7 EXISTING CONDITIONS IN THE PROJECT AREA
7.1 Environmental surveys completed in the project area
The environmental baseline description has been prepared on the basis of surveys undertaken along the proposed NSP2 route corridor, peer-reviewed scientific literature, relevant EIAs (e.g. the
national EIA reports for NSP and the NSP2 base case route, which provided valuable sources of empirical data for the area), data from the monitoring programme for NSP, as well as other relevant technical reports and data for the area. The existing information includes survey data for a number of parameters relevant to the baseline descriptions for this EIA. Specifically, the following environ-mental surveys have been performed in the area relevant to the NSP2 route:
• 2005-2006: Peter Gaz surveys for the planning of the NSP route;
• 2015-2016: surveys for the planning of the NSP2 base case route;
• 2018-2019: surveys for the planning of the NSP2 route.
The present data basis for this EIA is described in more detail in the sections below Survey data basis for this EIA
Several surveys were conducted in Danish waters in connection with preparation of the national EIA report for the NSP2 base case route /73/. These surveys serve as valuable sources of empirical data for the general area of the proposed NSP2 route. These surveys were conducted in order to inform route development as well as to ensure a solid basis for the baseline descriptions and sub-sequent impact assessment. Surveys have also been undertaken through the previously disputed area between Denmark and Poland in connection with an earlier route alternative considered for NSP (carried out by Peter Gaz, /86/).
The general locations of prior sampling events (i.e., in Danish waters east and south of Bornholm) are similar in character to the area of the proposed NSP2 route. It is furthermore assessed that conditions in the Danish section of the Baltic Sea have not changed significantly since the comple-tion of these surveys. As such, the data gathered in the previously described surveys are considered to be relevant to the present EIA.
New surveys were conducted along the proposed NSP2 route (SE route) corridor and along the NSP2 route V2 corridor in August-September 2018, in order to verify the validity of the previously collected data in the general project area and to provide a more robust data basis for the baseline descriptions and impact assessments provided in this EIA /87//88//92/.
These prior environmental surveys are described in general terms below, whilst further details can be found in the survey reports, see references below.
7.1.1.1 Surveys along the NSP2 base case and proposed NSP2 route (SE route)
Environmental baseline surveys were undertaken in the Danish waters east and south of Born-holm in 2015 and 2016 in order to inform route development for the NSP2 base case route. In August-September 2018, surveys of the same environmental parameters were completed along the Danish section of the proposed NSP2 route and NSP2 route V2, with the purpose of providing baseline data for use in the EIA report. These surveys are described further below, and the sur-vey results have been included in this report where relevant.
Seabed sediment
In October 2015, an environmental survey of surface sediment conditions was undertaken in Dan-ish waters in connection with the NSP2 base case route /89/. These survey results were supple-mented in August-September 2018 with surveys of surface sediment along the proposed NSP2 route (SE route) and NSP2 route V2 (SE route V2) /87/. The locations of the survey stations per-tinent to the route alternatives assessed in this EIA are shown in Figure 7-1.
Figure 7-1 Survey stations for analysis of surface sediment conditions in Danish waters.
The surveys included the following sampling activities /89/:
• Photographic documentation of the sediment surface at all sampling stations using a video camera mounted in a frame;
• Analysis of surface sediments performed with a HAPS core sampler.
Equipment used for the survey is shown in Figure 7-2.
Figure 7-2 Sampling of the surface sediment was undertaken using a video camera (left) and HAPS core sampler (right).
The surface sediment was analysed for standard physical and chemical conditions (e.g. dry weight, loss on ignition (organic content), grain-size distribution) and concentrations of heavy metals, pol-ycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides, organotins, CWA, and nutrients /89/.
Key results of the survey are presented in sections 7.3, 7.4 and 7.5.
Infauna
In October 2015, an environmental survey of infauna was undertaken in Danish waters in connec-tion with the NSP2 base case route /90/. These survey results were supplemented in August-September 2018 with surveys of infauna along the proposed NSP2 route (SE route) and NSP2 route V2 (SE route V2) /88/. The locations of the survey stations pertinent to the route alternatives assessed in this EIA are shown in Figure 7-3.
Figure 7-3 Survey stations for analysis of surface infauna (macrozoobenthos) in Danish waters.
The surveys included the following sampling activities:
• Quantitative sampling of infauna performed with a Van Veen sampler;
• Photographic documentation of the sediment samples used for infauna analysis;
• Analysis of infauna.
Figure 7-4 Sampling of infauna was undertaken with a Van Veen sampler (left). An example of an infauna sample (right).
Organisms were identified to species level (except for Oligochaeta and Nemertea) and counted, measured and/or weighed. A number of statistical analyses, e.g. diversity indices and Bray-Curtis dissimilarity indices, were carried out. The key survey results are presented in section 7.8.
Chemical warfare agents in seabed sediment
In October 2015, an environmental survey of CWA was undertaken in Danish waters along the NSP2 base case route and through the risk area /91/. During surveys conducted in August-Sep-tember 2018 /92/, sampling was undertaken at approx. 5-km intervals along the NSP2 route V2, where the 2015 NSP2 base case route survey identified a higher frequency of CWA-positive sam-ples. This part of the route is relatively close to the known chemical munitions dumping area and within the risk area in which fishing vessels are required to have first aid gas equipment on board. Sampling was undertaken at approx. 10-km intervals along the remaining, western part of the route. The locations of the survey stations sampled in 2015 and 2018 are shown in Figure 7-5.
Figure 7-5 Survey stations for CWA in Danish waters.
The survey included the following sampling activities:
• Seabed sampling performed with a Van Veen sampler or HAPS core sampler (see Figure 7-2 and Figure 7-4);
• Photographic documentation of the sediment samples used for CWA analysis.
The surface sediment was analysed for intact chemicals as well as degradation products and de-rivatives /91/, as summarised in Table 7-22. The key survey results are presented in section 7.3.3.8.
7.1.1.2 Peter Gaz surveys
In 2005 and 2006, Peter Gaz conducted surveys of seabed sediments and benthic fauna in the waters of Russia, Finland, Sweden, Denmark and Germany /86/. The surveys included sampling of:
• Organic pollutants and radionuclides in sediments, sampled with a grab sampler to a sedi-ment depth of up to 20 cm (12 stations in the Danish EEZ).
• Metals and organic carbon in sediments, sampled with a grab sampler to a sediment depth of up to 20 cm (12 stations in the Danish EEZ).
• Biomass and abundance of phytoplankton in six main groups. Water samples for phytoplank-ton investigation were taken from the subsurface layer (approximately 1 m depth) and from the near bottom layer (2 m above the bottom) and mixed. Water sampling was carried out simultaneously with hydrochemical sampling using plastic bathometers, attached to sub-merged hydrological rosette probe. The samples were fixed in lugol for further identification (six stations in the Danish EEZ).
• Biomass and abundance of zooplankton in four main groups, as well as six species of cope-pod, sampled with an inversely coned net (BJN – Big Jedi Net) with a filtration cone made of capron sieve № 68 (mesh size 76 μm) (six stations in the Danish EEZ).
• Biomass and abundance of zoobenthos in six main groups, as well as four species of bivalve, sampled with a 0.025 m2 Petersen grab scoop bottom sampler (six stations in the Danish EEZ);
• Planktonic fish, sampled with a special net made of capron sieve № 38 (mesh size approx.
0.4 mm) (five stations in the Danish EEZ).
Sampling stations in the Danish EEZ are shown in Figure 7-6.
Figure 7-6 Survey stations for the Peter Gaz surveys in 2005 (blue diamonds) and 2006 (red dots) in the Danish EEZ.
Key results are presented in sections 7.3, 7.7 and 7.8.
Surveys along the proposed NSP2 route V1
Additional environmental baseline surveys were carried out in January 2019 along the NSP2 route V1. The objective of these surveys is to verify the validity of the baseline data used in the EIA re-port (i.e. data collected during investigations of previously considered route alternatives for NSP2, as described in section 7.1.1) and thereby confirm the assessments and conclusions con-tained herein. The results of the surveys can be provided to the authorities upon request.
The baseline surveys included:
• Survey of the physical and chemical characteristics of the seabed sediment;
• Survey of benthic infauna;
• Survey of CWA in seabed sediment.
The surveys are performed by sample collection and subsequent analysis. Details of each surveyed parameter are provided in the sections below.
7.1.2.1 Seabed sediment
The purpose of the seabed sediment baseline surveys is to map the physical and chemical char-acteristics of the surface sediment along the proposed NSP2 route V1 inside the Danish EEZ.
Sediment was sampled at approx. 10 km intervals along the proposed NSP2 route V1. Sediment was sampled with a HAPS core sampler (or alternatively with a Van Veen grab) for physical and chemical analysis. The locations of the survey stations along the proposed NSP2 route V1 are shown in Figure 7-7.
Figure 7-7 Surface sediment stations along the proposed NSP2 route V1 in the Danish EEZ.
7.1.2.2 Infauna
The purpose of the infauna baseline survey was to map the current characteristics of and varia-tion in the benthic macrozoobenthos communities along the proposed NSP2 route V1.
The seabed was sampled at approx. 10 km intervals along the proposed NSP2 route V1. The sur-vey was completed by taking three replicate samples of the seabed with a van Veen sampler at each station for macrozoobenthos analysis. The locations of the survey stations along the pro-posed NSP2 route V1 are shown in Figure 7-8.
Figure 7-8 Macrozoobenthos stations along the proposed NSP2 route V1 in the Danish EEZ.
7.1.2.3 Chemical warfare agents in seabed sediment
The purpose of the CWA baseline survey is to map the concentrations of CWA in the surface sedi-ment along relevant sections of the proposed NSP2 route V1.
Sampling was undertaken at approx. 5-km intervals in the eastern part of the proposed NSP2 route V1, where the 2015 NSP2 base case route survey identified a higher frequency of CWA-positive samples (see section 7.1.1). This part of the route is relatively close to the known chemi-cal munitions dumping area and within the risk area in which fishing vessels are required to have first aid gas equipment on board. Within the area in which bottom trawling, anchoring and sea-bed intervention works are discouraged due to known and suspected historical chemical muni-tions dumping, through which the NSP2 route V1 crosses, sampling was undertaken at approx.
2.5-km intervals. The locations of the survey stations along the proposed NSP2 route V1 are shown in Figure 7-9.
Figure 7-9 CWA stations along the proposed NSP2 route V1 in the Danish EEZ.
Preliminary data from this survey have been received, and are referred to in sections 7.3.3.8 and 8.4.4.
7.2 Bathymetry
General conditions
The Baltic Sea is characterised by its deep basins and shallow sills that, together with meteorolog-ical conditions, control the exchange of saltwater with the North Sea. As will be described in this section, this influences the conditions for life both in the water column and on the seabed. The depth of the seabed is also a defining factor for marine life. The bathymetry of the Baltic Sea is therefore considered an important receptor.
The Baltic Sea is one of the largest brackish water bodies in the world. It is located between 53°
and 66° N and between 10° and 26° E and is bordered by the Scandinavian Peninsula, the mainland of northern, eastern and central Europe and the Danish islands. The sea covers an area of 415,000 km2, and its total volume is approximately 21,700 km3. The catchment basin is approximately 1.7 million km2, stretching from densely populated temperate areas in the south to subarctic rural areas in the north. The average depth is 52 m, and the maximum depth is 459 m /93//94/. The topography of the seabed is characterised by several basins separated by sills at different depths /95/. The names of the major basins of the Baltic Sea are shown in Figure 7-10, and the bathymetry is shown in Figure 7-11 and in Atlas Map BA-01-D.
The Baltic Sea is connected to the North Sea through the shallow and narrow Danish straits Little Belt, Great Belt and Oresund (0.8 km, 16 km and 4 km wide, respectively). Two sills in this tran-sition zone (the Dars Sill in the Femern Belt, with a water depth of 18 m, and the Drogden Sill in the Oresund, with a water depth of 8 m) effectively limit the inflow of saline, oxygen-rich water to the Baltic Sea to rare occurrences of storms from the west.
Figure 7-10 Major basins in the Baltic Sea.
The Danish waters around Bornholm include the Arkona Basin (maximum depth of 55 m) and the Bornholm Basin (maximum depth of 106 m, within the Swedish EEZ). The maximum depth of the Bornholm Strait, which separates the Arkona Basin from the Bornholm Basin, is 45 m. The inflow to the Arkona Basin is controlled by the sills at Dars and Drogden. The outflow of the Bornholm Basin is controlled by the Stolpe Channel, which separates the Bornholm Basin and the Gotland Deep and reaches depths of approximately 60 m /96/. The bathymetry of the Danish waters around Bornholm and the areas mentioned above is shown in Figure 7-11. The bathymetry and sub-basins in the Baltic Sea and Danish waters are shown in Atlas Map BA-01-D.
Figure 7-11 Bathymetry in the Danish sector of the Baltic Sea.
Proposed NSP2 route with NSP2 route V1
The bathymetry along the proposed NSP2 route with NSP2 route V1 is illustrated in Figure 7-12, and is very similar to the bathymetry along the proposed NSP2 route with NSP2 route V2 (compare Figure 7-12 with Figure 7-13).
Figure 7-12 Water depth (m) along the combination of the proposed NSP2 route with V1 in Danish waters.
The profile for Line A is shown, but the depth profile is also representative for Line B.
0 10 20 30 40 50 60 70 80 90 100 110
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Water depth (m)
KP (kilometer point)