The Gauja River is a river in Vidzeme, Latvia. It is the only large river of Latvia that begins and ends its flow in Latvia. Its length is 460 km, of which 1/5 or 93.5 km are in Gauja National Park. In this part, the Gauja River flows through a spacious ancient valley, which is 1 to 2.5 km wide, and the maximum depth near Sigulda is 85 m. The Gauja River is known for its beauty.
| Gauja | |
|---|---|
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| Physical characteristics | |
| Mouth | Carnikava, Gulf of Riga |
| Length | 452 kilometres (281 mi) |
The sandstone rocks on the banks of the Gauja and its adjoining rivers started forming 370 to 300 million years ago during the Devonian period.
The Gauja Valley started forming approximately one million years ago in the Quaternary geological period. The final formation of the ancient valley of the Gauja River occurred during a period of glacial activity. The glaciers melted and covered the territory of Gauja National Park several times, and the melting waters settled in the terraces of the Gauja and transported field stones, gravel, and clay. The ancient valley of the Gauja River gradually gained its current look during the last 10,000 to 20,000 years.
The Gauja River used to serve as a trade route and border river between the Liv (Finno-Ugrian) and Latgalian (Indo-European) lands. In some territories, they used to live mixed together. The Livs suffered greatly during the Northern War and plague in the 18th century. That was the period when the remaining Livs assimilated with the Latvians. When Liv languages were still present along the Gauja River and the sea, it used to be called Koivo–Bērzupe or Svētupe (the Saint River) (derived from the Finno-Ugric languages). In Latvian, the name of the Gauja River used to mean 'a great amount', 'a crowd', and was therefore called the 'big river'.
The Gauja River tends to change its bed rapidly. Therefore, it has gained the reputation of being deceitful. The bed of the river is made of unconsolidated sand and gravel deposits that move along with the current. In some places, the bed is pebbly, thus forming impressive boulder rapids: Kazu, Raiskuma, Rakšu, and Ķūķu. The bottom of the river in Gauja National Park is 60 to 120 meters wide with a rapidly changing depth from 0.3 m to 7 m. The decline is 0.5 m/km. The speed of flow during low water is 0.2 to 0.4 m/s, and during the spring water period 2 to 3 m/s. Due to the fluctuations in water level, current speed, and special flow features, the Gauja River may be characterized as a rather non-homogeneous watercourse.
Usually the Gauja River freezes over in the mid-December, and the ice starts moving in late March. During warm winters, the river does not freeze over. Much underground water flows into the Gauja River. It therefore has a lower water temperature than other large rivers in Latvia.