Gulf Of Riga

Gulf of Riga
Location in Northern Europe.
Gulf of Riga
Location	Europe
Coordinates	57°45′N 23°30′E / 57.750°N 23.500°E / 57.750; 23.500
Primary inflows	Daugava, Pärnu, Lielupe, Gauja, Salaca
Surface area	18,000 km2 (6,900 sq mi)
Average depth	26 m (85 ft)
Max. depth	54 m (177 ft)
Water volume	424 km3 (344,000,000 acre⋅ft)
Residence time	30 years
Frozen	Most or all during winter
Settlements	Riga, Jūrmala, Pärnu, Kuressaare, Salacgrīva, Saulkrasti, Ainaži

The island of Saaremaa (Estonia) partially separates it from the rest of the Baltic Sea. The main connection between the gulf and the Baltic Sea is the Irbe Strait.

The Gulf of Riga, as a sub-basin of the Baltic, also includes the Väinameri Sea in the West Estonian archipelago.

Extent

 

The International Hydrographic Organization defines the Gulf of Riga's western limit as "A line running from Lyser Ort (57°34'N), in Latvia, to the South extreme of Œsel Island, through this island to Pammerort (22°34'E), thence to Enmast Point, the S extreme of Dagö, through Dagö to Takhkona Point, the North extreme thereof, and on to Spithamn Point in Estonia".

Islands

Major islands in the gulf include Saaremaa, Kihnu, and Ruhnu, which are all controlled by Estonia. Kihnu covers an area of 16.4 square kilometres (6.3 sq mi). Saaremaa island is responsible for the brackish water of the Gulf of Riga, as it is partially "shielded" from the Baltic Sea. The Baltic itself is already less salty than the global oceanic average, but this effect has a north–south and east–west gradient.

Cities

Notable cities around the gulf include Riga, Pärnu, Jūrmala, and Kuressaare. The main rivers flowing into the gulf are Daugava, Pärnu, Lielupe, Gauja, and Salaca.

The freshwater runoff entering the Baltic sea accounts for two percent of its volume. A narrow connection to the North Sea means that water stays in the Baltic for an average of 30 years. These two characteristics work to make the Baltic Sea one of the largest brackish bodies of water in the world. The Gulf of Riga has an average salt concentration for the Baltic Sea, which is around six to ten parts per thousand. Freshwater has a concentration of 0.5 parts per thousand, and seawater is about 30 parts per thousand.

In winter, most or all of the Bay occasionally freezes. This is due to low salinity and the calming effect of the partial closure of the entrance of the gulf. During the winter, many people walk over the bay. The thickest recorded ice was 90 centimetres (2 ft 11 in) thick in the winter of 1941–42. Ice hole fishing has been a traditional source of winter food, and remains a common activity. The ice usually melts between March and April. In late March 2013, when the ice started to melt, 200 people had to be rescued from ice floes.

• Battle of the Gulf of Riga
• Pärnu Bay