Evaluation of material circulation in lakes by continuous tracking of river water

通过河水连续跟踪评价湖泊物质循环

• 批准号: 16540397
• 负责人: ENDOH Shuichi
• 金额: $ 2.05万
• 依托单位: Shiga University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540397/
• 关键词: River water; Material circulation; Lake Biwa; Density current; Electric conductivity; Dissolved oxygen

Hydrological observation has been carried out in Lake Biwa to evaluate the material circulation caused by inflowing river water, especially focused on the River Yasu, which has a maximum catchment area among river flowing into Lake Biwa. In every month of 2005, three dimensional distribution of water quality, such as water temperature, electric conductivity, turbidity, chlorophyll, dissolved oxygen, were measured by vertical profiler in the lake. Continuous measurements of water current and water quality were also made off the river mouth.Water quality of the River Yasu is rather good in the upstream area, but is getting worse especially downstream of the branch of "Omoi gawa River", where many industrial waste water released into the river. As a result, water quality of the River Yasu at the river mouth is worse than that of the lake.In the spring season, river water inflows in the surface layer because river water is warmer (denser) than lake water. In this case, river water spreads in a radial manner. On the other side, river water sinks at the river mouth and deflect to the right in the season of summer, fall, and winter. This is due to the Coriolis effect on the density current.

在比瓦湖（Lake Biwa）进行了水文观察，以评估流入河水引起的材料循环，尤其是集中在Yasu河上，该河流在流入Biwa湖的河流中有最大的集水区域。在2005年的每个月中，水质的三维分布，例如水温，电导率，浊度，叶绿素，溶解的氧气，通过湖中的垂直分析仪测量。连续的水流和水质测量也从河口中进行了。Yasu河的水质在上游地区相当不错，但越来越糟，尤其是“ Omoi Gawa河”分支的下游，许多工业废物都有许多工业废物水释放到河中。结果，河口在河口的水质比湖泊的水质还要糟。在这种情况下，河水以径向的方式蔓延。另一侧，河水沉入河口，在夏季，秋季和冬季的季节向右偏转。这是由于科里奥利对密度电流的影响。