Physical and chemical environment
9.3 Onshore landfall Narva Bay General siting
9.3.1
The proposed construction and operation area required for the onshore part of NSP2 is situated on the south-western edge of the Kurgalsky Peninsula. The dominant landforms between the PTA and the shoreline comprise glacial moraines underlying a series of ancient dunes leading to a narrow beach to the west (Figure 9.11). Drainage on the west side of the dune lines tends to be east to west. To the east of these dune lines, impervious clay layers form a basin where rainfall-fed bogs have developed, with organic material accumulating to produce peat that is mainly shallow but in places reaches up to 2 m deep.
The onshore route cuts through the northern edge of one of these large bogs, the Kader swamp, where drainage is mainly south-west to north-east. A series of artificial ditches intercepts this flow and diverts it to the meandering and slow flowing Mertvitsa River. This river lies outside of the NSP2 area, to the east of the landfall site, and flows north and into the Luga River. The Gazprom gas supply pipelines cross the river.
The topography is steeper to the west, with two distinct dune ridges with a longer shallower profile to the east of the ancient dune ridge. Elevations are generally between 3-8 m with the highest elevation of 15 m being the ancient dune ridges (Figure 9-10).
Figure 9-10 Cross section of the onshore route at the Russian landfall.
Geomorphology and topography 9.3.2
The preferred landfall in Russia is located in the north-western part of the Russian Plain within the Narva-Luga Klint Bay (see Figure 9-11 and Figure 9-12). It is a coastal lowland that has experienced slow but uneven land uplift and complex water level changes with alternating lacustrine (the build-up of sedimentary layers by lake formation) and marine stages /106/.
Marine transgressions between 7500–4000 years before present produced the Littorina Sea, which covered much of the present coastline. As water levels changed, a series of barrier beaches were formed that now form elongated sandy dunes parallel to the coast, up to 10-30 m high. The NSP2 onshore route will cross two dune ridges: a coastal dune up to 7 m high and a relict dune system that reaches an elevation of around 15 m approximately 1.5-2 km inland. The coastal landscape of Narva Bay is characterised by these beach ridges with dunes colonised with grass and lichen pine forests. This landform is known as the Nizhneluzhsky landscape and is typical of the coastal areas around the Gulf of Finland.
The landforms characterised by the coastal dune, natural forest, relict dune and Kader swamp show limited evidence of anthropogenic modification, while the modified habitat shows moderate signs of human intervention, as it contains a number of artificial drainage ditches.
The soil types of the landfall area are mainly podzols 9, bog-podzols and bog soils, characterised by low humus content and high acidity. Poor drainage arising from the settlement of glacial silt in hollows produces extensive areas of bogs and lakes, most notably the Kader swamp. This area has shallow peat (maximum depth 2 m).
Erosion is associated with both permanent and temporary watercourses cutting into floodplain terraces, but gully erosion is confined to the steep slope of the sand dunes on the edge of the marine terrace. There is potential for dune erosion if vegetation is disturbed. No landslides have been observed.
Figure 9-11 Landforms and digital elevation model of the preferred Russian landfall.
(9) Infertile acidic soil with an ash-like subsurface layer (from which minerals have been leached) and a lower dark stratum.
Figure 9-12 Beach on the coast of Narva Bay, overgrown with reed up to 1.5 m high. The dip angle of the surface is approximately 30. It is composed of fine-grained, light-grey sand with dark silt and a minor quantity of shells /76/.
Freshwater hydrology 9.3.3
There are two main hydrological features associated with the project area, the Kader swamp and the Mertvitsa River, and number of handmade ditches and channels which were created previously for agricultural purposes /76/.
The central part of the Kader swamp is a complex of pool-and-hummock ridges. The groundwater table varies between 1 m and 10 m from the surface. Plant communities at the periphery include sphagnum, sedges, cotton grass, sub-shrub and pine. The northern part of the Kader swamp has experienced natural fires in the last decade and land reclamation included planting of young pines and the creation of fire protection ditches (Figure 9-13). The bogs are mainly rainfall fed (ombrogenous) and drain north and east into the River Mertvitsa (Figure 9-14) via culverts in the A121 road. The river runs to the north and east of the landfall area and after a slow meandering course joins the Luga River.
A B
Figure 9-13 A. Northern part of the Kader swamp suffered from fire.
B. Central part of the Kader swamp, 2.5 km south of the proposed landfall area /76/.
The water levels in the Mertvitsa River are largely dependent on the much larger Luga River to the east. The Mertvitsa River normally has no drift ice in it. As noted above, the NSP2 route does not cross the river, but the feeder lines of the upstream gas connection pipeline do.
Figure 9-14 The Mertvitsa River to the east of potential landfall area (riverbed width is 10 m) /76/.
Climate and air quality 9.3.4
9.3.4.1 Climate
The location of the preferred landfall on the coast of the Gulf of Finland and the proximity of the Baltic Sea gives its climate the features of a marine climate. This is manifested, e.g., in the shift of the temperature minimum from January to February and the lower annual air temperature variation between the average temperatures of the warmest and coldest months. Owing to the frequent penetration of warm air masses from the Atlantic Ocean, the winters in the Russian landfall area are generally not severe /75/.
9.3.4.2 Air quality
The calculated background concentrations of air pollutants in the Narva Bay landfall area are given in Table 9-9. The values shown were calculated by the state meteorological authority in Russia for the two villages closest to the landfall and represent the period 2014-2018.
Table 9-9 Background concentrations of pollutants in the atmospheric air of Khanike village and Ropsha village (Kingisepp area) /75/. The values (representing the period 2014-2018) are shown relative to the maximum permissible concentration (MPC) in the last column.
Parameter Concentration MPC Concentration/MPC
ratio
PM 195 µg/m3 500 µg/m3 0.39
SO2 13 µg/m3 500 µg/m3 0.026
NO2 54 µg/m3 200 µg/m3 0.27
CO 2.4 mg/m3 5 mg/m3 0.48
As shown in the table above, the calculated air quality conditions in the two villages is good, with no MPC values exceeded, and with baseline concentrations of all calculated pollutants less than 50% of MPC. The primary local sources of air pollution in the area are expected to be traffic and fuel combustion for local heating. As the above concentrations have been calculated in villages, baseline concentrations in areas with no human developments can be expected to be lower than the above values.
9.4 Onshore landfall Lubmin 2