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Change of Agricultural Water Management and Its Evaluation of Influence on Hydrological and/or Water Quality Environment in the Area of Lake Shinji and Nakaumi

宍道湖和中海地区农业用水管理变化及其对水文和/或水质环境的影响评价

基本信息

批准号：
09556048
负责人：
FUKUSHIMA Akira
金额：
$ 8.26万
依托单位：
Shimane University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

The basic purpose of this study is to develop a technique offering the hydrological and water quality information needed for agricultural water management of Hii River. It also provides an useful information for future way of water environment in this district. The results are as follows : 1. (1) Availability of a proposed method for indentification of runoff model was examined , in which was improved with respect to evaluate a set of runoff model parameter in the any significant digit designated for each parameter. (2)A runoff analysis system was developed by UNIX workstation. (3)But, it was recognized that the further improvement of runoff model and investigation of identification method was necessary for the analysis considered inundation phenomena and condition of agricultural water management. 2. (1) The pollutant fluxes of pollutants were elucidated in a paddy field watershed where a circular irrigation system was implemented. The contribution of pollutant flux in return flow to theater environment was evaluated. (2)The pollutant runoff from upland fields in the mountainous area was evaluated, The nitrogen outflows including the pollutants on rainy days were monitored in experimental lysimeters. It was concluded that saving fertilizer application using resin-coated fertilizer can contribute to the reduction of nitrogen outflows from upland fields. 3. (1) Drainage from undisturbed paddy soils, upland field soils and forest soils were analyzed using soft X-ray radiography. Drainage proceeded from macropore first then to matrix in paddy and upland field soils. On the other hand for forest soils, drainage has occurred in matrix only. Unsaturated hydraulic conductivity obtained from inverse problem showed discontinuity between saturation and near-saturation, which indicated flow region was different. Macropore was considered to channel the drainage at early stage, then matrix conducted the water flow.

这项研究的基本目的是开发一种技术，为Hii河农业用水管理提供所需的水文和水质信息。为该地区今后的水环境治理提供了有益的信息。研究结果如下：(1)考察了径流模型识别方法的有效性，改进了径流模型参数的任意有效位数的识别方法。(2)在Unix工作站上开发了径流分析系统。(3)但人们认识到，要分析考虑淹水现象和农业用水管理条件，还需要进一步改进径流模型和研究识别方法。2.(1)对采用循环水灌溉系统的稻田流域污染物通量进行了研究。评价了回流中污染物通量对战区环境的贡献。(2)对山区旱地的污染物径流进行了评价，并利用蒸渗仪监测了雨天氮素的排放。因此，采用树脂包膜肥料节约施肥量有助于减少旱地氮素外流。3.(1)利用软X射线照相技术对原状水稻土、旱地土壤和森林土壤的排水进行了分析。在水田和旱地土壤中，排水是先从大孔到基质再到基质。另一方面，对于森林土壤，排水只发生在基质中。由反问题得到的非饱和导水率在饱和和近饱和之间表现出不连续性，这表明流动区域不同。早期考虑大孔导流，然后基质导流。