The main river running through Valladolid, Spain, is the Pisuerga, which flows in a southwesterly direction through the city. A tributary, the Esgueva river, enters Valladolid from the east along a man-made channel and converges with the Pisuerga in the north of the city.
The 283-kilometer (or 176-mile) long Pisuerga originates some 145 kilometres (or 90 miles) north of Valladolid at the Covarrés glacial basin in the Cantabrian Mountains, between Brañosera and San Juan de Redondo in the province of Palencia. From there, the water flows underground at Sel de la Fuente and emerges 3 kilometers later at Fuente Cobre, continuing southwards, through two reservoirs, eventually reaching Valladolid.
It continues for a further 12 kilometers (or 7.5 miles) to Pesqueruela where it converges with the Douro river, which flows generally westward into Northern Portugal, ultimately to the Atlantic Ocean at Porto.