• Title/Summary/Keyword: Imha Dam

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Study on the Hygenic Water Quality in Imha Dam (임하댐의 위생학적 수질조사 연구)

  • 이희무
    • Journal of environmental and Sanitary engineering
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    • v.10 no.1
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    • pp.25-34
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    • 1995
  • A Study on environmental Investigation in Imha Dam for the finding the degree of water quality and heavy metals was carried out at 4 sampling station during the period from August 15, 1993 to May 7, 1994. The results were as follows. 1. The ranges of values of pH for water were st. 1-7.56, st.2-7.77, st.3-7.9, st.4-7,7 on the average. Total average of pH values were 7.56-7.9 2. The ranges of values of DO for water were st.1-8.71($mg/{\ell}$), st.2-8.64($mg/{\ell}$), st.3-10. 25($mg/{\ell}$), st.4-9.01($mg/{\ell}$) on the average. Total average of DO of values were 8.64-10.25($mg/{\ell}$). 3. The ranges of values of BOD for water were st.1-1.1($mg/{\ell}$), st.2-1.0($mg/{\ell}$), st.3-0 86($mg/{\ell}$), st.4-0.99($mg/{\ell}$) on the average. Total average of BOD of values were 0.86-1.1($mg/{\ell}$). 4. The ranges of values of COD for water were st.1-1.12($mg/{\ell}$), st.2-1.4($mg/{\ell}$), st.3-0 98($mg/{\ell}$), st.4-1.46($mg/{\ell}$) on the average. Total average of COD of values were 0.98-1.46($mg/{\ell}$). 5, The ranges of values of T- N for water were st.1-0.36($mg/{\ell}$), st.2-0.49($mg/{\ell}$), st.3-0 23($mg/{\ell}$), st.4-0.83($mg/{\ell}$) on the average. Total average of T-N of values were 0.23-0.83($mg/{\ell}$). 6. The ranges of values of T-P for water were st.1-0.053($mg/{\ell}$), st.2-0.06($mg/{\ell}$), st.3-0.02($mg/{\ell}$), st.4-0.07($mg/{\ell}$) on the average. Total average of T-P of values were 0.02-0.07($mg/{\ell}$). 7. In the E. soli group distribution were counted st.1-1130, st.2-1113, st.3-152.3, st.4-1253 by the MPN test. Total distribution of E. soil group were 152.3-1253. 8. The concentration of heavy metals of Cu, Mn, Pb, Zn were measured st.1-0.59, 0.18, 0 04, 74.6( ${\mu}g/{\ell}$), st.2-0.39,0.29,0.03, 54.3(${\mu}g/{\ell}$), st.3-0.1,0.3, ND, 8(${\mu}g/{\ell}$), st.4-0.96, 0 26,0.23,45.6(${\mu}g/{\ell}$) on the average. Cd, Hg, Cr were not detected in the sampling site.

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Assessment of Climate Change Impact on Imha-Dam Watershed Hydrologic Cycle under RCP Scenarios (RCP 기후변화 시나리오에 따른 임하댐 유역의 미래 수문순환 전망)

  • Jang, Sun-Sook;Ahn, So-Ra;Joh, Hyung-Kyung;Kim, Seong-Joon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.18 no.1
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    • pp.156-169
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    • 2015
  • This study was to evaluate the RCP climate change impact on hydrological components in the Imha-Dam watershed using SWAT(Soil and Water Assessment Tool) Model. The model was calibrated for six year(2002~2007) and validated for six year(2008~2013) using daily observed streamflow data at three watershed stations. The overall simulation results for the total released volume at this point appear reasonable by showing that coefficient of determination($R^2$) were 0.70~0.85 and Nash-Sutcliffe model efficiency(NSE) were 0.67-0.82 for streamflow, respectively. For future hydrologic evaluation, the HadGEM3-RA climate data by scenarios of Representative Concentration Pathway(RCP) 4.5 and 8.5 of the Korea Meteorological Administration were adopted. The biased future data were corrected using 34 years(1980~2013, baseline period) of weather data. Precipitation and temperature showed increase of 10.8% and 4.9%, respectively based on the baseline data. The impacts of future climate change on the evapotranspiration, soil moisture, surface runoff, lateral flow, return flow and streamflow showed changes of +11.2%, +1.9%, +10.0%, +12.1%, +18.2%, and +11.2%, respectively.

Quantitative Analysis of Effects on Tree Growth of the Changes in Meteorological Environment around Imha Dam (임하댐 주변지역(周邊地域)의 기상환경(氣象環境) 변화(變化)가 수목생장(樹木生長)에 미치는 영향(影響)에 관한 정량적(定量的) 분석(分析))

  • Shin, Man Yong;Chun, Jung Wha
    • Journal of Korean Society of Forest Science
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    • v.85 no.3
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    • pp.462-471
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    • 1996
  • This study was conducted to investigate the effects of meteorological changes on tree growth due to the reservoir construction. First, climatic normals were estimated before and after the reservoir construction at the area of Imha, through the topoclimatological relationships. Secondly, the amount of meteorological changes was quantified based on the difference analysis of the climatic normals. Thirdly, the diameter increments of Pinus densiflora around Imha area were measured with increment borer. Sample trees were taken on the 6 points of 30m, 100m, 500m, 1km, 3km, and 5km from the reservoir, respectively. Finally, effects of meteorological changes on tree growth were investigated based on the analysis of tree ring increment patterns. Results showed that the growth of trees within the range of 1km from the reservoir had been increased, but the growth of ones out of 1km range had no relationship with meteorological changes after the reservoir construction. It seems that the diameter increment of trees grown near reservoir has been increased mainly due to the increased solar radiation in spring and the increased total amount of precipitation during growing season, compared with those before the reservoir construction. It is supposed, however, that the changes of monthly mean temperature has little effect on the tree growth because of its small amount of changes.

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Study on Precipitation of the Minerals in the Soil of Imha Reservoir Watershed (임하호 유역 토양의 광물학적 침전성 연구)

  • Kim, Yeonjeong;You, Samhwan;Jeong, Hyungjin;Baek, Seungcheol;Lee, Sungmin;Seo, Eulwon
    • Journal of the Korean GEO-environmental Society
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    • v.11 no.4
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    • pp.13-18
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    • 2010
  • The present study was undertaken to investigate the characteristic of suspended matter in soils of Imha-Dam area by turbidity. Soil sampling was conducted at 5 points of Yeongyang (Turbid area) and 2 points of Cheongsong (Clean area). Experimental analysis was conducted using those samples. The pH of water in the soils at turbid area was higher than that of clean area. X-ray diffraction analysis showed that every sample consists in mainly quartz, illite and feldspar before precipitation. After precipitation for 3 days, the content of quartz and feldspar was decreased and the content of illite was increased at turbid area. The soil of Sinheung (St. 6) at clean area was analyzed only illite. SEM-EDS analysis showed the much content of $SiO_2$ as to every sample before precipitation, but $K_2O$, MgO, $Al_2O_3$, CaO and $Fe2O_3$ with illite was increased after precipitation for 3 days as to every sample. Experimental results exhibited that the major mineral of turbid water was illite at turbid area and clean area.

Synthetic Streamflow Generation Using Autoregressive Modeling in the Upper Nakdong River Basin

  • Rubio, Christabel Jane P.;Oh, Kuk-Ryul;Ryu, Jae-H.;Jeong, Sang-Man
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.1
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    • pp.81-88
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    • 2010
  • The analysis and synthesis of various types of hydrologic variables such as precipitation, surface runoff, and discharge are usually required in planning and management of water resources. These hydrologic variables are mostly represented using stochastic models. One of which is the autoregressive model, that gives promising results in time series modeling. This study is an application of this model, which aimed to determine the AR model that best represents the historical monthly streamflow of the two gauging stations, namely Andong Dam and Imha Dam, both located in the upper Nakdong River Basin. AR(3) model was found to be the best model for both gauging stations. Parameters of the determined order of AR model ($\phi_1$, $\phi_2$ and $\phi_3$) were also estimated. Using several diagnostic tests, the efficiency of the determined AR(3) model was tested. These tests indicated the accuracy of the determined AR(3) model.

A Case Study of Spillway Design of Imha Dam (임하댐 비상여수로 설계 사례 소개)

  • Kim, Dong-Min;Kim, Tae-Hyun;Jang, Min-Chul
    • 기술발표회
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    • s.2006
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    • pp.364-371
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    • 2006
  • 최근 기상이변에 따른 이상홍수가 빈번하고, 댐 설계홍수량 설계기준이 가능최대홍수량(PMF)으로 강화되었으며, 최근의 주요 호우사상을 고려하여 산정한 임하댐 유역의 가능최대강수량(P.M.P)이 설계 당시보다 증가됨에 따라 가능최대홍수량(PMF) 유입시 댐 안정성 확보가 필요한 것으로 검토되었다. 따라서, 본 과업은 “댐의 수문학적 안정성검토 및 치수능력증대 기본계획 수립, 2004. 9. 건설교통부/한국수자원공사”에 의거하여, 최근의 태풍 ‘RUSA’(’02) 및 ‘MAEMI’(’03)와 같은 이상호우에 대한 댐 및 여수로의 안정성을 확보함으로써 국민의 생명과 재산을 보호할 수 있도록 비상여수로를 계획하였다. 비상여수로는 수문학적 안정성을 검토한 후, 가능최대홍수량(PMF)과 같은 홍수유입시 댐의 안전을 위하여 신속히 홍수를 배제시킬 수 있는 수리적.구조적인 안정성 확보가 가능하고, 시공성, 경제성 및 환경성 측면을 고려하여 댐우안 300m 지점에 터널규모 D15m${\times}$3련 ${\times}$L1,262m (L1=379m, L2=421m, L3=462m)의 월류형 터널식으로 계획하였다.

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Applicability of Robust Decision Making for a Water Supply Planning under Climate Change Uncertainty (기후변화 불확실성하의 용수공급계획을 위한 로버스트 의사결정의 적용)

  • Kang, Noel;Kim, Young-Oh;Jung, Eun-Sung;Park, Junehyeong
    • Journal of Climate Change Research
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    • v.4 no.1
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    • pp.11-26
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    • 2013
  • This study examined the applicability of robust decision making (RDM) over standard decision making (SDM) by comparing each result of water supply planning under climate change uncertainties for a Korean dam case. RDM determines the rank of alternatives using the regret criterion which derives less fluctuating alternatives under the risk level regardless of scenarios. RDM and SDM methods were applied to assess hypothetic scenarios of water supply planning for the Andong dam and Imha dam basins. After generating various climate change scenarios and six assumed alternatives, the rank of alternatives was estimated by RDM and SDM respectively. As a result, the average difference in the rank of alternatives between RDM and SDM methods is 0.33~1.33 even though the same scenarios and alternatives were used to be ranked by both of RDM and SDM. This study has significance in terms of an attempt to assess a new approach to decision making for responding to climate change uncertainties in Korea. The effectiveness of RDM under more various conditions should be verified in the future.

Application of Benefit Transfer Method to Estimate the Willingness-to-pay in Planning the Construction of the Integrated Sewerage System at the Catchment Areas of Dams (댐상류지역 하수도시설 확충사업에 관한 지불의사액 추정을 위한 편익전환기법의 적용)

  • Jeong, Dong-Hwan;Jin, Young-Sun;Park, Kyoo-Hong
    • Journal of Korean Society of Environmental Engineers
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    • v.28 no.1
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    • pp.74-80
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    • 2006
  • Benefit transfer is a method, which obtains an estimate for the economic valuation of non-marketed commodities at a given site through the analysis of studies that have been previously carried out to value similar commodities at a different location. The objective of this study was to estimate benefit transfer values for the construction of the integrated sewerage system in the catchment area of dams in Korea. For pooled data analysis, five models were suggested in this study. Among five models, model 2 showed only 6 to 7% errors when the willingness-to-pay(WTP) predicted in the policy-site, Dam Soyang was compared with that estimated using contingent valuation method(CVM) in the study-sites, Dams Namgang, Hapcheon, and Daecheong. However, the WTP estimate predicted by model 1 showed the absolute errors of 42 to 47% when it was compared with WTP estimated using CVM in Dams Andong and Imha. It seemed that residents of Dams Andong and Imha have feeling of being victimized since two dams were constructed very adjacently, the upstream area was designated as drinking water source protection zone, and thereafter their developmental economical actions have been significantly restricted.

Improvement of turbid water prediction accuracy using sensor-based monitoring data in Imha Dam reservoir (센서 기반 모니터링 자료를 활용한 임하댐 저수지 탁수 예측 정확도 개선)

  • Kim, Jongmin;Lee, Sang Ung;Kwon, Siyoon;Chung, Se Woong;Kim, Young Do
    • Journal of Korea Water Resources Association
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    • v.55 no.11
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    • pp.931-939
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    • 2022
  • In Korea, about two-thirds of the precipitation is concentrated in the summer season, so the problem of turbidity in the summer flood season varies from year to year. Concentrated rainfall due to abnormal rainfall and extreme weather is on the rise. The inflow of turbidity caused a sudden increase in turbidity in the water, causing a problem of turbidity in the dam reservoir. In particular, in Korea, where rivers and dam reservoirs are used for most of the annual average water consumption, if turbidity problems are prolonged, social and environmental problems such as agriculture, industry, and aquatic ecosystems in downstream areas will occur. In order to cope with such turbidity prediction, research on turbidity modeling is being actively conducted. Flow rate, water temperature, and SS data are required to model turbid water. To this end, the national measurement network measures turbidity by measuring SS in rivers and dam reservoirs, but there is a limitation in that the data resolution is low due to insufficient facilities. However, there is an unmeasured period depending on each dam and weather conditions. As a sensor for measuring turbidity, there are Optical Backscatter Sensor (OBS) and YSI, and a sensor for measuring SS uses equipment such as Laser In-Situ Scattering and Transmissometry (LISST). However, in the case of such a high-tech sensor, there is a limit due to the stability of the equipment. Therefore, there is an unmeasured period through analysis based on the acquired flow rate, water temperature, SS, and turbidity data, so it is necessary to develop a relational expression to calculate the SS used for the input data. In this study, the AEM3D model used in the Water Resources Corporation SURIAN system was used to improve the accuracy of prediction of turbidity through the turbidity-SS relationship developed based on the measurement data near the dam outlet.

Stability Analysis of the Spillway Tunnel Located on the Granite Region Including Fault Fractured Zone (단층파쇄대를 포함한 화강암지역의 여수로 터널 안정성 분석)

  • Han, Kong-Chang;Ryu, Dong-Woo;Kim, Sun-Ki;Bae, Ki-Chung
    • Tunnel and Underground Space
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    • v.18 no.1
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    • pp.58-68
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    • 2008
  • The construction of an emergency spillway of Imha Dam is being in progress on the granite region including fault fractured zone. Considering that this tunnel is being excavated in three paralled rows, the pillar width between each tunnel and the face distance between each tunnel face were evaluated. The Influence of the fault fractured zone for the tunnel stability was investigated by numerical modelling in 3D. Various geophysical investigations and rock engineering field tests were carried out for these purposes. It was suitable that the second tunnel would be excavated in advance, maintaining the face distance between each tunnel face of minimum 25 m. The results of numerical modelling showed that the roof displacement and the convergence of the second tunnel were insignificant, and the maximum bending compressive stress, the maximum shear stress of shotcrete and the maximum axial force of rockbolt were also insignificant. Therefore, it was estimated that the stability of the spillway tunnel was ensured.