• Journal of Environmental Science International
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• v.22 no.2
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• pp.195-203
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• 2013

I investigated the river morphology and river naturality according to the environment of the Hwang River. The numbers of flexions at the upstream regions were more than those of downstream regions. The Hwang River showed very low overall diversity of the flow. Materials of river shore at low channel width were mainly boulders or gravel at the upstream regions, and the middle and downstream were silts and clay. Artificial masonry and natural materials were mixed from materials of river levees. The Hwang River was some of the natural herbaceous vegetation to riparian zones. Land utilities for floodplain were extremely overall farmland were predominant, and partly used by natural vegetation in the forest, a soccer field, some park facilities, residential, and commercial facilities. The water was width sleep / rivers beam ratio of 10 to 20%. Currently estimation for river naturality widely used in rivers were consisted of a narrow wide a variety of items and did not reflect the actual.

• Journal of Environmental Science International
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• v.4 no.3
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• pp.187-196
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• 1995

Phosphorus and nitrogen loadings from the main tributaries into the Nakdong River were estimated by measuring phosphorus and nitrogen concentration in the main tributaries, Nakdong River(Kangjung), Kumho River, Heichun, Hwang River, Nam River, Milyang River, and Yangsanchun from May 1994 to October. Total Phosphorus concenuation of Kumho River was vary high, average 1.0 mgP/1. The other rivers were the range 0.05 ~0.15 mgP/1. Total nitrogen concentration of Kumho River was vary high, average 6.27 mgN/1. The other rivers were the range 1.5~3.0 mgN/l. The phosphorus loading from Kumho River, Nakdong River(Kangjung), Nam River, Milyang River, Hwang River, Yangsanchun, and Heichun were calculated to be 1, 108, 603, 198, 57, 34, 23, and 21 tP/yr, respectively. Therefore, the loading from Kumho River accounted for 45 "yo of total loading, 2, 042 tP/yr, The nitrogen loading from Nakdong River (Kangjung), Kumho River, Nam River, Milyang River, Hwang River, Heichun, and Yangsanchun were calculated to be 12, 636, 7, 411, 2, 611, 1, 523, 779, 608, and 391 tN/yr, respectively. Therefore, the loading from Nakdong River(Kangiung) and Kumho River accounted for 50 % and 30% of total loading, 25, 959 tN/yr, respectively.vely.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.158-158
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• 2022

Ecological drought consequences have received a lot of attention in recent years. Thus, ecological drought was proposed as a new drought category to characterize the impact of drought on ecosystems. The current study used a unique drought index, the standardized supply-demand water index (SSDI), and a run theory to detect ecological drought occurrences and characteristics such as drought-affected area, drought severity, drought duration, drought frequency, and drought orientation in the Hwang River, an environmentally valuable region. Hence, to assess drought-prone areas, the bivariate probability and return period will be calculated using a two-dimensional joint copula. The core results show that (a) the Spatio-temporal characteristics of ecological drought were successfully recognized using the spatial and temporal identification approach; (b) in comparison to the SPEI meteorological drought index, the SSDI is more credible and can more readily and effectively capture the entire properties of ecological drought information; (c) the Hwang river had seen the most severe drought occurrences between the late 1990s and the mid-2020s, with 48.3 percent occurring before the twenty-first century; (d) Severe ecological drought occurrences occurred more frequently in most areas of the Hwang River (e) Only the drought duration and severity in the Hwang area were more responsive to temperature when temperatures rise around 1.1℃, the average drought duration and severity rise around 16 % and 26 %, respectively. This suggested that the Hwang River has been exposed to more severe heat stress in the twenty-first century. Thereupon droughts in the twenty-first century occurred with bigger affected regions, longer durations, higher frequency, and more intensity.

• River and Culture
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• v.5 no.4
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• pp.97-106
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• 2009

• River and Culture
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• v.2 no.1
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• pp.31-35
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• 2006

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.398-405
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• 2022

The research was based on long-term studies on the major physico-chemical and hydrological factors and zooplankton community dynamics in the Hwang River. We had 341 times survey and collected zooplankton samples in the Hwang River of mid-Nakdong River from 1995 to 2013. We identified 97 zooplankton species, including 77 rotifers, 16 cladocerans, and 4 copepods. The total zooplankton abundance and species diversity were shown distinctive temporal variation (ANOVA, p<0.001). Annual average of zooplankton population density was 58.4±3.2 ind L^-1 (n=341) and the lowest was 17.0±3.8 ind L^-1 (1996, n=20), while the highest was 151.5±32.3 ind L^-1 (2010, n=22). For zooplankton, small rotifer groups(e.g., Keratella sp., Brachionus sp., Trichotria sp.) dominated the study site for 19 years survey. Statistical analysis revealed that there were positive relationships with SiO₂ (p=0.002) and water level (p<0.001) for the high abundance of rotifer community. There were considerable variations both the total cladocerans population and the number of cladocerans' species concerning annual precipitation. Despite the appearance of various zooplankton in the Hwang River, the mean population density remained low. Due to the lateral structures in the Nakdong River, the downstream basin of the Hwang River is inevitably affected. The zooplankton community in our study site is considered to be mainly influenced by external factors that can stably increase and maintain the volume of the water body and internal factors that induce an increase in food sources through the inflow of nutrients into the water body.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.5
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• pp.19-29
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• 2012

The purpose of this study is to suggest improvements of Eco-Natural map preparation guideline by presenting assessment methods that can be applied to the result of river ecosystem health survey and assessment, using the Geographic Information System. The area for studying is the main stream of the Hwang River where is easy to collect data and available to compare before and after of river assessment. It was reevaluated by reflecting the result of river ecosystem health assessment of the Ministry of Environment. As the result, Eco-Natural map of the study area reflecting the river assessment, the changes in the area ratio by grade have been increased from 1.14% to 14.03% in the first-grade and from 24.64% to 43.91% in the second-grade. It is considered to present more realistic grade due to the assessment of the rivers that have not been reflected in the meantime. Consequently, the result of this study will be useful for establishing the development projects on the rivers, providing the foundation for more realistic and active protection.

• River and Culture
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• v.5 no.1
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• pp.34-43
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• 2009

• River and Culture
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• v.5 no.1
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• pp.92-95
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• 2009

• Journal of Environmental Science International
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• v.16 no.3
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• pp.333-345
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• 2007

As analyzed the estimated values of the daily delivery loads from thirteen major side streams such as Naesung-river, Keumho-river, Hwang-river, Nam-river during five years (from 1999 to 2003), the daily BOD inflow into the main stream of Nakdong river in 2003 shows the highest quantity as 31.1 ton and the daily BOD inflows in 1999, 2000, 2001, and 2002 are 26.7 ton, 22.5 ton, 21.0 ton, 25.8 ton, respectively. The daily TN in-flow into the main stream of Nakdong river in 2003 shows also the highest quantity as 64.9 ton and the daily TN inflows in 1999, 2000, 2001, and 2002 are 55.19 ton, 46.27 ton, 39.5 ton, 53.38 ton, respectively. The daily TP inflow into the main stream of Nakdong river in 2003 shows the highest quantity as 2.70 ton likewise and the daily TP inflows in 1999, 2000, 2001, and 2002 are 2.17 ton, 1.87 ton, 1.60 ton, 2.10 ton, respectively The rate of BOD loads from each side main stream into the main stream of Nakdong river shows that the BOD loads of Keumho-river are the highest as the values range from 32.8 % (2002) ${\sim}$ 35.1 % (2003) and the BOD loads of Nam-river, Naesung-river, Hwang-river are high in the order named. The rate of TN loads to the main stream is also similar to the trend of BOD loads. The contribution of the TN loads of Geumho-river to the contamination of the main stream is also the highest having a range from 27.0 % (2002) to 28.8 % (1999) among the main side streams and the TN loads of Naesung-river, Nam-river, and Heachun-river are high in the order named. The rate of TP loads is quite different from the trend of BOD and TN loads. The TP rate of Keumho-river, however, is still the highest as ranging 58.6 % (2002) to 61.7 % (2003) and the river has the biggest portion (over 50%) of the entire pollution to the main stream of Nakdong river.