Integration of watershed information with GIS and its application for mechanism analysis and environmental planning

湖泊水质受流域内各种因素的影响，通过物理、化学和生物反应发生变化。为了保护水环境或改善水质，必须弄清因果关系。然而，与这一问题有关的信息量太大，一个组织无法收集。因此，为了更容易地同时利用这些各种数据，建立了“环境信息数据库”，其中包括一些生物观察到的环境质量信息和有关琵琶湖的社会状况。（1）建立了琵琶湖流域的八项基本信息（湖泊水质、流域性质、子湖、地下水、温泉、灌溉、宪法/法令/建设计划）的数据库。(2)该数据库可以在Web浏览器上访问，如互联网主页。(3)本研究所建立的数据库是对琵琶湖及其流域进行综合管理的第一步。通过该数据库，可以更详细地了解湖泊水质的决定机制，从而采取更有效的对策。

Water quality in a lake is affected by various things in watershed, and changes through physical, chemical and biological reactions. In order to preserve water environment or to improve water quality, the relation between cause and effect must become clear. However, quantity of information relevant to the issue is too large to collect by one organization. Therefore, "an environmental information database" was constructed which include information on environmental quality observed by some organisms and social situation about Lake Biwa in order to utilize such various data at one time more easily. Achievement of this research is as follows :(1) Basic eight information (water quality in the lake, watershed property, sub -lakes, groundwater, hot spring, irrigation, constitution/ordinance/construction plan) in Lake Biwa watershed was stored in a database.(2) The database can be access on web browser like internet homepage.(3) Examples of utilizing the database were shown.The database constructed in this research is the first -step of the comprehensive management or Lake Biwa and its watershed. It is expected more detailed mechanism that determines water quality in the lake will become clear with this database and more effective and efficient countermeasures will be taken as a consequence.