• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.4
• /
• pp.642-648
• /
• 2012

To evaluate the water quality in Juksancheon constructed wetlands for treating non-point source pollution, the removal rates of nutrients in water and the total amounts of T-N and T-P uptakes by water plants were investigated. Chemical characteristics of T-N and T-P in sediment were investigated. The concentrations of BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), SS (Suspended Solids), T-N and T-P in inflow were 0.07~1.47, 0.60~2.65, 0.50~4.60, 1.38~6.26 and $0.08{\sim}0.32mg\;L^{-1}$, respectively. The removal rates of BOD, COD, SS, T-N, and T-P were -10, 51, 66, -3 and 5%, respectively. The maximum amount of T-N uptake by water plants in August was $368.7mg\;plant^{-1}$ in the $2^{nd}$ treatment stage by Nymphoides peltata, $1314.6mg\;plant^{-1}$ in the $3^{rd}$ treatment stage by Iris pseudacorus, $1160.4mg\;plant^{-1}$ in the $4^{th}$ treatment stage by Nymphaea tetragona GEORGI, respectively. The maximum amount of T-P uptake by water plants in August was $121.7mg\;plant^{-1}$ by Nymphoides peltata in the $2^{nd}$ treatment stage, $268.7mg\;plant^{-1}$ by Iris pseudacorus in the $3^{rd}$ treatment stage and $212.0mg\;plant^{-1}$ by Nymphaea tetragona GEORGI in the $4^{th}$ treatment stage, respectively. Organic matter contents in sediments were not different. Contents of T-N and T-P in sediments were higher in spring. Microbial biomass C:N:P ratios in sediments in spring, summer, autumn and winter were 117~140:1~4:1, 86~126:5~6:1, 68~101:2~6:1 and 47~138:2~4:1, respectively. We could conclude that Juksancheon constructed wetlands show high removal efficiencies of COD and SS. However, improvements of management in winter season should be considered to improve the removal efficiencies of pollutants.

• Journal of Environmental Impact Assessment
• /
• v.24 no.1
• /
• pp.16-34
• /
• 2015

Impervious covers(IC) are artificial structures, such as driveways, sidewalks, building's roofs, and parking lots, through which water cannot infiltrate into the soil. IC is an environmental concern because the pavement materials seal the soil surface, decreasing rainwater infiltration and natural groundwater recharge, and consequently disturb the hydrological cycle in a watershed. Increase of IC in a watershed can cause more frequent flooding, higher flood peaks, groundwater drawdown, dry river, and decline of water quality and ecosystem health. There has been an increased public interest in the institutional adoption of LID(Low Impact Development) and GI(Green Infrastructure) techniques to address the adverse impact of IC. The objectives of this study were to construct the modeling site for a samll urban watershed with the Storm Water Management Model(SWMM), and to evaluate the effect of various LID techniques on the control of rainfall runoff processes and non-point pollutant load. The model was calibrated and validated using the field data collected during two flood events on July 17 and August 11, 2009, respectively, and applied to a complex area, where is consist of apartments, school, roads, park, etc. The LID techniques applied to the impervious area were decentralized rainwater management measures such as pervious cover and green roof. The results showed that the increase of perviousness land cover through LID applications decreases the runoff volume and pollutants loading during flood events. In particular, applications of pervious pavement for parking lots and sidewalk, green roof, and their combinations reduced the total volume of runoff by 15~61 % and non-point pollutant loads by TSS 22~72 %, BOD 23~71 %, COD 22~71 %, TN 15~79 %, TP 9~64 % in the study site.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.17 no.4
• /
• pp.57-67
• /
• 2014

The vigor condition of trees is an important indicator for the management of urban forested area. But difficulties in how to assess the tree vigor condition still remain. Previous efforts were limited in the 1) measurement of single indicator rather than using multiple indices, 2) purpose-oriented measurement such as for air-pollution effect or specific pathological symptom, and 3) ordinal-scale evaluations by field crews 4) despite human errors based on his/her experiences or prior knowledge. Therefore, this study attempted to develop a quantitative and objective methodology for assessing tree vigor condition, by measuring multiple modules and building the profile inventory. Furthermore, the possibility and limitations were discussed in terms of schematic frames describing tree vigor condition. The vigor condition of 56 flowering cherry plants in urban park were assessed by in-situ measurements of following eight items; growth of crown(Gc), growth of shoots, individual tree volume(Vol), plant area index, woody area index, leaf area index, leaf chlorophyll content(Lc) and leaf water content(Lw). For validation, these measurements were compared with the ranks of holistic tree vigor condition, which were visually assessed using a 4-point grading scale based on the expert's knowledge. As a result, the measures of each evaluation item successfully highlighted a variety of aspects in tree vigor condition, including the states of both photosynthetic and non-photosynthetic parts. The variation in the results depending on evaluated parts was shown within an individual tree, even though the broad agreement among the results was found. The result of correlation analysis between the tested measurements and 4-point visual assessment, demonstrated that the state of water-stressed foliage of the season (Lw) or the development of plant materials since sapling phase (Vol) could be better viewed from the outer appearance of trees than other symptoms. But only based on the visual assessment, it may be difficult to detect the quality of photosynthesis (Lc) or the recent trend in growth of trees (Gc). To make this methodology simplified for the broad-scale application, the tested eight measurements could be integrated into two components by principal component analysis, which was labelled with 'the amount of plant materials' and 'vigor trend', respectively. In addition, the use of these quantitative and multi-scale indicators underlies the importance of assessing various aspects of tree vigor condition, taking into account the response(s) on different time and spatial scale of pressure(s) shown in each evaluated module. Future study should be advanced for various species at diverse developing stages and environment, and the application to wide areas at a periodic manner.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.43 no.6
• /
• pp.109-126
• /
• 2015

This study is for constructing detailed data to secure biological diversity and maintain a healthy ecosystem in Backsasil Valley Ecological and Scenery Conservation Area, and for preparing an ecological management plan fit for the protected area. The period for this study was from April 2010 to May 2013. Recently, the increase of visitors to Baeksasil Valley, as well as the plantation and dissemination of introduced vegetable species, become factors accelerating ecological disturbance. Major research contents included the reviews of the management system of the protected areas, the necessity of ecological management at the basin level, establishing the system of a management plan, research and analysis of environment ecology, analysis of threatening factors, goal-setting, management strategies, and a plan through SWOT analysis. Survey items were the natural environment, major components of ecosystem, and human-use. The goals of ecological management were basin zone management for amphibians, conservation and restoration of forest vegetation for conservation habitat of Dryocopus martius, conservation habitat of Zelkova serrta for nature landscape, and management of users for environment protection. The conservation management plan at a basin zone level contains the management of point and non-point pollution sources in the upstream, securing growing conditions for native plants, securing safe habitats for amphibians, and securing of habitats for major wild birds. Also, restoration of natural forests, management of native plants and introduced vegetable species, and restoration of degraded forest paths are suggested for the restoration plans.

• Journal of Wetlands Research
• /
• v.9 no.3
• /
• pp.43-49
• /
• 2007

A ditch is a facility for managing washed-off runoff from parking lot area. Washed-off runoff inflows into ditches where it is retained for a short period of time. At this point, it is assumed that a ditch is a preliminary unit for runoff treatment. This research carries out the distribution of particle size and chemical compound for sediment in parking lot ditch. This work is important to understand the amount of generated sediment from this area to be able to determine different particle size ranges for treatment. Metal concentrations for sediment according to particle size are analyzed. From the distribution of particle size, the weight ratio with the range of $425-850{\mu}m$ is the highest. Considering its weight ratio, the metal concentration of coarser particles is high, otherwise metal concentration increases as particle size decreases. Metal load of the range is higher and the ratio of total metal load in the case of Cu, Pb, Zn is nearly 30%. Moreover metal concentration associated with particle size depends on particle ratio. To manage non-point source pollution for parking lot area, these results can be used with this ditch unit.

• Microbiology and Biotechnology Letters
• /
• v.39 no.3
• /
• pp.301-307
• /
• 2011

Oil pollution was world-wide prevalent treat to the environment, and the physic-chemical remediation technology of the TPH (total petroleum hydrocarbon) contaminated soil had the weakness that its rate was very slow and not economical. Bioremediation of the contaminated soil is a useful method if the concentrations are moderate and non-biological techniques are not economical. The aim of this research is to investigate the influence of additives on TPH degradation in a diesel contaminated soil environment. Six experimental conditions were conduced; (i) diesel contaminated soil, (ii) diesel contaminated soil treated with microbial additives, (iii) diesel contaminated soil treated with microbial additives and the mixture was titrated to the end point of pH 7 with NaOH, (iv) diesel contaminated soil treated with microbial additives and accelerating agents and (v) diesel contaminated soil treated with microbial additives and accelerating agents, and the mixture was titrated to the end point of pH 7 with NaOH. After 10 days, significant TPH degradation (67%) was observed in the DSP-1 soil sample. The removal of TPH in the soil sample where microbial additives were supplemented was 38% higher than the control soil sample during the first ten days. The microbial additives were effective in both the initial removal rate and relative removal efficiency of TPH compared with the control group. However, various environmental factors, such as pH and temperature, also affected the activities of microbes lived in the additives, so the pH calibration of the oil-contaminated soil would help the initial reduction efficiency in the early periods.

• Journal of Korea Water Resources Association
• /
• v.54 no.2
• /
• pp.121-133
• /
• 2021

Suspended Solids (SS) generated in rivers are mainly introduced from non-point pollutants or appear naturally in the water body, and are an important water quality factor that may cause long-term water pollution by being deposited. However, the conventional method of measuring the concentration of suspended solids is labor-intensive, and it is difficult to obtain a vast amount of data via point measurement. Therefore, in this study, a model for measuring the concentration of suspended solids based on remote sensing in the Nakdong River was developed using Sentinel-2 data that provides high-resolution multi-spectral satellite images. The proposed model considers the spectral bands and band ratios of various wavelength bands using a machine learning model, Support Vector Regression (SVR), to overcome the limitation of the existing remote sensing-based regression equations. The optimal combination of variables was derived using the Recursive Feature Elimination (RFE) and weight coefficients for each variable of SVR. The results show that the 705nm band belonging to the red-edge wavelength band was estimated as the most important spectral band, and the proposed SVR model produced the most accurate measurement compared with the previous regression equations. By using the RFE, the SVR model developed in this study reduces the variable dependence compared to the existing regression equations based on the single spectral band or band ratio and provides more accurate prediction of spatial distribution of suspended solids concentration.

• Korean Journal of Environmental Biology
• /
• v.34 no.4
• /
• pp.320-328
• /
• 2016

This study was conducted to provide important basic information about effective management of the marine environment at major inflow streams in Lake Andong and Lake Imha. The investigation was conducted 8 times from May, 2015 (AD1, AD2, IH1, IH2) to September, 2016 (AD3, AD4, IH3, IH4), and 8 surveyed sites were selected at Lake Andong (4 sites) and Lake Imha (4 sites). The inquiry identified 114 species, $59,913.7inds.\;m^{-2}$ in Lake Andong and 112 species, $39,038.4inds.\;m^{-2}$ in Lake Imha. The results indicate that the number of species and individuals in Lake Andong is more than that in Lake Imha, because Lake Andong has a variety of riparian vegetation and a richness of organic materials. Community analysis at Lake Imha revealed a dominant index of 0.57 (${\pm}0.18$), a diversity index of 2.87 (${\pm}0.31$), an evenness index of 0.73 (${\pm}0.04$), and a richness index of 4.17 (${\pm}0.71$). The results of functional feeding group analysis showed that a high proportion of species and individuals are gathering collectors. The results of functional habitat group analysis showed that a high proportion of species and individuals are clingers. The result of a physico-chemical water assay and dissolved oxygen and electric conductivity tests revealed that these measures increased when the water temperature decreased. The result of Pearson's correlation analysis by biological factors and physico-chemical factors showed that species and electric conductivity are highly correlated with one another. Major inflow streams of Lake Andong and Lake Imha were exposed to various point pollution sources and non-point pollution sources. This implies a necessity for continuous monitoring of the aquatic ecosystems in order to effect systematic water quality management of Lake Andong and Lake Imha.

• Journal of Korea Water Resources Association
• /
• v.45 no.8
• /
• pp.795-804
• /
• 2012

Recently, changes in rainfall intensity and patterns have been causing increasing soil loss worldwide. As a result, the water ecosystem becomes worse and crops yield are reduced with soil loss and nutrient loss with it. Many studies have been proposed to estimate runoff and soil loss to predict or decrease non-point source pollution. Although the USLE has been used for many years in estimating soil losses, the USLE cannot reflect effects on soil loss of changes in rainfall intensity and patterns. The WEPP, physically based model, is capable of predicting soil loss and runoff using various rainfall intensity. In this study, the WEPP model was simulated for sediment yield, runoff and peak runoff using data of 5, 10, 30, 60 minute term rainfall, Huff's method and design rainfall. In case of rainfall interval of 5 minutes and 60 minutes, the sediment and runoff values decreased by 24% and 19%, respectively. The peak rate runoff values decreased by 16% when rainfall interval changed from 5 minutes to 60 minutes, indicating the peak rate runoff values are affected by rainfall intensity to some degrees. As a result of simulating using Huff's method, all values (sediment yield, runoff, peak runoff) were found to be the greatest at third quartile. According to the analysis under various design rainfall conditions (2, 3, 5, 10, 20, 30, 50, 100, 200, 300 years frequency), sediment yield, runoff, and peak runoff of 906.2%, 249.4% and 183.9% were estimated using 2 year to 300 year frequency rainfall data.

• Korean Journal of Soil Science and Fertilizer
• /
• v.40 no.1
• /
• pp.18-24
• /
• 2007

Paddy fields are apparently nonpoint source pollution and influence water environment. In order to improve water quality in rivers or lakes, to low nutrient load from paddy fields are required. To establish comprehensive plan to control agricultural non-point source pollution, it is imperative to get a quantitative evaluation on pollutants and pollution load from paddy fields. A field monitoring study was carried out to investigate the water balance and losses of nutrients from fields in Sumjin river basin. The size of paddy fields was 115 ha and the fields were irrigated from a pumping station. The observed total nitrogen loads from paddy fields were larger than those of the unit loads determined by Ministry of Environment data (MOE). It is because the nitrogen fertilization level at the studied field was higher than the recommended rate and the high irrigation and subsequent drainage amount. On the contrary, total phosphorus loads were less than those addressed by MOE since phosphorus fertilization level was lower than that of standard level. Therefore, it was found that fertilization, irrigation, and drainage management are key factors to determine nutrient losses from paddy fields. When the runoff losses of nutrients were compared to applied chemical fertilizer, it was found that 42 to 60% of nitrogen lost via runoff while runoff losses of phosphorus account for 1.3 to 7.6% of the total applied amount during the entire year.