• Journal of Environmental Science International
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• v.12 no.3
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• pp.287-297
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• 2003

To investigate water quality and pollution states of rivers in Gwangju city, total of 30 water samples were taken from the main stream of Yeongsan river, Hwangryong river and Gwangju stream in dry and flood seasons. Physico-chemical characteristics of above streams according to pH-Eh and Piper's diagrams we, typically, assigned to natural river water. In the streams, BOD, COD, T-N and T-P indicating water quality mostly increase toward downstream. Notably, water qualities in area near connection between the Gwangju stream and the main stream of Yeongsan river are polluted over V level in rivers and lakes water quality standard. The pollutions are influenced by lift and agricultural foul waters from Gwangju City and farming areas around upstream branches of the Yeongsan river, reasonably. Besides, heavy metals are below the standard in those streams. So, it is considered that the streams are polluted by not industrial but life/agricultural foul waters.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.2
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• pp.81-95
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• 2022

The present study was performed to investigate the effects of NH₃-N and nitrifying microorganisms on the increased BOD of downstream of the Yeongsan river in Gwangju. Water samples were collected periodically from the 13 sampling sites of rivers from April to October 2021 to monitor water qualities. In addition, the trends of nitrogenous biochemical oxygen demand (NBOD) and microbial clusters were analyzed by adding different NH₃-N concentrations to the water samples. The monitoring results showed that NH₃-N concentration in the Yeongsan river was 22 times increased after the inflow of discharged water from the Gwangju 1st public sewage treatment plant (G-1-PSTP). Increased NH₃-N elevated NBOD levels through the nitrification process in the river, consequently, it would attribute to the increase of BOD in the Yeongsan river. Meanwhile, there was no proportional relation between NBOD and NH₃-N concentrations. However, there was a significant difference in NBOD occurrence by sampling sites. Specifically, when 5 mg/L NH₃-N was added, NBOD of the river sample showed 2-4 times higher values after the inflow of discharged water from G-1-PSTP. Therefore, it could be thought other factors such as microorganisms influence the elevated NBOD levels. Through next-generation sequencing analysis, nitrifying microorganisms such as Nitrosomonas, Nitroga, and Nitrospira (Genus) were detected in rivers samples, especially, the proportion of them was the highest in river samples after the inflow of discharged water from G-1-PSTP. These results indicated the effects of nitrifying microorganisms and NH₃-N concentrations as important limiting factors on the increased NBOD levels in the rivers. Taken together, comprehensive strategies are needed not only to reduce the NH₃-N concentration of discharged water but also to control discharged nitrifying microorganisms to effectively reduce the NBOD levels in the downstream of the Yeongsan river where discharged water from G-1-PSTP flows.

• KIEAE Journal
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• v.6 no.3
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• pp.19-26
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• 2006

The word "soundscape" proposed by Canadian composer R. Murray Schafer is now became very popular. So various soundscape design based on soundscape idea are carried on worldwide for acoustic ecology. Also in Korea, several soundscape design were made for the public spaces such as river, park and bridge but, basic concept behind soundscape design was not reflected and studied sufficiently. In that sense, this study aims to arrange the concept of soundscape design process and to review the design proposals of Gwangju River. In this process, the reproduction concept of soundscape, natural sound, light with sound, cultural and historical sound and etc. were classified and the final design was proposed to recover the natural environment and harmonize the sound with surroundings as creative soundscape.

• Journal of the Korean Solar Energy Society
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• v.25 no.4
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• pp.111-118
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• 2005

The purpose of this study is to address the progress of the heat island phenomenon and the scheme to decrease in heat island phenomenon through analysis of micro-climates according to land use and make a plan to construct wind ways. The result is: 1) Analysis of temperature and humidity at 6 spots for 24 hours showed that heat island phenomenon was considerably intense around center road of Gwangju and can be mild through making lakes and green zones. 2) Analysis of the direction and velocity of the wind at 2 spots for 24 hours showed that the direction of the wind at the center of Gwangju was SSW(South-South-West) and average velocity of the it was $1.2{\sim}1.5\;m/s$. To make the inflow of the low-temperature air current from Mt. Mudeung into the city through Gwangju river, efficient management of Gwangju riverside parks should be considered for Gwangju river itself to be wind way. 3) Analysis of mobile temperature measurement on 3 courses for 24 hours showed that the low-temperature air current of Mt. Mudeung and a micro-climate of Gwangju river can lighten thermal storage phenomena of the city in that the temperature was lowest at Gwangju riverside. These outcome is from a day term measurement. So, to figure out accurate condition of heat island phenomenon in Gwangju City, it is needed to have long term measurements and accumulation of those information.

• Korean Journal of Ecology and Environment
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• v.45 no.1
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• pp.42-51
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• 2012

This study investigated the characteristics of natural organic matter (NOM) with general water characteristics (pH, DO, electrical conductivity, BOD, COD, TN, TP, Chl-$a$, DOC, $UV_{254}$, SUVA) and the 3D fluorescence excitation-emission matrix (FEEM) in the Yeongsan River basin. FEEM was used to classify protein-like and fulvic & humiclike substances with fluorescence intensity in the matrix of excitation and emission wavelength. The concentration of BOD, COD, TN, electrical conductivity and DOC in the region of Gwangju city (Gwangju sewage treatment plant: GJS, Gwangjucheon: GJC, Gwangju 2: GJ2) was relatively higher than the upper reaches and lower reaches of the Yeongsan River basin. SUVA in most sites was lower than 3 L $mg^{-1}\;m^{-1}$ as the hydrophilic substances, except Damyang (DY) in the upper reaches of Yeongsan river was higher than 3 L $mg^{-1}\;m^{-1}$ as the hydrophobic substances during winter and autumn. In the FEEM investigation the fulvic and humic substances were found in most sites, and in sites regarding Gwangju city (GJS, GJC, GJ2) during winter and GJC in summer, protein-like substances were found. The trend of fluorescence intensities from the upper reaches to the lower reaches in most sites corresponded to that regarding the concentration of water characteristics (BOD, COD, TN, DOC). That is why the region of Gwangju city (GJS, GJC, GJ2) was relatively higher. This results were an equivalent trend to those of fluorescence index (FI) in most sites, and the higher FIs in the sites of Gwangju city indicate more microbial-derived substances due to enormous effluent organic matters (EfOM) from huge Gwangju sewage treatment plants.

• Journal of Environmental Science International
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• v.31 no.5
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• pp.431-445
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• 2022

The Gwangju Stream is a major tributary of the Yeongsan River. To maintain environmental and ecological functions in the stream, the flow is secured by natural water from the Mudeung Mountain as well as waters discharged from Lake Juam and the Gwangju sewage treatment plants. A substantial amount of water is supplied into the upper reaches of Gwangju Stream from Lake Juam. To examine the ecological effects of the water input from Lake Juam on the Gwangju Stream, a field survey of phytoplankton community species and an evaluation of water properties was conducted at five stations, from station GJ1 before the inflow to station GJ5 in the lower region. Nutrient levels decreased in the vicinity of the Lake Juam inflow, suggesting that this water inflow can contribute to the reduction of eutrophication in the stream. The phytoplankton community was mainly composed of Bacillariophyceae, Chlorophyceae, and Cyanophyceae, and the community structure was similar to that of the other study sites located near the water inflow regions. The inflow of water from Lake Juam can affect water quality and the phytoplankton community over a limited area, reducing eutrophication and increasing water flow in the Gwangju Stream.

• Journal of Korean Society on Water Environment
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• v.21 no.5
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• pp.520-527
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• 2005

In order to investigate the geochemical characteristics of surface sediments in streams of upper Yeongsan River drainage system, sediment samples from the main stream of Yeongsan river, Hwangryong river, Gwangju and Jiseok streams were collected and analyzed for grain size and metal and organic carbon contents. The metal contents in the sediments are mainly dependent on organic matter contents in the domestic sewage, grain size of the sediments and geology around the streams. Enrichment factor (EF) and index of geoaccumulation (Igeo) representing the degree of metal contamination in the sediments are relatively low in the main stream of Yeongsan river main stream, Hwangryong river and Jiseok stream. However, those of Gwangju stream show the EF maximum values of P=8.30, Cu=5.55, Zn=14.29 and Pb=7.45 and the Igeo maximum values of P=3.58, Cu=4.43, Zn=3.22 and Pb=1.59.

• Korean Journal of Ecology and Environment
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• v.44 no.4
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• pp.358-363
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• 2011

This study investigated the characteristics of natural organic matter(NOM) with tXAD resin and FT-IR in the Yeongsan river system of Gwangju region. NOM fractionation by XAD 8/4 resins was used to classify hydrophobic and hydrophilic substances. FTIR was applied to classify functional groups in the structure of NOM. In the XAD investigation, most of the four site-samples were mainly hydrophilic substances. In March, hydrophobic substances were dominant in the Gwangju 1 site (GJ-1), while hydrophilic substances were dominant for the other sites. In May, samples of all four sites were hydrophilic with a vigorous activity of microorganism due to increasing temperatures. The October results were very similar with those from March. In the FT-IR investigation, most of the broad and large peaks were assigned to the aliphatic group, particularly the OH group, C-H, $C-H_2$, $C-H_3$, and C-O alcohol group. All were related to hydrophilic substances. Other peaks showed the aromatic group, particularly the C=O (Ketone) Group. As a result, there is an identification of NOM in the Yeongsan river system composing mainly of hydrophilic substances and functional groups (OH, C-H etc.) of the aliphatic compound.

• Korean Journal of Environmental Biology
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• v.23 no.2 s.58
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• pp.120-128
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• 2005

This study was compared the flora and distribution of hydrophytes with physicochemical environment in the 14 sites selected in Yeongsan River through Gwangju Metropolitan city from March to October, 2003. In this survey, hydrophytes were classified 94 taxa; 35 families, 68 genera, 85 species and 9 varieties. It was compared the physicochemical characters with the hydrophytes distribution in each stream according to the index of contamination. Persicaria japonica and Rumex crispus were dominated at Youduk-Dong, the most contaminated area. Aquatic contamination sensitive floating-leaved plants and submerged plants were not identified. Hwangroung River and Yeongsan River area were a little contaminated area, appeared to good vegetation such as Phragmites japonica, Persicaria thunbergii and Miscanthus sacchariflorus. The stream of Youduk-Dong, the lower reaches of Gwangju-cheon was not grown with hydrophytes because of contamination by inflow of life sewage; therefore it is required to persevere in the townsmen's efforts for improvement of water environment.

• Journal of the Korean association of regional geographers
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• v.10 no.1
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• pp.192-205
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• 2004

The purpose of this paper is to analyze the factors, which have influence upon changes of hydrological environment in time series, and evaluate water balance changes caused by urbanization. The results of the analysis and evaluation are as follow: At first, the river runoff at Gwangju River Basin keep base flow of river by storage capacity recharged in June to September and show peak in August and minimum flow in May. The groundwater recharge by urbanization accounted for 46.1% of rainfall at early-urban stage, and decreased to 36.5% and 29.9% in the 1960's and the 1990's respectively, and is likely to decrease to 27.8% in the 2010's. On the other hand, the overland flow was 9.6% of rainfall in the 1960's and 16.2% in the 1990's, and is likely to increase to 18.3% in the 2010's. When such a phenomenon is kept continuously, distorted water balance shall be worsened to create not only frequent occurrence of urban flood but also decreased base flow of Gwangju River to accelerate dry stream phenomenon. The time series study on urban redevelopment and environment maintenance describes distorted phenomenon to supply the information for nature-friendly land use, and examines relations between human activities and natural environment.