Despite the unfamiliar term "multifunctionality of agriculture" and the tremendous number of debates made over the past 10 years, multiple benefits from paddy rice farming in the Asian monsoon region are very significance due to the various inherent characteristics of paddy rice in this lesion. They were identified as rural vitalization, social security, nature and environmental preservations, and social and cultural functions. As studies estimating the monetary value of nature and environmental functions in Korea and Japan revealed, the economic value of multifunctionality from paddy rice farming reached to 70∼150% of total annual rice production cost of each country, and would have been even higher, had other functions been included. Therefore, interdisciplinary and international researches within the monsoon Asian countries are necessary to develop counter-measure logics against the Western dry land farming countries, emphasizing the efforts to disseminate worldwide the significance and recognition of the multifunctionality of paddy rice farming under the Asian monsoon climate.

Rainfall and runoff data from a forested watershed and irrigated rice paddies at the Bal-an experimental watershed were monitored and analyzed to investigate the variations of runoff characteristics with different land use. The comparisons were conducted fourteen storm events ranging 21.8∼190.2 mm of rainfall. Field data showed that direct runoff from paddies and forested watershed are not significantly different in volume. The peak discharge from forest watershed was less than that from paddies far lighter storms, but became greater fur heavier storms. The peak runoff from the forest watershed was 39 percent greater than from the paddies. The results demonstrate that paddies play an important role to reduce peak discharge from heavy storms as compared to forest.

Nominal shear strength of concrete beam is the combined strength of concrete shear strength and steel shear strength in current design code. But Torsional moment strength of concrete is neglected in calculation of the nominal torsional moment strength of reinforced concrete beam in current revised code. Tensile stress of concrete strut between cracks is still in effect due to tension stiffening effect. But the tensile stresses of concrete after cracking are neglected in bending and torsion in design. The torsional behavior is similar to the shear behavior in mechanics. Therefore the torsional moment strength of concrete should be concluded to the nominal torsional moment strength of reinforced concrete beam. To verify the validity of the proposed model, the nominal torsional moment strengths according to CEB, two ACI codes(89, 99) and proposed model are compared to experimental torsional strengths of 55 test specimens found in literature. The nominal torsional moment strengths by the proposed model show the best results.

This study is performed to evaluate characteristics of plantable concrete using waste stone and stone dust. The test result shows that the void ratio is decreased as the size of waste stone smaller and the content of stone dust increased. The strength of neutralized plantable concrete is decreased by approximately 4∼5% than that of the normal plantable concrete. The reduction effect of pH value is achieved by chemical treatment. Also, the plant is grown well with increase of the void ratio and size of waste stone.

The advent or high-strength steel has enabled the arch structures to be relatively light, durable and long-spanned by reducing the cross sectional area. On the other hand, the possibility of collapse may be increased due to the slender members which may cause the stability problems. The limit analysis to estimate the ultimate load is based on the concept of collapse mechanism that forms the plastic zone through the full transverse sections. So, it is not appropriate to apply it directly to the instability analysis of arch structures that are composed with compressive members. The objective of this study is to evaluate the ultimate load carrying capacity of the parabolic arch by using the elasto-plastic finite element model. As the rise to span ratio (h/L) varies from 0.0 to 0.5 with the increment of 0.05, the ultimate load has been calculated fur arch structures subjected to uniformly distributed vertical loads. Also, the disco-elasto-plastic analysis has been carried out to find the duration time until the behavior of arch begins to show the stable state when the estimated ultimate load is applied. It may be noted that the maximum ultimate lead of the parabolic arch occurs at h/L=0.2, and the appropriate ratio can be recommended between 0.2 and 0.3. Moreover, it is shown that the circular arch may be more suitable when the h/L ratio is less than 0.2, however, the parabolic arch can be suggested when the h/L ratio is greater than 0.3. The ultimate load carrying capacity of parabolic arch can be estimated by the well-known formula of kEI/L$^3$where the values of k have been reported in this study. In addition, there is no general tendency to obtain the duration time of arch structures subjected to the ultimate load in order to reach the steady state. Merely, it is observed that the duration time is the shortest when the h/L ratio is 0.1, and the longest when the h/L ratio is 0.2.

Most of the agricultural structures are in shortage of feasible facility management because these structures are small in size and spacially distributed in rural area. Inspection tools based on visual inspections are generally used for agricultural structures in most of the countries, including Korea. It is necessary to survey data of the irrigation structures to maintain records, and to develop the interface program by constructing database of inspection data. This study was conducted to develop a system for safe appraisal and repair works on agricultural irrigation structures. Repair and rehabilitation method can be chosen from an optimum viewpoint if the information between the method and life-cycle management cost of agricultural structures is constructed in the database. In this study, the system assisting onsite field investigation and determining the typical rehabilitation method of typical agricultural structural problems such as fractures and cracks of members was developed.

This study was performed to estimate the degree of consolidation using excess pore water pressure in the very soft ground. The final settlement prediction methods by Hyperbolic, Asaoka and Curve fitting methods from the measured settlement data were used to compare with the degree of consolidation estimated by excess pore water pressure. The dissipated excess pore water pressure during embankment construction and the peak excess pore water pressure on the completed embankment were used for the estimation of the degree of consolidation. After completion of embankment, it was concluded that the degree of consolidation estimated from dissipated excess pore water pressure was more reliable than that from the peak excess pore water pressure. And, the degree of consolidation estimated from the surface settlement was nearly the same as settlement of each layer. The degree of consolidation estimated from dissipated excess pore water pressure was a little larger than that from settlement.

Although fly ash possesses viable engineering properties, an overwhelming majority of fly ash from coal combustion is still placed in storage or disposal sites. Similarly, sludges generated from various water treatment operations are predominantly subjected to the fate of land disposal. To prepare sludges fur land disposal typically requires time consuming dewatering schemes, which can become extremely difficult to execute depending upon the composition of the sludge and its affinity for water. This study was undertaken to reuse fly ash and sludge as construction materials. This paper includes geotechnical properties of fly ash and fly ash-lime-sludge mixture and results of compaction test, UU-test, falling head test, leaching test and CBR test. The effect on mixing fly ash with sludge and lime and the effect of curing period and the results are obtained from this test.

Monitoring data from agricultural reservoirs throughout the country were analyzed to evaluate the limiting factor fur algal growth and relationships between Chl-a, total phosphorus (TP), and total nitrogen (TN). Total 394 reservoirs ranging from below 500 ㎥ to over 50 million ㎥ in storage volume were monitored from 1990 to 2000 with respect to TP, W, Chl-a, and their annual mean values were used fur the analysis. Based on N/P ratio, the dominant limiting factor for algal growth was turned out to be phosphorus in agricultural reservoirs (about 83%). Therefore, the proper managements of phosphorus in the agricultural watershed appear to be crucial to prevent excessive on algal growth. The effects of phosphorus and nitrogen ware most eminent during the summer period. And the effect of nutrients on the algal biomass (Chl-a) development appeared to be greater in smaller the reservoirs than in larger ones. Generally, Chl-a and TP demonstrated a close relationship while that of Chl-a and TN showed less correlationship. Chl-a and chemical oxygen demand (COD) also showed a good relationship. Beth ratios of Chl-a / TP and Chl-a / COD relationships were within the range of literature values. Quantitative analysis of TP and COD is relatively convenient compared to that of Chl-a, and the relationship between TP and COD and Chl-a from this study could be used beneficially for water quality management of agricultural reservoirs and related water quality modeling.

The objective of this study was to develop a modified CREAMS model for paddy field conditions. The model simulates daily balance of water and nutrient from irrigated paddies using meteorological, irrigation, and agricultural management data. The model simulates daily evapotranspiration of paddy using Penman equation and determines daily flooding depth changes. Total nitrogen and phosphorus concentrations within flooding water, surface runoff, and leaching water from a paddy field also can be simulated. Parameters of the model were calibrated using observed data of the Agricultural Experiment Station of the Seoul National University in Suwon Korea. The model was applied for the irrigation period of paddy field in Gicheon area when 1,234 mm annual rainfall was occurred. The simulated losses of the total nitrogen and total phosphorous were 11.27 kg/ha and 0.98 kg/ha, respectively. There was a good agreement between observed and simulated data. It was found that CREAMS-PADDY model was capable of predicting runoff and nutrient losses from irrigated paddy fields.

This study was performed to appraise multi-functional roles of agricultural lands in urban areas. The roles of agricultural lands as a part of urban environment were investigated to develop and establish an effective urban development planning with GIS-based analysis. Fifteen administrative districts at Chuncheon, Korea were selected to examine the roles of agricultural hands in these districts as educational, disaster-preventing, open-space, and recreational aspects. GIS was utilized to identify the distribution of agricultural lands and their accessibility to residential areas, school zone, public facilities, and major roads. The results obtained in this study can be efficiently used to guide decision makers to develop environmental-friendly urban planning at initial stage.