2013 Fiscal Year Final Research Report
Changes of water quality under an agricultural water use restructuring project and possibility of introduction of an environmental water
| Project/Area Number |
23580324
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Multi-year Fund |
|---|
| Section | 一般 |
|---|
| Research Field |
Irrigation, drainage and rural engineering/Rural planning
|
|---|
| Research Institution | Hokkaido University |
|---|
Principal Investigator |
YAMAMOTO Tadao 北海道大学, (連合)農学研究科(研究院), 講師 (00312398)
|
|---|
| Project Period (FY) |
2011 – 2013
|
| Keywords | 窒素 / 水質 / 河跡湖 / 農業水利 / 基盤整備 |
|---|
| Research Abstract |
The objective of this study is to evaluate the impacts of the agricultural water use restructuring project on the physical and chemical water properties of the oxbow lake in Hokkaido, Japan. We predicted that decreased water removal after the pumping station was abolished would increase TN concentrations in the lake water. Though removal of water by pumping tends to take pollution from the lake, TN concentrations fell after pumping station was abolished. The cause of decreased TN concentration was mainly decreased organic nitrogen concentration. Moreover, the TN load balance changed from an outflow type to a storage type in 2011 and 2013 despite decreased input load into the lake.
We suggest that this reduction in TN concentration after 2011 reflects the decreased organic nitrogen concentration due to biological purification effects. This is because increasing retention time caused load removal from the lake, and the water retention time also increased significantly in this lake.
|
