Study on Construction and utilization of a comprehensive lake water quality database system

监测是了解湖泊水质状况的基本步骤，许多湖泊都存储着大量的水质数据。然而，这些过去的记录并没有得到有效利用。本研究项目旨在开发一种新的水质数据库系统，该系统拥有目标湖泊中记录的几乎所有数据，并具有熟练使用这些数据的功能，不仅满足一般公众，而且满足专家。琵琶湖被选为研究湖。然后，对琵琶湖过去和现在的调查项目进行了调查，并收集和分析了水质数据。结果表明，这些调查在调查方法上有多种多样的不同模式；采样点数为1 ~ 5个，深度数为1 ~ 12个，一年采样次数为1 ~ 365次，测量项目数为8 ~ 100个。整个项目确定了86个不同的采样站和44个不同的湖泊深度。调查方法的多样性表明，简单的电子表格不能系统地处理整个数据，需要使用关系数据库应用软件。然后，引入Access 2000来组织所有的数据。构建的数据库由1个主表、2个子主表和7个小解释表组成，存储了15个调查项目5万个样本的67万WQI数据。它的应用软件也是在VBA （Visual Basic for application）的帮助下为不熟悉Access的一般用户开发的。该系统在数据管理和应用方面具有很高的灵活性，便于系统的进一步扩展。

Monitoring is a fundamental step to understand water quality conditions in lakes, and many lakes have been storing a huge amount of water quality data. However, these past records are not effectively used. This research project aims to develop a new water quality database system, which possesses almost all data recorded in a target lake with functions to use them skillfully, and satisfies not only the general public, but also specialists. Lake Biwa was chosen as the research lake.Then, past and present investigation projects in Lake Biwa were surveyed and their water quality data were collected and analyzed.The results indicate these investigations have various and different patterns on their investigation methods; the number of sampling stations ranges 1 to 5, that of depths ranges 1 to 12, that of times in a year ranges 1 to 365, and that of measured items ranges 8 to 100 more. The whole projects identified 86 different sampling stations and 44 different depths in the lake. The variety of investigation methods suggested that simple spread sheet can not handle the whole data systematically, and that the use of a relational database application software is needed. Then, Access 2000 was introduced to organize all of the data.The constructed database consists of one main table, two sub-main tables and seven minor explanatory tables, and has stored 670,000 WQI data for 50,000 samples from 15 survey projects. Its application softwares were also developed with the help of VBA (Visual Basic for Application) for general users who are not familiar to Access. This system has high flexibility on the data management and application, so that further extension of the system can be easily achieved.