Nitrogen outflow and its variance after rainfall events were investigated at the small watershed with pig farms. The unlined storage ponds are used to store animal waste in this area. The area of watershed is 15.3 ha and the number of pigs is about 800. Pig stocking density is 52 head/ha. Water sampling and measuring of discharge was conducted for 70 days by parshall measuring flume and automatic water sampler. Nitrate nitrogen concentrations were very high during ordinary time unaffected by rain, and the average was 44.8 mg/L. After rainfall, the discharge increased rapidly, and decreased gradually almost within a few days. During the period affected by rain, nitrate nitrogen concentration decreased by dilution, and the average value in this period was 34.5 mg/L. Nitrate nitrogen load increased during this period, because the load was washed out by rain. The average concentration of total flow was 42.5 mg/L, which correspond to 95% of the value of ordinary flow. This shows that the concentration at the ordinary time may be used for presumption of the total amount of outflow load at this watershed.

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There has been no official, standard assessment procedure for use in determining the money used for settling replotting accounts. To cope with the situation, the Japan Land and Water Association formed a Study Committee, which has assembled the concepts suitable for such a procedure and has issued a report to the public in March 200
This study, based on the above mentioned report, states that the assessment procedure must be formed in such a way that the amount due is always equal to the amount to be collected, because the legal factors, the bounds and the payment due which form a basis of designing a framework of procedure should always be balanced as shown as in a balance sheet. This study further states that the standard assessment procedure in liquidation when replotting must incorporate the following four steps; 1) Evaluation of the land, 2) Assessment of the estimated value of the land, 3) Adjustment of differences of estimated values, and 4) Determination of the amount due upon liquidation.
In conclusion, this study addresses issues which have been difficult in the valuation process, including the matter of how to adjust differences of estimated values.

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This paper clarifies the properties of ground motions observed by K-net and KiK-net of National Research Institute for Earth Science and Disaster Prevention during the Geiyo earthquake in 2001, and non-linear seismic response analyses with Ramberg-Osgood model are conducted for a damaged dam. To investigate the relationship between crack generation and properties of the dam, especially to verify the effect of soil stabilized by lime and water level of reservoir, 4 cases of analyses are carried out. As a result, soil stabilized by lime is shown to have a significant effect on the crack generation at the top of dam and these are independent of water level. Sliding failure during the earthquake was not occurred and also the slope stability can be confirmed by the evaluation with local safety factor derived from the analytical results.

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Settlement or hardsetting of upland field following to irrigation has been observed in recently developed upland fields in aerial deposit area of Loess Plateau, Northwest China When irrigationiwater was infiltrate into the soil, skeleton of the soil was collapsed instantaneously. This phenomenon is called collapse settlement, which is different to consolidation in soil mechanics. Presenting study used soil ccre and measured stress, strain during applying water subsequent to loading. To explain relations between stress and strain as a function of time, a rheological model was proposed. According to spectrum analysis of generalized Voigt model, the model consisted of a series of one spring. which represents instant large strain and two Voigt elements, which shows delayed compression strain, could explain collapse settlenent of the Loess soiL Proposed model could also explain the collapse settlement characteristics of the Loess soil.

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An one-dimensional finite element mass transport model with nitrogen species transformation was developed to predict the transport of nitrate-nitrogen (NO₃-N), nitrite-nitrogen (NO₂-N), and ammoniumnitrogen (NH₄-N) in porous media. Field experiments using sulfate ammonium wereperformed and temporal and spatial distributions of NO₃-N concentration and volumetric water content were measured. The numbers of nitrifers and denitrifers, and pH values were also measured. The rate of aquifer recharge and rate coefficients of the transformation were calibrated to fit the measured distributions of water content and NO₃-N concentration at 28th day of experiments. The validity of this model was examined and confirmed by comparing the results of numerical analysis under the calibrated values with measured data at 42nd day of experiments. It was found that there is a good correlation between the number of microbe and rate coefficients, which greatly affect the prediction results. The variation of the NO₃-N concentration is able to be predicted through this model in the experimental site when appropriate rate coefficients are used based on environmental conditions, which have the effect on microbial activity.

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In order to decrease nitrate nitrogen (NO₃-N) loads in upland fields to prevent migration to the subsoil (or groundwater), we measured NO₃-N reduction potential of soil in an upland field. The soil texture is loam and was taken from the Kanto Plains. Samples of soil were submerged and methanol was added to the soil as carbon substrate for biological denitrification. As a result oxygen consumption rates and NO₃-N reduction rates of the samples were relatively low until day after the start of the measurement after which both rates increased considerably. NO₃-N reduction rates of the surface soil and the soil at the 30cm depth from the surface increased up to 0.8mgN 100g^-1 dry-soil d^-1. However, NO₃-N reduction rate of the soil at the 60cm depth from the surface was less than half that of the preceding top soil. The surface soil or the soil inthe upper layer, rather than the soil in the lower layer, in upland fields is suitable for NO₃-N reduction.

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Thermal conductivities were measured to clarify the effects of water content and NaC1 concentration on thermal conductivity of swelling clay, Kunigeru V1, and nonswelling clay, Kaolin, by the twin heat probe method.
The thermal conductivity of nearly saturated Kunigeru V1 decreased inversely with mass basis water content, to the value of water thermal conductivity. When NaC1 concentration was limited within a range where no flocculation of Kunigeru V1 occurs, thermal conductivity was not affected by NaCl concentration. On the other hand, the thermal conductivity of Kaolin increased linearly in the range of 10-30 % of water contentand maintained its maximum value at higher water content. Contrary to our expectation, thermal conductivity of Kaolin either decreased, or maintained constant values with NaCl concentrations. The empirical formula for each clay, which describes the effects of both water content and NaCl concentration was proposed.

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The rock salt layers underlie at shallow depth under 50m-100m in depth and saline groundwater is distributed in Phra Yuen area, northeast Thailand. The G1 and F 1 faults were inferred by analyses of geological columns at 16 sites (A1-A16) of the regular 1 km grid covered 3km×3km area and photo-lineaments interpretation. The electromagnetic prospecting, the electric prospecting, and the soil temperature survey at 1m depth were carried out along the survey lines of A5-A7 and A10-Al2 to verify the inferred faults. The conductivity sections by electromagnetic survey showed the vertical distributions of high conductivity zone around the inferred G1 and F 1 faults. The resistivity section showed the vertical distributions of high resistivity zone around F1 fault. The results of soil temperature survey revealed an anomaly low soil temperature zone over the F 1 fault. The cross-check of different methods of physical prospecting ensures the possibility of inferred G1 and F 1 faults. The monitoring result of groundwater showed that the electric conductivity of groundwater changes seasonally and locally. The evidences of groundwater with a high electric conductivity and distribution of ponds with water salinization along inferred faults support that fault has a function of pathway for upward movement of the saline groundwater.

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he objectives of this study were to obtain the dispersion coefficient and dispersivity based on a statistical model using image analysis and to investigate dye tracer movements in two-dimensional saturated and unsaturated porous media through laboratory experiments. Flow fields with the different water levels were composed of two types of glass beads in two-dimensional tank to examine dispersion phenomena. Dye tracers were injected into the capillary and saturated zones of the flow system under the steady state flow conditions and the images of tracer movements, which were recorded periodically with a digital camera, were used in the process of the estimate of the dispersion coefficient. The outlines of distributions of the tracers computed by numerical analysis were consistent with the measured results. It was found that while the flow velocity became small with the decrease of the mean grain size, the dispersion coefficient and dispersivity became large. It was also observed that dispersivity in the capillary zone is larger than that in the saturated zone

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In this paper, Creager's equation and Group's equation are algebraicaly examined to determine an equation of an enveloping curve for regional flood peaks from the viewpoint of the curve profile.The applicability of a small drainage area with little observed data on flood peak discharge was examined in comparison to specific flood peak discharge calculated by a rational formula using data of maximum rainfall. In the algebraical consideration, the Creager's equation had an extreme value at a drainage area A=1.0 km², and the specific flood peak discharge became a maximum. Flood peak discharge calculated by Group's equation had an extreme value at a drainage area A=6, 568km², and it became a maximum. In about 1, 178 km² or less, the value and curve profile of Group's equation using a maximum value of the local coefficient approximated the specific flood peak discharge calculated by the rational formula using the maximum rainfall data from Japan. Except for Hokkaido, the specific flood peak discharge calculated by the rational formula using local data of maximum rainfall considerably approximated the value and curve profile of Group's equation at about 1, 178 km² or less. From the above research results, the Group's equation is applicability better than the Creager's equation, as the drainage area A is 1, 178 km² or less.

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One of the fundamental problems of farmland policy in Japan today is to adjust the unstable factors of long-term food supply and demand, while the structural excess of rice crop products is held short-terminable. As a solution for such problems, the authors have proposed the extensive management as a method for the agricultural land resource maintenance. In this paper, from the restoration cost of the abandoned paddy fields' point of view, we gave an estimate of the possibility of utilization of agricultural land resource economically, so we attempted to make a model of relationship between elapsed years after abandonment and restoration cost of abandoned field lot according to the case.
We surveyed in Ohshima where is one of the most snowy district in Japan. As the result, we cleared that continual maintenance by little operation year by year at an early stage of abandonment is more effective from the economical point of view, and advanced proposals on conservation measures of farm land resource.

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The objective of this study is to examine the possibility of the utilization as a coarse aggregate for the concrete of air-cooled slag from incineration ash from municipal solid waste. We inspected the quality of the 3 kinds of air-cooled slag (slag O, H and K), and concrete that used its as a coarse aggregate in research. As a result, the following have been clarified:(1) All of the slag have excellent physical and chemical properties as coarse aggregate for the concrete, though SO₃ content is abounding.(2) Almost all slag of the slag elutes hardly any heavy metals at all.(3) The strength of the concrete using the slag aggregate were equal to or lower than ordinary concrete.(4) The freeze-thaw resistance of the concrete using slag 0 is high, but the concrete using slag K and H is very low.

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Gas concentration in soil air is different from that in atmosphere, because it is affected by activity of microorganisms and gas diffusion. In our previous study, it was shown that the gas concentrations varied at a hard pan in the field, but the mechanism of the hard pan on gas behavior was not clearly elucidated. In this study, we evaluated the effects of a hard pan on CO² and O² gas behavior in soil in column experiments and in simulations. In soil column, it was found that, below the hard pan, CO² concentration was higher and O² concentration was lower than above it. Both CO² and O² concentration distributions in the column were similar to those in a field with the hard pan. Simulations with measured gas concentration of column experiment suggested that the generation of CO² gas from microorganisms at the hard pan might be larger, and also, prevention of gas movement by water, and soil particles above the hard pan or large gas flux through the top layer might have kept CO² concentration low above the hard pan.

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This paper presents the experience of establishing a water users' organization in the Chao Phraya Delta in Thailand. Based on the results of experience, the presentation will propose a new policy for establishing a water users' organization in the Chao Phraya Delta. The proposals cited are as follows:(1) one Water Users' Group (WUG) shall be established in each beneficiary area of irrigation ditches, and an Integrated Water Users' Group (IWUG), that integrates all WUGs within the same lateral canal, shall be established at the same time;(2) auditors shall become part of the IWUG;(3) responsibilities and functions for irrigation water distribution shall be identified, and the Royal Irrigation Department (RID) shall then provide necessary information to farmers for their decision making;(4) to provide motivation to farmers to organize, only water users' organizations that have been established by farmers themselves can apply to the RID for the execution of rehabilitation works on irrigation ditches;(5) laws shall be enacted to secure the activities of water users' organizations.

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A methodology is developed to identify the extent of non-point contamination sources and the fluxes to steady-state groundwater flow, using an extended genetic algorithm (GA). The methodology has two search steps for identification. The first step searches for the center element of non-point contamination sources. The second step searches for the extent of non-point sources and the fluxes, outward extending the contamination area around the center element obtained at the first step. In both steps, the extended GA is employed to asymptotically determine the contamination sources and the fluxes with the object of achieving a good coincidence of observed and computed concentrations at observation wells. To test the capability of the methodology, fictitious contamination in a real groundwater basin is considered. Solute transport simulations reproduce the concentrations observed at the monitoring wells. The search results using the observed concentrations indicate that the methodology developed is capable of identifying the extent of non-point contamination sources and the fluxes.

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We investigate the relationship between the selection of objective functions (functions for error estimation) used in calibration of rainfall-runoff models and the goodness of fit simulated hydrograph. The Tank Model, which has 16 unknown parameters including 4 initial storage depths, is calibrated by the SCE-UA (shuffled complex evolution) method using the 7 objective functions for the Eigenji, Osako and Syorenji Dam basin. The results are summarized as follows: 1) The runoff volume of model calibrated by using RMSE (Root Mean Square Error), MAE (Mean Absolute Error) and LOG (RMSE of logarithm transformation flow) is almost equal to the observed runoff volume. Using other objective functions, the runoff volume is consistently underestimated, so that the constraint of the permitted water balance error is indispensable. 2) RMSE emphasizes most the goodness of fit at high flows. LOG, χ, RE (Relative Error) and RR (Root Mean Square of Relative Error) emphasize low flows. 3) The calibration results using RMSE are most consistent in the parameter estimates. In the functions emphasizing low flows, the RR calibration results are most consistent. 4) Using about 4-year data period, parameter estimates don't much depend on calibration period and stable results are obtained.

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A study of groundwater concentrations of nitrate nitrogen was conducted in M City in the Miyakonojo Basin, based on measurements taken over a four-year period from August 1996 to August 2000. Most wells where measurements were taken were shallow wells with a depth of 20 m or less. Groundwater concentrations of nitrate nitrogen at most measurement points remained relatively stable, with few points exhibiting increasing or decreasing tendencies. However, some measured points where levels remained stable exhibited significant fluctuations in nitrate nitrogen concentrations, and the higher the groundwater nitrate nitrogen concentration, the greater the fluctuations. M City was divided into six areas, and mean nitrate nitrogen concentration was calculated for each area. The resulting values ranged from 2-10 mg/L, and the mean concentration of nitrate nitrogen remained relatively stable during the survey period in all areas. Furthermore it turns out that there is an area where the well exceeding 10 mg/L in nitrate nitrogen concentration exists no less than 44%.

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This research is considered on SanQiao Village of the ZhangJiaBang coast green area in PuDong New Area, which is taken as an example toward the policy for setting up formation and farmland preservation of rational land use order, which is including both city and farm village, while its verifying is based on the field survey upon the actual condition and the effect of the wedge type green Area. Then, various problems, such as the principle, the procedure, realization means and the actual measure of land use, the factor of country immigration, are performed to the wedge type green area plan. The following proposals were performed to the future wedge type green area plan, aiming at the rational Induction of land use in suburban rural area of a big city. a) The clarification of the contents and the reservation of the regulation technique of wedge type green area plan. b) The production and the realization method of a plan. c) Integrated improvement including rural nd urban area etc. On the other hand, it is also proposed a kind of combination of the Chinese conditions of a country and the countermeasures against country emigration etc.

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