Ōi River
The Shiogō Dam was built in an area where the Ōi River made a number of turns over swift rapids. The area was a popular fishery for "ayu" and Japanese dace, which the dam replaced with an area of stagnant, algae-polluted water with an offensive smell. The dam also reduced the amount of sand and silt reaching the mouth of the Ōi River, thus further contributing to shoreline erosion. Legal efforts by local municipalities and landowners to recover water rights over the Ōi River and force the dismantling of the dam have consistently failed in courts.