• Journal of Korea Water Resources Association
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• v.51 no.5
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• pp.425-438
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• 2018

Existing studies that analyze the causes and effects of water circulation use mostly rainfall - runoff models, which requires much effort in model development, calibration and verification. In this study, hydrological sensitivity analysis which can separate quantitatively the impacts by natural factors and anthropogenic factor was applied to the Hwacheon dam upper basin from 1967 to 2017. As a result of using various variable change point detection methods, 1999 was detected as a statistically significant change point. Especially, based on the hydrological sensitivity analysis using 5 Budyko based functions, it was estimated that the average inflow reduction amount by Imnam dam construction was $1.890\;billion\;m^3/year$. This results in this study was slightly larger than the those by existing researchers due to increase of rainfall and decrease of Hwacheon dam inflow. In future, it was suggested that effective water management measures were needed to resolve theses problems. Especially, it can be suggested that the monthly or seasonal analysis should be performed and also the prediction of discharge for future climate change should be considered to establish resonable measures.

• Journal of Korean Society of Forest Science
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• v.108 no.2
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• pp.241-258
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• 2019

The aim of this study was to analyze the factors that affect the habitat of fishes and amphibians in a mountain stream that is part of an experimental forest at Kongju National University, Gongju, Chungcheongnam, Korea, and examine the differences in the presence of fishes and amphibians in the stream before and after construction of an erosion control dam. The results showed that the factors that affect the presence of fishes are pH, electrical conductivity (EC), dissolved oxygen (DO), flow velocity, and step-pool number, and that the factors that affect the presence of amphibians are monthly rainfall, pH, EC, DO, and crown density. Of these factors, pH, EC, flow velocity, and monthly rainfall were significantly different before and after dam construction; however, the differences among the other three factors from dam construction, except EC, might not have been enough to affect the presence of fishes and amphibians. Our results suggest that the difference in the frequency of fishes and amphibians surveyed before and after dam construction in the upper and lower stream sections were not statistically significant. One exception to this was the presence of amphibians in the lower stream section during and after dam construction, which could have been the result of a large amount of sediment produced by excavation that led to high EC.

• Journal of Korean Society on Water Environment
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• v.35 no.6
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• pp.557-566
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• 2019

Paldang is a river reservoir in the Midwest of Korea, which is a drinking water source for the metropolitan area. Since the Paldang Reservoir is shallow, and has a short hydraulic residence time, its water quality is directly impacted by two incoming rivers, the north Han River (NHR) and the south Han River (SHR). The NHR has different seasonal patterns of water temperature from the SHR because the NHR is greatly impacted by the discharge water from upstream dams. The electrical conductivity (EC) and other material concentrations of the SHR are usually higher than those of the NHR because its basin is limestone-based. The difference in water temperature in the two rivers causes density flow, and the distribution of the EC within the reservoir can be an indicator for monitoring density flow. From the vertical gradient of the EC at the dam site, from spring to fall, it was confirmed that the SHR flowed into the upper layer, and the NHR flowed into the lower layer, and vice versa at other times. The relative difference (RD) of the EC between the upper layer and the lower layer at the dam site was used as an indicator for density flow. The RD of the EC showed a very significant correlation with the RD of total organic carbon (r = 0.70, p < 0.001) and the RD of total nitrogen (r = 0.58, p < 0.01). This relationship is based on the assumption that the difference in electrical conductivity and water quality between the SHR and the NHR is constant. However, in many cases this assumption is inconsistent. Thus, further study is needed on more suitable indicators to evaluate the impact of density flow on water quality.

• 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.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.40-48
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• 2008

The Waimea Basin is located on the northern tip of the South Island of New Zealand. It is a highly productive area with intense water use with multi-stakeholder interest in water. Irrigation from the underground aquifers here makes up the largest portion of used water; however the same aquifers are also the key urban and industrial sources of water. The Waimea/Wairoa Rivers are the main sources of recharge to the underlying aquifers and also feed the costal springs that highly valued by the community and iwi. Due to the location of the main rivers and springs close to the urban centre the water resource system here has high community and aesthetic values. Recent enhanced hydrological modelling work has shown the water resources in this area to be over allocated by 22% for a 1:10 year drought security for maintaining a minimalistic flow of 250 l/s in the lower Waimea River. The current irrigated land area is about 3700 hectares with an additional potential for irrigation of 1500 hectares. Further pressures are also coming on-line with significant population growth in the region. Recent droughts have resulted in significant water use cutbacks and the threat of seawater intrusion in the coastal margins. The Waimea Water Augmentation Committee (WWAC) initiated a three year stage 1 feasibility study in 2004/2005 into the viability of water storage in the upper parts of the catchment for enhancing water availability and its security of supply for consumptive, environmental, community and aesthetic benefits downstream. The project also sought to future proof water supply needs for the Waimea Plains and the surrounding areas for a 50 - 100 year planning horizon. The broad range stage 1 investigation programme has identified the Upper Lee Catchment as being suitable for a storage structure to provide the needs identified and also a possibility for some small scale hydro electricity generation as well. The stage 2 detailed feasibility investigations that are underway now (2007/2008), and to be completed in two years is to provide all details for progressing with the next stage of obtaining necessary permits for construction and commissioning a suitable dam.

• Journal of Forest and Environmental Science
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• v.15 no.1
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• pp.89-97
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• 1999

This study was carried out to obtain basic data on the kinds of aquatic insects and their living conditions in the mountain stream. The investigation was done in Bongmyung stream. Experimental Forest, Kangwon National University on aquatic insects, anions and river-bed materials. The results are as follows. 1. At every plot surveyed, diversity index, richness index and evenness index of aquatic insects appeared higher at upper stream than at lower stream in erosion control dam. 2. Anion concentrations were almost the same in plots A, B, C, D and E, but plot F at the lower stream showed 1.5 to 89 times higher concentration than the others. 3. In river-bed materials analysed, particle diameter was bigger at the upper stream than at the lower stream. At the down stream of erosion control dam showed high pebble composition ratio. 4. The number of aquatic insects showed the negative relation with the anion concentration and the positive one with the size of river-bed materials. Especially, they were affected much by the distribution chart of boulder.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.6
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• pp.723-731
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• 2009

Recently, it has been strangely increasing rainfall and rainfall meter by global warming. so flood damage is being increase. It has happened there are so many damaged by influence by backwater of dam. However, the alleviative solutions of flood damages are focused on the lower river basin where the density of population is higher than upper river basin. This research proceeds based on design and build 3D topography model and reflects the topographical factors of upper river basin. It also simulated the circumstances of flooding by investigation of factors of outflow, hence, as a result, we would find out the vulnerable area for flooding and scale of damages effectively. This research suggests the solution and method of flooding for vulnerable area of the flooding to reduce the damages by predicting flooding. Thus, the suggestion may support to make a decision efficiently to prevent the damage of flooding.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.30-30
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• 2023

This study aims to establish the multi-reservoir operation system model in the Upper Mun River Basin which includes 5 main dams namely, Mun Bon (MB), Lamchae (LC), Lam Takhong (LTK), Lam Phraphoeng (LPP), and Lower Lam Chiengkrai (LLCK) Dams. The knowledge and AI technology were applied aiming to develop innovative prototype for SMART dam-reservoir operation in future. Two different sorts of reservoir operation system model namely, Fuzzy Logic (FL) and Constraint Programming (CP) as well as the development of rainfall and reservoir inflow prediction models using Machine Learning (ML) technique were made to help specify the right amount of daily reservoir releases for the Royal Irrigation Department (RID). The model could also provide the essential information particularly for the Office of National Water Resource of Thailand (ONWR) to determine the short-term and long-term water resource management plan and strengthen water security against flood and drought in this region. The simulated results of base case scenario for reservoir operation in the Upper Mun from 2008 to 2021 indicated that in the same circumstances, FL and CP models could specify the new release schemes to increase the reservoir water storages at the beginning of dry season of approximately 125.25 and 142.20 MCM per year. This means that supplying the agricultural water to farmers in dry season could be well managed. In other words, water scarcity problem could substantially be moderated at some extent in case of incapability to control the expansion of cultivated area size properly. Moreover, using AI technology to determine the new reservoir release schemes plays important role in reducing the actual volume of water shortfall in the basin although the drought situation at LTK and LLCK Dams were still existed in some periods of time. Meanwhile, considering the predicted inflow and hydrologic factors downstream of 5 main dams by FL model and minimizing the flood volume by CP model could ensure that flood risk was considerably minimized as a result of new release schemes.

• Journal of Environmental Health Sciences
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• v.16 no.2
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• pp.83-87
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• 1990

This study was carried out to investigate the pollution of heavy metals in soil of seven stations from the upper spot (Yeungchun Dam) of Kumho River to the downstream(Gangchang Bridge). The results obtained were as follows: 1. The content of heavy metals in soil of Kumho River basin was highest at Gangchang Bridge [expresed in $\mu$g/g : Mn(246.0), Cd(1.90), Fe(551.2), Cu(108.2), Zn(86.4), Cr(80.2), respectively]. Whereas, the content of heavy metals expect for Mn, Cu was lowest at Yeungchun Dam [Cd(0.40), Fe(548.0), Zn(30.7), Cr(6.2), respectively] Also, the content of Cr, Zn was increased when the sampling areas are changed from upstream to downstream except for Hayang Bridge, and Hayang Bridge was the diverging point of the heavy metals content. 2. There were relatively correlated between Mn : FE, Cu, Zn, Cr, Fe : Cu, Zn, Cr(0.40 < $\left$\mid${r}\right$\mid$$ < 0.70), and were high correlated between Cd : Mn, Fe, Cu, Zn, Cu : Zn, Zn : Cr(0.70 < $\left$\mid${r}\right$\mid$$ < 0.90). Particularly, there was higest correlated between Cd : Cr, Cu : Cr(0.90< $\left$\mid${r}\right$\mid$$ < 1.0)

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.851-858
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• 2012

This study conducted a result analysis on operation of 26 Rural Community Sewage Treatment Plant (RCSTP) newly constructed in Yeong-yang, Bong-hwa and An-dong areas which are located at the upper region of An-dong Dam and Im-ha Dam. Based on operation result, an analysis on characteristics of sewage in each area and the treatment efficiency of the installed treatment process was conducted. The result of analysis on characteristics of sewage has shown the difference in concentration of the sewage according to area characteristics. Sewage in areas with frequent occurrence of agricultural water and livestock wastewater had high concentration. It is important to select the most suitable treatment process when selecting a treatment process for RCSTP according to properties of sewage in each area. As a result of operation, the disposal efficiency for organic matter and suspended solids was stable with less fluctuation, but the disposal efficiency for nitrogen and phosphorus showed high fluctuation. This signifies that it is necessary to pay attention to operation condition management of nitrogen and phosphorus when operating RCSTP.