The Cidacos is a tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the Ebro

Ebro

The Ebro or Ebre is one of the most important rivers in the Iberian Peninsula. It is the biggest river by discharge volume in Spain.The Ebro flows through the following cities:*Reinosa in Cantabria.*Miranda de Ebro in Castile and León....

. Its source is Los Campos, in Soria

Soria (province)

Soria is a province of central Spain, in the eastern part of the autonomous community of Castile and León. Most of the province is in the mountainous Sistema Ibérico areaIt is bordered by the provinces of La Rioja, Zaragoza, Guadalajara, Segovia, and Burgos....

, and it flows for 77 km (48 mi) until its reaches the Ebro at Calahorra

Calahorra

Calahorra, , La Rioja, Spain is a municipality in the comarca of Rioja Baja, near the border with Navarre on the right bank of the Ebro. During ancient Roman times, Calahorra was a municipium known as Calagurris.-Location:...

 (La Rioja

La Rioja (Spain)

La Rioja is an autonomous community and a province of northern Spain. Its capital is Logroño. Other cities and towns in the province include Calahorra, Arnedo, Alfaro, Haro, Santo Domingo de la Calzada, and Nájera.-History:...

).

It flows through or past various towns like Villar del Río

Villar del Río

Villar del Río is a municipality located in the province of Soria, Castile and León, Spain. According to the 2004 census , the municipality has a population of 172 inhabitants.-Villages:*La Cuesta...

, Yanguas

Yanguas

Yanguas is a municipality located in the province of Soria, Castile and León, Spain. According to the 2004 census , the municipality has a population of 128 inhabitants....

, Enciso

Enciso, La Rioja

Enciso is a small municipality in the southern part of La Rioja, Spain, near Arnedo. The main village rises is located above the Cidacos River....

, Peroblasco, Arnedillo

Arnedillo

Arnedillo is a village in the province and autonomous community of La Rioja, Spain....

, Santa Eulalia Somera, and Bajera, Herce

Herce

Herce is a town and municipality in La Rioja province in northern Spain.- External links:*...

, Arnedo

Arnedo

Arnedo is the third largest town in La Rioja, Spain. It is located near Calahorra, and has a population of about 14,500 people.Its economy is based on the shoe industry.-History:The area of Arnedo has been inhabited as early as the Neolithic Age...

, Quel

Quel, La Rioja

Quel, La Rioja is a village in the province and autonomous community of La Rioja, Spain.-References:...

, Autol

Autol

Autol is a village in the province and autonomous community of La Rioja, Spain....

, and Calahorra

Calahorra

Calahorra, , La Rioja, Spain is a municipality in the comarca of Rioja Baja, near the border with Navarre on the right bank of the Ebro. During ancient Roman times, Calahorra was a municipium known as Calagurris.-Location:...

. The river is used for irrigation

Irrigation

Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...

purposes and is often dried up near Calahorra.