Water resources in Latvia

From WaterWiki

Groundwater resources

The internal renewable groundwater resources are estimated at 2.2 km3/year. Part of the groundwater flows to the sea or is withdrawn by wells, and part is drained by the surface network. That part of the groundwater flow which does not contribute to the total IRWR (overlap) is estimated at 2 km3/year. Groundwater use is estimated at about 800 000 m3/day. In some regions, rapid depletion of the water table is observed. Quite a large quantity is used by cities. In the Jürmala area, close to the capital Riga, the groundwater is famed for its medicinal qualities (thermal baths).

International agreements

Under Soviet administration, no agreements existed with neighbouring republics. Being independent, agreements are now recognized as a necessity. An agreement with the Russian Federation and Belarus concerning the prevention of pollution of the water courses in the Daugava basin is under preparation, as is an agreement with Lithuania on the prevention of water pollution in the Lielupe, Venta and Barta rivers. No agreements on water sharing exist. Lakes and dams

There are about 2 250 lakes with a total area of about 850 km2. About 36% of them are located in the Latgales upland in the southeast of the country.

Dams have been constructed for two main reasons: to control floods and to build hydro-electric power stations. Before the Second World War, about 300 such stations had been built. After the Second World War, the construction of another 547 small stations was planned, but only 267 were built. At present, no small power stations are functioning, though the reservoirs still exist.

Three large hydropower dams have been constructed on the Daugava River, with a total full reservoir capacity of 1.005 km3 and a surface area of 101.9 km2. The Kegums reservoir, with an area of 24.8 km2 and a full capacity of 0.157 km3, was constructed before the Second World War. Since the Second World War, the Plavinas reservoir, with an area of 34.9 km2 and a full capacity of 0.509 km3, and the Riga reservoir, with an area of 42.2 km2 and a full capacity of 0.339 km3, have been constructed. The total dam capacity in Latvia is estimated at 1.050 km3.

Water withdrawal and wastewater

In 1994, the total water withdrawal for agricultural, domestic and industrial purposes was estimated at 285.2 million m3, of which about 12.7% for agriculture (Figure 3). Other water use, including water use for hydro-power, was 149.1 million m3.

In 1994, the total quantity of produced wastewater was 215.8 million m3, of which 119.4 million m3 were classed as clean without treatment, while 66.7 million m3 were treated to meet the quality standards. The remaining 29.7 million m3 were not treated. The largest quantity of untreated wastewater flows into the Daugava and Lielupe river basins. In 1994, the total quantity of re-used treated wastewater amounted to 11.8 million m3.

According to hydrobiological and hydrochemical data, 85% of all surface water is slightly polluted or polluted. Eutrophication is the main problem, caused by untreated municipal wastewater and runoff from agricultural lands.