Abstract
While the idea of compensatory mitigation was defined in the Environmental Impact Assessment Law of 1997 at the first time in Japan, the issues/doubts currently discussed can be summarized as:(1) Is it possible to restore/create lost ecosystems?(2) Whether this might become an excuse to initiate environmentally unsound development projects. These issues/doubts were examined by analyzing an off-site compensatory mitigation project in which the author participated, and is the largest riparian wetland mitigation project in the United States. The decision-making process related to the formation of a compensatory mitigation project is guided by consultation provisions of laws such as NEPA or Clean Water Act, comprehensive guidelines and technical manuals on compensatory mitigation, relevant industries such as mitigation consultants and national policies such as “no net loss.” Also new mechanisms such as mitigation banking system and habitat evaluation procedures were innovated for overcoming problems of traditional compensatory mitigation. It is suggested that compensatory mitigation would become an effective tool for ecosystem conservation in Japan. But it should have:(1) clear consultation provisions in EIA systems, (2) sequencing requirement of mitigation measures, (3) guidelines and manuals for compensatory mitigation measures, (4) basic land-use policies on the existing natural/semi-natural ecosystems and finally (5) support systems such as mitigation banking which reduce developers' costs.
