1.1.1.WATER RESOURCES Estonia can be divided into five hydrological basins: the Lake Peipus-Narva basin in the east; the Gulf of Finland basin in the north; the Gulf of Riga basin, including the Salaca River, in the southwest; the Muhu Sound basin, including the Gauja River, in the southeast; and the Islands. The internal renewable surface water resources (IRSWR) are estimated at 11,712 million m3/year. A total quantity of about 96 million m3/year is estimated to flow from Latvia and the Russian Federation into Estonia, while an estimated 406 million m3/year flow from Estonia into Latvia and the Russian Federation The artificial Lake Narva in the northeast was created in 1956, when the Narva hydropower plant started operating. Its total area is 191km2, of which 38km2 are located within Estonia. Its average depth is 1.8m, its deepest point 15m. Estonia is rich in groundwater resources. The internal renewable groundwater resources are estimated at 4km3/year. The main recharge area is in the Pandivere uplands, where limestone areas and sand/gravel ridges are locally important. Generally, in southern Estonia the groundwater of the Devonian aquifer is used, while in western and sporadically in central Estonia the water of the Silurian-Ordovician horizon is used. Groundwater covers about two-thirds of the drinking water supply. Part of the groundwater flows out to the sea and part returns to the surface water system. This latter part, which is already accounted for in the runoff (overlap), has been estimated at 3km3/year. Estonia is located within a transition zone from maritime to continental climate. The active cyclonic activity of the northern part of the Atlantic Ocean makes the weather very variable, causes strong winds, high precipitation and fluctuations in temperature, and the Baltic Sea causes significant differences between the climate of coastal and inland areas. As mentioned, Estonia is very small by area, but at the same time temperatures may vary by 20°C, e.g. + 10°C on islands and -10°C in inland areas. Due to the climate conditions and latitude the average annual temperature in Estonia is only +5°C and Estonia also has a great seasonal variation in daylight. Because of that, people in Estonia need extra electricity and heating during most of the year, from September until May. Due to rather high precipitation (about 630 mm/year), the need for irrigation is much less significant than in southern European countries.

1.1.2.WATER USE In 1995, the water withdrawal for agricultural, domestic and industrial purposes was estimated at 158 million m3, of which only 5 per cent was for agricultural purposes. In addition, more than 1.2 million m3 were used for cooling in the thermal power production in the Narva region and about 172 million m3 for fisheries. For the majority of towns and settlements, groundwater is the only source of drinking and industrial water, except in the towns of Tallinn and Narva near the coast where groundwater resources are very limited. In 1995, about 88 per cent of the population had access to drinking water supply. The total quantity of wastewater produced in 1995 was 396 million m3, of which 378 million m3 was treated.

1.2.WATER QUALITY, ECOSYSTEMS AND HUMAN HEALTH Intensive agriculture has led to an increase in nitrogen concentration in groundwater through the intensive use of fertilizers. A decline in the use of fertilizers in recent years seems to have already resulted in a decrease in the nitrogen concentration in groundwater wells. While deeper groundwater layers meet the existing drinking water standards, upper groundwater layers in many regions are still polluted with nitrogen components. Close to former military bases, groundwater is often polluted with oil products. The drastic reduction in economic activity since 1989 and the construction of new wastewater treatment plants, have already reduced pollution considerably. Municipal and industrial pointsource pollution loads in Estonian rivers have decreased significantly since 1992: organic pollution (measured as BOD), by 90 per cent, nitrogen by about 60 per cent and phosphorus by about 75 per cent. The decreases at the beginning of the 1990s were due mainly to the reduction in overall production activities. The further decreases since then are associated with the modernisation of production, construction and renovation of wastewater treatment plants, structured legislative drafting and increases in the pollution charge. The concentration of nitrogen in rivers depends mainly on the diffuse load and correlates quite well with the amount of precipitation for the year. The high nitrogen content in rivers at the beginning of 1990s was the result of intensive agriculture at the end of Soviet period. Since that time, the area of crop-land and the use of mineral fertilizers have fallen by nearly a factor of two. The number of animals, and as a result the amount of manure, have also been reduced. The average mean nitrogen content has increased, due mainly to steep increases in rivers with more considerable agricultural impact, despite these being in a minority. In the majority of Estonian rivers the increase has been quite moderate and the average nitrogen content varies around 2 mgN/l depending on hydrological conditions. Nevertheless water quality in monitored Estonian rivers is relatively good and in most rivers it has no significant negative impact on biological quality. Generally high and good status of phytobenthos, which mainly indicates the trophic level, confirms the good water quality. The main Country Overview - Estonia reason why macro-invertebrates have a moderate or poor status in one sixth of water courses is hydro-morphological alterations caused by land drainage. Organic pollution from municipal and industrial wastewater has decreased substantially and only impacts aquatic organisms in a few rivers. Compared with other biota, the status of fish populations is worse. In about 30 per cent of monitored water courses the fish status is moderate or worse. In addition to land drainage – straightening rivers, lowering water level, sediment load, etc. – the main reason for this is the number of dams. In addition to man-made constructions, beaver dams also have a substantial negative impact on fish status, in particular trout, in smaller rivers and streams. As ecological assessment using current methodology has only been carried out for the first time, no reliable trends can be demonstrated, but comparison of single indicators for macroinvertebrates and phyto-benthos indicate an improvement in their status in rivers, where water quality was the limiting factor 5-15 years ago. Regarding lakes’ water quality, the increase and intensification of agriculture in the 1970s and 1980s was the main reason for their rapid eutrophication. Due to a decline in agriculture and implementation of water protection measures in the 1990s there has been a considerable improvement, although there are departures from the general trend. In 2004-2008, the status of 79 small lakes was assessed under the national monitoring programme. Despite a general reduction in pollution loads, about 20 per cent of lakes were classified as moderate or poor. The reasons for this are various and can be divided into past factors and current pressures. For several lakes - especially for those with a slow water exchange rate – past pollution from farms or municipal wastewater discharges or lowering of water levels are still the main reasons for their moderate or poor status. Currently, construction work or other human activity changing the landscapes on the edges of lakes has, in some cases, resulted in considerable pressures

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