The objective of the paper is to compute the half-month rainfall-runoff erosivity factor for revised universal soil loss equation (RUSLE). RUSLE is being used to develop soil conservation programs and identify optimum management practices. Rainfall-runoff erosivity factor (R) is a key input parameter to RUSLE. Rainfall-runoff erosivity factor has been calculated for twenty six stations from the nationwide rainfall data from 1973 to 2002 in south Korea. The average annual Rainfall-runoff erosivity factor at the analyzed stations Is between 3,130 and 10,476 (MJ/ha)ㆍ(mm/h). According to the computation of the half-month Rainfall-runoff erosivity factor for locations, 66-85% of the average annual R value has occurred during the summer months, June-August. The half-month R values from this study can be used for RUSLE.

In this study, durability performance of blended cement mortars is evaluated when various mineral admixtures are used with the cement. A comprehensive evaluation of the effects of mineral admixtures on the mortar performance was made. The properties of fresh and hardened blended mortars investigated include slump flow and compressive strength. The durability characteristics of cement materials incorporating the mineral admixtures under various physical and chemical causes of deterioration was investigated. The laboratory test results indicate that mechanical and durability properties of blended cement mortars have superior performance rather than ordinary cement mortars.

Due to the economic growth and the improvement of life standards in the country, the quantities of waste glasses have been yearly increased. About 65% of them are recycled and the rest are reclaimed. The reclaimed waste glasses can cause some problems such as the environmental pollution as well as the processing cost of them. Thus, the purpose of this experimental research is to investigate the properties of mortar using powdered waste glasses(PWG) as a cementitious materials in mortar to recycle the reclaimed waste glasses For this purpose, the workability and strength of mortar specimens using PWG have been tested and analyzed in various grain size of them by changing the replacement ratio. As a result, considering the workability and strength of mortar specimens using PWG, it is concluded that the optimum grain size and replacement ratio of them will be existing.

Hwangto would be an environment-friendly material that can be readily used. The purpose of this study is to obtain the absorption ratio, ultrasonic pulse velocity and neutralization of the mortar with non-active Hwangto and stone dust. The absorption ratio and neutralization depth are increased with increase of non-active Hwangto. But, the ultrasonic pulse velocity is decreased with increase of non-active Hwangto. In results of SEM analysis, the crystals are increased with increase of non-active Hwangto.

The objective of this study is to evaluate the stability of the design criteria recommended by Betram and Terzaghi as compared with the experimental result. A series of NEF tests was conducted to determine the loss of volume in base soils. The three kinds of base soils classified as CL, SC and SM are used for the NEF tests with various hydraulic pressures and filters following upper and lower bond of the criteria. Volume loss characteristics of the base soils was examined closely by the results of the test successfully. Firstly, it was found that the loss of base soils was mostly eroded at the first stage of seepage. Secondly, the amount of loss volume was ranked CL > SM > SC in order of their amounts for upper criteria, and SM > CL > SC orderly for lower criteria. Thirdly, the volume loss of all soils was increased with increasing the hydraulic pressures. And lastly, the needs of the new design criteria was proved for the control of seepage and piping.

Methods of fuzzy C-means have been used to characterize geotechnical information from static cone penetration data. As contrary with traditional classification methods such as Robertson classification chart, the FCM expresses classes not conclusiveness but fuzzy. The results show that the FCM is useful to characterize ground information that can not be easily found by using normal classification chart. But optimal number of classes may not be easily defined. So, the optimal number of classes should be determined considering not only technical measures but engineering aspects.

Photoreactivation of microorganism following UV-disinfection is one of the research topics of interest in assessing the UV-disinfection performance. Apparent photoreactivation was examined under fluorescent lamp and solar radiation as well as in darkness. Total coliform, fecal coliform, and Escherichia coli were used as indicator microorganisms, and their concentration was monitored with time after UV-disinfection. Under the darkness, their initial concentration of 10∼30 MPN/100 mL increased to the level of 100 MPN/100 mL after 24 hours, which implied that part of damaged microorganisms by UV-disinfection might be repairable with time. Under the fluorescent lamp, photoreactivation was more apparent that their concentration increased up to 1,000 MPN/100 mL which might significantly impair the water uses specially in reuse of reclaimed wastewater. However, their concentration further decreased down to below 2 MPN/100 mL under the solar radiation primarily due to additional disinfection by solar radiation rather than photoreactivation. Samples not disinfected by UV-disinfection also demonstrated substantial decrease of their concentration under solar radiation from about 5,000 MPN/100 mL to less than 30 MPN/100 mL in 24 hours. But direct reuse of effluent without disinfection is not recommended because natural decay by solar radiation may take time and be affected by climatic conditions. The result suggests that photoreactivation of pathogenic microorganisms may not be concerned in agricultural reuse of reclaimed wastewater because solar radiation may provide further disinfection after UV-disinfection.

A hydrologic and water quality monitoring network were established in the Balkan-reservoir watershed, which has 29.79 $km^2$ in size, to analyze the characteristics of pollutant loading from an agricultural small watershed. Soil type, land use, hydrologic soil group, population and livestock were also surveyed to make clear the pollutant sources and to calculate the pollutant loadings by the unit loading factor method which was proposed by the Ministry of Environment. From the 5-year hydrologic monitoring results, sub-watersheds located in the upstream of the reservoirs showed higher average runoff ratio. The calculated daily pollutant loadings by the unit loading factor method from HP#2 sub-watershed in the downstream of Balkan reservoir, were much greater than observed.

This study examines groundwater movement system analysis and movement forecast algorithm using finite element method. The target is Cheongha-myeon area, Bukgu, Pohang-city which has many difficulties in water supply during drought period. From the comparison of the differences between obtained values by WINFlOW model and observed values, it is thought that groundwater head distribution under steady flow is reflected well at the level of reliability Groundwater movement of study area shows stable pattern from western watershed to eastern coastal area while flow path is dense and steep in the center of the coastal area. The results of particle tracing for each well show a comparatively straight line from the western boundary side to the observation position at the upper area of the well, and are analyzed as it diffuses according to getting closer to the coast at the lower area of the well. The result of effect circle examination attendant on pumping amount in study area shows variation tendency that groundwater head decreases at the side and the lower area more than at the upper area of the well when groundwater flows from west to east(coast). As mentioned above, satisfactory results of groundwater movement analysis using WINFlOW model, two dimensional groundwater movement analysis model, are obtained through the great decrease of physical uncertainty of groundwater movement system.

In this study, we research about the relationships of human longevity and environments, inducted the significant factors of longevity from the statistical analysis, and represented spatial distribution of longevity using geographic information system. The factors confining human longevity can be categorized by geography/geology, climate/weather, economy, and social welfare. After analyzing statistical data, dependent variable which means the longevity index is defined by the ratio of population more than 85 years old among population more than 65 years old. The results of analysis show that longevity are related with waterworks ratio, temperature, local tax ratio, and latitude. In this study we discussed about the spatial characteristics which are represented by variance of the longevity index and described a spatial relationship between the longevity index and significant factors which are chosen by statistical analysis. In the further study, in order to sustain the longevity of a region, it is necessary for the effective rural planning to propagate a longevity of rural areas.