• Journal of Environmental Science International
• /
• v.33 no.2
• /
• pp.139-160
• /
• 2024

The community structure of benthic macroinvertebrates in the Madongho Wetland protected area and inflow river located in Goseong-gun, Gyeongsangnam-do, was investigated in 2022 and 2023. We collected and identified 3,582 individuals belonging to 7 classes, 23 orders, 51 families, and 78 species over the 2 years from six sites. Gnorimosphaeroma naktongense was the dominant species with a ratio of 20%, and Caridina denticulata denticulata was the subdominant species with a ratio of 13.32%. Predators and gathering collectors were the most abundant in the functional feeding group, while sprawlers were the most diverse and numerous in the habitual dwelling group. Diversity, richness, dominance, and evenness were calculated as the biological indices. In addition, various biological water quality indices were calculated. Most insects in the inflow rivers belonged to group I in evaluating relative resistance and resilience, showing high colony stability. The results of analyzing the correlation between salinity and substrate particle size with brackish water species showed that Gnorimosphaeroma naktongense and Hediste japonica had a significant positive correlation with salinity, while Assiminea lutea and Neomysis awatschensis had a significant positive correlation with substrate particle size. Additionally, Sinelobus kisui was found to be a new record of Korean Tanaididae in this study.

• Korean Journal of Environment and Ecology
• /
• v.30 no.4
• /
• pp.684-693
• /
• 2016

Daemyung retarding basin located near the confluence floodplain of the Nakdong and Kumho River is a large spawning site for the endangered Kaloula borealis, and needs for protecting the habitat of the endangered species are increasing. However, scientific studies are rarely conducted on the population characteristics and ecological knowledge on the species in the basin. This paper aims to estimate the population size and spatial distribution of the species that inhabited at the Daemyung retarding basin, using the capture-recapture method. Also, pitfall traps were installed in each habitat types classified with micro-topographic features, slope aspects, and vegetation communities to identify the spatial distribution characteristics of the Kaloula borealis of each habitat in the retarding basin. Field survey on the species was conducted from May 2013 to October 2014, showing that the species emerged in May, became more active during July and August and started to hibernate at the end of October. Using capture-recapture method, the first survey was carried out from July to August, 2014. Ninety-eight toads were captured, marked, and released back into the site. In the second survey, 68 toads including 5 marked toads of the previous survey were captured. Based on these two-sample surveys, around 535-2,131 individual toads are estimated to inhabit the Daemyung retarding basin. Fifty-seven pitfall traps were installed in four habitat types: mounded and vegetated flatland, lowland swamps, and slope areas of both the southern and western parts of the basin in order to delineate spatial abundance of the endangered Kaloula borealis during the rainy season when the species is actively spawning. Pitfall traps at the spatially explicit array indicated that the species gradually move to the slope areas near the Daemyung stream, showing high occurrence density of the Kaloula borealis compared to the lowland swamps after the spawning season. The emergence of Kaloula borealis in the lowland swamps appeared to be comparatively higher during the spawning season. However, after the spawning season the toads species rapidly moved into the neighboring land of relatively high elevation such as the slope area towards the Dalsung protected wetlands and Daemyung River. These results are closely related to the migration patterns that toads tend to return to the sheltering sites and/or hibernating grounds after the spawning season. Also, the Kaloula borealis moved to the nearest high-level vegetated areas as the lowland swamps of their spawning grounds deteriorated with the expansion of permanent ponds due to the rise in the groundwater level.

• Journal of Korea Water Resources Association
• /
• v.49 no.6
• /
• pp.519-528
• /
• 2016

Frequently torrential rain is occurred by climate change and urbanization. Urban is formed with road, residential and underground area. Without detailed topographic flooded analysis consideration can take a result which are wrong flooded depth and flooded area. Especially, flood analysis error of population and assets in dense downtown is causing a big problem for establishments and disaster response of flood measures. It can lead to casualties and property damage. Urban flood analysis is divided into sewer flow analysis and surface inundation analysis. Accuracy is very important point of these analysis. In this study, to confirm the effects of the elevation data precision in the process of flooded analysis were studied using 10m DEM, LiDAR data and 1:1,000 digital map. Study area is Dorim-stream basin in the Darim drainage basin, Sinrim 3 drainage basin, Sinrim 4 drainage basin. Flooding simulation through 2010's heavy rain by using XP-SWMM. Result, from 10m DEM, shows wrong flood depth which is more than 1m. In particular, some of the overflow manhole is not seen occurrence. Accordingly, detailed surface data is very important factor and it should be very careful when using the 10m DEM.

• Korean Journal of Environmental Agriculture
• /
• v.17 no.2
• /
• pp.140-144
• /
• 1998

A survey on four tributary streams in agricultural areas along Nakdong River was carried out to evaluate the effect of agricultural practices on the quality of streamwater. Typicalpaddy and upland farmings were major agriculturalpractice in two survey areas. Apple orchards were located along Imgo -Cheon. Intensive farming in plastic film house was conducted along the Habin cheon. Electriclal condutivity and nutrient contents were measured. Comparing to the reference water sample collected from very upper part of Yangsang -Cheon in Moonkyong, water in the streams studied were quite polluted and such pollution could be due to the farmings conducted along the streams. Phosphorus content were higher than the minimum level for eutrophication (0.01-0.05 mg/L). Nitrogeon content were also significantly high in many sites to cause harmful effects on crops when normalfertilizer level was applicated. Among the four stream, water quality in paddy area were relatively less polluted. High nitrogen level in Imgo-Cheon and high level of EC in Habin-Cheon were problematic. As farming is the major sources of pollution in the streams studied, this are traceable to the agricultural nonpoint sources. To maintain water quality of the stream, the agricultural nonpoint source along thributary streams should be properly controlled.

• Korean Journal of Environment and Ecology
• /
• v.29 no.3
• /
• pp.410-420
• /
• 2015

In order to estimate the influence of environmental factors on zooplankton communities in lentic freshwater ecosystems, 20 reservoirs and wetlands were monitored by season in 2013. A total of 109 species of zooplankton were identified during the study period. Zooplankton assemblage showed a different distribution in its density and diversity in accordance with the seasons. In particular, the density of zooplankton (98 species and 603ind. L-1) was the most in autumn when compared to the other seasons. In order to effectively analyze zooplankton distribution that are affected by various environmental factors, a Self-Organizing Map (SOM) was used, which extracts information through competitive and adaptive properties. A total of 11 variables (8 environment factors and 3 groups of zooplankton) were patterned on to the SOM. Based on a U-matrix, four clusters were identified from the model. Among zooplankton communities, rotifer displayed a positive relationship with water temperature, and cladocerans and copepod were positively related to conductivity, chlorophyll a, and nutrient factor (i. e. TN and TP). In contrast, high dissolved oxygen appeared to have a negative effect on zooplankton distribution. Consequently, the SOM results depicted a clear pattern of zooplankton density clusters partitioned by environmental factors, which play a key role in determining the seasonal distribution of zooplankton groups in lentic freshwater ecosystem.

• Journal of the Korean association of regional geographers
• /
• v.10 no.4
• /
• pp.744-756
• /
• 2004

The purpose of this study is to investigate the natural environments and the changing socio-economic activities of the rice and fruit - centered rural village located in Sangju region, Kyongsangbuk-do. Its results are summarized in the followings. Firstly, most of the rural villages in Sangju region is located on the erosional basin of Sobaek range and the sedimentary region of Nakdong river and the farmer's life of those regions has been influenced by such a natural environment. Secondly, the reproduction structure of population in the rural village of Sangju region had been maintained until the 1970s. After that, however, it was broken because the young generation of the rural villages moved to large cities to get a job or to receive high level of education. Thirdly, the changing path of the rural villages of Sangju region was different based on a type of crop and its related mode of production after the 1980s. The socio-economic structure of the rural village has been developed based on either a rice oriented traditional mode of production or a fruit-oriented commercial mode of production. The two villages, Ch'ekdong 1 ri, Hamch'ang-up and Sinch'on 2 ri, Modong-myon have been changed according to the path of a traditional and commercial mode of production, respectively.

• Journal of Wetlands Research
• /
• v.23 no.1
• /
• pp.27-34
• /
• 2021

In this study, the main influencing factors of the occurrence of cyanobacteria at each of the eight Multifunctional weirs were derived using a random forest, and a categorical prediction model based on a Algal bloom warning system was developed. As a result of examining the importance of variables in the random forest, it was found that the upstream points were directly affected by weir operation during the occurrence of cyanobacteria. This means that cyanobacteria can be managed through efficient security management. DO and E.C were indicated as major influencers in midstream. The midstream section is a section where large-scale industrial complexes such as Gumi and Gimcheon are concentrated as well as the emissions of basic environmental facilities have a great influence. During the period of heatwave and drought, E.C increases along with the discharge of environmental facilities discharged from the basin, which promotes the outbreak of cyanobacteria. Those monitoring sites located in the middle and lower streams are areas that are most affected by heat waves and droughts, and therefore require preemptive management in preparation for the outbreak of cyanobacteria caused by drought in summer. Through this study, the characteristics of cyanobacteria at each point were analyzed. It can provide basic data for policy decision-making for customized cyanobacteria management.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.294-294
• /
• 2019

The system for predicting flood of river at Flood Control Office is made up of a rainfall-runoff model and FLDWAV model. This system is mainly operating to predict the excess of the flood watch or warning level at flood forecast points. As the demand for information of the management and operation of riverside, which is being used as a waterfront area such as parks, camping sites, and bike paths, high-level forecasts of watch and warning at certain points are required as well as production of lowland flood forecast information that is used as a waterfront within the river. In this study, a technology to produce flood forecast information in lowland areas of the river used as a waterfront was developed. Based on the results of the 1D hydraulic analysis, a model for performing spatial operations based on high resolution grid was constructed. A model was constructed for Andong district, and the inundation conditions and level were analyzed through a virtual outflow scenarios of Andong and Imha Dam.

• Journal of Korea Water Resources Association
• /
• v.44 no.8
• /
• pp.653-666
• /
• 2011

The purposes of this study are to suggest flood vulnerability assessment method on climate change with evaluation of this method over the 5 river basins and to present the uncertainty range of assessment using multi-model ensemble scenarios. In this study, the data related to past historical flood events were collected and flood vulnerability index was calculated. The vulnerability assessment were also performed under current climate system. For future climate change scenario, the 39 climate scenarios are obtained from 3 different emission scenarios and 13 GCMs provided by IPCC DDC and 312 hydrology scenarios from 3 hydrological models and 2~3 potential evapotranspiration computation methods for the climate scenarios. Finally, the spatial and temporal changes of flood vulnerability and the range of uncertainty were performed for future S1 (2010~2039), S2 (2040~2069), S3 (2070~2099) period compared to reference S0 (1971~2000) period. The results of this study shows that vulnerable region's were Han and Sumjin, Youngsan river basins under current climate system. Considering the climate scenarios, variability in Nakdong, Gum and Han river basins are large, but Sumjin river basin had little variability due to low basic-stream ability to adaptation.

• Journal of Korea Water Resources Association
• /
• v.54 no.9
• /
• pp.693-704
• /
• 2021

The purpose of this study is to evaluate the relationship between heat wave and river water quality. The daily maximum air temperature (Tmax) of 91 meteorological stations of the Korea Meteorological Administration and 13 river water quality factors (DO, BOD, COD, TOC, TN, DTN, NH4-N, NO2-N, NO3-N, TP, DTP, PO4-P, Chl-a) of Ministry of Environment were analyzed. The correlation analysis was performed on Tmax and water quality factors, and the determination coefficients (R²) of DO, Chl-a, and TN with Tmax showed high values of 0.782, 0.609, and 0.691 respectively. To analyze the spatial impact between heat waves and water quality factors, the heat wave intensity (HWI) and heat wave duration (HWD) were calculated using the Tmax. The hotspot and spatial statistical analyses were applied for spatial impact evaluation. As a result of hotspot analysis, the heat wave index (HWD, HWI) showed high spatial pattern in the downstream of Nakdong River basin, and Chl-a and TN showed the same pattern. In case of spatial statistical analysis for water quality due to heat wave, the most obvious spatial variability was DO.