Water profile of Latvia
Latvia is one of the three Baltic states. It is bordered in the northeast by Estonia, in the east by the Russian Federation, in the southeast by Belarus, in the south by Lithuania and in the west and northwest by the Baltic Sea and the Gulf of Riga. Its total area is 64,600 square kilometers (km2). The country became independent from the Soviet Union in May 1990. Administratively, it is divided into 26 districts and 7 district towns.
Latvia consists of a continental part in the east and the Kurzeme peninsula (Kurland) in the west. The continental consists of morainic uplands that are crossed by several rivers flowing to the lowlands, of which the main ones are the Daugava, Gauja, and Salaca rivers. The highest point of the country is in the Vidzeme uplands with an altitude of almost 312 meters (m) above sea level. The continental part is separated from the peninsula in the west by the Lielupe River, which flows through the Zemgales plain. In the peninsula are the Kurzeme uplands, which are lower than the continental uplands and crossed by several rivers, of which the Venta River is the most important. The highest point in these uplands is at 184 m above sea level. About 57% of the country lies below 100 m above sea level and only 2.5% lies above 200 m.
The cultivable area is estimated at over 2.5 million hectares (ha), which is 39% of the total area of the country. In 1994, the cultivated land was estimated at 1.2 million ha, of which over 98% was covered by annual crops. The soils in Latvia are generally not very fertile. Around 230,000 ha are threatened by wind erosion and around 380,000 ha by water erosion. According to various estimates, marshes cover 5-10% of the total area of the country. Some swamps of peat ground reach a depth of 5 m. The fertile marshy black soils can be found only in the Zemgales plain.
Until 1989, 60% of the area was cultivated by kolkhoz (collective farms) and 40% by sovkhoz (state farms). In 1989, as a result of the proclamation of the `Act on Land Reform in Rural Areas', private farms started developing. In 1994, the private sector, including peasant farms, household plots, private auxiliary farms and private fruit gardens, cultivated over 1 million ha (Figure 1). The average size of private farms does not exceed 20 ha.
The total population is 2.5 million (1996), of which 27% is rural. The population density is 39 inhabitants/km2. In 1994, about 1.3 million people lived in the seven district towns, 857,000 of them in the capital Riga. During the 1980s, the annual population growth averaged 0.3%. In 1990, it was only 0.1%, while it 1994 it was negative, -0.7%. This decrease is related, on the one hand, to a reduced natural population growth, and on the other, to the fact that people of other nationalities (in particular Russians, but also people from Belarus and Ukraine) have been leaving Latvia. In 1996, 14% of the economically active population was engaged in agriculture, with women making up 35% of the agricultural labor force. About 13% of all employed women and 24% of all employed men were engaged in agriculture. Agriculture, including fishery, forestry, and hunting, accounted for almost 8% of the gross domestic product (GDP) in 1995.
Climate and Water Resources
The average annual precipitation, including snowfall, has been estimated at 743 mm. Four climatological regions can be distinguished in Latvia:
- The coastal region, covering 25% of the country, includes the Zemgales plain and the whole coastal region from Lithuania to Estonia. The average annual precipitation is 600 millimeters (mm). The average temperature varies from -3°C in January to 16.5°C in July. Humidity is low.
- The Latgales region, covering 28% of the country, includes the southeast of the country. The average annual precipitation is 700 mm. The average temperature varies from -7°C in January to 17°C in July. Humidity is high.
- The Vidzeme region, covering 30% of the country, includes the northeastern inland part of the country. The average annual precipitation is 700-850 mm. The average temperature varies from -7°C in January to 16.5°C in July. Humidity is high.
- The Kurzeme region, covering 17% of the country, includes the inland part of the Kurzeme peninsula. The average annual precipitation is 700-850 mm. The average temperature varies from -4°C in January to 16.5°C in July. There is medium humidity.
For agriculture, drainage is more important than irrigation. Over 90% of the agricultural land in Latvia can be intensively cultivated only if drained. Irrigation is generally supplementary irrigation.
River Basins and Surface Water Resources
Depending on the physical and geographical conditions, a large part of the river discharge comes from either snow melt, groundwater or direct surface runoff. About 50-55% of the waters of the Daugava, Venta, Lielupe, and Musa rivers is melted snow, while for the Gauja and Amata rivers it is 35-40%. About 10-20% of the flow of some tributaries of the Lielupe (Memele and Svete) and the Aiviekste tributary of the Daugava is fed by groundwater, while for the Daugava and Gauja rivers it is 35-40%. In the Kurzeme peninsula and in the middle uplands, direct surface runoff accounts for 40% of flow of the rivers, while in the Zemgales plain it represents 20-30%.
The country can be divided into eight river basins (Figure 2):
- The Daugava basin. Its total area is 87,900 km2, of which 28% is located in Latvia. The Daugava River rises in the Russian Federation, flows through Belarus (where it is called the Western Dvina), enters Latvia in the southeast and flows northwest to the Gulf of Riga. Several tributaries enter the Daugava River inside Latvian territory, including four large ones: Ogre, Aiviekste, Dubna, and Rezekne.
- The Gauja basin. Its total area is 8,900 km2, of which 88% is situated in Latvia. The Gauja River rises in the Vidzeme upland and flows east, then turns northwest, becomes the border between Latvia and Estonia for a short distance, and then flows southwest to the Gulf of Riga.
- The Salaca basin. It covers the north of the country, near the border with Estonia. Its total area is 3,600 km2, of which 92% is located in Latvia. The Salaca River rises in Lake Burtnieks in the north and flows west to the Gulf of Riga.
- The Lielupe basin. Its total area is 17,600 km2, of which 50% is situated in Latvia. The Lielupe River rises in Lithuania, enters Latvia in the south and flows north to the Gulf of Riga through the most fertile regions of the country. It has many tributaries, the most important being the Memela, Jecava, and Svete.
- The Venta basin. Its total area is 11,800 km2, of which 67% is situated in Latvia. The Venta River rises in Lithuania, enters Latvia in the southwest and flows north through the Kurzeme lowland to the Baltic Sea. The Venta has many tributaries, but only one of them, the Abava River, exceeds 100 kilometers (km) in length.
- The coastal basins between Lithuania and the Venta. Their total area is 5,100 km2. This area includes rivers such as the Barta, Durba, Riva, and Uzava, which flow to the Baltic Sea.
- The basins within the coastal lowland, on the opposite shores of the Gulf of Riga. Their combined area is 3,800 km2. This area includes rivers such as the Irbe, Stonde, Roja, Svetupe, and Vitupe.
- The Velika basin. This basin consists of a number of smaller rivers flowing into the Velika in the Russian Federation. Its area within Latvia is 3,200 km2. The total discharge of the Velika amounts to 4.2 km3/year, of which 16% is generated within Latvia.
The total internal renewable water resources (IRSWR) are estimated at 16.540 km3/year, incoming surface water resources at 18.709 km3/year.
Renewable Surface Water Resources (RSWR) by Major River Basin
|Name of||Area within Latvia||IRSWR||Inflow||Total RSWR||Outflow|
|river basin||km2||% of total||km3/year||km3/year||from||km3/year||to|
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 cubic meters per day (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).
Under Soviet administration, no agreements existed with neighboring 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 hydroelectric 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 cubic kilometers (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 hydropower, 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.
Irrigation and Drainage Development
The more important works connected with land drainage started in the eighteenth century in the east of the country. At the beginning of the nineteenth century, large-scale hydraulic works were carried out on the Bera, Auce, Riva, and Lielupe rivers; dikes were built along the Roja, Abava, Riva, and Pededza rivers; and the Starpinupe canal connecting Lake Kanaris with the Gulf of Riga was constructed. In the middle of the nineteenth century, a canal connecting Lake Lubans with the Aiviekste River was constructed. Subsurface drainage started in 1850. Until 1924, all hydraulic works were carried out without the use of any machinery. In 1924, machines and excavators were purchased, which facilitated the excavation of cross-cuts, made it possible to straighten riverbeds and to shape new ones. The first land improvement act was passed in 1937.
By 1995, almost 1.6 million ha, including agricultural land, meadows, pastures, and land used for construction, had been drained (Figure 4). The area has not increased during the last five years because of financial problems. Most of this area, almost 1.5 million ha, has been provided with subsurface drains, using ceramic or polymer pipes (Figure 5). The state only finances improvements and maintenance of the system. For 1996 and 1997, $US 3.3 million has been earmarked for these purposes. In spite of financial difficulties, there are two or three specialized companies functioning in each district. These companies carry out improvements and undertake maintenance work on individual commissions on private farms.
In 1994, fodder crops covered a large part of the drained area (49.5%), followed by cereals (40.9%), vegetables and potatoes (8.2%) and industrial plants (1.4%) (Figure 6). The drained lands produce 80% of all vegetable production. It is assumed that, generally, crop yields on drained land are 20-25% higher than those on undrained land. In 1992, the yield of cereals on drained lands was 2.7-3.0 t/ha and exceeded those on undrained lands by 1.0-1.5 t/ha. Calculations by the Land Improvement Administration at the Ministry of Agriculture reveal that, in order to fully cover the country's demand for cereals, a further 150,000-200,000 ha should be drained and 200,000 ha manured with lime every year.
In order to increase yields, improve quality and secure production, experiments with sprinkler irrigation on vegetable plantations, early potatoes and sugar beet started in the 1970s. The first sprinkler systems were installed on the Peternick experimental farm in the Jelgava district and then on the Uzvara kolkhoz in the Bauska district and on the Kekava kolkhoz in the Riga district, all in the Zemgales plain. At present, the irrigated area covers about 20,000 ha (Figure 7). All irrigation is sprinkler irrigation, and irrigation in general is supplementary irrigation. The main irrigated crops are potatoes, vegetables, and sugar beet.
The following institutions are involved in water resources management:
- The Ministry of Agriculture is responsible for water management. It includes the Department of Land Reclamation in Riga and local departments in every district. On behalf of the local departments, a land improvement specialist supervises the drainage networks of two or three communes. The funds allocated for the reconstruction and maintenance of the networks are managed by district departments and are allotted after consultations with farmers' organizations (mainly the Latvian Farmers Federation).
- The Ministry of Environmental Protection and Regional Development, with the Environmental Protection Department, collects information on the quantity and quality of water, and is responsible for preventing pollution of water, agricultural land, and air.
- The Ministry of Power Engineering is responsible for the hydroelectric power stations.
- The Latvian Hydrometeorological Agency deals with recording the water quantities of the rivers, lakes, and reservoirs.
- The Melioprojects Company VU in Riga keeps all the records concerning the process of land improvement. There are detailed maps, to a scale of 1:50,000 and 1:100,000, of particular districts, with newly drained areas.
- The Latvian University of Agriculture in Jelgava carries out large-scale scientific research on irrigation and land reclamation.
- The Latvian State Research Institute, Agriculture Polymers and Water Management in Jelgava deals with matters of land reclamation, protection of the water against natural and anthropogenic pollution, and hydraulic modeling.
- The University of Latvia in Riga conducts research on hydrology, climate, geography of water resources (Faculty of Geography) and in environmental sciences (Faculty of Geography, Centre for Environmental Studies). It collects statistics and information on water management, agriculture, and irrigation.
Trends in Water Resources Management
A top priority for the 1995 National Environment Policy Plan for Latvia is the environmental protection of water courses in the Baltic Sea basin, since 85% of the surface water resources are classed as either slightly polluted or polluted. Eutrophication is the most important problem.
Another task is to extend the agricultural period through faster draining during spring. Since 1991, there has been no drainage development at all in Latvia. Over 66,000 km of drainage ditches (almost all the existing ditches) require rehabilitation. During the next ten years, it is planned to drain an additional 150,000-200,000 ha in order to achieve self-sufficiency in cereals.
- Andersons, I., Renknere, V., Liepa, I. 1994. Influence of water basin factor and climate on river discharge in Latvia. In: Proceedings of the Latvian Academy of Sciences. Section B, No 4/1994. Riga.
- Bergström, S., Carlsson, B. 1994. River runoff to the Baltic Sea: 1950-1990. In: Ambio, Vol. 2-3.
- Cabinet of Ministers of the Republic of Latvia. 1995. National Environmental Policy Plan for Latvia. Riga.
- Cimdin, P., Liepa, R. 1989. Small rivers of Latvia (Malye reki Latvii). Riga. (In Russian). ISBN: 5796603345
- Drainage and water management (Vodnoe Khoziaistvo). 1988. In: Melioratsia i Vodnoe Khoziaistvo. Spravoènik No 5, 1988. Moscow.
- Nesterov, J.A. 1992. What is new about drainage in Latvia? (Kak dela u meliorantov Latvii?). In: Melioratsia i Vodnoe Khoziaistvo No 7-8, 1992. Moscow.
- Shkinkis, C.N. 1991. Some results of study on drainage in Latvia (Nekatorye itogi meliorativnich issledovanii v Latvii). In: Melioratsia i Vodnoe Khoziaistvo No 1, 1991. Moscow.
- Smilga, H. 1994. Rates of surface water runoff for designing drainage systems. In: Proceedings of the Latvian Academy of Sciences. Section B, no 4/1994. Riga.
- Water Profile of Latvia, Food and Agriculture Organization.
- World Factbook: Latvia, Central Intelligence Agency.
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