Voltoya River province of Ávila and enters that of Segovia , to pass through Juarros de Voltoya and the Nava de la Asunción. Voltoya River The Voltoya is a river in Spain. It is a tributary river of Eresma River which is, in turn a tributary of the Adaja River that emerges from Douro River. Its starts in the mountains of Guadarrama and Malagón. The water from Dehesa de la Cepeda , enclave of the city of Madrid and the Azálvaro Field also flow into the Voltoya . It runs through the Castilian-Leonese provinces of Ávila and Segovia . Its mouth is
Iowa River cities of Eldora, Marshalltown, Tama, and Marengo, and through the Amana Colonies in Iowa County. In Johnson County, it becomes impounded by the Coralville Dam in the Coralville Reservoir, which turns southward to the spillway. The river runs generally south and passes through Iowa City and the University of Iowa campus. A lowhead dam at Burlington Street in Iowa City is the last dam before the river's confluence with the Mississippi. South of Iowa City, it is joined in Washington County by the English River, and then in Louisa County it is joined by the Cedar River to flow into