Assessment of natural environment and maintenance of infrastructure for co-existence with environment in Ariake and Yatsusiro Coastal region

（1）对整个有明海和白川、绿川两个河口进行了潮流和海浪的数值分析。研究了这些区域悬浮物的流速场特征和浓度分布随潮汐水位和河流入流率的变化。此外，数值方法分析潮滩和冲沟的形式。基于风暴潮、高波和潮汐的相互作用，开发了风暴潮风险图及其最大发生概率预测。采用准三维海洋环流模式POM（Princeton Ocean Model）模拟了具有复杂底地形的北部湾的海流和物质输运。POM中平流计算的数值格式由中心差分改为TVD格式，以提高其可移植性。试验模拟结果表明，改进方案在平流项下是有效的。(2)底质土分类 ...更多信息 对艾德的7个碎屑进行了硫化物、硫含量、COD/I、COD/硫含量4个变量的碎屑分析，发现碎屑的主要种类因碎屑而异。提出了一个定量反映潮滩底栖生物丰富度的丰富度指数IR。该指数由公式IR = H'× WWU定义，其中H'是Shannon函数的多样性指数，WWU是单位面积底栖动物的湿重。该指数在一定程度上反映了潮滩群落的结构特征，但各群落间的指数差异不明显。今年对影响该指数的一些因素进行了分析，发现潮滩适宜的干化时间有利于底栖动物的丰富度。(3)对有明内海和八代内海潮滩的反硝化能力进行了估算，并确定了影响反硝化的因素。结果表明，污泥中的泥砂和粘粒含量对反硝化能力有较大影响。因此，泥质中粉砂和粘粒含量较高的佐贺区潮滩的反硝化速率高于其它潮滩。夏季由于雨季降雨量大，氮源和碳源丰富，反硝化细菌活跃，反硝化能力最强。本研究的目的在于评估白川江潮滩反硝化作用中的潮汐作用和底栖动物如阿萨翁。利用装有近岸沉积物的管道，在有污水和无污水的情况下，进行了反硝化速率与沉积物特性关系的试验。根据潮汐作用对NO3-N浓度的影响，计算了反硝化速率。结果表明，生物扰动对反硝化速率的影响受沉积物COD浓度和氧化还原电位的影响。(4)根据熊本近海21 ~ 44 m水深的4个活塞岩心的沉积相、硅藻和底栖有孔虫组合和~ <14>1C年龄，研究了有明海中部近万年来的环境变化。结果表明，在距今约9,500年前，海水侵入到现在海平面以下约50米的区域，熊本近海的整个区域成为与现在7,400年前相同的中央海湾环境。此外，海洋环境不断向内陆扩展，并完全覆盖了现在的熊本平原地区约5，400 yrBP。(5)本研究的目的是使用双界二分选择法（DB-DC）来检验条件价值评估法（CVM）。由于CVM使用的是SP（Stated Preference）数据，它可以衡量非市场商品的存在价值。然而，评价的可靠性不如显示偏好（RP）方法。在CVM评估非市场商品价值时，有必要检查SP数据的偏差。本文的研究目标有两个。一是通过不同的支付方式测试云服务器的评价。二是检查和消除DB-DC方法中的起点偏差和肯定偏差。在本研究中，采用了两种支付方式。一个是基于新的税收，另一个是基于税收再分配。将两种支付方式下的评价结果与理论结果进行了比较，并对CVM评价结果的可靠性进行了检验。少

(1)Numerical analysis of tidal flows and ocean waves were performed for all of Ariake-sea and the both estuary of Sirakawa and Midorikawa rivers. Velocity field characteristics and concentration distributions of suspended solids in those areas were evaluated as a function of tidal levels and river inflow rates. Also, numerical methods for analyzing the form of tidelands and their gullies were developed. Hazard Mapping for Storm Surge based on Interaction between Storm Surges, High Waves and Tide, and Their Maximum Occurrence Prediction were developed. Quasi-three dimensional ocean circulation model POM (Princeton Ocean Model) was applied to the simulation of current and material transport in the bay, which has complex bottom topography. Numerical scheme for advection computation in POM was changed from the central difference to TVD scheme to improve its transportability. Test simulation made clear the effectiveness of the modified scheme in advection term.(2) Bottom soils ware classifi … More ed to seven clasters by claster analysis with four variables, mad content, sulfieds, COD/I gnission loss and COD/mad content, and it was found that major species are different by claster. Also, authors proposed a richness index, IR, which quantitatively shows richness in benthos in tidal flats. The index is defined by the equation, IR = H' x WWU, where H' is diversity index by Shannon function and WWU is the wet weight of benthoses in unit area. The feature of the clasters of tidal flats was presented by the index in some degree but the clear difference in the index between clusters was not found, hi this year, some factors supposed to influence on the index were examined, and it was found that the appropriate length of dried period on the tidal flat may be desirable for the richness of benthoses.(3) Denitrification capability of the tidal flats in Ariake Inland Sea and Yatsushiro Inland Sea was estimated and factors that affect denitrification were determined. It was found mat denitrification capability was largely influenced by die silt and clay content of mud. Therefore the denitrification rate of tidal flats in Saga area where the silt and clay content of mud was much high was higher than the other tidal flatsexamined. And the denitrification capability is highest in summer when the source of nitrogen and carbon was rich because of heavy rainfall in the rainy season and Denitrifying bacteria was active. The objectives of this study is to evaluate the tidal action and benthic animals such asseawom in denitirification activities of the tidal flat in Shirakawa river. Experimental were conducted to determine the dependence of denitirification rate on sediment character using tubes filled with costal marine sediment both with and without sewaorm. Based on the tidalaction-dependent decrease of NO3-N concentrations, denitirification rate were calculated. The result indicate that the effect of bioturbation on denitirification rate ware influenced by sediment COD levels and redox potential.(4) On the basis on sedimentary facies, diatom and benthic foraminiferal assemblages, and ^<14> C ages of 4 piston cores, 21 to 44 meters in water depth, off Kumamoto, environmental changes in the central part of the Ariake Sea were examined during the last 10,000 years. As a results, it is clarified that marine water invaded into the area around 50 meters below a present sea level about 9,500 yrBP, and the whole area off Kumamoto became to be underlain in the central bay environment same as a present about 7,400 yrBP. Further, the marine environment spread to inland continuously and covered entirely all over the present Kumamoto Plain area about 5,400 yrBP.(5) The aim of this study is to check the Contingent Valuation Method (CVM) using double-bounded dichotomous choice (DB-DC) method. Since CVM uses Stated Preference (SP) data, it can measure existence value of non-market goods. However, reliability of the evaluation is inferior to Revealed Preference (RP) Method. It is necessary to check the bias based on SP data when value of non-market goods is evaluated by CVM. There are two targets in this paper. One is a test of evaluations by CVM through different payment types. Another is to check and to get rid of a starting point bias and a yea-saying bias in DB-DC method. In this study, two types of payment way were applied. One was based on new taxation, and another was based on tax reallocation. The evaluations through two payment types were compared with theoretical results, and reliability of the evaluations by CVM was tested. Less