Under the Rivers Act of 1964 the Iwaki is designated as a Class 1 River and is managed by the Japanese Ministry of Land, Infrastructure, Transport and Tourism.[1][2] The Iwaki River is the longest river in Aomori Prefecture, and is the source of irrigation for the large-scale rice and apple production of the prefecture.[3][4][5][6] The Iwaki River, in the Tōhoku region north of the Fukushima Daiichi Nuclear Power Plant, remains unpolluted by radioactive materials after the Fukushima Daiichi nuclear disaster. Testing for caesium-134 and caesium-137 is carried out and published on a bimonthly basis.[7]