Impacts of instream water rights on river water conservation in Oregon

摘要

This study investigates the effects of instream water rights on river water conservation in Oregon in the USA. The instream water rights in Oregon were established in 1987 for the purpose of maintaining the water level and preserving the environment. "Instream" is usually defined as water for ecological conservation, landscape preservation, and recreation activities. Instream water rights in Oregon are under the control of the state government, which is trusted by the public to administer these rights. Each instream water right is given a priority order, in the same way as appropriative water rights, and is dealt with according to each priority order. That is, if the priority ranking of an appropriative water right is higher than that of an instream water right, the former is given priority over the latter in the case of drought. Therefore, it is anticipated that the effects of instream water rights on the environment would be limited, but there are no studies that empirically examine this. In order to fill in the gap, a regression analysis is conducted by using a time series data on streamflows of John Day River, Grant County, Oregon. The results of this empirical analysis show that the impact of the instream water rights on the environment is limited, but that they are positive for river environments.