Study on the Characteristics of Salinity Intrusion and Change of Salt Wedge in Abashiri River

Abstract

This paper deals with the characteristics of the salinity intiusion in Abashiri River, which located in thenortheast of Hokkaido Island we found that the chief factors influencing mechanical properties of salinity irittusion istidal current and the river profile in Abashiri River. The present authors had alirady proposed the changing condition of mixing pattern of salt wedge under the influence of tidal cunrnt. By using these concept, it is possible to evaluate the change of the mixing pattern with salinity inbusion under the influences of the disturbance due to wind on the surface of the water and the river profile couldbe negligible in Abashiri River. However, we found that the salt wedge was completely broken down without the influence of tidal current at the 4km poirit (Kagamibasi-bridge) away from mouth of river, where a large projection exists on the bed. Hence it is necessary to apply the modified changing condition

Dynamic behaviours of anoxic saline water in Lake Abashiri, Hokkaido, Japan

“…The anoxic water was produced by deoxidization of intruded seawater during a long residence time ( probably more than several years (Mori, 1975)). Some researchers have investigated the upslope movement of seawater in the lower Abashiri River, the behaviours of intruded seawater and the lower saline water, and entrainment of the lower water in Lake Abashiri by ®eld observations and numerical simulation (Hirano et al, 1991;Yamada et al, 1996;Ikenaga et al, 1997Ikenaga et al, , 1998Shimizu et al, 1997). However, they did not systematically discuss how the intruded seawater, the lower saline water, and the upper freshwater in the lake interact.…”

Influence of Stokes Drift on Salt Wedge Intrusion Evaluated Using Fully-Nonlinear and Strongly-Dispersive Wave Equations

“…In the previous studies regarding salt-wedge intrusion, many investigations have been done for understanding the mechanisms based on tidal and wind effect (Kuwajima et al 1993;Ikenaga et al 1998;Ikenaga et al 1999;Yoshikawa and Watanabe 2006;Yoshikawa et al 2007). One of the previous studies proposed the theory for estimating the distance of salt-wedge intrusion using the difference between sea-water and lake-water levels.…”