The Site is a small wetland consisting of man-made ponds that were constructed initially for irrigation purposes in Agano City. At present, these ponds serve as habitats for various plants and animals including threatened species such as Japanese crucian carp (Carassius cuvieri) and common pochard (Aythya ferina). At least 117 bird species have been recorded here, among which many are migratory and use the Site as non-breeding habitats. The Site is particularly important for the conservation of tundra swan (Cygnus columbianus), as over 3,000 individuals migrate here every year. It also shelters about 3% of the regional population of northern pintail (Anas acuta). Hunting is prohibited at the Site and local residents are involved in its conservation. Dredging and invasive species are major threats, but a management plan is being implemented. The Site has also been designated as a Special Protection Area within the Hyo-ko National Wild Protection Area.