In 2005, the phenomenon of turbid water effluence from the Hitotsuse Dam Reservoir lasted over 8 months due to an unusually large flood. In response, the “Advisory Committee for Countermeasures against Turbid Water Effluence in the Hitotsuse River System” was organized by the Miyazaki Prefectural Government, composed of the prefecture, municipalities in the Hitotsuse River basin, a number of independent experts, and Kyushu Electric Power Co., Inc. (hereafter referred to as “KEPCO”). The committee proposed renewed countermeasures to shorten the duration of high turbidity in the river.