m^3/day)$로 지하수를 개발할 시에 양수정 주변지역으로 유입되는 염소이온의 확산면적은 1일 $9.32\;m^2$ 정도일 것으로 나타났다.적인 $OH{\cdot}$ 의 생성은 ascorbate가 조직손상에 관여할 가능성을 시사하였다.었다. 정확한 예측치를 얻기 위하여 불균질 조직이 조사야에 포함되는 경우 보정이 요구되며, 골반의 경우 골 조직의 보정이 중요한 요인임을 알 수 있었다. 이를 위하여 불균질 조직에 대한 정확한 정보가 요구되며, 이는 CT 영상을 이용하는 것이 크게 도움이 되리라 생각된다.전시 슬러지층과 상등액의 온도차를 측정하여 대사열량의 발생량을 측정하고 슬러지의 활성을 측정할 수 있는 방법을 개발하였다.enin과 Rhaponticin

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