Urdaibai Estuary

The Urdaibai Estuary has an elongated and narrow shape of 12 km length and 1 km maximum width. The tidal range is 4.5 meters; therefore it is classified as a mesotidal estuary. This mouth is semiconfined by a sandy bar: the beach of Laida. Author and source: Service of Urdaibai Biosphere Reserve