Abstract
Kankyou-yousui-suiriken, the water right for biodiversity conservation, is permitted as a special water right that envisages the diversion of water in a river into other water environments. Conversely, other water rights are generally permitted for off-stream use. Because such water environments are not subject to the River Act, the significance of this system offers the river administrator a new and supplementary option concerning low-flow management.
Having the major shift of conception of water in a river, this water right is novel in valuing the sustainability of biodiversity. It also shows some peculiarities in that this water right is permitted only when other water-right holders enjoy full appropriation, and it is provisional in terms of a short renewal period.
One of the practical cases of this water right is utilizing irrigation and drainage infrastructures for the purpose of improving water quality by dilution. In this respect, it should be noted that land improvement districts (LIDs) could make many contributions to this water-right system through experience and knowledge in operation, maintenance, and management of related facilities. In fact, these contributions would minimize the initial investment and management costs. Involvement of LIDs could result in a win-win situation for both a right holder and districts.
