A RIPPLE EFFECT OF AGRICULTURAL POLICY ON WATERSHED ECONOMIC DEVELOPMENT AND WATER QUALITIY CONSERVATION

摘要

Regional economic development and environmental sustainability will be an inevitable subject regardless of regional scale. This paper intends to develop an effective model to address this subject in the watershed scale. Considering regional demographic movement and policy variable as subsidy, a watershed dynamic CGE model is formulated coupling with a COD emission model based on input-output tables. In the computation of proposed model, a constrained genetic algorithm, αGA, is adopted and its applicability is verified. For a practical watershed management in Japan, we investigate how an agricultural subsidy policy, which will be expected to improve cultivation abandonment and reduce non-point source discharge from paddy field, influences on the watershed economic growth and water quality for a long time period. Especially, we discuss the impact of a strong COD emission control, whose rate exceeds population reduction rate, on the watershed economic growth from aspects of some agricultural subsidy policy and a regional self-sufficient ability in goods production.