The swift urbanization of the area in the east-south of Osaka City resulted in the poor drainage.
 So the area was often flooded by hard raining.
 Hiranogwa drainage-adjustment pond was aimed to meet the situation.
 The big drainage works are made so that rainwater is kept in store as a drainage-adjustment pond in a big tunnel and discharged afterwards gradually into the Hirano and Imagawa river.
 The project was divided into three terms.
 The first term was commenced from the 56th fiscal year of Showa and completed the second fiscal year of Heisei.
 The big tunnel was founded under 22 meters of the Kizugawa ueban planning streets line, which was 10meters of the internal diameter, 1.9kilometers in length and 140,000cubic meters.
 The second term was completed under the same Kizugawa urban planning streets line in the 7th year of Heisei, which was around 1.2kilometers in length and 100,000 cubic meters and there is no other drainage adjustment pond like this in the world that has the total quantity of storage 240,000 cubic meters.
 The third term is under construction to be completed in the 13th fiscal year of Heisei under the Nagai Park-dori, which is around 1.7 kilometers in length, 120,000cubic meters.
 Naniwa Big Route for discharge of water was a large sewer pipe that was founded under the ground from the Hirano-ku to the Suminoe Chusuisho though the Nagai Park-dori, Suminoe-dori, 6.5meters in the internal diameter, about 12.2kilometers in total length and was completed in April, 12th year of Heisei.