• Journal of Korean Society on Water Environment
• /
• v.31 no.2
• /
• pp.110-119
• /
• 2015

The construction of the eight large weirs in the Nakdong River, the second largest river in Korea, caused big changes in the physical environment of the water system. Algal communities and their correlations with environmental factors, mainly nutrients were studied at five weir areas in the Nakdong River from 2010 to 2013. Water quality, hydrodynamics and algal composition were investigated. Results showed that flow velocities were reduced compared with that before weir construction near the areas where are located in the mid and upstreams of the Nakdong River. A seasonal algal community succession was observed and it was mainly correlated with temperature and phosphorus. Diatoms were dominated from winter to spring months and massive diatomic blooms of Stephanodiscus sp. occurred early in March during survey period. Cyanobacterial blooms of Microcystis sp. occurred from July to September 2013 and was preceded by the lower total phosphorus concentration of $0.05mg\;L^{-1}$. The correlations between total phosphorus concentrations and algal abundances were not significant during the survey periods. However, significant correlation with cyanobacteria was found in the period of weir construction after only at the GG survey site and blooms periods of 7 times in the survey sites, and its correlation coefficients were 0.53 (p<0.001) and 0.42 (p<0.01) respectively. When algal bloom was observed, partially low nutrient concentration was observed in the Nakdong River. In conclusion, partially low nutrient concentration which may result from algal bloom was observed, and we presume it caused the reduction of algal abundunces.

• Environmental Engineering Research
• /
• v.23 no.2
• /
• pp.150-158
• /
• 2018

The deteriorating role of Nakdong River due to the Four Major Rivers Project has caused a series of problems, including water pollution, drying streams, aggravation of the hydroecology. Geumho River and Gyeongseong-cheon had a higher concentration index and is believed to impact the water quality of the main stream. The influence index of Geumho River and Nam River between 2015 and 2016, which have a large amount of discharge, was the highest among the tributaries in terms of the load material balance. Showing the highest average concentration and average load in the index assessment, Geumho River is believed to require an intensive management for improving the water quality of the main stream. Furthermore, when the cumulative percentage of the average concentration and average load was compared based on the water quality improvement of the tributaries mixed to Nakdong River, which was set to 60%, Geumho River, Nam River, Topyeong-cheon, and Cha-cheon, which showed the highest ratio in that order, were determined to require a water quality management program as a priority.

• Journal of Environmental Impact Assessment
• /
• v.12 no.4
• /
• pp.259-270
• /
• 2003

To investigate the water quality and the pollution state of lower Yeongsan river system, 38 water samples were taken from the main stream of the Yeongsan river, Gomakwon and Hampyeong streams of the system in dry and flood seasons, May and August, 2001. The Yeongsan river is typically natural in accordance with pH-& diagram. But the chemistry based on Piper's diagram indicates that the river is influenced by seawater. BOD increases as the sampling sites are approaching the downstream in Gomakwon and Hampyeong streams overwhelming WQS V grade of 12.40mg/l. T-N and T-P of the river are mainly loaded not in above branch streams but in the main stream of the river, which are caused by manure for farming, domestic animal discharges and life-sewage, in possible. Meanwhile, heavy metal contents are below WQS or not detect in whole water samples. So, it shows that the above river waters be polluted by not industrial but life/agricultural foul waters.

• Journal of Environmental Science International
• /
• v.5 no.3
• /
• pp.297-316
• /
• 1996

This research emphasizes the necessity of the understanding and cooperation among focal governments to preserve the water quality of the Nak-dong river that runs through four local governments. First, this research considers the status of water-pollution in the Nakdong river, describes and finds problems within the central government's. "Clean Water Supply Plan" and local governments' water quality-related policies. Second, it deals with the conflict among local governments concerning the planning and building of "Wicheon Industrial Complex" in the middle-upstream of the Nakdong river which has triggered the opposition movement of the local governments and residents of the river's downstream area. With stressing the necessity of the understanding and cooperation among local governments, this research emphasizes roles of central government, of academic experts, and of local news-media in preserving the water quality. Key words : the Nakdong river, water quality policy, the conflict among local governments, the activation of local autonomy, Wicheon Industrial Complex, the cooperation among local governments.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.1151-1154
• /
• 2008

The water level data sets among hydrologic observation data are correspond to the hydraulic head for each observation point and determine flow direction. The level difference among reservoir, river, and groundwater determines groundwater flow direction, just like water flows in the downstream direction because the water level of upstream point is higher than that of downstream point. We can analyze the relationship among the components in hydrologic cycle by comparing the water level differences. This research dealt with the data from Nakdong river watershed in Gyungsangnam-Do. Three data group are used for the analysis and onr group is composed of reservoir, river, and groundwater data sets. The data sets are closely(within 10 km) located in the interested area.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2010.05a
• /
• pp.1026-1030
• /
• 2010

The Geum river being used as drinking water sources has contaminated due to inflow of inadequately treated wastewater from the tributaries into the river. The characteristics of water quality in the upper regions showed good grade(BOD<3mg/L) in the Geum river, the Mankyung river and the Dongjin river, while that in the lower regions and the upper region of the Sapkyo river did not achieve the good grade. This resulted in the inflow of domestic, industrial and livestock wastewater not adequately treated by wastewater treatment systems. For lakes, the mouth of the kyungchun lake, the Sapkyo lake and the Yedane lake showed the eutrophication phenaminon with higher COD concentration. In particular, total phosphorus and chlorophyll-a concentration were higher in the Sapkyo lake than other lake.

• Journal of Environmental Science International
• /
• v.27 no.6
• /
• pp.371-381
• /
• 2018

Multifunctional weirs constructed through the Four Major Rivers Restoration Project are operated as management water levels. The purpose of this study was to evaluate the effect of water level in the main stem on the tributary water level according to multifunctional weir operation, because the operation of multifunctional weirs for water level management influences the drainage of tributaries. In this study, water level pressure gauges were installed and spatial and temporal water quality was observed. The LOcally Weighted Scatterplot Smoothing (LOWESS) technique was applied to the Nakdong River and the Baekcheon Junction, both upstream of the Gangjeong-Goryeong weir, in order to analyze water quality trends. When considering the overall analysis and observations, it was found that the water quality forecasting point located at the Baekcheon estuary point should be transferred to the Dosung Bridge, which is located upstream of the Sunwon Bridge.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.67-74
• /
• 2008

The regional-scale transient groundwater-river interaction model is developed to gain a better understanding of the regional-scale relationships and interactions between groundwater and river system and quantify the residual river flow after groundwater abstraction from the aquifers with climate variability in the Waimea Plains, New Zealand. The effect of groundwater abstraction and climate variability on river flows is evaluated by calculating river flows at the downstream area for three different drought years (a 1 in 10 drought year, 1 in 20 drought year, and 1 in 24 drought year) and an average year with metered water abstraction data. The effect of future water demand (50 year projection) on river flows is also evaluated. A significant increase in the occurrence of zero flow, or very low flow of 100 L/sec at the downstream area is predicted due to large groundwater abstraction increase with climate variability. Modeling results shows the necessity of establishing dynamic cutback scenarios of water usage to users over the period of drought conditions considering different climate variability from current allocation limit to reduce the occurrence of low flow conditions at the downstream area.

• Journal of Environmental Science International
• /
• v.7 no.2
• /
• pp.171-176
• /
• 1998

This study was conducted to evaluate water quality utilizing principal component analysis in the Nakdong River Estuary. From the results of analysis, water quality in the Nakdong River Estuary could be explained up to 65.3 Percente by three factors which were Included In river loadlnwastes from the Nakdong River and rainfalls : 39.1%1, sediment resuspension(13.7BS) and metabolism(12.5%). In the eastern part of estuary In flowing the Nakdong River, river loading factor score(factor 1 Pas higher than that In western part. Sediment resuspension factor score(factor 2) was high in shallow water, while metabolism factor score(factor 3) was high in deeper water. For seasonal variations of factors score, factor 1 was h19h- 1y related to rainfall season.

• Journal of Korea Multimedia Society
• /
• v.21 no.12
• /
• pp.1431-1438
• /
• 2018

In this paper, we proposed a river water level detection and tracking of the river or dams based on image processing system. In past, most of the water level detection system used various water sensors. Those water sensors works perfectly but have many drawbacks such as high cost and harsh weather. Water level monitoring system helps in forecasting early river disasters and maintenance of the water body area. However, the early river disaster warning system introduces many conflicting requirements. Surveillance camera based water level detection system depends on either the area of interest from the water body or on optical flow algorithm. This proposed system is focused on water scaling area of a river or dam to detect water level. After the detection of scale area from water body, the proposed algorithm will immediately focus on the digits available on that area. Using the numbers on the scale, water level of the river is predicted. This proposed system is successfully tested on different water bodies to detect the water level area and predicted the water level.