Pisuerga

a river in northern Spain, a right tributary of the Douro River. It is 283 km long and drains an area of 14,000 sq km. Originating on the southern slopes of the Cantabrian Mountains, it flows mainly through the Old Castile Plateau. The mean flow rate is 70 cu m per sec; there are freshets in winter and spring. The Pisuerga is used for irrigation. The city of Valladolid is situated on the river.