The Okutadami - Otori hydro-power expanding project was completed in June 2004. During four years of construction period, the Golden Eagle pair nesting nearby site succeeded breeding and two young birds left them home. Aiming at coexistence of protection of the precious bird and construction works, an adaptive management method was introduced. The method is consisting of (1) a way to increase the amount of construction gradually, (2) continuous monitoring of young bird's reaction against works and its suitable feedback to improvement of works etc., The young eagles are becoming independent and growing after that.

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It is very important for us to understand the interaction between aquatic community and habitat conditions for proper assessment of river ecosystems. In this study, we investigated the effect of FBOM (Fine Benthic Organic Matter, 63-1000 µm) on benthic invertebrate community at two sites in Tama River before and after floods. As a result, there wasn't clear correlation between organic carbon of FBOM and weight of benthic invertebrates. By using Py-GC/MS, it was found that composition of FBOM sample at lower site (Hino-city) recovered after floods although that at upper site (Ome-city) was changed by floods. The biomass and taxonomic structure of benthic invertebrate community seemed to be affected by composition of FBOM.

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Based on RAPD, the genetic structures of Stenopsyche marmorata, Hydropsyche orientalis, and Ephemerella nigra populations found above and below reservoirs with various water surface areas were investigated. The results of the genetic distance showed that amongst the six reservoirs, the genetic differentiations of H. orientalis were found in the third smallest and in the largest reservoirs while those of S. marmorata were shown in the two largest reservoirs. The size of reservoir influenced the genetic differentiations for S. marmorata, but did not for H. orientalis. The expected heterosygosity indicated that genetic diversities of H. orientalis were constrained by both effects of habitat fragmentation and population size while the rest of the species were constrained only by the latter's effect.

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Nutrient removal ability of a constructed wetland channel planting with Luffa cylindrica was examined for eutrophic lake water. The DIP removal by the channel was expressed as primary reaction with a reaction rate constant of 20.8 day^-1. Nutrient absorbed by filamentous green algae (FGA) breeding in the channel occupied 67 and 90 % of total DIN and DP removed in the channel, revealing the significance of FGA in the nutrient removal. Since the FGA existed around the root of L. cylindrica, it could be considered that L. cylindrica contributed to support the inhabitation of FGA. High nutrient removal ability despite low nutrient concentration in the lake water demonstrates the applicability of the channel planting L. cylindrica on direct nutrient removal from eutrophic lake water.

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New observation well allocation algorithm was developed with point process model. The presented model can evaluate the observation well allocation in consideration of the geographic information system data and the contaminated source facilities. The efficiency of the presented model was examined by the numerical analysis. In the series of the numerical analysis, two kinds of contaminants were calculated by actual site data. In calculation, the effect of presented model was investigated in detail. In this paper, outline of the point process model is explained and the numerical analysis results are shown. The presented model can rationalize the allocation and number of the observation well.

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This study proposed a new sewage treatment system that combined a two-step UASB reactor (for removal of organics and denitrification) and an aerobic biofilm reactor. The laboratory-scale, combined system had been operated for 210 days by feeding a low-strength synthetic wastewater simulating domestic sewage. The combined system exhibited a very satisfactory performance in organics and nitrogen removal (achieving the removal rate of 91% and 61% respectively) at a HRT of only 4.7 h under the temperature range between 10 and 20°C with a circulation ratio of 2. Vial activity tests of retained sludge in the UASB reactor were conducted after the 210 days' operation.

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The sewage sludge generated in the sewage treatment process was changed in quality by electrolytic treatment, and reused as deodorizer. In this research, the heat behavior at the deodorizing process was visualized by the infrared thermal imaging device so that the adsorption mechanism was analyzed, because adsorption always generates heat. The result is that the adsorption heat was immediately generated on the surface of the treated sludge and the heat penetrated vertically into the whole treated sludge. Another result is the unequal adsorption heat; the heat was generated on some points of the surface earlier than other points. Moreover, the heat was generated repeatedly on the same points. The measurement of the vertical movement of heat shows that, first, the adsorption heat penetrated into the sludge exponentially at the earlier stage, and then penetrated while repeating the heat generation and the endothermic reaction, and lastly disappeared by desorption.

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As the discharge of sewage and sewage sludge is increasing, more effective utilization ways of them are required. In this research we studied the applicability of various phosphorous recovery technologies to sewage treatment systems, because phosphorous is an important exhaustible resource. First, mass balance in real sewage treatment plant was investigated. Second, the phosphorous recovery ratios of phosphorous recovery technologies such as MAP, Crystallization were formulated from literatures and experiments. Third, using an object oriented analysis program, it was simulated the mass balance, cost, environmental load of phosphorus recovery from sewage treatment system. Then by making them into indicators, the optimum recovery technologies and their applied points were selected. From simulation of 80,000 sewage treatments systems, it was selected Crystalization applied to the dewatered filtrate and Ultrasound extraction with recovery using Ca(OH)₂ applied to the thickend excess sludge.

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In this study, we investigated the nitrogen budget with fine weather and factors of preservation at the natural tidal flat near the city. Furthermore, we examined the amount of the inflow load to the tidal flat at rainy days. As results, the Ulva and Benthoses contribute for the nitrogen fixation in the tidal flat. The runoff water load is relatively little as the amount of inflow load to the tidal flat. On the estuary tidal flat in wakayama are controlled by the amount of the treated water load from the wastewater treatment plant and the amount of the pump water load up from the tidal flat

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The amount of discharge and recycling of concrete waste (CW) and asphalt concrete waste (ACW) was predicted until 2020 in Yamaguchi prefecture. Although CW discharge and recycled crushed stones (RCS) supply is going to increase because of high rate of building demolition, RCS will become overstock influenced by decreasing public works. On the other hand, ACW discharge and recycled aggregate for asphalt mixture (RAAM) supply is going to change parallel based on governmental works investment. Recycling rate of RAAM can be increased even though it becomes overstock. Reduction of virgin material and expansion of recycled material should be important for sustainable recycling system.

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Mathematical simulation is performed to investigate the importance of watershed management on the utilization plan of Dam Lake as a water source. Setting recreations, water quality conservation and regional exchange as watershed problems for the utility value of waterfront, we use conjoint analysis to show the current status of utility value and its gap among local residences based on the environmental economics. Furthermore, the influence of the positivity for planning by inhabitants on the utility value of waterfront is examined developing the game theory. The expectable sociality among the watershed citizens is described.

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In order to removal of disinfection by-production THM precursor and reduction of TOC, two-stage treatment of ozonation and advance oxidation and BAC treatment were proposed. The result suggest that it was a difference on the removal of the DOC, THM precursor in ozonation and O₃/H₂O₂. And it was proven that the treatment effect raised the optimum combination. On the other hand, in the range of this study, it was proven that the O₃/H₂O₂ treatment was the optimum combination for the front stage treatment for ozonation.

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Considerable increases in turbidity and inorganic content in suspended solids were observed in Lake Kasumigaura during the last decade. Turbidity change in response to wind was analyzed to estimate the critical bottom shear stress and sediment resuspension rate; thus, a decrease in the stress and a rise in the rate were found to indicate a gradual attnuation in resistance to sediment resuspension. Turbidity and size-distribution of suspended particles were well simulated by a numerical model with these parameters, suggesting that the growth in sediment resupension resulted in turbidity increase during not only strong wind events but also calm periods. Then, the causes for the increased resuspenson were discussed roughly.

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Lakeshore vegetation has been deminishing owing to lakebank construction, lakeside development and water pollution; hence, it threats the biodiversity of lakeshore. As a countermeasure, lakeshore restoration and rehabilitation projects are carrying out in various regions. The technique for restoration, however, is still under development. In this paper, we proposed the index, named Lakeshore Energy Flux (LEF), to evaluate the vegetation growth potential. The index is calculated by wave energy flux along shore and littoral slope. The critical value of LEF for vegetation growth is less than 20 kg•m/day/m, and the vegetation expands in width as LEF decreases in value. LEF can be used to evaluate the possibility of vegetation growth along lakeshore and predict the potential for vegetation width at a restoration site.

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Several flood-analysis models have been already developed in construction consulting companies, universities and public research organizations. Some flood-analysis models, such as MOUSE, Info Works and SWMM have been generally used by Japanese construction consulting companies. Each formula describing the energy loss at the manhole in a storm sewer is, however, different from each software application, and consequently the results of simulation of prediction on inundation, flood area and water depth on the ground surface in urban areas are also different. A more exact estimation of the energy loss at a manhole is necessaly in flood analysis. This paper proposes a new formula for energy loss coefficients that considers structural and hydraulic elements, such as manhole size, pipe size, drop between upstream and downstream pipes, connecting angle of pipes, and water depth for a two-way circular drop manhole. In the proposed formula, calculated values of energy loss at the manhole are within an error of ±30% of the measured values in accuracy except some structural conditions for the manhole and connecting pipes.

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Leakage of leachate through landfill bottom liner and overflow of leachate from waste storage dam were modeled under various options for design, construction and maintenance. The model includes lateral flow on an intermediate cover, a bypass flow through vertical pipes (ex. gas venting pipes), and leachate accumulation in a landfill caused by clogging of leachate collection pipes and inadequate capacity of leachate storage pond. By using this model, the amounts of leakage through three types of bottom liners were calculated and compared. Moreover, the mounts of leakage and overflow were calculated under various options for design, construction, maintenance and waste characteristics. The calculation results showed that the hydraulic conductivity of sand drainage layer, the number of geomembrane sheet defects, the diameter of a sheet defect and the hydraulic conductivity of clay used in the single composite liner incresed leakage rate severely. This shows that for the reduction of leakage rate through the bottom liner, the selection of material for sand drainage layer, quality assurance of sheet, technical skill of operators and the installation of clay liner are very important. In addition, the calculation results showed that the functional failure of gas collection pipe could cause overflow of leachate from waste storage dam, particularly when the soil with low permeability was used as the cover material.

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Nitrous oxide (N₂O) fluxes and concentrations were measured in the rivers placed in urban and agricultural areas in Kanto and influencing factors were determined. The highest concentration of N₂O (20.3 μgN/L) was detected in the river where high concentration of nitrate, around 20mgN/L, was found. The 8 years ago survey at the same river indicated that high organic materials influenced on N₂O production. However, nitrate becomes current influencing factor due to improvement of water quality after river reconstruction. The batch experiments using water and sediment of the river also indicated that organic materials and nitrate are important factors influencing on nitrous oxide production.

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This study investigated the effect of sewage effluent on river water quality using algal assay. AGP (Algal Growth Potential) and algal growth inhibition tests were conducted in this research.
As a result, the AGP level and nutrient concentration were considerably raised after inflow of sewage effluents. This indicates that the inflow of sewage effluent seriously affect to eutrophication of the river. Meanwhile, as a result of algal growth inhibition test, toxic effect of river water on algae was slightly raised after inflow of sewage effluents. Although the toxic level was low, it will be necessary to note the long-term influence to the aquatic ecosystem.

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In this study, we evaluated the amount of the reduction of the combined sewer overflow (CSO) load by the execution of real-time control (RTC) for the combined sewer system region where storage basin was constructed. Especially, the effect of the reduction of the load is high for the amount of rainfall is 10 mm. Moreover, the amount of BOD load has been reduced 18-26%, and overflow frequency has been reduced 14-29% by RTC system as a result of annual analysis. In addition, it was clarified that the effect of the reduction of cost of RTC system was high as a result of cost-effectiveness analysis. It was clarified that the introduction of RTC system was effective as one of the CSO measures.

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