• Journal of Soil and Groundwater Environment
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• v.27 no.5
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• pp.1-9
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• 2022

A correlation analysis was performed to investigate differences in the response of surface water and groundwater to drought using the Standardized Precipitation Index (SPI). Water level data of 20 agricultural reservoirs, 4 dams, 2 rivers, and 8 groundwater observation wells were used for the analysis. SPI was calculated using precipitation data measured at a nearby meteorological station. The water storage of reservoirs and dams decreased significantly as they responded sensitively to the drought from 2014 to 2016, showing high correlation with SPI of the relatively long accumulation period (AP). The responses of rivers varied greatly depending on the presence of an upstream dam. The water level in rivers connected to an upstream dam was predominantly influenced by the dam discharge, resulting in very weak correlation with SPI. On the contrary, the rivers without dam exhibited a sharp water level rise in response to precipitation, showing higher correlation with SPI of a short-term AP. Unlike dams and reservoirs, the responses of groundwater levels to precipitation were very short-lived, and they did not show high correlation with SPI during the long-term drought. In drought years, the rise of groundwater level in the rainy season was small, and the lowered water level in the dry season did not proceed any further and was maintained at almost the same as that of other normal years. Conclusively, it is confirmed that groundwater is likely to persist longer than surface water even in the long-term drought years.

• Journal of Environmental Science International
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• v.22 no.12
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• pp.1643-1650
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• 2013

This study investigated water quality of effluents and stream from the sewage treatment plants located at Gumi Complex 4, Gumi, and Wonpyeong in Gumi. Downstream region was found to increase the concentration of nutrients for sewage treatment plant effluent. Both phosphorus and nitrogen were accounted most as soluble form. In particular, the high ratio of dissolved effluent of sewage treatment plants were investigated. In the streams, Phosphorus concentration was high during rainy season and nitrogen concentration was high in the dry season. Sewage treatment plant effluent was relatively less microbial activity and nutrient concentrations were higher in the winter. TN/TP ratio was the highest in the upstream region and the lowest in the sewage treatment plant effluent. The effect of the nutrient matter from a discharge of a sewage treatment plant on rivers varied depending on the size of the river and the treatment plant. However, the influence of the concentration was greater than that of flowrate. Sewage treatment plant effluent loads phosphorus, nitrogen accounted for 8% and 6% respectively at the point N3 of the Nakdong river.

• Journal of Korean Society of Forest Science
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• v.35 no.1
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• pp.36-38
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• 1977

Some characteristics of rainfall interception and surface runoff from total rainfall at a forest stand mixed with Pinus densiflora and Alnus hirsuta in 1975 was analysised and the results obtained are as fellow; 1. The annual interception of rainfall by the forest canopy was 19.3 percent to annual rainfall 1,072.7mm. 2. The rate of rainfall interception in the dry season as spring and early summer was of 20 to 50 percent and less than 15 percent in the rainy season as summer. 3. About 50 percent of rainfall was intercepted in case of less than 10mm of every rainfall by the forest canopy and, in more than 20mm, about 20 percent intercepted.

• Journal of Korea Water Resources Association
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• v.42 no.8
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• pp.643-657
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• 2009

The major reason to construct large dams is to store surplus water during rainy seasons and utilize it for water supply in dry seasons. Reservoir storage has to meet a pre-defined target to satisfy water demands and cope with a dry season when the availability of water resources are limited temporally as well as spatially. In this study, a Hedging rule that reduces total reservoir outflow as drought starts is applied to alleviate severe water shortages. Five stages for reducing outflow based on the current reservoir storage are proposed as the Hedging rule. The objective function is to minimize the total discrepancies between the target and actual reservoir storage, water supply and demand, and required minimum river discharge and actual river flow. Mixed Integer Linear Programming (MILP) is used to develop a multi-reservoir operation system with the Hedging rule. The developed system is applied for the Han River basin that includes four multi-purpose dams and one water supplying reservoir. One of the fours dams is primarily for power generation. Ten-day-based runoff from subbasins and water demand in 2003 and water supply plan to water users from the reservoirs are used from "Long Term Comprehensive Plan for Water Resources in Korea" and "Practical Handbook of Dam Operation in Korea", respectively. The model was optimized by GAMS/CPLEX which is LP/MIP solver using a branch-and-cut algorithm. As results, 99.99% of municipal demand, 99.91% of agricultural demand and 100.00% of minimum river discharge were satisfied and, at the same time, dam storage compared to the storage efficiency increased 10.04% which is a real operation data in 2003.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.1037-1042
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• 2009

Safety regulation of railway embankment is restricted by safety factor in dry season or rainy season in Korea. Safety factor which is results from the limit equilibrium analysis is varied by various external conditions. And because it has no reflection point, it is very difficult to manage the safety of trains. Safety regulation such like warning sign, reduce speed and train stop is the best choice to reduce the damage of embankments where it is worried about occurrence of disasters. In this study, additional index is proposed to support present safety standards based on unsaturated soil mechanics and reliability analysis. It is velocity of failure probability. It has an apparent reflection point near present safety regulation. It is possible to modify the regulation for safety management and monitoring system of embankments by using this index.

• Economic and Environmental Geology
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• v.41 no.1
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• pp.63-79
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• 2008

Physicochemical characteristics of stream water, leachate, mine water and groundwater were investigated to estimate the influences of the tailing and waste rock from the abandoned Uljin mine area. Total extraction analysis and mineralogical studies were carried out to understand sulfide weathering and to determine the distributions of trace elements in the soil affected by mine waste (tailing, waste rock and leachate). The pH and EC value of the leachate from the tailing disposal ranged 2.9-6.0, $99{\sim}3,990{\mu}S/cm$, respectively, and the concentrations of dissolved major (up to 492 mg/l Ca; 83.8 mg/l Mg; 45.2 mg/l Na; 44.7 mg/l K, 50.8 mg/l Si) and trace elements (up to $826,060{\mu}g/l$ Fe; $131,230{\mu}g/l$ Mn; $333,600{\mu}g/l$ Al; $61,340{\mu}g/l$ Zn; $2,530{\mu}g/l$ Cu; $573{\mu}g/l$ Cd; $476{\mu}g/l$ Pb) were relatively high. The stream water showed the variation of dissolved metal concentrations in seasonally and spatially. The dissolved metal contents of the stream water increased by influx the leachate from the tailing disposal, but these of the down stream have been considerably decreased by mixing of dilute tributaries. The dissolved metal concentrations of the stream water at dry season (as February) were lower than these at rainy season (as May and July). These represent that the amounts of the leachate varied with season. However, stream water could not be effectively diluted by confluence with uncontaminated tributaries, because the flux of tributaries and streams reduced at dry season. Thus attenuations by dilution had been dominantly happened in rainy seasons. The order of accumulations of trace element in soils compared with background values revealed Mn>Fe>Pb>Cu>Zn. Sulfide minerals were mainly pyrrhotite, sphalerite and galena and chalcopyrite. Pyrrhotite was rapidly weathered along the edge and fractures, and results in the formation of Fe-(oxy)hydroxides, which absorbed a little amount of Zn.

• Economic and Environmental Geology
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• v.38 no.4 s.173
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• pp.463-479
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• 2005

The Sr and Pb isotopic ratios and chemical composition were measured for atmospheric bulk deposition samples collected in the Jeonju, Gunsan and Namweon areas over a period of one year. Acidity of deposition ranged pH $4\~7$ with little higher in dry season, and around pH 5.0 in rainy season. The EC and TDS of rainy season was low showing dilution effect, and increased during dry season. Sulfate $(SO_4)\;and\;NO_3$ are atmospheric aerosols largely of anthropogenic origin in winter. Sodium was concentrated in winter deposition, Ca was concentrated in spring to summer deposition. Namweon has lower EC and TDS than those of other, and Jeonju has higher. Namweon was concentrated in $HCO_3$ and Cunsan was concentrated in Cl. Aluminium, Cu, and Zn show good correlation index with TDS, indicating of their origin atmospheric. $^{87}Sr/^{86}Sr$ ratios of bulk deposition ranged from 0.7109 to 0.7128. The isotopic variations are correlated with mixing of isotopic compositions of local soils, road deposit and biogenic aerosol. In order to constrain further the origin of aerosols in rainwater, it will be necessary to collect additional Sr isotopic data for aerosols. Lead isotope ratios for all areas were similar and belonged to Pb isotope ratios of Seoul's aerosols, but little different with Beijing's aerosols. It showing that Pb in the Korea mainly derived from the gasoline combustion, not exclusively from the Beijing.

• Journal of Korean Society on Water Environment
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• v.34 no.5
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• pp.462-469
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• 2018

There are differences in method and cycle of flow rate survey depending on purpose of the operating department. To verify and use results of flow data according to the purpose, flow data of the directly measured and tele monitoring system were compared to verify validity. Flow measurement in the Ministry of Environment is aimed at setting up a standard flow of target water quality for water quality management and securing flow data of low and normal water level seasons for water quality evaluation. In this study, correlation analysis result ($R^2$) of same time zone data by direct measurement and tele monitoring system (TMS) at Seombon D point, a unit watershed of Seomjin river, for six years ('10 ~ '15) according to implementation of Total Daily Maximum Load (TDML) was wading 0.716, boating 0.962 and on bridge 0.943, and effectiveness of measurement method was verified by characteristics of flow duration as a season of dry and low-water; normal and high water are appropriate for wading, boating, and on bridge respectively. Results revealed it is reasonable to use directly measured results using the wading and boating method for low water level and dry seasons, and TMS data for rainy seasons. It can be used important data for future policy decisions.

• Journal of Bio-Environment Control
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• v.32 no.3
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• pp.226-233
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• 2023

High solar radiation in summer season causes excessive respiration of crops and reduces photosynthesis. In addition, the rainy season, which mainly occurs in summer, causes a low light condition inside the greenhouse. A low light condition can reduce crop growth and yield. This study was conducted to evaluate the effect of shade and supplemental lighting on the growth and yield of cucumber during summer season. Cucumber grafted seedlings were transplanted in two plastic greenhouses on August 30, 2022. To reduce the light intensity inside the greenhouse, a 50% shading screen was installed in one greenhouse. Supplemental lighting was conducted from September 7, 2022 to October 20, 2022. HPS (high-pressure sodium lamp), W LED (white LED, red:green:blue = 5:3:2), and RB LED (combined red and blue LED, red:blue = 7:3) were used for supplemental lighting sources, and non-treated (nonsupplemental lighting) was as the control. The supplemental lighting was conducted before sunrise and after sunset for 2 hours with a photosynthetic photon flux density of 150 ± 20 µmol·m^-2·s^-1. The plant height, leaf length, leaf width, and SPAD value tended to increase in the shading group. RB LED increased stem diameter regardless of shading treatment. Fresh and dry weights of fruits were not significantly different in shading and supplemental lighting. Average fresh weight of fruits was not significantly different among supplemental lighting as the harvest date passed. In conclusion, in this study 50% shade treatment significantly improved the growth of cucumber during the summer season. In addition, the growth and fruit characteristics are better than the control without supplemental lighting. This study can be used as basic research data for applying supplemental lighting technology to cucumber cultivation.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.8
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• pp.1108-1117
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• 2003

In Guadeloupe small ruminants (SR) are reared for meat production under pasture conditions. Intensive rotational grazing systems (irrigated, fertilised and high stocked) allow reasonable levels of production but generate high post-grazing residues. Experiments were designed to control them. A system in which residuals were mown (RM) was tested in comparison to the control system (Residuals Remained, RR). The same design was carried out for two years with Creole goat (G) and Martinik sheep (S). An accelerated reproductive rate (3 parturitions over 2 years) was carried out. Systems were compared at three parturition seasons per year(dry, intermediate and rainy seasons). Each group was composed of 20 goats ($36.0{\pm}2.5kg$) or 20 ewes ($46.8{\pm}2.4kg$). The female body traits did not vary according to pasture management and seasons. The stocking rate averaged 1,400 kg LW/ha. The mean fertility rate for does varied significantly (p<0.05) within the kidding season, from $80.4{\pm}0.5%$ to $93.7{\pm}2.9%$ while the mean litter size was $2.30{\pm}0.07$ total kids born. No effect of pasture system was observed. Corresponding values for ewes were $83.2{\pm}12.8%$ vs. $75.6{\pm}12.5%$ (p<0.05) and $2.43{\pm}0.24$ vs. $2.03{\pm}0.29$ (p<0.01) total lambs born for SRM and SRR ewes, respectively. A seasonal effect was observed upon ewe performances. The preweaning mortality of kids and lambs averaged 16.3% and 14.4%, respectively. It was 7 and 9 percentage points more (p<0.01) for RR than for RM kids and lambs, respectively. For both species, weaning took place at an average age of $81.4{\pm}3.6days$. In Creole kids, live weight at birth and at weaning were $1.9{\pm}0.2kg$ and $8.9{\pm}0.8kg$, respectively. In the Martinik sheep, the traits averaged $2.9{\pm}0.2kg$ and $18.9{\pm}0.9kg$. For both traits in both species, significant (p<0.05) group${\times}$season interactions were recorded. The consequences of elimination of post-grazing residues varied according to the SR species, the environmental conditions and the animal physiological status. The forage characteristics were not limiting factors since forage availability in the RM systems (2,300 and 2,600 kg DM/ha, respectively) and chemical composition were at satisfactory levels (CP content averaged 12 and 10%). It is recommended to develop new grazing system which would allow the use of post-grazing residues instead of mowing the refusals.