It is well known that muds exposed to fluid stressing are eroded, and is very important to understand the mechanism of mud layer erosion for the fluctuation of water quality. The patterns of mud surface affected with the flow are classified in longitudinal rectilinear grooves, linguoid ripple mark as internal wave, parting-step lineations and current ripple. These patterns are controlled by the shear resistance of muds in triaxial compression to frictional and cohesive properties, effective stress, soil structure, rate of strain, and temperature. And velocity and shear stress are often used interchangeably in erosion studies.
Data are presented showing that the activation energy is directly proportional to water content, mobility of strainrate superposed on the expanded Ostwald fluidity curve and the number of interparticle contacts per unit area of mud cross section. For the activation energy of contact on the interparticle is concerned with the cohesion of mud layer, this parameter isintroducedintothe basic factors to explain the fluidity, surface patern and eroded mud quantity. Consequently, the mud fluidity is synthetically explained by the microscopic activation energy of interparticle, and by the dimensions of macroscopic hysteresis loop signified internal friction energy.

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Gamoo lagoon (Miyagi Prefecture) is well known us a resting and feeding place of migratory bird such as snipes and plovers. This study reports a series of measurement of SS, salinity, flow velocity, water level and bottom sediments in Gamoo lagoon with a aim of the conservation of the ecosystem. The present study revealed a large deposition along the bottom of inner region of the lagoon. This is mainly due to SS in the water inflowed from the Nanakita river, waste water dischage from fisher farm behind the lagoon, and the sand transported by the water over the beach during storm at Senday bay.

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The specific release rate of algal extracellular products was investigated employing continuous flow stirred tank reactors (CFSTR) which have hydraulic retention times of 0.5, 1.0, 1.5, 2.0, and 4.0 (days), respectively. The results of this investigation indicated that the apparent specific release rate of algal extracellular products decreased from 1.12 (1/day) to 0.04 (1/day) with the increase of hydraulic retention time. This phenomenon was explained by the transition of algal species in CFSTR from the green algae to the diatom with the increase of hydraulic retention time. That is, the green algae was a dominant species in CFSTR with a short hydraulic retention time, whereas the diatom was a dominant species in CFSTR with a long hydraulic retention time. Therefore, taking it into account that the apparent specific release rate of algal extracellular products decreased with the increase of hydraulic retention time, it was concluded that the diatom could release more extracellular products than the green algae.
The experiments on the uptake of algal extracellular products by heterotrophic bacteria made it clear that the consumption of algal extracellular products by them was negligible in obtaining the net specific release rate.

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This is the system for purifying the water in large area by using the energy of the waves and the tide. We have found that the wave-breaking breakwater with much void in them have a lot of effects on purifying the water. And this time, we fence off the area which we want to purify, and call it “the system of purifying the water area” or “Utsuro; the unsubstance of the water area and the ocean”. Not only this “Utsuro” is effective for such polluted wateras red water, river pollution, sewage drainage and pollution by oil, but also, by using the energy of waves, high tide, and tsunami, it turns “disasters” into harmless things rather to be more useful. Therefore, this “Utsuro” makes good efforts on preserving and developing the environment.

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ABSTRACT: This study was performed in order to investigate the mechanism of suspended sediment transport and the water quality behaviour in the tidal river.Field observations were carried out at several times in the River Rokkaku which shows strong mixing of salinity. The following results were obtained: 1) A turbidity maximum moved toward up-and doun-stream with erosion and deposition of suspended sediment according to tidal action; 2) Suspended solids affect the water quality.Phaeo-pig.and COD have a relationship to suspended solids through the year and 3) Suspended matter have a tendency to be transported upstream during one tidal cycle.

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The purpose of this study is to investigate the NO-NO₂ reaction in areas along road applying the statistical analysis to the data of measurements on the roadside.And the simple formula was derived, by which we can predict NO₂ concentration from NOx concentration of gas exhausted from automobiles as accurately as other expressions which had been already proposed.

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Compliance with water quality standards for a stream is evaluated by comparing the probabilistic water quality with the given stream standards. In Japan. the probabilistic water quality corresponding to cumulative probability of 75% is used for the above evaluation.At first, factors giving effect to the accuracy of probabilistic water quality estimated from limited data are discussed theoretically. As the above factors, the population parameters of a water quality variable, cumulative probability and a sample number are picked up. For the case of a water quality variable distributed log normal the confidence limits are nearly determined by σ²/n and the selected cumulative probability, where σ² and n are the variance of logarithm of a water quality variable and a sample number respectively.Secondarily, the estimation method used by a water quality management agency is discussed based on observations. The confidence limits of the estimated values are shown comparing with the observations.

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The water quality in coastal waters, lakes and lagoons is controled by various processes of the different time scale as second, minute, day, week, month, season, or more than several years. At the same time, the water quality distribution is determined by the resultant of the accumulation from the past. On the seawater quality prediction, the acquisition of the detail data of the past is mostly imposible, and the model that accurately reproduces all phenomena varied with different time scale could not exist. For this reason, each process such a current, .temperature, illumination, dissolved oxygen, settling rate is treated by its averaged value with respect to diurnal, monthly, seasonal, or annual mean. This paper describes the applicability of time averaging treatment of internal production rate, decomposition rate, oxygen uptake rate, O-P settling rate, etc. According to the present investigation, the application of the average with preferable time scale makes the prediction procedure easy and produces the similar result as the analysis due to the time-varying parameters.

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Classical Monod model is often unadequate to the experimental data of the biological treatment processes. In some cases it is important to consider the poorly-decayed substrates or metabolic products. One of the surprising phenomenon from chemical engineering point of view is an effect of the influent pollutant concentration on the pollutant consumption rate. This phenomenon is explained in the paper by a heterogeneous nature of the pollutant and biomass. The corresponding mathematical models are discussed. These models show that a mean solids retention (biomass turn-over) time is a very important integral parameter of the biological treatment processes. Under the population shifts the consumption rate of the summary pollutant can be dependent on the influent pollutant concentration.

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The capital city of Thailand, which is located on a low-lying delta, suffers chronic flood problems due to rapid urbanization associated with very fast land-subsidence. Through bilateral co-operation, appropriate systems have been studied for her flood-protection and drainage project. It is recognized that mechanical system is not soley effective; namely an existing flood-plain management is expected to be integrated into the more comprehensive measures under the local socio-economic conditions.

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The current water's edge environment of the Kakehashi river in Komatsu has been critically reviewed on the basis of the literature survey and field study.
It is realized that the water's edge environment is far superior to that of rivers flowing through the big cities such as Tokyo and Osaka in Japan, and is still keeping an excellent ecological system consisting of animals, plants as well as human beings. There are many forests and buried cultural properties around the river.Each of the forests normally belongs to the shrine that has been the centre of the people's belief and life, whereas the distribution of the buried cultural properties reflect the sphere of their activity since the 2nd century or more ancient time.
It is strongly recommended to preserve the water's edge environment of the Kakehashi river including a valuable shrine Komatsu-temmaangu, the forests and the buried cultural properties for the further development of the characteristic culture in Komatsu, where Komatsu-temmangu was founded by the third dynast of Kaga-han, Toshitsune Maeda in 1657 and was designated as a national important cultural property in 1961. Hence, any countermeasure for the flood contradicting to these propositions must be modified so as to meet them or the alternative countermeasure must be newly considered.

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The symbols of environmental resources involve peculiar meaning for residents' consciousness of neighborhood environment. An image map technique for public awareness and a psychological assessment technique for iconic sensation are applied to identification of the peculiar meaning of the symbols which residents are specially concerned about and are deeply attached to. By data analyses using semantic differential method and a quantification technique, familiarity with the symbols is extracted as a significant concept apart from imageability, visibility and aesthetic appreciation in impressions of residents. The familiarity in mind of residents is more intensified wi th the passage of the residence time, furthermore as they have experience of knowing more their environment and of voluntary action for environmental betterment, judging from the differences of their attitudes to the symbols among citizens movement participants and non-participants.

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It is the essential factor in citizen participation in the planning of urban renewals that there are good mutual communications between local residents and planners. Citizen participation in the three-dimensional urban data generating process provides manyfunctions to attain full communication among the persons concerned with the planning. This paper discusses the fundamental concepts of citizen participation in the 3-D urban data generating process, and proposes the data generator for non-specialists. An actual case study in the renewal area in the city of Sanda in Hyogo Prefecture is presented to explain the techniques and the characteristics of the data generator. It is emphasized that actual operations have been done by the residents. Cityscape simulations also have been carried out using the data generated by the operations. And besides measurement of the communication effects by the simulations has been tried in the actual explaining meeting.

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We have to judge the condition of the environment around us to keep our life from danger. The environment is such abstract conception that we cannot observe it directly to judge its codition. We need observe several phenomena happening around us to estimate the condition. Indexes of environment are tools to grasp the phenomena and to discribe their conditions. The contents of indexes are regarded as messages from the environment to observers. They try to receive as many messages as possible to judge the condition more correctly. The degree of contribution to correctness is amount of information carried by the message. Important indexes are those which send messages conveying large amount of informa tion to the observer.
This paper stands on recognition above to aim at analysing the role of indexes in discrimination of environment.

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The purpose of this study is to establish quantitative evaluation indices for the amenity of the urban living envirnment. By means of cannonical correlation analysis between the degree of satisfaction of inhabitants and the characteristics of surrounding environment, three pairs of canonical variables are extracted. The first canonical variable for the psychological variables explains the trade-off relationship between the amenity and the conveniences. Then, the relationship between the consciousness for amenity of inhabitants and the physical condition of the living environment is examined by means of multiple regression analysis. By applying the derived equation to Setagaya Ward. this equation is of to evaluate the amenity of the urban living environment.

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The study gives a thorough analysis of the information control system of industrial wastes. It presents major purposes and effects of the system introduction and based on an analysis of the system application needs in some municipalities, it gives a trial design of regional network system for the information control. Finally, the system structure is analized and the proper procedure for the system introduction is studied. Through interviews and questionnaire studies given to some municipalities and evaluation of cost and functions of the system, it appeared feasible to establish, in the first phase, an independent system based on personal computers with compiling of data base, calculation of the reported data, and handling of materials flow as their major functions, and to, as a next stage, connect these systems to establish a regional network system.

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In late 1960's the social conflicts between local sufferers and unspecified majority of beneficiaries had been actualized in Japan caused by intensive expansion of public works in response to rapid economic growth. The Japan Society of Civil Engineers established the Subcommittee on Environmental Problems in July, 1970, with the purpose to cope with the above social situation and also to get an integrated view for environmental impacts which have ever been separately concerned in different disciplines. This paper deals with the approach to “environmental management”, which has been the recent target of the Subcommittee's activities, focusing on its difference from pollution abatement program or environmental impact assessment and categorization of management methodology. In addition to recent trend of environmental management in public works, the roles of professionals and citizens are discussed in detail for the case of river works as the most typical example of the approach. The future functional scope of environmental engineers including academic society is also suggested for the environmental management in information-oriented age. The content of this paper refers mainly to Workshops and Symposia promoted by the Subcommittee

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