• Proceedings of the Membrane Society of Korea Conference
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• 1997.06a
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• pp.67-92
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• 1997

Tap water should be shown the complexity of measures neccessary to secure water quality, especially with respect to drinking and bathing. Designated reservoirs Paldang and Daechung as the Special Environment Protection Areas to regulate new pollution sources and to facilitate construction of wastewater treatment facilities. In this country, 91% of total drinking water resource, consist of 66% stream water, 25% dam water, 7% dune flitrate, 1% each of spring and ground water, are from the surface water. The total volume of annual mean water resources due to precipitation. Over 8% of the total resources are class III as shown in the table., eapecially the water quality of downstream of Nakdong and Yeongsan river are getting worse due to continued economic and social development.

• Journal of Korea Water Resources Association
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• v.54 no.11
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• pp.985-998
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• 2021

In general, the upstream dam changes downstream flow regime dramatically, i.e., from natural flow regime to hydropeaking flows. This study investigates the impact of the natural flow pattern on downstream fish habitat in a regulated river in Korea using the physical habitat simulation. The study area is a 13.4 km long reach of the Geum-gang River, located downstream from the Yongdam Dam, Korea. A field monitoring revealed that three fish species are dominant, namely Zacco platypus, Coreoleuciscus splendidus, and Opsariichthys bidens, and they account for 70% of the total fish community. Specially, Opsariichthys bidens is an indigenous species in the Geum-gang River. The three fish species are selected as target fish species for the physical habitat simulation. The Nays2D model, a 2D shallow water equation solver, and the HSI (Habitat Suitability Index) model are used for hydraulic and habitat simulations, respectively. To assess the impact of the natural flow pattern, this study uses the annual natural flow regime and hydropeaking flows from the dam. It is found that the natural flow regime increases significantly the Composite Suitability Index (CSI) in the study reach. Then, using the Building Block Approach (BBA), the scenarios for the modifying dam operations are presented in the study reach. Both Scenario 1 and scenario 2 are proposed by using the hydrological method considering both magnitude and duration of the inflow and averaging the inflow over each month, respectively. It is revealed that the natural flow regime embodied in scenario 1 and scenario 2 increases the Weighted Usable Area (WUA) significantly, compared to the hydropeaking flows. In conclusion, the modifying the dam operations by restoring to the natural flow pattern is advantageous to fish community.

• Current Research on Agriculture and Life Sciences
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• v.17
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• pp.31-38
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• 1999

Trend of some hydrologic features such as precipitation, runoff and reservoir storage rates in the five great river systems of Han, Nakdong, Keum, Yeongsan and Seomjin river watershed areas were surveyed and analysed. The sample period of Sept. 1994 to Aug. 1998 (four years) was chracterized by unusual climatic features such as El Nino, La Nina and areal terrible storms. And also average values of rainfall and runoff of the priod of 1961 to 1990 (30 years) were surveyed and analysed compared with the sample preiod events for the same river systems. In case of the monthly mean rainfall of the sample period (Sept. 1994 to Aug. 1998 : 48 months) in the five great river systems, 20 months, 19 months, 20 months, 21 months and 18 months in the Han, Nakdong, Keum, Yeongsan and Seomjin river system respectively were higher than monthly average rainfall records of the 30 year records. For the monthly runoff in the same river systems, 7 months, 9 months, 7 months, 11 months and 11 month in the Han, Nakdong, Keum, Yeongsan and Seomjin river systems respectively were higher than the monthly average runoff of the period of 30 years. For the storage rates, most of the dams in the Han river systems were highly stored through the year continuously and Paldang dam was specially higher than the other dams in the same river system. And most of the dams in the other river systems were stored irregularly but getting much better than early time during the 48 months. And special climatic features were not found during the sample period of 48 months, Sept. 1994 to Aug. 1998.

• Water for future
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• v.16 no.2
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• pp.111-122
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• 1983

The water demand has been rapidly increased by the growth of population, industrialization, unbanization, water pollution and so on. This study carried out the seasonal pre-reserved planning for the five zones, comparing the water demand with the available water resources up to the goal year, 2001. The results of this study are as follows; 1) It is principle that the monthly water demand is supplied by the surface and ground water as the increasing tendency of it, and the deficit of water is supplemented by the water supplying capacity of dam. And water demand should be completely reserved before supplying the deficit of water. 2) The monthly and seasonal maximum deficit of water demand take place in June and summer. 3) The periods when the deficit of water demand exceeds the water supplying capacity of dam are 1984-1990, 1994-2001 in zone III. 4) To reserve the deficit of water demand in zone III, we would like to pre-construct Masan-Keumbo estuary barrage from 2001 to 1991 in Seomjin river basin, the deficit of water demand is supplied by the diversion of water from Yeongsan river basin with the developments of the ground water and small reservoirs until 1986.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.4
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• pp.64-78
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• 2013

To achieve economic efficiency in a basin flood mitigation planning, it is important to determine optimal sizes of investment alternatives. Investment alternative means decision proposals composed with one more individual proposals, and it is not easy to determine an optimal one because there are so many individual proposals. This study aims to propose the approach of determining the optimal project size for raising dam height. This study applies two scenarios to determine investment alternatives for the 4 dams in the Yeongsan River basin. 'Scenario1' calculates flood mitigation for each individual proposal. And 'Scenario2' calculates that for each investment alternative composed with one more individual proposals. As the results, 'Scenario2' is better than 'Scenario1' for selecting a economically optimal dam height considering watershed conditions comprehensively.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.3
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• pp.180-190
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• 2014

It has been customary to exclude top 10-20% of velocity profiles in the Acoustic Doppler Current Profiler (ADCP) measurement due to side lobe effects at the boundary. To better understand the mixing in the Yeongsan estuary, the freshwater advection speed (FAS) was recovered from highly contaminated ADCP data near the surface. The velocity profiles were measured by using ADCP at two stations in the Yeongsan estuary during August 2011: one was located in front of the Yeongsan estuarine dam and the other was deployed near Goha Island. The FAS was recovered from the ADCP data set by applying rigorous post-processing methods and compared with the sediment advection speed (SAS). The SAS was determined by the peak time difference of suspended sediment concentration between two stations in the channel, divided by the distance of two stations. The FAS and the SAS showed very similar value when the freshwater discharge was greater than $2.0{\times}10^7$ ton and the SAS was a bit greater when the freshwater discharge was smaller. Since the FAS was on average about 0.8 m/s greater than the velocity at 0.8 of water depth from the bottom, the net discharge, estimated with recovered FAS and integrated over water depth and tidal cycle, was directed seaward during the high discharge contrary to the onshore direction of the net discharge estimated with 0.8 of water depth from the bottom. Moreover, the velocity shear and Richardson number changed when the FAS was used. Thus, the importance of the true FAS is appreciated in the investigation of the surface layer stability. If currents, temperature and salinity were observed for longer time in the future, it could be possible to more accurately understand the formation and decay of stratification as well as the suspended sediment transport processes.

• Journal of Korea Water Resources Association
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• v.53 no.12
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• pp.1081-1095
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• 2020

This study is to evaluate stream flow and water quality changes of Yeongsan river basin (3,371.4 km2) by inter-basin water transfer (IBWT) from Juam dam of Seomjin river basin using SWAT (Soil and Water Assessment Tool). The SWAT was established using inlet function for IBWT between donor and receiving basins. The SWAT was calibrated and validated with 14 years (2005 ~ 2018) data of 1 stream (MR) and 2 multi-functional weir (SCW, JSW) water level gauging stations, and 3 water quality stations (GJ2, NJ, and HP) including data of IBWT and effluent from wastewater treatment plants of Yeongsan river basin. For streamflow and weir inflows (MR, SCW, and JSW), the coefficient of determination (R2), Nash-Sutcliffe efficiency (NSE), root mean square error (RMSE), and percent bias (PBIAS) were 0.69 ~ 0.81, 0.61 ~ 0.70, 1.34 ~ 2.60 mm/day, and -8.3% ~ +7.6% respectively. In case of water quality, the R2 of SS, T-N, and T-P were 0.69 ~ 0.81, 0.61 ~ 0.70, and 0.54 ~ 0.63 respectively. The Yeongsan river basin average streamflow was 12.0 m3/sec and the average SS, T-N, and T-P were 110.5 mg/L, 4.4 mg/L, 0.18 mg/L respectively. Under the 130% scenario of IBWT amount, the streamflow, SS increased to 12.94 m3/sec (+7.8%), 111.26 mg/L (+0.7%) and the T-N, T-P decreased to 4.17 mg/L (-5.2%), 0.165 mg/L (-8.3%) respectively. Under the 70% scenario of IBWT amount, the streamflow, SS decreased to 11.07 m3/sec (-7.8%), 109.74 mg/L (-0.7%) and the T-N, T-P increased to 4.68 mg/L (+6.4%), 0.199 mg/L (+10.6%) respectively.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.285-292
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• 2019

Our study was based on the long-term surveys with respect to the major reservoirs located in the Yeongsan and Seomjin river basins. A total of 45 survey sites have been surveyed four times a year from 2008 to 2017. We identified 166 zooplankton species, including 127 rotifers, 26 cladocerans, and 13 copepods. Mean population density and species number of small reservoirs were higher than those of mid and large reservoirs. Considering outliers exceeding the 90th percentile between species occupancy and mean abundance, 10 of 11 habitat generalists were rotifers, and Bosmina longirostris was the only cladoceran. Habitat specialist consisted of three species of rotifers and emerged from one to three survey sites. According to the modularity results, it was found that the survey sites covering the entire river basins were characterized into five groups, which was similar to the classification by maximum water surface areas(MWSA). The result of the eigenvector centrality showed that the size of MWSA had a greater impact on the similarity of zooplankton community structure between reservoirs than the difference in distance between reservoirs. In the case of survey points in near dam or estuary bank of Juam and Youngsan reservoirs, modularity class were separated from other internal survey points of those. Given that the zooplankton interactions may contribute to freshwater functions more than species diversity. These topological features provide new insight into studying zooplankton distribution patterns, their organization and impacts on freshwater-associated function.

• Journal of Korea Water Resources Association
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• v.47 no.5
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• pp.491-500
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• 2014

To estimate the severity of streamflow drought, this study introduced the concept of streamflow drought index based on threshold level method and Seomjingang Dam inflow was applied. Threshold levels used in this study are fixed, monthly and daily threshold, The $1^{st}{\sim}3^{rd}$ analysis results of annual drought, the severe hydrological droughts were occurred in 1984, 1988 and 1995 and the drought lasted for a long time. Annual compared to extreme values of total water deficit and duration, the drought occurred in 1984, 1988, 1995 and 2001 was serious level. In the results of study, because a fixed threshold level is not reflect seasonal variability, at least the threshold under seasonal level was required. Threshold levels determined by the monthly and daily were appropriate. The proposed methodology in this study can be used to forecast low-flow and determine reservoirs capacity.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.116-116
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• 2019

2018년 환경부에 따르면, 영산강은 5대강 중 수질이 가장 열악하고 유량이 적어 수질개선이 어려우며 상류에 다목적댐이 없기 때문에 하천유지용수 확보가 어렵다고 보고 하였고, 섬진강은 생태 및 염해 피해 문제와 섬진강 유역의 수자원의 약 81%는 영산강과 동진강 및 남해로 공급되고 있어 이에 따른 용수 배분에 대한 문제가 지속적으로 발생하고 있음을 보고했다. 이와 같은 수량문제는 두 개의 유역환경에 영향을 미치고 유역에 위치한 도시지역들의 갈등 심화 및 두 개의 수계에 대한 미래 수자원 계획과 관리에 있어서 어려움을 가중시킬 것으로 예상되어 영산강과 섬진강수계에 대한 물수지 분석을 통한 물수급 관리가 필요하다. 이에 본 연구에서는 영산강유역 ($3,371.4km^2$)과 섬진강유역($4,896.5km^2$)을 대상으로 SWAT(Soil and Water Assessment Tool)모형을 이용하여 주암댐 도수에 따른 영산강유역과 섬진강유역의 수문 영향을 평가하고자 하였다. 두 개의 유역의 물수지 분석을 위해 각 유역을 표준단위 유역으로 구분 하였고, 기상자료와 섬진강 내 다목적댐 2개(섬진강댐, 주암댐)과 영산강 내 다기능 보 2개(승촌보, 죽산보)의 운영 자료와 국가 수자원관리 종합 정보 시스템(WAMIS)에서 관측 및 관리하고 있는 수문, 기상 자료와 도수의 영향을 파악하기 위해 주암댐에서 방류하는 실제 도수유량 자료를 수집하였다. SWAT 모형의 신뢰성 있는 수문과 수질 보정을 위해 영산강과 섬진강의 소유역 내 위치하는 다목적 댐 2개와 다기능 보 2개의 실측 방류량을 이용하여 댐과 보 운영모의를 하였으며, 댐 운영 자료와 수질 자료를 이용하여 모형의 검정 및 보정(2005~2017)을 실시하였다. 주암댐에서 도수하는 것을 모의하기 위해 영산강에서는 SWAT 모형 내에 있는 Inlet 기능을 이용하여 외부 유량을 유역 내 적용할 수 있도록 유역을 재구축 하여 실제 도수유량자료를 적용하였고 섬진강에서는 매개변수를 이용하여 실제 도수유량 만큼을 제하고 방류 할 수 있도록 설정하여 모의기간(2005~2017)에 대해 주암댐도수에 따른 영산강 유역과 섬진강 유역의 수문 영향 평가를 실시하였다.