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Ramboll Oil & Gas, Denmark EIA studies for the Nord Stream pipelines in the Baltic Sea January 2008

EIA studies for the Nord Stream pipelines in the Baltic … studies for the Nord Stream pipelines in the Baltic Sea Ref. 7774001/4.1-03-EP(1) I Table of contents 1. Introduction 1

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Page 1: EIA studies for the Nord Stream pipelines in the Baltic … studies for the Nord Stream pipelines in the Baltic Sea Ref. 7774001/4.1-03-EP(1) I Table of contents 1. Introduction 1

Ramboll Oil & Gas, Denmark

EIA studies for the Nord Stream pipelines in the Baltic Sea

January 2008

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Rambøll Danmark A/S Teknikerbyen 31 DK-2830 Virum Danmark Phone +45 4598 6000 www.ramboll.dk

January 2008 Ref 7774001 4.1-03-EP(1) Version 1 Date 2008-01-20 Prepared by NES Checked by JLA/PSK Approved by NES

Ramboll Oil & Gas, Denmark

EIA studies for the Nord Stream

pipelines in the Baltic Sea

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Table of contents

1. Introduction 1

2. Nord Stream Project Definition 1

3. Overview of Planning and Studies 2 3.1 General 2 3.2 Planning and permitting 2 3.3 Nord Stream EIA Scoping of Environmental Studies 3

4. Methods used for describing environmental conditions 4 4.1 General 4 4.2 Geophysical field investigations 5 4.3 Geotechnical surveys 7 4.4 Environmental Field Investigations 7

5. Methods used for impact assessment 8 5.1 Modelling of spreading of sediments 9 5.2 Modelling of sediment spreading from pipelay directly on the seabed 11 5.3 Modelling discharge of pressure-test water 12 5.4 Modelling temperature difference between pipelines and environment 12 5.5 Munitions surveys 13 5.6 Cultural Heritage mapping - Example from Finland 15

6. Ramboll as independent expert 16

7. Ramboll’s expertise with other comparable projects in the Baltic Sea 16

Appendix Table of content for transboundary EIA report Contact person: Neel Strøbæk Project Director Ramboll Teknikerbyen 31 DK-2830 Virum ph. +45 4598 8641 mob +45 2168 6239 [email protected]

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1. Introduction

This brief describes the framework conditions for development of comprehensive Environmental Impact Assessments (EIA) in the Baltic Sea.

Hence, the document presents the data procurement (desk studies as well as field sampling campaigns), and the methodologies applied for assessment of the most important impacts originating in the project overall lifetime.

The EIA reporting is still ongoing at the time of writing.

2. Nord Stream Project Definition

The Nord Stream Project comprises two parallel 48” offshore high-pressure natural gas pipelines, creating connection between the Russian United Gas Grid at Vyborg in Russia and European gas network. The pipeline system furthermore includes an in-termediate service platform to be located north east of the Swedish island of Got-land. Hence, Nord Stream is regarded as a grid-to-grid connection.

The natural gas is delivered to Nord Stream after being compressed to approx. 220 bars at a location approx. 3,5 km from the Russian Baltic coast. At the shoreline the pipelines are lowered into the ground and are entered into the Baltic Sea below the seabed. The pipelines will depending of the seabed conditions be located on or be-neath the sea bed until they are reaching the German coast in Lubmin, where the connection to the onshore system takes place approx. 0,5km in land.

Consequently, the EIA studies and reporting for the Nord Stream pipelines will de-scribe the offshore pipeline system through the Baltic Sea.

Separate environmental impacts assessments of the onshore pipelines have been carried out in Russia by OAO Gazprom. And EIA studies are ongoing in Germany (OPAL and NEL pipelines) under the responsibility of Wingas and EON.

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3. Overview of Planning and Studies

3.1 General The overall project activities from idea to decommissioning after use can be de-scribed in the following phases:

1. Planning and permitting (including EIA reporting) 2. Construction (all construction activities) 3. Pre-commissioning and commissioning (prepare and bring Nord Stream into

operation – this phase includes also the integrity testing) 4. Operation and maintenance 5. De-commissioning (demolishing the pipeline system) From experience with offshore pipeline projects, the most important project phases in terms of generating environmental impacts are the phases 1-3, and phase 5 if a total removal of the project shall take place.

3.2 Planning and permitting Route Selection criteria The idea that later has become Nord Stream, was born in the 1990es. Several pipe-line routes were studies (incl. onshore through Finland and Sweden) in finding the best route connecting the Russian gas fields with the markets in Germany and West-ern Europe.

For the offshore pipelines, the following route selection criteria have been valid throughout the examination of routes and route sections:

• Avoiding areas of special concern. These include nature protection areas, ar-eas with sensitive flora and fauna, areas with cultural heritage, etc.

• Avoiding areas where other marine activities may conflict with the installa-tion and operation of the pipeline. These include areas for fishery, areas for extraction of raw materials, areas of military activity, offshore wind farms and appointed anchoring areas.

• Respecting ship traffic routes and composition. This minimises risk from sur-face vessels (dropped anchors, sinking or grounding ships).

• Avoiding areas with unsuitable seabed soil conditions and/or bathymetry. These areas may influence the stability of the pipeline as well as increasing the need for trenching into the seabed and/or supporting the pipeline through dumping of rock berms.

• Respecting routing of existing cables. • Minimising overall length. This will - in a global view - ensure a minimised

permanent occupation of the sea bed and thus a minimised environmental impact through installation and operations. It furthermore maximises the overall performance of the pipeline system.

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The application of the selection criteria is and has been important to avoid conflict with protection measures, competing projects and other users of the sea.

The route selection is probably the largest single activity of greatest importance to the protection of the nature and environment.

Nord Stream permitting procedure The permitting of Nord Stream shall take place in 5 countries and the project is fur-thermore subject to environmental impact assessment in a transboundary context.

As part of the permitting procedure, the following EIA documentation shall be devel-oped:

• National EIA for the Russian Section offshore (the part that is Nord Stream) • National EIA for the Nord Stream section in Finland • National EIA for the platform located in the Swedish section of the pipelines • National EIA for the German section of the pipelines • National EIA for the Danish section of the pipelines • Transboundary EIA according to the Espoo Convention The authorities in Denmark require the Danish EIA to describe the overall pipeline project, and the Danish National EIA is therefore covered by the transboundary EIA.

International consultations takes place according to national legislation and interna-tional consultations follows the procedures in the Espoo Convention.

3.3 Nord Stream EIA Scoping of Environmental Studies

Espoo Notification and Scoping of EIA programmes Notification took place according to the Espoo Convention Art. 3, with public consul-tations held in all countries between November 2006 and February 2007. Within the same period, scoping of national EIA programmes in Finland and Germany took place with official statements on the EIA programmes. In Russia, Sweden and Denmark the scoping procedure is not regulated in detail and no formal statement to a pro-posed EIA programme is given.

Meeting in June 2007 for a Common Standard In June 2007 an expert meeting was held in Hamburg, Germany by invitation from the Federal Agency for Maritime Traffic and Hydrography (BSH). The meeting had participation from 30 experts and scientists from all the Baltic States and from NGOs. The meeting aimed at establishing a mutual understanding of common stan-dards for the EIA investigations and documentation. The meeting was divided into three themes: munitions, assessment of impacts from seabed intervention works, and flora, fauna, habitats. The meeting concluded that for some issues, e.g. muni-tions, it was natural to find a common understanding, whereas flora, fauna, habitats investigations and assessments need to follow national standards and traditions.

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Nord Stream has in all assessments used national standards, where applicable, sup-plemented with Helcom guidelines.

Discussion of survey programme and assessment of risks from munitions Investigation and management of munitions were discussed at a Nord Stream semi-nar in September 2007 with participation from all the Baltic States, including experts from the naval forces. The issues addressed were detection methods (including ad-vanced magnetometer methodology), interpretation of side-scan and video investi-gations, and management of finds. Nord Stream appreciates the cooperation with government experts in this field and depends on continuous cooperation.

Discussion of draft of transboundary EIA report In December 2007, Nord Stream submitted a draft of the transboundary EIA report, outlining its methods to the authorities involved in the international consultations, in line with international law (Espoo Convention). In this case, early discussion of pro-cedures and content ensures that all important environmental aspects are taken into account. The finalised transboundary EIA report will be published in April 2008 (see table of content of the comprehensive report in appendix 1).

4. Methods used for describing environmental conditions

4.1 General The Baltic Sea is located in Northern Europe, from 53° to 66° northern latitude and from 20° to 26° eastern longitude. It is bounded by the Scandinavian Peninsula, the mainland of Northern Europe, Eastern Europe, Central Europe and the Danish Is-lands. It drains into the Kattegat by way of the Oresund, the Great Belt and the Little Belt.

The Baltic Sea is the largest body of brackish water in the world, and the Baltic ma-rine area encompasses 415,266 km2, whilst the associated catchments’ is about four times as large. The area is generally divided into five main sub-areas: Baltic Proper, Gulf of Bothnia, Gulf of Finland, Gulf of Riga and the Belt Sea - Kattegat. The Nord Stream project concerns the two sub-areas Gulf of Finland and Baltic Proper, includ-ing the Greifswalder Bodden in Germany.

The description of the environment for the Nord Stream Offshore pipeline project focuses on the area around the planned pipeline route. Therefore the description of the environmental baseline condition does not cover the entire Baltic Sea. Excluded from the baseline description are the near coast areas of especially Estonia, Lithua-nia, Latvia, Poland, as well as the eastern nearshore areas of Sweden.

The purpose of the description of the existing situation is to identify key issues that are particularly sensitive to disturbance and/or may be subject to economic or pro-tective value. The identification of key issues of this report will be used as back-ground information and will serve as guidelines for further investigations that need

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to be made in order to conduct the final Environmental Impact Assessment (EIA), and serve as baseline for the evaluation of the environmental impact from construc-tion, pre-commissioning and operation of the planned Nord stream offshore gas pipelines in the Baltic Sea.

The description of the existing situation based on literature research, contact to au-thorities, institutions in the different countries (especially the countries crossed (na-tional water and EEZ) by the planned pipelines), organisations and experts of the countries around the Baltic Sea, including the results from the geophysical and envi-ronmental surveys along the pipeline route that have been carried out in 2004 – 2007, in order to update and/or supplement the acquired information.

4.2 Geophysical field investigations The pipeline alignment has been investigated through several geophysical surveys. In 2005 the initial alignment study was executed. This was a reconnaissance survey covering a 2,000 m wide corridor by nominally placed parallel lines at 200 m spac-ing, acquiring:

• Bathymetry in a 5x5 m grid • Side-scan sonar, frequency 100 kHz, 200 m range, target resolution 1 m • Sub-bottom profiling with 0.5 m resolution and penetration up to 50 m into

seabed • Magnetics using a single-sensor magnetometer

Based on the results of the reconnaissance survey, more detailed routes were devel-oped for the two pipelines. The nominal distance between the two pipelines was de-termined to be 100 m, but that distance could be larger depending on seabed condi-tions.

Figure 1.1 shows an example of the width of the corridors examined in each step of the geophysical field investigations.

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Figure 1.1 Example showing contour lines of the seabed bathymetry from the reconnais-sance, colour contours from the detailed investigation and the pipeline routes determined from detailed engineering.

During 2006 a more detailed study was conducted, surveying each of the two pro-posed pipeline routes by three parallel lines at 50 m spacing, acquiring:

• Bathymetry in a 3x3 m grid • Side-scan sonar, frequency 375 kHz, 75 m range, target resolution approxi-

mately 0.25 m • Sub-bottom profiling with 0.5 m resolution and penetration up to 50 m into

seabed • Magnetics using a single-sensor magnetometer.

In areas assumed to have higher risk of encountering munitions, two additional lines were surveyed 50 m further on each side.

Following more detailed engineering, the next iterations of the pipeline routes were made and a new detailed survey was launched. In 2007 each of the two pipeline routes was surveyed along three parallel lines at 50 m spacing, acquiring:

• Bathymetry in a 2x2 m grid • Side-scan sonar, frequency 600 kHz, 75 m range, target resolution approxi-

mately 0.05 m

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• Sub-bottom profiling with 0.5 m resolution and penetration up to 50 m into seabed

• Magnetics using a single-sensor magnetometer Further, the two installation corridors, each 15 m wide, were surveyed by magnetic gradiometer mounted on an underwater remotely operated vehicle (ROV). The ROV carried the gradiometer 1-1.5 m above the seabed, providing complete coverage along the entire alignment. From the ROV continuous video recordings of the seabed were acquired.

The munitions screening was carried out by underwater video inspection of all tar-gets found by side-scan sonar and/or magnetic gradiometer, see below

4.3 Geotechnical surveys During 2006 detailed geotechnical testing and sampling took place along the entire alignment. This testing comprised in-situ strength tests and core samples to ap-proximately 6 m below the seabed. Laboratory classification tests of the samples were carried out, including, for example, water content, unit weight, solid particles density and particle size. Laboratory geochemical tests comprised carbonate content, organic content, pH, resistivity, thermal conductivity and H2S content. Further, labo-ratory soil strength tests were made.

The alignment was further optimised during 2006 and 2007, and better alignment was determined for some sections. Geotechnical testing and sampling of the opti-mised sections will take place in late 2007/early 2008.

4.4 Environmental Field Investigations The Nord Stream environmental field investigations that have been carried out in 2005 – 2007 have included the following environmental surveys: • Environmental field survey along the planned pipeline route in 2005 and 2006

inside Russian, Finnish, Swedish and Danish water. The survey included the route south of Bornholm and was carried out by OOO Petergaz.

• Environmental field survey in 2006 and 2007 along the pipeline route south of Bornholm, and the route north of Bornholm, inside German territorial water and EEZ by Institut für Angewandte Ökologie (IFAOe)

• Bird study inside Danish water at Rønne Banke in 2006 by IFAOe. • Field investigations along the route North of Bornholm inside Danish territorial

water and Danish EEZ in autumn 2007 by Danish Hydraulic Institute (DHI). • Field investigations along the planned pipeline route inside Swedish EEZ in au-

tumn 2007 by Swedish Geological Survey (SGU) and Stockholm University. • Field investigations along the planned pipeline route inside Finnish EEZ in au-

tumn 2007 by the Finnish Marine Research Institute (FIMR).

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The environmental field investigations included studies as described below: Environmental field investigations in 2005 and 2006 by OOO Petergaz The survey in 2005 and 2006 included sampling and measurements as described: • Oceanographically parameters: Measurements of temperature, salinity, conduc-

tivity, water transparency, oxygen content, ph etc., and the contents of con-taminants

• Sediment: grain size and contents of inorganic and organic contaminants • Macrozoobenthos (infauna) organisms, including chemical analysis of content of

contaminants • Phyto- and zooplankton • Fish fauna, including age determination and content of contaminants • Observations of birds and marine mammals. • Video Environmental field investigations in 2006 and 2007 by IFAOe The environmental field investigations by IFAOe inside German territorial water and EEZ included: • Oceanographically parameters: Measurements of temperature, salinity, conduc-

tivity, water transparency, oxygen content, ph etc. • Sediment: grain size and contents of inorganic and organic contaminants • Mapping of marine habitats from video survey • Macrozoobenthos (infauna) organisms • Fish fauna • Birds and marine mammals Environmental field investigations in autumn 2007 by Danish Hydraulic In-stitute, Swedish Geological Survey and Finnish Institute for Marine Re-search The environmental field investigations included sampling of sediment samples for physical and chemical analysis of grain size, inorganic- and organic contaminants, nutrients (Nitrogen and phosphor), and sampling of macrozoobenthos (infauna) samples.

5. Methods used for impact assessment

The purpose of the environmental study is to perform an evaluation of the environ-mental consequences for construction, pre-commissioning (pressure testing) and operation of the Nord Stream offshore pipelines.

The environmental impact study has been a process with the following objectives:

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• To locate and operate the offshore pipelines in the Baltic Sea at a route where the environmental impacts are acceptable or minimized.

• To construct and carry out pressure testing of the pipelines with methods causing limited or acceptable environmental impacts.

• To predict possible impacts and propose feasible measures to reduce the im-pacts as much as possible at reasonable costs.

The environmental impact of the construction, pre-commissioning and operation of the Nord Stream pipelines is described and evaluated in relation to:

• Dumped chemical and conventional munitions

• The physical and chemical environment

• The biological environment

• The socio-economic environment

To assess the impacts from seabed intervention works on the physical, chemical, biological and socioeconomic environment, mathematical modelling of sediment spreading and sedimentation of suspended sediments has been carried out.

5.1 Modelling of spreading of sediments The numerical particle analysis model MIKE 3 PA is used to simulate the transport and fate of dissolved and suspended substances in three dimensions. The substances may be discharged or accidentally spilled in estuaries, coastal areas or in the open sea.

MIKE 3 PA requires that current velocities and water level are prescribed in time and space in a computational grid covering the model area. This information is provided as results from a hydrodynamic model simulation.

The simulated substances may be a pollutant of any kind, i.e., suspended sediment, chemicals or nutrients. The spilled material is represented by a large number of par-ticles, each of a specific mass. The mass may change during the simulation due to decay. The particles are released at a source point for discharge (e.g., the location of dredging) and successively moved as the simulation progresses.

The model uses a Lagrangian-type approach, which involves no other spatial discre-tisations than those associated with the description of the bathymetry current and water level fields.

The hydrodynamic data includes current, temperature, salinity and water level and is available as three-dimensional grid data. The data has a horizontal resolution of 3 nautical miles (nm), a vertical resolution of 1 m to a depth of 210 m (surface layer ~2.5 m) and covers the entire Baltic Sea, including Danish waters. The data is avail-able with a temporal resolution of one and six hours.

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Based on an analysis of the currents in the Baltic Sea three different time periods have been defined, representing calm, average and rough conditions in relation to spreading of sediment. These periods are used to study the variability in the spread-ing associated with different hydrographical conditions.

Contaminants in the sediment For all chemicals a predicted no-effect concentration (PNEC) value can be estimated. The PNEC value reflects a risk of 5% for environmental effect by long-term exposure. If the ratio between the predicted environmental concentration (PEC) and the PNEC is greater than 1 continually, there is a risk of effect on the marine environment. The longer the time of exceedence and the higher the PEC/PNEC ratio, the greater is the risk of effects on the marine environment.

The re-suspension of sediments may lead to re-suspension of chemical compounds that have the potential to cause toxicological effects in the ecosystem and/or bioac-cumulate. The potential ecotoxicological effects on the Baltic ecosystems are evalu-ated as risk characterisation ratios (RCRs), describing the ratio between the PEC in the aquatic compartments and the PNEC determined from aquatic ecotoxicity test results.

The chemical compounds known to be present in the sediment and known to have the potential to cause adverse effects include:

• Heavy metals, such as cadmium (Cd), mercury (Hg), lead (Pb), zinc (Zn), arsenic (As), copper (Cu), chrome (Cr), nickel (Ni)

And

• Organic contaminants, such as:

• Polycyclic aromatic hydrocarbons (PAHs).

• Polychlorinated biphenyls (PCB).

• Dichlorodiphenyltrichloro-ethane (DDT) and its metabolites and derivatives.

• Hexachlorobenzene (HCB).

• Hexachloro-cyclohexane (HCH) and its isomers.

• Chlordane (cis- and trans chlordane)

• Tributyltin (TBT), Dibutyltin (DBT) and Monobutyltin (MBT)

The main ecotoxicological impact potential of the Nord Stream pipeline project is not caused by discharge of chemicals in the traditional sense, but more correctly a redis-tribution of up to centuries-old depositions of chemical compounds already present in the Baltic Sea.

The distribution and concentrations of sediment-bound chemical compounds in the Baltic Sea have been analysed and described as presented in “Baltic Sea Environ-ment Proceedings No. 82B” and in the request from FIMR (Finnish Marine Research

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Institute) “Implementation of the North European gas pipeline project – Data inven-tory and further need for data for environmental impact assessment”. Further analy-ses are based on a large number of field measurements available from SGU, ICES, FIMR, GTK, and from the Nord Stream AG environmental field surveys that were carried out from 2005-2007. From these studies the relevant substances have been identified and the concentrations have been calculated for the relevant areas.

The data has large spatial variations in concentration and density. Therefore, as a conservative measure, the 90th percentile concentrations in Russia, Finland, Sweden, Denmark and Germany respectively have been adopted for this study.

Ecosystem effects The chemical compounds present in the Baltic seabed sediment may affect organ-isms inhabiting the Baltic Sea area in quite different ways. Following re-suspension of the sediment and after desorption and dissolution the sediment-bound chemical compound becomes bioavailable. Being dissolved and bioavailable the chemical com-pounds may cause acute or chronic effects on lower organisms and/or be bioaccu-mulated where higher organisms may be exposed to the chemical compounds.

Those chemicals known to have the potential to cause acute ecotoxicological effects are characterised by applying RCRs describing the ratio between the PNEC (esti-mated lower limit of the concentration range known to cause effects) and the PEC (estimated exposure measure).

The RCRs or PEC/PNEC ratios are used as ecotoxicological risk quantification accord-ing to the following interpretation pattern defined as:

• RCR = PEC/PNEC ≤ 1: No adverse effects are anticipated. • RCR = PEC/PNEC > 1: Adverse effects may occur.

5.2 Modelling of sediment spreading from pipelay directly on the seabed

During the pipe-laying process, sediments from the seabed may be suspended due to the following processes:

• The current generated in front of the pipeline when it falls through the water column near the seabed may potentially bring sediment into suspension

• The pressure from the pipeline when it hits the bottom may create an upwards movement of sediment.

The sediment composition and seabed conditions vary along the pipeline corridor. This analysis does not address the various conditions throughout the alignment. In-stead, the suspension of sediment during the pipe-laying process has been estimated based on analytical considerations to determine the order of magnitude of the sus-pension for a worst-case scenario.

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5.3 Modelling discharge of pressure-test water The environmental impacts on water quality during pre-commissioning could occur due to discharge of pressure-test water. Pressure testing of the pipeline will be per-formed with filtered seawater as the test medium.

The base case for the pre-commissioning will be to use filtrated seawater treated with an oxygen scavenger and a biocide for flooding.

This treatment is assumed to represent a safe solution for the integrity of the pipe-line. It is however an objective of the project to investigate also alternatives to this base case. The alternatives include a lower chemical dosage or even no use of chemicals at all. These alternatives will be investigated in a laboratory test program. It is the objective of Nord Stream to reduce the use of chemicals to an absolute minimum whilst still maintaining the safety and integrity of the pipeline, i.e. to ex-clude any risk of detrimental corrosion damages to the pipeline when it will be filled with water only. Final decision on chemical treatment of the pressure test water, if any, will be based on the results of the laboratory tests.

Laboratory testing will determine for alternative treatments of the water for the fol-lowing alternatives will be considered:

• Base case; Water treated with an oxygen scavenger and a biocide. • Filtrated untreated seawater • Water treated with an oxygen scavenger • Water treated with an oxygen scavenger and a pH-increasing agent as NaOH.

The water treatment in the base case will be based on a typical oxygen scavenger as Sodium Bisulphite, NaHSO3. An oxygen scavenger concentration of 65 mg/l of Na-HSO3 will be required. A typical biocide, which has been used for pressure-testing in many earlier pipeline projects, is Glutaraldehyde with a dosage of 50 - 75 mg / l.

The intake of water for pressure testing may take place at the Intermediate Service Platform (ISP) and will be discharged at the same location. Therefore, the salinity of the water will not change where the water is discharged.

The impact on water quality caused by the discharge of pressure test water will be temporary and concentrated in the area around the discharge location.

5.4 Modelling temperature difference between pipelines and en-vironment

Computational Fluid Dynamics, CFD, is used in the simulations of the temperature impact from the pipeline to the surroundings. CFD is a powerful computational tool for solving complex phenomena such as fluid flow, conjugate heat transfer, etc. The software used is ANSYS CFX v.11.

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The simulations performed are two-dimensional and consist of a conjugate heat transfer problem in the concrete of the pipe and seabed and a two-dimensional heat transfer problem between the pipe and the surrounding water.

5.5 Munitions surveys Nord Stream needs to rule out all risk associated with munitions dumped sites. Therefore extensive surveys have been performed in order to determine whether the pipeline or the environment can be compromised by chemical or conventional muni-tions in any way. Geophysical surveys were launched by PeterGaz during 2005 and 2006. The 2006 survey was designed to efficiently map munitions along two corri-dors of 150 m width.

A detailed survey was contracted by Nord Stream in 2007 to the Swedish survey company Marin Mätteknik AB. A newly developed methodology for munitions screen-ing proved very promising and it was thus decided to expand this survey to carry out munitions screening along all sections of the pipeline route. The survey is ongoing as this report is being prepared and the final results of the survey are expected in the 2nd quarter of 2008.

The munitions survey is undertaken in three steps and carried out using 2-3 vessels. First step comprises high resolution side scan sonar investigations, multibeam echo sounder measurements, sub bottom profiling and single magnetometer recordings. The second step of the munitions screening comprises very detailed magnetic gradi-ometry using a purpose-built instrument with 12 gradiometers mounted on a boom on a Remotely Operated underwater Vehicle (ROV), see Figure 5.1. This instrument covers a width of approximately 7.5 m.

Each pipeline is covered by two passes 3.5 metres each side of the centreline thus providing two 15 m wide installation corridors. The magnetic gradiometers are ex-tremely sensitive and will record the magnetic field from very small objects – the threshold is set to leave out small pieces of metal scrap, e.g. paint buckets. Video cameras are also mounted on the ROV to continuously record the seabed surface as the ROV moves along over the seabed.

The third step is based on the analysis of the recorded data from the high resolution side scan sonar and the magnetic gradiometer. Any anomaly in the gradiometer data and any side scan sonar target within 25 m of the pipeline routes and interpreted as being of possible anthropogenic origin are subject to further inspection. This inspec-tion is executed by visiting each anomaly/target individually and documenting the findings by ROV-mounted underwater video. As first stage of a classification objects that are obvious not munitions related (shopping trolleys, bicycles etc.) are classified as such.

The remaining objects are likely to represent both munitions objects and objects with no munitions relation. E.g. distinction between oil drums and depth charges are diffi-cult. Objects will therefore be reviewed by the respective national authority in the countries concerned. If munitions are encountered a detailed risk assessment will be

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executed to facilitate possible rerouting or annihilation of the munitions piece. All classified targets are documented in a GIS.

Figure 5.1 Part of the munitions screening survey is being carried out from an ROV. A gra-

diometer array with 12 sensors that screen the pipeline corridor for munitions is mounted on the ROV.

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5.6 Cultural Heritage mapping - Example from Finland Along the planned pipeline routes the seabed has been scanned carefully using a 600 kHz side scan instrument. High resolution images are obtained and objects of poten-tial cultural heritage relevance are selected. In the Gulf of Finland 7 objects of poten-tial cultural heritage value are identified within a 100 m distance from the pipeline routes. Figure 5.2 exemplifies the side scan imagery of the wreck of a wooden ves-sel, approximately 26 m long.

All wrecks are being investigated further by underwater video and an expert assess-ment is being prepared.

Figure 5.2 Side scan imagery of wreck of wooden vessel. Probably late 19th to early 20th century.

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6. Ramboll as independent expert

Nord Stream AG commissioned Ramboll in 2006 to prepare the Environmental Impact Assessment with all investigations required. Ramboll is one of the largest European consulting companies with head quarter in Denmark, and with subsidi-aries in a/o Sweden, Finland, Russia and Estonia, The EIA studies and reporting are therefore taken place partly at the head office in Denmark and partly from the national offices in order to ensure in-depth knowledge and understanding of the environment on the national level as well as sensitivity towards national procedures and traditions. Ramboll has extended expertise in planning and constructing large infrastructure projects and in executing appropriate environmental impact studies, among other gained from the large offshore infrastructure works in inner Danish waters (Great Belt Bridge, Øresund Bridge) and from the Danish and Norwegian part of the North Sea. The EIA experience in the natural gas sector includes offshore and onshore pipelines and construction and decommissioning of platforms and off-shore storage facilities. Ramboll’s inhouse staff comprise marine biologists, eco-toxicologists, environ-mental chemists and engineers as well as engineers, geophysicists and geologists with in-depth offshore experience. Further expertise is found in Ramboll’s large network in the scientific community at the Scandinavian Universities. Ramboll is owned by the Ramboll Foundation and is independent of government, industry and suppliers interests.

7. Ramboll’s expertise with other comparable projects in the Baltic Sea

Ramboll has in the last 15 years carried out a large number of feasibility studies for natural gas pipelines in the Baltic Sea, and has thereby gained large experience within this specific field. An overview of projects are shown in the fidure below.

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Ramboll has prepared the EIA for the offshore part of the Baltic Gas Interconnector planned to bring gas from Germany to Denmark and Sweden. The project has been approved in Sweden and Denmark.

Ramboll has also prepared EIA for the Baltic Pipe from Denmark to Poland. This pro-ject was put on hold on the Danish side after the Espoo Consultation of the EIA re-port in 2002. Plans to re-open this project have been announced by the Polish Oil & Gas Company (PGNIG) in 2007.

The environmental impact assessments of the pipeline from Finland to Estonia (Baltic Connector) are presently in its programming phase in Finland and Estonia. This pro-ject is led by Gasum Oy, Finland.

The studies connected to the Nord Stream project is by far the most comprehensive and advanced carried out to this date. The environmental data collected and the studies made will be available not only for the environmental impacts assessments, but also for the research communities in the countries around the Baltic Sea.

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Appendix

Table of Contents for the Espoo EIA reporting

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