The Eresma is a river in central Spain. It flows through

Castile and Leon Castile, Castille or Castilla may refer to: Places Spain *Castile (historical region), a vaguely defined historical region of Spain covering most of Castile and León, all of the Community of Madrid and most of Castilla–La Mancha *Kingdom of ...

(specifically the provinces of

Segovia Segovia ( , , ) is a city in the autonomous community of Castile and León, Spain. It is the capital and most populated municipality of the Province of Segovia. Segovia is in the Inner Plateau (''Meseta central''), near the northern slopes of th ...

and

Valladolid Valladolid () is a Municipalities of Spain, municipality in Spain and the primary seat of government and de facto capital of the Autonomous communities of Spain, autonomous community of Castile and León. It is also the capital of the province o ...

). It has a total length of 134 km and drains a basin with an area of 2940 km².

Name

The name of the river has been derived from the Iberian "Iri-sama" which means "that which surrounds the big city". The city referred to here is not

itself as sometimes thought, but rather the town of

Coca Coca is any of the four cultivated plants in the family Erythroxylaceae, native to western South America. Coca is known worldwide for its psychoactive alkaloid, cocaine. The plant is grown as a cash crop in the Argentine Northwest, Bolivia, ...

located some 50 km away.

Geography

The Eresma River starts in Valsaín valley of the

Sierra de Guadarrama The Sierra de Guadarrama (Guadarrama Mountains) is a mountain range forming the main eastern section of the Sistema Central, the system of mountain ranges along the centre of the Iberian Peninsula. It is located between the systems Sierra de G ...

, where the confluence of several streams forms the river. Most of these streams descend from the slopes of mountains like Peñalara,

Siete Picos The Sierra de Guadarrama (Guadarrama Mountains) is a mountain range forming the main eastern section of the Sistema Central, the system of mountain ranges along the centre of the Iberian Peninsula. It is located between the systems Sierra de Gr ...

and Montón de Trigo. Its most important tributaries are Moros and the Voltoya that flow northward. After passing through

San Ildefonso San Ildefonso (), La Granja (), or La Granja de San Ildefonso, is a town and municipality in the Province of Segovia, in the Castile and León autonomous region of central Spain. It is located in the foothills of the Sierra de Guadarrama mounta ...

and

Palazuelos Palazuelos may refer to: People * Palazuelos (surname) Places *Palazuelos, Guadalajara Palazuelos is a village in the Spanish province of Guadalajara, in the north of the autonomous community of Castilla-La Mancha. Presently it is included in t ...

, it reaches the city of

, which it surrounds in a closed

meander A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of an outer, concave bank ( cut bank) and deposits sediments on an inner, convex bank ...

. Eresma river then runs northwest, passing near Hontanares, Los Huertos, Bernardos, Navas de Oro, Coca and Villeguillo. It enters the province of Valladolid through Olmedo, Pedrajas,

Alcazarén Alcazarén is a town and municipality in the Province of Valladolid, part of the autonomous community of Castile and León, Spain. with a population of 702 (as of January 1, 2004 census). Its name originates from the Arab "al-qasrayn" which mea ...

and Hornillos. Later it flows from the right into the

Adaja The Adaja is a river of Spain located in the centre of the Iberian Peninsula, a major left-bank tributary of the Douro. Featuring a total length of 163 km, its river basin drains an area of 5,328 km2. It has its source in the so-called Fuent ...

Matapozuelos Matapozuelos is a municipality located in the province of Valladolid, Castile and León, Spain. According to the 2004 census (INE), the municipality had a population of 1,024 inhabitants. Gallery File:Iglesia de Matapozuelos Valladolid.JPG, M ...

. The Eresma River has a

pluvio-nival regime The river regime generally describes the character of the typical fluctuations of flow of a river, but can also refer to the mathematical relationship between the river discharge and its width, depth and slope. Thus, "river regime" can describe one ...

, which means that it has a period of high water flow in the autumn and winter season in proportion to precipitation and a short, violent water flow in the spring when the snow melts.

References

{{Authority control Rivers of Castile and León Rivers of Spain Tributaries of the Adaja