LAKE ÜLEMISTEmacroflora & water

treatment

Karena KiisTÖ-51

Largest of the lakes surrounding Tallinn Main part of the Tallinn water supply system The Tallinn Water Company, AS Tallinna Vesi, has a

treatment plant on the North shore of the lake which supplies 90% of the water to the city

Other 10% from ground water wells On 18 March 2010 a DHL Antonov An-26 aircraft

made an emergency landing on the ice of Lake Ülemiste and 1,5 tons of fuel leaked into the water

Lake Ülemiste

Lake Ülemiste

Max. length 4.1 km

Max. width 3.2 km

Surface area 9.436 km2

Average depth 2.5 m

Max. depth 4.2 m

Shore length 15.219 km

Surface elevation 35.7 m

Macrophyte vegetation covered 5.4% of the lake, 6% in 2004

The mean width of the zone of macrophytes was 48.4 m and the mean depth 1.4 m.

Widest belt was in south-west part of the lake – 286 m

The list of the macrophytes found over the entire lake contains 41 species of vascular plants, 1 moss species, and 5 species of macroalgae.

Macroflora of lake Ülemiste in 2000

Emergent macrophytes

Common reed /pilliroog

Common club-rush / järvkaisel

Common rivergrass /

rooghein

Floating-leaved macrophyte

Water knotweed / vesi-kirburohi

Submerged macrophytesShining

pondweed / läik-penikeel

Clasping-leaf pondweed/

kaelus-penikeel

Sago pondweed /

kamm-penikeel

Grassy pondweed /

hein-penikeel

Species Number of findings Frequency, % Depth limits, m

Common reed / pilliroog 133 57.3 0.2-2.5

Common club-rush / järvkaisel 97 41.8 0.2-1.9

Water knotweed / vesi-

kirburohi62 26.7 0.3-2.0

Common rivergrass / rooghein

36 15.5 0.2-2.0

Shining pondweed / läik-

penikeel35 15.1 0.5-2.5

Clasping-leaf pondweed/

kaelus-penikeel 25 10.8 0.7-1.3

Sago pondweed / kamm-penikeel 8 3.4 0.5-1.5

Grassy pondweed / hein-

penikeel7 3.0 0.4-1.4

Water-level fluctuations throughout 4 periods 8 dry periods during 20th century CaHCO3 on the leaves of submerged macrophytes Renovations on shorelines Fish like bream

NB! Submerged macrophytes are a very important structural element in lakes and may markedly affect environmental conditions of a lake by their ability to stabilize the clear-water state.

Affective environmental factors

.. has been treating water since 1927 .. produces an average of 60,000 m3 of water per day Average water consumption in 2013 was 93 litres per

inhabitant

.. treats water by a treatment scheme often used world-wide Ozone is used in the treatment process to improve the quality,

odour, colour and taste Small amounts of chlorine is added in the drinking water,

which is effective protecton against bacteria as it travels through the network

Ülemiste WTP constantly develop new technologies and proceed to improve our water drinking experience

Ülemiste Water Treatment Plant

Surface water is gathered to Lake Ülemiste and directed to Water Treatment Plant.

Raw water passes through screens and microfilters, which remove algae and plankton from the water.

Water is led into reservoirs, where a mixture of ozone in air is injected into the water to oxidize organic substances.

A water treatment chemical coagulant is added to clarify the water. During the clarification phase particulate matter, chemical flocks and

precipitates are removed from the water. Water passes through filters. In summer, dependent on the quality of raw

water coming into the plant, activated carbon may be added in order to remove any remaining particles and to improve the taste of the drinking water.

Chlorine is added to the water for disinfection purposes. The water is directed to drinking water reservoirs, from which it is pumped

to the city water network in accordance with demand.

Water treatment process

Drinking water quality is required to comply with “Quality and Control Requirements and Analysis Methods for Drinking Water”

The water quality is monitored following the Drinking Water Quality Monitoring Programme approved by the Health Board.

Drinking tap water is a growing trend Raw water quality indicators are analysed once a day at the

intake to the treatment system

Drinking water quality

Drinking water quality

Thank Your for listening!