Seirou Shinoda

Assessing environmental improvement options from a water quality perspective for an urban-rural catchment

The ability of environmental systems to persist while experiencing sharp discontinuities is an issue of great importance to todays environmental managers and planners. This study quantified the relationship between land use and the total nitrogen (TN) load in a catchment using a mass balance model based on multivariate analysis. This model considered the spatial arrangement of observed data and the quantity of different land-use types to examine the relationship between the environmental improvement effects of various policy measures and the TN load in the Gyaku River basin, Japan. The distribution of the land uses was estimated from LANDSAT/TM data using ISODATA clustering. The aim was to develop concrete controls for improving the environment (i.e., an environmental improvement policy). The TN load was governed largely by the distribution of human-related factors such as industrial wastewater discharge, agricultural production, population density, and livestock density. The optimal environmental state was determined by examining various factors influenced by human activities and natural phenomena. The analysis incorporated previously published data from the early stages of stand development. First, the boundaries of the self-governing bodies that would enforce the proposed measures were located on maps of the environment and settlements in the study catchment. A proposed plan was then developed based on concrete procedures. The study catchment contained a predominantly agricultural area and an urban area. Thus the environmental improvement policy had to consider both urban and rural characteristics of the catchment. The qualitative effects of various measures and combinations of measures were simulated, considering inflows and outflows from both the agricultural and urban areas. This study is particularly useful because many visible aspects of Japanese environmental management are not those that rationally based paradigms of decision making would associate with environmental improvement and resilience.

Estimation of total nitrogen transport and retention during flow in a catchment using a mass balance model incorporating the effects of land cover distribution and human activity information.

The load of total nitrogen (TN) in stream water was surveyed in the Nagara River Basin (2,000 km(2)), central Japan. Multivariate analysis placed the TN data in an environmental and social context, relating TN to land use conditions such as geologic features, population density, and percentage of the population using the sewer system. Multivariate analysis was used to examine relationships among the land use distribution with and without human activity and the amount of pollution effluent from waste water treatment plants (WWTP). The pollution load in stream water is related to characteristics of the land cover in the river basin, so the influence of land use on the pollutant load was investigated. However, key factors affecting the pollutant load are human activities associated with the land use. In this study, a relationship between pollutant load, land use, and human activity is developed. Land use was estimated from Landsat data using ISODATA clustering. The distribution of the land cover factors was related to human activities, i.e. population density, agricultural production, industrial wastewater discharge, percentage of sewered population, and stock breeding in the catchment. Multivariate analysis related the TN data to land use and human activities. However, the types of land use were found to be insufficient to evaluate the TN, which appeared to be largely governed by other human-related factors such as industrial wastewater discharge, agricultural production, population density, and livestock density. Socioeconomic data, were obtained from government agencies. The results indicate that the TN load outflow characteristics of the study catchment were affected not only by outside human activity, but also largely by the various human activities in the small drainage basin. Industrial waste water contributed as much to the pollution load outflow as did human activity. This is shown quantitatively in that land use information collected at the same time as that collected on human activities provides effective baseline data. The model proposed here is suitable for evaluating best management practices.

Estimating the collapse of aggregated fine soil structure in a mountainous forested catchment.

This paper describes the relationship of forest soil dryness and antecedent rainfall with suspended sediment (SS) yield due to extreme rainfall events and how this relationship affects the survival of forest plants. Several phenomena contribute to this relationship: increasing evaporation (amount of water vapour discharged from soil) due to increasing air temperature, decreasing moisture content in the soil, the collapse of aggregates of fine soil particles, and the resulting effects on forest plants. To clarify the relationships among climate variation, the collapse of soil particle aggregates, and rainfall-runoff processes, a numerical model was developed to reproduce such aggregate collapse in detail. The validity of the numerical model was confirmed by its application to the granitic mountainous catchment of the Nagara River basin in Japan and by comparison with observational data. The simulation suggests that important problems, such as the collapse of forest plants in response to decreases in soil moisture content and antecedent rainfall, will arise if air temperature continues to increase.

SOLITON-MODE WAVEMAKER THEORY AND SYSTEM FOR COASTAL WAVES

A special reflecting wall 12 m long and 2.1 m high was built off the beach at Reggio Calabria, and 30 wave gauges were assembled before the wall and were connected to an electronic station on land. It was possible to observe the reflection of wind waves generated by a very stable wind over a fetch of 10 Km. The experiment aimed to verify the general closed solution for the wave group mechanics (Boccotti, 1988, 1989), for the special case of the wave reflection.Significant features on Wadden Sea wave climate are evaluated in respect of the state of the art. Main emphasis was laid on an analysis of the governing boundary conditions of local wave climate in island sheltered Wadden Sea areas with extensions being sufficient for local wind wave growth. Explanatory for significant wave heights a reliable parametrization of local wave climate has been evaluated by using generally available data of water level and wind measurements.

Long-term comparison of the climate extremes variability in different climate types located in coastal and inland regions of Iran

The present study examined annually and seasonally trends in climate-based and location-based indices after detection of artificial change points and application of homogenization. Thirteen temperature and eight precipitation indices were generated at 27 meteorological stations over Iran during 1961–2012. The Mann–Kendall test and Sen’s slope estimator were applied for trend detection. Results revealed that almost all indices based on minimum temperature followed warmer conditions. Indicators based on minimum temperature showed less consistency with more cold and less warm events. Climate-based results for all extremes indicated semi-arid climate had the most warming events. Moreover, based on location-based results, inland areas showed the most signs of warming. Indices based on precipitation exhibited a negative trend in warm seasons, with the most changes in coastal areas and inland, respectively. Results provided evidence of warming and drying since the 1990s. Changes in precipitation indices were much weaker and less spatially coherent. Summer was found to be the most sensitive season, in comparison with winter. For arid and semi-arid regions, by increasing the latitude, less warm events occurred, while increasing the longitude led to more warming events. Overall, Iran is dominated by a significant increase in warm events, especially minimum temperature-based indices (nighttime). This result, in addition to fewer precipitation events, suggests a generally dryer regime for the future, which is more evident in the warm season of semi-arid sites. The results could provide beneficial references for water resources and eco-environmental policymakers.

THE RELATION OF A BASIN CHARACTERISTIC AND MICROSCOPIC SOIL PARTICLE DISSOLUTION IN NAGARA RIVER BASIN

In order to clarify the correlation of a climate change and a forest surface change of state, data analysis was conducted concerning the secular fluctuation tendency of temperature and rainfall runoff and SS. And the model applicable in a forest basin was built and the microscopic soil particle quantity of production from forest ground was predicted based on the global warming scenario. Due to a pronounced increase in the number of days exceeding 25°C in the forest region, the quantity of soil moisture evaporation is increasing. As a result, the amount of soil moisture in the forest ground surface layer is decreasing. As soil moisture in the forest soil surface decreases, the soils ability to resist the collapse of its aggregated structure decreases. Consequently, even small and medium-scale precipitation events can easily cause soil dissolving. When microscopic soil particles dissolve in large quantities, soil porosity increases, and the decrease in soil moisture and increase in subsurface flow rate combine to accelerate dissolving of microscopic soil particles, thus creating a vicious circle. Finally, changes in forest soil due to global warming can have a marked effect on forest ecosystems. KEYWORDS; global warming; minute particles; colloid; silt; ground dryness; global environment change 1.は じめ に 近年、流域環境学の分野では降雨流出特性の変化等の問題が顕在化 している。都市、山地、耕地などが混 在する流域環境を評価す る場合、土地利用状態、動植物活動状態および水文 ・水質状態などを総合的に評価 しなければならない。それ らの中でも、評価の基礎 となる水循環特性を理解することは重要である。降雨流 出特性の変化の原因は、しばしば豪雨の局地化などに代表 され るような水文特 性の変化や都市開発や樹木伐 採などに代表 される地表面状態の改変に基づ くものとして捉えられてきた。そして最近では、気候変動 と流 出特性の関係について多くの研究がなされてお り一下定の成果を上げている1)。一方、評価の対象を森林流域 に限定した場合でも同様に降雨流出特性の変化等の問題が顕在化 している2)。 そこで本研究では、森林流域 における気候変動と微細土粒子生産特性の変化お よび流出特性の変化の関係を明らかにした。 2.長 良川の水 文 特性 と微細 土粒 子生 産 の関係 森林流域における流出特 性を規定する変動要因として森林土壌を構成 している団粒構造について考えた。 通常、森林土壌の成分は礫のような大きな粒子(直径1.0m程 度)か らシル トや コロイ ドのような超微細粒子 (直径0.1μm程 度)までで構成されている。特に、森林土壌の団粒構造を形成 している成分の内、コロイ ドや *岐 阜 大 学 総 合 情報 メ デ ィア セ ン タ ーInformation and Multimedia Cente, Gifh University