Astra-Project - Estonia- Tallin and Pärnu

Estonia

Cities of Tallinn and Pärnu

Description of case study area:

1.Tallinn case study area

Tallinn is the Capital of Estonia with population more than 400 000 and area 158 km². Coast line length of the city is 70 km.

Ülemiste Lake (water volume 0.34 km³) is the main source of drinking water for Tallinn (water consuming from the lake is more than 1 m³/sec). The lake is feeding from Pirita River catchment system with the area more than 1000 km². Lake Ülemiste is located at 20-30 m higher than the most part of Tallinn. The barrier between the lake and downtown consists of friable sediments (sand, silt, gravel). During long raining periods the water level rises essentially.
Risk factor: Possible overflow and flooding the downtown; possible pollution of water reservoir from flooded areas.

Water table of Harku Lake is only 1.2 m a.s.l. The lake is located in the immediate neighborhood of Õismäe habitation area.
Risk factor: Strong and long precipitation and sea level rise may cause floods.

Tallinn downtown is influenced by changing climate and sea level rise.
Main risk factor: Strong storms and floods in the coastal zone.

2. Pärnu case study area

Pärnu River catchment area is 6900 km², mean river discharge is 64 m³/s. Increased risks as a result of combining meteorological and geological factors.
Meteorological factors caused by climate changes:

Rise of sea water level
Direction and rising intensity of storms
Quantity and duration of precipitation

Geological factors:

Regional neotectonic movements of the earth's crust
Local vertical movements of ground surface (mainly caused by overpumping of ground water)
Properties of bedrock and sedimentary cover
Hydrology (character and dimensions of catchment areas)

Overview map and photos of the case study area:

Location of the case studies in Estonia

Floods and coastal erosion in Pärnu case area.

Floods in Harku Lake and in Tallinn downtown.

Planned work and results in the case study area:

Main questions to be solved in the course of the ASTRA Project:

Finding out the dynamics of sea coasts based on regular monitoring of study areas.
Prognosis of the influence of possible climate changes to the dynamics of sea coasts.
Prognosis of the influence of strong storms to sea coasts.
Presentation of the results of the winter storm of 2005 on example areas.

Tasks:

Detailed study of ground movements in Tallinn and Pärnu areas; prognosis of normal sea level height for years 2050 and 2100.
Prognosis of additional rising of sea level caused by extreme storms like in 1967 and 2005; trends of storms.
Behaviour of near-shore streams caused by strong storms; their influence on shore and near-shore pollution-hazardous objects (fuel stations, stores of chemicals etc.);
Detailed study of geology of shore areas susceptible to abrasion and landslides.
Finding out the influence of climate changes to hydrology of catchment areas of Pirita and Pärnu river basins.
Presentation of results in form of maps, figures, explanatory notes etc.
Impact analysis on underground buildings and communications network and pipelines(sewage, water and gas tubing etc.).
Formulating recommendations for minimisation of negative influence of climate changes on studied and other similar hazardous areas.
Dissemination of results and recommendations to state and municipal institutions; making the results public through the press, radio and TV.

Description of project partner:

Geological Survey of Estonia/ Eesti Geoloogiakeskus (EGK)

The Geological Survey of Estonia is a government-owned enterprise belonging to the Ministry of Environment. The number of employees is 95 persons including 5 PhDs, 11 MScs, 46 engineers and 22 technicians. Main fields of activity of the Geological Survey of Estonia (EGK) are the following:

geological mapping
exploration of mineral resources
exploration of groundwater
compiling and administering of the national registers and databases pertaining to the Earth´s crust and natural resources
environmental monitoring pertaining to the Earth´s crust.

Since the year 2003 EGK is a member of EuroGeoSurveys. EGK has joined the ASTRA project because research of environmental problems in connection with geology is one of the main aims of the institution.