Arakawa River Live Cam

Geological Origins and Hydrological Profile of the Arakawa River

The Arakawa River begins high in the Chichibu Mountains of Saitama Prefecture, where clear mountain streams coalesce at elevations exceeding 2,000 meters. As the river descends toward the Kanto Plain, it carves through ancient granite and andesite outcrops, gradually depositing volcanic ash and alluvial sediments along its banks. Before reaching Tokyo Bay, the river travels approximately 173 kilometers, transitioning from narrow valleys to a broad floodplain. This floodplain, composed of layers of sand, silt, and clay, has long served as both a fertile agricultural zone and a critical buffer against seasonal flooding.