A natural river space is needed by many people and conservation of it is eagerly needed. Recently in Japan, many researchers have tried to conserve the ecological environment of a river. The purpose of this study is to investigate the infulence Of the changes of river environment and to built an expert system of hydro-ecological model. A knowledge-based expert system for the prediction of hydro-ecological environment of a river is presented.
The technology and applications of the Internet now extend beyond the realm of communication.
World Wide Web is a simple but most popular communication tool of the Internet.
To communicate directly with this system, data access through WWW browsers.

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The performance of corporations was highlighted from the view point of physical, human and information resources to strengthen risk preparedness and redundancy in urban area. Citizen activities in the suffered areas were supported by the suffered private companies as well as companies outside.
In order to clarify the enhancing mechanism in rescue and life support, decision making models were applied to each company behavior following to interviews and a questionnaire survey to the suffered corporations which had supported the suffered persons and individuals.
As result of the principal component analysis, extracted major principal component factors were interpreted to explain each decision sub-model respectively. In cluster analysis using these factors, the samples were divided into four clusters and some enhancing factors were extracted for each cluster. Those are as follows: 1) intimate communication in the channels of daily life activities of employee in local community, 2) opened active corporate management having area-wide information and product-based networking, and 3) past experiences of emergency control or disaster management education for executive directors of the corporation.

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The purpose of the study is to know the problems of environmental education in the open air. There are many types of definitions of environmental educations in Japan. At first the concepts of environmental educations are divided into two classes. The social survey of 69 associations of environmental education had done and analyzed with the quantification method 3 by Hayashi. The result shows that these associations and education styles are classified into 6 types; i.e. 1) environmental survey group, 2) city park group, 3) natural place group, 4) museum group, 5) teacher training group, 6) symposium group. Then The environmental education program in the case of M-dam was proposed.

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Face of excavation slope is difficult to reforestation introducing various treespecies, since it is rock-exposed and steep site. The authors propose a method for reforestation under the strict environment of face of excavation slope.
This method was tested at face of slope of dam site in Surikamigawa-river dam, Fukushima (under construction) and summarized as (1)-(4).(1) The most important properties of face of excavation slope are thin top soil and dry condition. Expected vegetation (vegetation that finaly expected to stabilize on the site) was selected from forest vegetation based on the properties of the face of slope.(2) More resistive species against dry condition were picked up as species for introduction among the whole species of selected forest vegetation. A vegetation table was constructed from phytosociological vegetation reserch at 45 points around there, and the table produced the species.(3) Seedlings of the selected species were introduced on the face of slope by spraying basement (alternative top soil) after put of the seedlings, and covering the root of them.(4) The basement was mainly composed of sandy soil to make poor nutrient condition.

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Several factors of the household waste emission in the Japanese local public bodies were investigated. We classified more than 2500 local public bodies into some clusters by using regional characteristics and factor analysis. These classifications could extract a significant administrative management system of the household waste. A significant correlation between many factors in relation to business, commercial and consumer's activities and the per capita emission of the household waste was obtained. Especially, a coefficient of correlation taken from the big cities was high because urbanization should promote the mixture of commercial waste into the household waste. In the big cities, the per capita floor area of house was related to the reduction of per capita emission of waste. A difference of collecting system for the mixed waste from system for the classified w aste was significant and per capita emission in the big cities with collecting system for the mixed waste was significantly high. An effect of waste reduction with the charged collecting system was also extracted.

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This paper aims to clarify the characteristics of the effects that the introduction of fee charging had on the reduction of household wastes in Tonami City in Toyama Pref. and Minokamo City and Takayama City in gifu Pref., each of which introduced a different charge system for disposal of household wastes. Using statistical data, an investigation was conducted on the changes in the amounts of wastes by those cities in recent years. To identify the causes of wastes reduction, a questionnaire survey was administered to the inhabitants. The questionnaire included questions about their attitudes toward the charge systems, and their behavior concerning household wastes. The analysis of statistical data revealed that after the introduction of the charge systems there was a significant reduction in the amount of wastes. The analysis also clarified the respective amounts of household wastes and office wastes. the responses to questionnaire yielded the following findings: 1) the inhabitants' recycling efforts and disposal of wastes on their own were major causes of the reduction with the three cities showing different ratios; 2) the local governments' enlightenment efforts were effective in enhancing the inhabitants' awareness of the wastes problem.

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Gross Resources Consumption and CO₂ emission in relation to cement and concrete industrial systems were investigated in this study. The reuse of waste by-product in the cement production and recycling process of concrete lump were also considered. Gross CO₂ emission related to the Japanese cement and concrete industrial systems in 1990 indicated 8.72 Mt-C (45%) based on the fossil fuel origin and 10.69 Mt-C (55%) based on the limestone origin. Most of those CO₂ emission were caused in the process of cement production. Many kinds of waste by-products of approximately 2.3 Mt were committed into the cement production, and those shared 19 % of all committed materials. As for an estimation of the Gross Resources Consumption related to an industrial system with much reuse of waste by-product, the Process Analysis Method was more effective than the Input-Output Analysis Method in which it was difficult to treat many kinds of byproduct.

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Objective of this study is to analyze the energy demand and the associated carbon emission pertinent to production of recycled aggregates used for road construction. The energy for operation of facilities to produce the aggregates, “direct energy”, is estimated by “parts-by-parts accounting” method. The energy pertinent to the production of these facilities themselves is obtained using the two different methods; the input-output model method and the “parts-by-parts accounting” method. This energy is divided by the depreciation term of the facilities and is accounted for the “indirect energy” of the aggregates production. The indirect energy calculated by the former method is slightly larger than that by the latter method. The total energy consumption (direct and indirect energy) and the related carbon emission at the production of a unit volume of recycled aggregates is 9.32-16.90 kcal/kg and 0.48-1.18kg-C/ton, respectively. Those of the production of virgin aggregate are 5.0kcal/kg and 0.32kg-C/ton. The main cause which increases the energy consumption of the production of recycled aggregates is the process of removal of foreign substance.

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This paper presents on attempt of integration LCA into comprehensive assessment of economic benefit and environmental load pertinent to the construction and maintenance of civil infrastructures. Energy consumption and carbon dioxide emission induced by unit monetary demand of consumption work projects are calculated, using national IO-Tables and other statistical data. Then, the transportation infrastructures in Japan are taken up, and the total of the life cycle environmental load (LCE and LC-CO₂) for the past 30 years (from 1961 to 1993) is estimated. The road system accounts for 50 to 70 per cent of the total environmental load related to transportation infrastructures, while the share of air transport significantly increased since 1970s. Finally, the role played by the improved transportation infrastructures in the national economy is discussed.

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A framework of environmental resource accounting appropriate for a specific region such as an area of a certain prefecture or a municipality is presented and tested. Firstly, values of environmental resources are discussed in terms of economic benefits or environmental service they provide, and methods to estimate such values are reviewed. Then, the methods are applied to Fukuoka City. The cost to maintain the present quality of air and water in the City are estimated to be 5.5 and 70 billion yen, respectively. Willingness to pay (WTP) for them are 3.0 and 3.4 billion yen, respectively, while that for the natural environment 2.8 billion yen. The value of parks obtained by the Hedonic approach is 36 billion yen.

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Economic value of the living environment is estimated in Fukuoka city, taking up four environmental elements, i.e., clean air, calmness, access to the water and daily contact to the nature. The total value of these elements is between 2.8 to 3.6 billion yen according to an estimation based on WTP (willingness to pay) method, while it is 7 to 10.6 billion yen if WTAC (willingness to accept compensation) method is applied. Among the four elements, the value of calmness is the highest, followed by clean air, contact to the nature and access to the water. It is found that what man has experienced in his childhood determines his environmental values and attitudes to the nature. This tendency is most clearly demonstrated in the case of the conceived economic value of the sea. The paper also presents the value of some environmental resources of the City. The use value of the Hakata bay is estimated to be150 billion yen. That of the three largest city parks is 63 to 145 million yen accoding to the travel cost approach, and 215 to 405 million yen by the contingent valuation method.

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Waste management is one of the environmental issues. As Japan has little resources, especially oil resources, so energy price has influence upon the industry, national accounts, and waste generation in Japan.
In this paper, tetra-lateral relations of energy price, national accounts, family expenditure, and post-consumer waste are mentioned, as quantative as possible, by the statistic analysis from 1963 to 1991. We quested the elasticity between each two category. This paper deals with additional influence of energy price changes.
As energy price becomes 10% higher, family expenditure will decrease 0.22%, and post-consumer waste will decrease only 0.11%. So direct impacts of carbon-tax to waste generation is not big.

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This study presents an estimate of the trade balance of environmental load pertinent to the commercial production and trade of grains. The energy efficiency, i.e., the ratio of the caloric value of the produced grains to the inputted energy for their production is estimated with respect to soybean, wheat, rice and maize in Japan and the United States. The efficiency in Japan is always lower than that in the United States, reflecting Japan's “intensive” agricultural practices. As for Japanese rice, the ratio proves as small as between 1.01 and 1.64. Furthermore, the international flow of the nitrogen nutrient associated with the trade of agricultural products and fertilizers is estimated. It is found that Japan accumulated 480 thousands tons of nitrogen in 1994 as a result of her import of 600 thousands tons incorporated in agricultural products and her export of 180 thousands tons in fertilizers.

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We have, however, long recognized the meaning of PUBLIC PARTICIPATION as follws: public participation eqnals public involvement in a certain part of the framework projicted initiativerly by gozermental bodies. This is why this public participation is named administratively organized citizen involvemnt. This report will witness that community building can be common ground where inter-active collavoratin of citizens and administratons may give its full swing. From my long experience in approaching of participatory community building projects and workshops, I display the idea environmental education worksyop useful to facilitate the real PUBLIC PARTICIPATION by which the citizens show their primary power. This participatory learninng system which have focused mostly on awareness and sharing. This system may even more involve PUBLIC PARTICIPATION seeking the potential alternatives, and developing the supportive partnership between citizens and administrations.

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This paper reports students' participation teaching, using environmental education workshop and electric network, on sub-mej or cource of environment and faculty of civil engineering, at Ritsumeikan University. Students recognized various people's opinion of regional environment, and deepened awareness of environmental problem, by colaboration. We had educatoinal effects, but next problems. And so, we propose more effective environmental education workshop.

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The following ideas are theoretically described: A steady movement of conserving and developing the social environment must originate from a citizens' common sense that they and their properties are parts of the environment and they must play a role to sustain it. However, the recent expansion of public works makes them lose the common sense because the public works take care of them so much that they cannot recognize the relation between their lives and the environment. This fact causes the citizens behavior which has a bad influence upon the natural and social environment It also reduces the autonomous characteristics of our society. The government and public sectors must open the information with which they can realise that their lives depend much on the environment through the public facilities.

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Why have our public environment become hard and banal blandscape? How important is an aesthetically pleasing public environment to personal well-being? It emphasizes linkages between vitalization of people's life and life's fulfillment of environment, which I call creative community design.
This article describes the meaning of environment learning through creative community design with an analysis of the building and management process of Nekojyarashi Park. It is located in Setagaya ward. The site's size is 2700 After resident's movement for 5 years, they participated in planning process of the park.
As a communal task of a series of workshop, the community-build project has many benefits, that are often the oppsite to conventional building methods.
It can provide a place with special landscape taste and an interesing and worthwhile experience for those participating, and also an opportunity to produce a good and open human network in the neighbourhood.
Creative community design with a participatory design and management is a totally situated environment learning process. In such circumstance's work, it produces not only an aesthetically nourishing environment, but also inspiring the human spirit and relation.

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Opportunity, local initiatives and enabling system for community-based residential rebuilding are analyzed in areas damaged by Kobe earthquake. Voluntary environmental learning actions observed in those areas show wide varieties of stimulating consciousness, community survey, future image building, means-searching and valuation. The shortage of illustrative papers of lots reformation prosess and few case of interpretation of technical jargons to laymen are found at first glance, however, in this paper the author emphasizes the degree of understanding environmental and monetary spillover of pros (benefit) and cons (cost) of park and road services in lots reformation process prior to cost-sharing of urban rebuilding project. Leadership in community organization, partnership between local government and community development association and local coordination among various motivations and behaviors of stakeholders are essential to empowerment in public participation.

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Corresponding to the increase household expenditures due to leisure and recreation activities for the past several decades, the carbon dioxide (CO₂) emission patterns also have become various and complex structure. In this study, CO₂ emission patterns due to leisure-related household expenditure and activities were analyzed using life cycle analysis (LCA).
First, the trend of the structure of CO₂ emission due to leisure-related expenditure from 1970 to 1990 in every ten year was analyzed. Second, CO₂ emission from production of goods and land construction works, building works for auto-camp, golf and skiing were estimated.
The results revealed that: CO₂ emission from leisure-related expenditure accounted for over 10% of total household expenditure; CO₂ emission from production of goods and land construction works were different by construction and scale that were derived from differences of the variety in these activity.

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In this study, we recognize the action of the offerer and the accepter in Joint Implementation to be cooperative game, evaluate decisions on imputed volume of reduced environmental loads and associated cost allocation in Joint Implementation. And we theoretically make clear the domain of imputed volume of reduction and attributed cost allocation satisfied with each cost effect of emission reduction in Joint Implementation better than cost effect of independent reduction of environmental loads by each party, by means of the management of imputed volume of reduced environmental loads and associated cost allocation in Joint Implementation between two parties with different cost effect of emission reduction each other.
Even if the accepter in Joint Implementation has no share of the total cost needed for Joint Implementation, the extent that improves each cost effect of reduced emission is determined by the ratio of marginal cost of a unit of emission reduction of the offerer in Joint Implementation to average cost of a unit of emission reduction in Joint Implementation. It is clear that the offerer with higher marginal abetement cost of emission can give more imputed volume of reduction to the accepter in Joint Implementation.

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The trans-migration among 29 Provinces (except Tibet) in China during 1985-1990 is analyzed by a linear model. The model is consisted of four parameters, i. e. the distance, the difference of the income, the difference of the income growing rate, and dialects (as a dummy parameter). The model for the net migration (immigration minus emigration) is accepted as for 12 Provinces. The distance and the difference of income are found to be contribute the migration. Ten of the 12 Provinces are located along the coast which is rapidly develop the economy and attracting people, suggesting that active migration could be illustrated by the model.

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The purpose of this study is to discuss environmental implications of increasing transport volume in Asian countries which are achieving rapid economic development. Increase in the number of automobile vehicles is most remarkable in cities which do not have appropriate mass transportation systems such as subways. From the global viewpoint, increasing freight transport and motorization in China attract our attention. The share of the tracks already exceeds 80 percent of the total automobile transport in China, and is still increasing. On the other hand, railways plays a dominant role in China's freight transport; their share being around 80%. As a whole, tracks play an important role in the short distance transportation while railways are responsible for the long distance. Carbon dioxide emission of transportation sector in China has been increasing mainly due to the increase of track transportation, although tracks fuel economy has been improved. With China's economic development, especially in the coastal region, transportation of coal from the North and West to the South and East will cause heavy burden on the railway transportation system. The coal transport from Shanxi Province to Hubei Province, in particular, is expected to be increased toward the year of 2010.

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Economic development and growth of population in Asia have caused an increase in the demand for food. On the other hand, disappearing the cultivation area and global warming have caused a decrease in the supply for food. In 1995, China imported cereals from U. S. A for the first time.
To understand the future of Asia, it is required to make a model which concerns about reciprocal action among demand for food, supply for food, environment, economic development. This study proposes a model based on ecology and economics.
For example, this study includes a model based on income producing processes. Income is obtained from a calculation involving capital and labor using the Cobb-Douglas function. These data for income is then used to calculate the demand for food.

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Arakawa River flows nearly in the center of Saitama Prefecture from a mountainous region down through plains. This river is considered to be an ecological axis (an great artery of ecological networks) that links together diverse natural environment of the Prefecture.
A local environment NGO, Ecosystem Conservation Society-Saitama, has been suggesting the impo-rtance of creating ecological networks of Saitama Prefecture along Arakawa River as their axis and has beentaking an active part in various cnservation efforts in the basin of the River.
On the other hand, at the Ministry of Construction has also been engaged in conservation and creation of natural environments of the Basin in a positive manner, to meet the demands of the times, that considerations to the natural environments are highly indispensable, as well as cont-rol and utilization of water.
The biotope projects in the Arakawa River basin were launched in respons to both the NGO's efforts and the Ministry of Construction's policy.
Furthermore, some examples of biotope projects, on the axis of the national level ones, condu-cted by cities and towns in the Basin are now present.

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In enviromental education at primary schools, aquiring natural experience which deepen understanding about relations between nature and man becomes more important. But, most schools in big cities, lesson about natural observation is given under unsatisfactory circumstances. So we decided to construct a biotope in our primary school by ourselves, for children to be able to study about nature any time and freely and continuously. The object of this study is to indicate various conditions to construct the biotope and some educational effects to make good use of this one.

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The concepts of relationship between river modification and natural environment is defined. The habitats of rivers are consist of river space and water. River space are composed of bed materials, plants, river bank, facilities and so on. Water means water flow and water quality. Organisms use these habitats. It is important that we understand the human impacts (especially river modification) makes some changes of river habitats and grasping the relation between the impact and the response (habitat response).

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Difference on situation characteristic between Umino-koen and Nojima-koen is not artificial beach or natural beach, it is structure and position of beach park where is related to the sea. Umino-koen is a horizontal type, which has residential area where is set apart by the road at the back of beach park. Nojima-koen located at an island is a combined types of horizon and vertical, which has Hirakata Bay, a tranquility water area at the back of beach park. There was a different image by the people who visit these two beach parks, where Umino-koen is a formal place, and Nojima-koen is an ordinary place. These differences are not only because of fundamental structures, but also because of facilitiy materials and plans which are set up for landscape of the parks, especially, shade area and surface soil area in total area of the parks. Shortnecked clams propagate in these two beaches, and many people visit for gathering the clams every spring and autumn. At Nojima-koen, in addition there have waterways in vertical part, where many people visit for fishing. The waterway and Hirakata Bay located at the back of Nojima-koen are famous places for goby fishing. By the survey results, I suggest that waterways and also other vertical structures which are related to the sea are necessary to be introduced into planning and developing of beach park in future.

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An analitical system for urban climate is developed with the aid of GeographycalImformation System (GIS) based on personal computers. Basic data necessary for analyzing thermal environment of urban areas are systematically processed, transformed to maps and exhibited on the display. For example, grid data of artificial heat emission from three kinds of sources, i.e., households, business and commercial buildings, and motor vehicles can be visually demonstrated on a map.“Thermal Environmental Diagnosis System” or an expert system to assess thermal structure of towns is also developed and tested for Kumamoto City.

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Recently thermal environment deterioration has become one of the major problems in urban areas.“Tropical night” which means the night with high temperature in summer causes sleep discomfort and energy consumption increase. This study approached the phenomena focusing on the mechanism which discharge exhaust heat upwards from surface boundary layer and carried out some simulation calculations by a turbulent closure model to investigate the response of urban boundary layer to the exhaust heat load. The calculations showed the heat can be hardly discharged in the nighttime upwards when stable boundary layer forms on the surface and also suggested heat discharge capacity in the nighttime is lower than in the daytime.

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Modelling of heating and evapo-transpiration processes in the plant canopy requires knowledge about plant physiology, which includes water uptake by the root, water transport in the stem to the leaf, and transpiration at the leaf; and also the knowledge of radiation and heat transfer processes in the plant canopy. The temperature and water content of the soil are also important for the root water uptake. Thus, the model for heating and vapor transfer in the plant canopy in this paper consists of a submodel for radiation transfer in the plant canopy, a submodel for the heating of the canopy, a submodel for the transport of water in the root-stem- leaf system, and a submodel for the evapo-transpiration in the plant.

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The effects on the thermal environment of vegetation and layout of buildings were evaluated with numerical models for an imaginary development of a few square kilometers in area. Heat fluxes from various surface materials such as asphalt, concrete, and so on were calculated with a one-dimentional heat balance model for typical summer days. This model takes into account the static stability of the atmosphere in the boundary layer. Heat fluxes from trees are evaluated both at the tree crown and at the ground under the trees, while heat fluxes from the wall and the rooftop of buildings are also evaluated. Sensible heat fluxes thus obtained were then used as boundary conditions for a three-dimentional simulations of the air flow in the development area. The results of the simulation show that summer hot condition in the area varies significantly with the fractional coverage and the types of vegetation. It turned out that the fractional coverage of 30% of trees seemed to be suffisient to lower the air temperature in the area and that the trees were much more effective in moderating the thermal condition than the low vegetation such as grass. The method of this study can well be applied to optimal land-use design in zonal developments.

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This paper studied the energy consumption in urban areas in terms of urban thermal environment. First we showed a method to calculate energy consumption for various urban activites; household, office building, hospitals, hotels, factories, traffic and so on. Then we determined the values of yearly energy consumptions per the unit activities through investigating statistics regarding energy consumption load and checked the values of the loads in Tokyo by comparing the total value of energy consumption calculated using the loads with that of supplied energy. Second we showed the difference between the energy consumption and the heat exhaust on thermal environment and defined the heat exhaust load through analysing energy consumption processes. After calculating the heat exhaust loads, we showed some examples of those.

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A numerical model has been developed for the simulation of the heating and evaporation processes in the urban canopy layer. The three dimensional filtered Navier-Stokes equations, continuity equation and heat and moisture transfer equations in the in the air are solved using a Large Eddy Simulation (LES) technique to obtain the wind, air temperature and moisture fields in the canopy layer. The heat exchange between the roof, walls of buildings, pavement surface and the air is evaluated by solving the heat conduction equation for the roof, walls and pavement. The heat and moisture fluxes at the unpaved ground surface or porous pavement surface are evaluated by the solutions of equations coupling subsurface heat and moisture transfer, and the evaporation at the ground surface.
Using the model, the heating and evaporation process in the urban canopy layer, and its effects on the urban thermal environment can be evaluated.

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The construction byproducts which are secondary produced from construction works contain recycling resources and wastes. Construction surplus soil is recycle resources. It is important to establish circulated treatment system focusing on the recycling of construction surplus soil from the global viewpoints of an effective use of limited land space and resources, and preservation of the earth environment.
Ministry of Construction investigated the present situation of occurrence, utilization and treatment of the construction byproducts twice (in 1990 and 1993). The detailed analysis was conducted and subjects to be solved were identified. Based on the results, “Recycling plan 21” was proposed in April 1994. For the time being, various policies and actions with the recycling target until 2000 AD have been developed towards the goal.
This article explains the present situation, subjects, and activities to promote recycling for construction surplus soil especially in Chubu region (central part of Japan).

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Amount of waste soil from construction activities is increasing year by year. Some 437 million cubic meters of the waste soil is generated in a recent year. Much of this soil is disposed to disposal sites, some in-land and some sea bottom, which cannot be considered as an effective usage of the waste soil. In this study.a waste soil recycling promotion center is proposed which enables more effective recycling of the waste soil. A feasibility study is also carried out for a soil treatment plant which is an indispensable part of this waste soil recycling scheme.

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In order to utilize coal ashes which are Produced from thermal p ower plants as material to improve defective soil, the important factors and suitable level of addition of coal ashes to soil were found out by using statistic analysis (design of experiment and multiple regression analysis). The analytic results show that the coal ashes themselves have less strength effect, but are effective to create the environment (moisture content, pH) promoting chemical reaction in the soil. Furthermore, it has the catalytic function to promote the effect of quicklime which is main content of ashes. It is almost confirmed that the addition of ashes to soil could be more than 12%. KEYWORDS: improvement material of defective soil, surplus fly ash, quicklime, gypsum statistics technique.

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The pollution of the water quality with the eutrophication is a problem in shallow lakes and marshes. Especially, oxygen shortage in the bottom layer causes rendering down, doing of nourishment from the bottom mud, and the smell to be generated.
The bottom mud consumes the melting oxygen in the lake. And, living thing's inhabiting becomes difficult. The problem is lack of the melting oxygen. A desirable environment is made if there is more melting oxygen.
We examined the method of supplying oxygen to the bottom layer region. We devised the method of sending water which abundantly contained the melting oxygen with the pump and pipe lying on the bottom. We examined the practical use by using the simulation calculation. As a result, the result that we were practicable was obtained.

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The purpose of this study is to find the characteristics of sound of flowing water in the river and in the channel of experiment from frequency analysis by FFT. In the area of river improvement and river conservation works have tended to put importance to landscape from visual approach. But, in the future, it is necessary that the basic idea of acoustic approach called soundscape compared with visual approach is disscused in the river design.

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The purpose of this study is to investigate the benthic population and structural change of river beds where improvement works were conducted at different periods. The changes of periphyton and benthos densities were determined at the resectioned river beds from autumn to winter. The survey results suggested that structural divesity of river bed was dependent on length of period after the improvement works. River bed has larger variety of structure with longer period after resectioning works. There was a difference in benthic population and its density between block-type beds with and without deposited stones and sands. However there was not a remarkable difference in periphyton and benthos densities between block-type bed and stone-type bed, once stones have transported and deposited to some extent on the block-type bed. River bed points with larger biomass density had a tendency to have lower diversity index values, because biomass amount was deeply dependent on the accumulation of one or two predominant biomass groups.

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In this paper, we present a parameter identification procedure for the pollutant load runoff models in urban areas. The procedure consists of two steps: the parameter estimation based on the optimization method and the observation noise separation of the input-output data with the neural network model. This procedure is effective for most of the pollutant load runoff models in urban areas and expected to give a more reliable and stable model parameter estimation.

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The objectives of this study are to simulate the behavior of pollutants in an urban area, and to estimate theeffect in 1994 water shortage on pollutant runoff. The simulations using the series of precipitation data of 1994 as a droughtyear and 1988 as a normal year were done by the pollutant accumulation-runoff model which was developed from the data ofpollutants' behavior in urban areas observed continuously in 1993 and 1994.
As a result of the simulations, these following things are cleared.(1) The amount of annual runoff pollutant load is not sosmall compared to the small precipitation of 1994.(2) The behavior of pollutants in 1994 which accoumulated during summerand ran off at a stretch by a large storm in the middle of September was shown.(3) Road cleaning during dry periods candecrease pollutants which run off into the public water area during a storm event.
In the result, some available knowledge for the environmental management of water in urban areas has been obtained.

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1994 drought caused serious shortage of water, which had great influence on social activities as wellas water supply. The objectives of this study are to estimate the influence of the shortage of water onthe safety factor of water utilization using data of supplied water obtained during the drought period in1994, and to clarify the relationship between the consciousness of water consumers about waterutilization and water saving from results of questionnaire surveys. As a result, it was shown that theexperiences of past drought were not reflected in 1994 drought, which caused long-term shortage ofwater. And it was proved that a new appropriate strategy against shortage of water had to beestablished immediately. In addition, it was cleared that a strategy for enlightenment was alsonecessary, because of the insufficient understanding for shortage water which was shown in theinsignificant relationship between the consciousness of water consumers about water utilization andwater saving. In the result, some available knowledge for the safety factor of water utilization againstthe shortage of water were obtained

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Many water problems in a river area, such as the shortage of water, water pollution etc., are occasioned by the urbanization and the increase of water demand in addition to agricultural water use. To solve these water problems, an integrated water management in the watershed both in terms of water quality and quantity is needed. The final objective of this study is to develop the integrated water management system for the Onga area. Water problem analysis is a first important step for analyzing water policy and the integrated management system. As a first step of this study, the water problems of the Onga River are analyzed based on the observed data of the water quality of the river for the last twenty years. It is clearly shown that eutrophication in the estuary reservoir takes place in summer season, especially in the low flow rate period. The BOD concentrations in the reservoir increase with the concentration of algae. Finally, the necessity of establishing the alternative concepts for the integrated water management is pointed out through comparing the existing water management in terms of water quality and quantity.

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Many projects to create rivers rich in nature are pushed on. However, the aimed conditions of nature are not always clarified. The vegetation of rivers plays important roles in habitation of various animals. Therefore, as the first step towards clarifying the desirable vegetation, this study focuses on the actual conditions of vegetation and influences of both hydrological regime and population density along rivers on the number of plant communities and species. The vegetation on riverside lands was investigated mainly based on the nationwide survey of the vegetation on riverside lands carried by the Ministry of Construction. The vegetation on riverside lands is greatly different river by river and showed a tendency to increase in rivers with higher coefficient of regime and to be influenced by human activities.

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On the grassland soil, much fertilizer and droppings are spread and finally these are changed to N2 gas through the process of nitrification and denitrification. For denitrification, there are still many unsolved problems including the production rate of N2O gas. So, it is important to estimate the potential denitrification rate of grassland soil from the viewpoint of environmental problems. In this study, we try to estimate the potential denitrification rate of grassland soil. At the same time, we measure some properties of the soil, such as ignition loss and available nitrogen and also try to estimate the spatial variability of these properties including denitrification rate. Finally, we consider the most suitable sampling distance on estimation of the denitrification rate of the grassland soil, when taking the spatial variability of these properties into accounts.

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Recently, the public has become more and more concern of the recovery of a natural environment. Toward this goal, improvement of existing stream environments and the building of streamsin parks have been going on increasing numbers. Traditional Japanese gardens have had man-made streams - or YARIMIZU, as they are called - for centuries. However, there is not much scientific literature dealing with YARIMIZU, and there are no studies that we know of evaluating YARIMIZU from a hydraulical viewpoint. The authors are interestedinevaluating the stream environment of YARIMIZU to gain a better understanding of the ancient Japanese gardeningmethods in terms of up-dated hydraulical knowledge.

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An activated sludge model for water quality management was proposed on the basic of biological reactions of heterotrophic, autotrophic and phosphate accumulating bacteria. This model is one of extensions of“Activated Sludge Model No.2 (ASM2)” presented by the IAWQ Task Group, and was made by careful checks of all of the variables, reaction processes and rate equations in ASM2. Some of variables, processes were amalgamated or excluded for simplification, while some of rate equations were replaced by more rational ones. The following are the major improved reaction models which were made in this study:
(1) Simultaneous uptake of two kinds of substrates by heterotrophic bacteria.
(2) Interactive relationship among poly-phosphate, cell internal storage product and phosphate accumu-lating bacteria.
(3) Precipitation and redissolution among phosphate, metal ions and metal phosphate.
In addition, a new denotation method was introduced for expression of reaction rate and stoichiometrical parameters, so that the model becomes more rational and simplified. Then availability of the model was verified by the comparison of observed data and simulated ones.

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In general, electric power and dewatering-aids chemicals are introduced in the dewatering process. In this study, the relationship between the operational CO₂ consumption for a lower moisture content cake in dewatering process and CO₂ reduction due to fuel savings in incineration, was evaluated. As the results, the dosing rate control of polymer flocculant was the most effective method for overall reduction of CO₂ including dewatering and incineration, as well as for acquiring lower moisture content in the investigated dewatering processes; solid bowl centrifuge and belt press. As an additional investigation for effective energy utilization in sludge treatment system, life cycle assessment of CO₂ (LCCO2) of regional hot water supply system for a residential area using scrubber washing water of incineration exhaust gas was also conducted.

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