Adaptation to Salinity Change Induced by Sea-Level Rise in Hinuma Lake, Japan

Brackish water lake is home of peculiar organisms, as its salinity is middle of those of sea and fresh water. Its salinity changes sensitively with sea level, river flow rate and lake topography. Hinuma Lake is one of brackish water lakes in Japan and connects with the Pacific Ocean through a tributary and a major river. Therefore the inflow process of salt water to the lake is very complex. The purposes of this study are to estimate impact of sea-level rise on the lake salinity and to examine adaptation options to preserve ecosystem against the impact. To this end, we carried out a long-term observation on the inflow of sea water and seasonal change of salinity to understand the mechanism of sea water intrusion and to verify the numerical simulation model. The influence of topographic changes on salinity is also investigated for the last five decades.