Effect of Salt Wedge Intrusion in Kushiro Wetland Considering Sea Level Rise

Abstract

This paper describes the effect of sea-level rise (SLR) on the salt wedge intrusion in terms of ecological system in Kushiro wetland. Kushiro wetland was registered by Ramsar Treaty and the largest wetland in Japan. A previous study demonstrates that the salt wedge intrusion may not affect ecological system of Kushiro wetland, such as loss of freshwater plants along Kushiro River. However, it is revealed that SLR may occur in the end of the 21st century, which enhances the increase in the distance of the salt wedge intrusion along Kushiro River and the loss of endangered species of Kushiro wetland along Kushiro River. This study thus aims to investigate the influence of the salt wedge intrusion on freshwater plants along Kushiro River, and to clarify the salt wedge intrusion when SLR occurs due to climate change. We attempted to investigate the influence of SLR on endangered species along KyuKushiro River in which sea water is likely to intrude up to about 8 km from the river mouth. As results, it is suggested from field observations that salinity may decrease freshwater plants along Kushiro River, and it clarifies the possibility that the salt wedge intrudes Kushiro River due to SLR by using 3D hydrodynamic model, Fantom3D.

Adaptive management in Kushiro Wetland in the context of salt wedge intrusion due to sea level rise

“…Also, the validity of Fantom3D was confirmed in the application to stratified flow field (Maruya et al, 2010;Shintani and Nakayama, 2010;Nakayama et al, 2012). It should be noted that salt wedge intrusion was observed in field observations to reach the river mouth only in 2009 (Nakamoto et al, 2011).…”

“…The validity of Fantom3D in the Kushiro Wetland was investigated by comparison to field observations (Nakamoto et al, 2011(Nakamoto et al, , 2012. Also, the validity of Fantom3D was confirmed in the application to stratified flow field (Maruya et al, 2010;Shintani and Nakayama, 2010;Nakayama et al, 2012).…”