Evolving Issues on Development and Conservation of Lake Biwa – Yodo River Basin

Lake Biwa is situated in the uppermost reach of the Yodo River Basin and occupies one sixth of the prefectural territory of Shiga. In the downstream reach of the basin are such metropolises as Kyoto and Osaka, and the issues involving development and conservation of Lake Biwa have been extremely important for Shiga, Kyoto, Osaka and other suburban municipalities within the basin as well as in the neighbouring areas like Hyogo Prefecture. Throughout history, there were a number of upstream-downstream conflicts of interests. The Lake Biwa Comprehensive Development Plan, a plan involving development of a new water resource amounting to 40 m³/sec for Osaka and Hyogo, together with compensatory public work projects for Shiga, has been under implementation for almost 20 years and is about to be completed. The social and economic situations have changed over this period, and the actual demand for water has proven to be not as much as the prediction 20 years ago, based on which the plan was originally formulated. There had been claims against the Plan that a large-scale development plan involving lowering of the lake level by as much as 1.5 to 2.0m might cause irreversible damage to the lake. The paper reviews various issues evolved over years with respect to development and conservation of Lake Biwa - Yodo River Basin and the Comprehensive Development Plan.