Fundamental research related to watery environment improvement planning for agricultural infrastructure improvement and rural development

主要研究和思考了与农业基础设施改善和农村发展有关的两个问题。一个是农业管理造成的水污染问题，另一个是农村环境造成的恶臭问题。前者是一个重要的社会问题。即使进入河流的污染量总是相同的，河流中的水质也会根据水量（即排放量）而随时间变化。因此，水质数据应与排放一起测量。对宫崎县和宫崎市报告的主要河流水质数据进行了分析，结果表明，与环境质量标准相比，总氮数据密度特别高，且逐年恶化。为改善水质，应立即考虑采取强有力的对策。此外，普通排放或低水排放应更多。为了改善农村环境，应通过联合处理厂、污水处理厂等方式推进农村社区污水改善工程。这些工程应该对水环境的改善是有效的。水环境受气象和水文条件的影响，这些自然条件已被人工工程所改变。从水质和水量的角度来看，水环境的改善不仅对人类有必要，而且对生态系统也有必要。

Two problems were mainly investigated and considered in relation to agricultural infrastructure improvement and rural developement. The one is a water pollution problem resulted from agriculture managements, and the other is a bad and nasty smell problem occured from rural environments. The former is an important social problem. Even if the amount of pollution carried into the river is alwasys same, water quality in the river changes with time according to water quantity, i.e.dischage. So that, water quality data should be measured with discharge. Water quality data related to main rivers reported by Miyazaki prefecture and Miyazaki city were analyzed, and the result shows that total nitrogen data is especially high density as compared to environmental qality standard, and becomes worse year by year. Drastic countermeasure for water quality improvement should be considerd without delay. Still more, ordinary discharge or low water discharge should be more. And in order to improve rural environments, rural community sewerage improvement projects should be promoted by joint treatment plant, waste water treatment plant and etc. These projects ought to be effective to watery environment improvement. Watery environment is influenced by meteorological and hydrological conditions, these natural conditions have been changed by artificial works. Watery environment improvements are necessary only to human beings but also ecosystem from view points of both water quality and water quantity.