Colaborar a la formación de comunidades

It is estimated that the construction work of OL4 will produce at most some 310,000 m3 _{of quarry material and}

some 400,000 m3 _{of surplus soil. These soil masses will}

be temporarily deposited on the power plant site and utilised in civil engineering work, for example, in road and embankment structures. The rest of the masses will be deposited on a soil and rock material dumping site in Olkiluoto.

Extension of the operating waste disposal facility (VLJ Repository) requires underground quarrying, the environmental effects of which are related to the transportation and disposal of quarry masses, the waste waters produced when keeping the quarried cave dry and the flow of groundwater inside bedrock.

The quarry material produced by excavating the spent fuel repository will be dumped in compliance with the permit regulations issued for it. The rock material will be used as quarry or crushed aggregate for, among other things, the foundations of buildings and roads on the plant site, for the floor structures of the repository tunnels, and for filling in the repositories. The repository tunnels will be quarried as the final disposal progresses. Near the cooling water intake and discharge channels, the construction work will change the water depth readings and the properties of the sea bottom. The water structures of the cooling water system will not affect the water level of the area. The water construction work is carried out in a confined area in the immediate vicinity of the power plant. There is no such traffic on these waterways that would be significantly disturbed by the construction work.

The water construction work will primarily affect the water quality by introducing material that makes the water cloudy. Cloudiness will primarily occur in conjunction with dredging operations and dumping of dredging masses, but also to some degree in connection with filling-in water areas. The amount of material causing cloudiness depends on the composition of the dredged mass. The more fine particles the mass contains, the more cloudiness occurs. In cooling water discharge option A where the discharge takes place in the current location, cloudiness will be limited to the bay of Iso Kaalonperä, and in alternative B where the discharge takes place north of the current location, to the waters in front of Tyrniemi. In cooling water intake option C where the discharge takes place adjacent to the water intakes of the current plants, cloudiness will be limited to the Olkiluodonvesi, and in alternative D where the intake is located on the northern shore of Olkiluoto, to the Eurajoki inlet. The cloudiness will be localised and temporary, and it is not estimated to cause any significant detriment. The locations for cooling water intake and discharge are presented in Figure 2-5.

The water construction work for OL3 has not revealed any significant amounts of heavy metals or other hazardous substances in the ground soils of dredging, dumping or landfill sites. Therefore the dredging, dumping or landfill operations will not cause any detrimental changes in chemical water quality.

The impacts of constructing the structures required by OL3 to the aquatic environment were monitored in 2004. The monitoring did not reveal any impacts on the seawater quality during the construction work. The cloudiness and highest solid content were observed on the outermost observation station near Puskakari where the mixing of seawater layers and wind conditions had probably resulted in the nutrients and bottom algae being mixed in the water (Kirkkala 2004). From the point of fishes and fishing, the impacts will primarily depend on how the spawning and fishing waters are located in relation to the working sites and how much 

Envir

onmental

Impact

Assessment

silted solids travel to these areas. Taking into account the location of spawning sites and the small amount of material causing cloudiness, dredging and the associated dumping are not estimated to have a significant impact on the proliferation of fish. The water construction work is not estimated to impact fishing either because the significant fishing sites are rather far away from the work sites.

The dredging and dumping operations will temporarily limit the living area of seabed organisms that several species of fish feed on. Judging by the properties of the seabed outside Olkiluoto, at least Baltic tellin

(Macoma balthica) is found in the area; this mollusc is one of the main sources of food for flounder, for example. However, experience from similar situations has shown that the bottom fauna is revived rather quickly after the work has ended. The impacts are further alleviated by the fact that the dredging and dumping sites are in this case rather small. The closest fringes of Rauma archipelago (FI0200073) that belong to the Natura 2000 network are some two kilometres away from the westernmost point of Olkiluoto. The conclusion of the assessment made in 2001 regarding the impacts of OL3 on the Natura 2000 area of the Rauma archipelago was that the impacts will be minor both during the construction phase and operation, and they cannot be considered significant from the point of protection of the natural values of the Natura scheme.

According to the Natura requirements assessment completed in 2007 (Ramboll Finland Oy 2007d), the detrimental effect of the temporary cloudiness of water caused by construction work on the sea area is at its largest near the work areas and quickly decreases with distance. The affected area is at its largest as a result of strong and long-lasting easterly wind. In front of Iso Kaalonperä, the current jet of cooling water effectively mixes the water masses. This prevents the cloudiness effects from occurring in the nearest Natura area.

The area of cloudy water caused by the parts of the cooling water channels built in the sea will depend on the discharge area alternative under consideration. In alternative B where the northern bank of the discharge channel is continued to the front of Tyrniemi, some

cloudiness of water may also occur at times in the sea area surrounding individual islands and islets in the Natura area of the Rauma archipelago. However, the minor and temporary change in water quality will not cause significant detrimental effects on algae growth on the rocks and rocky shores. The islands and islets closest to Olkiluoto are not part of the conservation area. (Ramboll

Finland Oy 2007d.)

8.3 Dust and noise impact caused by building