Economic and geographic backgrounds of land reclamation in Japanese ports.

Under the present legal system, environmental impacts are usually assessed on condition that reclamation plans are given clearly. Although impact magnitude depends on reclamation scales, the economic and geographic backgrounds of reclamation scales have been rarely analyzed. Hence, properties of reclamation in port districts were investigated. The long-term trend showed that the area newly reclaimed per year has decreased rapidly since the first oil crisis; while the speed of the decrease dropped after 1984. The distributions of increased reclamation area planned against its water depth had one or two peaks in 1989-1991 and 1996-1998. These peaks resulted mainly from "island-type" reclamation, and shifted from shallow to deep sites. The areas of port districts had major effects on increased area of reclamation and maximum water depth in 1989-1991, while such effects were not observed in 1996-1998. Land price had some effects for deepening water depth of reclamation in both periods.