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Changes in Material Transport Depending on the Flood Scale. Civil Engineering Research Institute of Hokkaido ○ Y . Yoshikawa Y . Watanabe. Studied River. Saru River. Aims of Study. [ 1] To clarify the relationship between SS and nutrients during four floods
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Changes in Material Transport Depending on the Flood Scale Civil Engineering Research Institute of Hokkaido ○ Y . Yoshikawa Y . Watanabe
Studied River Saru River
Aims of Study [1] To clarify the relationship between SS and nutrients during four floods [2] To estimate the amount of nutrients deposited in the floodplain as the result of flooding Hugest flood Flood 4 Flood 1 Flood 2 Flood 3
[1] Clarifying the relationships between factors of material transport Saru River basin Nibutani Dam Pacific Ocean Sarugawa Bridge tributary tributary Observation locations on main stream 10km Data for study are from three observation locations downstream of Nibutani Dam on the Saru River.
[1] Clarifying the relationships between factors of material transport
[1] Clarifying the relationships between factors of material transport Relationship A [Q – SS] Flood 1 Flood 2 -Hugest flood- Flood 3 Flood 4
[1] Clarifying the relationships between factors of material transport
[1] Clarifying the relationships between factors of material transport Relationship B [Q – TN], [Q – TP] Flood 1 Flood 2 -Hugest flood- Flood 3 Flood 4
[1] Clarifying the relationships between factors of material transport
[1] Clarifying the relationships between factors of material transport Relationship C [SS – nutrients] Flood 1 Flood 2 -Hugest flood- Flood 3 Flood 4
[1] Clarifying the relationships between factors of material transport Snowmelt flood in 2003 ….. Flood 2 ・The ratio of SS to Q increased ・The ratio of TP to Q increased 1 Snowmelt flood in 2004 ….. Flood 4 Rainfall flood in 2001 ….. Flood 1 2 ・Each relation was changeless. Rainfall flood in 2003 ….. The Hugest flood ・Nutrients adhere to SS and transported regardless of flood scale. 3
[2] Estimating the amount of nutrients deposited on the floodplain as a result of flooding Correlation α X SS β nutrient = α,β : constant
[2] Estimating the amount of nutrients deposited on the floodplain as a result of flooding
Conclusion [1] Relationships between factors of material transport Between the two snowmelt floods (one before and one after the hugest flood), the ratio of SS to Q and the ratio of TP to Q increased. [2] Estimation of nutrient deposition on the floodplain by flooding Calculation found that locations of nutrient deposition differ by flood scale.