RE: TGS-NOPEC s EIA for the NEG15 seismic survey

Transcription

1 DCE DANISH CENTRE FOR ENVIRONMENT AND ENERGY AARHUS UNIVERSITY PINNGORTITALERIFFIK Greenland Institute of Natural Resources The Environmental Agency for the Mineral Resources Area (EAMRA) Jesper Bistrup Larsen RE: TGS-NOPEC s EIA for the NEG15 seismic survey David Boertmann Line Hermansen Josephine Nymand Date: 17. april dmb@bios.au.dk Page 1/7 Conclusions DCE and GINR acknowledge that the following initiatives contribute to reduce environmental impacts: A slightly smaller airgun volume is applied in 2015 compared to The streamer is solid. Additional mitigation measures regarding bowhead whales and the walrus closed area will be applied. UAV is tested as an alternative to helicopter. DCE and GINR miss: An impact assessment of the use of multibeam echo sounder and sub bottom profiling equipment. An impact assessment of leaving the tracking bouys in the area. That noise measurements performed in 2014 are not used in the 2015 EIA. DCE and GINR require that: Noise measurements are performed both on the NEG15 and the SEG15 surveys. DCE and GINR draw attention to that: That the results of the 2015 noise measurements shall be submitted to EAMRA within two months after the completion of the survey. That the use of the large airgun array (5,025 in 3 ) shall be reported. DCE and GINR do not agree on the evaluation of: Impacts of oil spills on some of the bird populations. The importance classification on some of the bird populations. The degree of disturbance classification of narwhal is too low, resulting in a too low assessment of sensitivity to noise. Walrus is assessed too low in the magnitude of impact classification. DCE and GINR evaluate that - except for the exceptions mentioned above: Generally the assessment of impacts is sound. DCE Aarhus University Frederiksborgvej 399 P.O. Boks Roskilde, Denmark PINNGORTITALERIFFIK Greenland Institute of Natural Resources Kivioq 2 P.O. Boks NUUK

2 Side2/7 Introduction TGS-NOPEC plans to undertake a seismic survey in the Greenland Sea in summer/autumn The survey period is indicated as 5 July to 31 October, but will be adjusted to the ice conditions and another survey in Southeast Greenland to be performed with the same ships. The survey will be a 2D regional survey, with grid lines generally spaced with more than 1 km, although in three subareas it will be reduced to 0.5 km. The application includes up to 10,000 line kilometers, however the actual length will most likely be shorter. The survey will take place in approx. the same area as in previous years (2011, 2012, 2013 and 2014) i.e. on the shelf between 75 and 80 N. The sound source is intended to be an airgun array with a total volume of 3,350 in 3, however a larger volume (5,025 in 3 ) may also be used. A single solid streamer, up to 8 km long will be deployed. The first mentioned airgun volume is slightly smaller than the volume applied in 2014 (3,680 n 3 ). This is acknowledged, as it may contribute to reduce the environmental impacts. Besides the seismic acquisition it is planned to use multibeam echo sounder and sub-bottom profiling equipment to acquire information on the seabed. Finally, up to four ice tracking bouys will be deployed. A helicopter will be used for ice reconnaissance. As a new initiative, unmanned aerial vehicles (UAV) will be tested for their applicability for ice reconnaissance. Besides the acquisition vessel, two more vessels will be used; an icebreaker and a support vessel. Based on the scoping document, DCE and GINR evaluated (8 Dec. 2014) that a proper Environmental Impact assessment (EIA) of the survey should be carried out. TGS-NOPEC has only submitted one document for this EIA-evaluation - the EIA report. The requested datasheets were submitted with the scoping documents in December The requested modelling of underwater sound propagation is the same as in 2013 and 2014 and there is referred to the report submitted in 2014.

3 Side3/7 The EIA Maritime operations The maritime operations will according to the EIA follow the general environmental shipping regulations by MARPOL, OSPAR and IMO regarding waste handling, discharges and use of chemicals. These regulations are followed during other maritime activities, such as scientific surveys or fishery in the Greenland waters, and as the NEG14 survey do not differ from such shipping, DCE and GINR have no further comments to these issues. Regarding emissions to air, the ships will use low sulphur (< 1.5%) marine gas oil (MGO) for the engines, which is a more environmental sustainable alternative than heavy fuel oil (HFO). The environmental descriptions The descriptions of physical and biological environment are in agreement with the guidelines, and many of the misunderstandings described in previous years EIA-reports are now corrected. There are, however, still some repetitions that should be corrected e.g. that thick-billed murre is mentioned as a breeding bird in the survey area (Table 4-1), that bowhead whale is listed as Near Threatened (Table 4-1) (the bowhead whales occurring in the survey area belong to the Spitsbergen stock, which is Critically Endangered), that polar cod is described as an important commercial species (p. 23) and that northern right whale may use the survey area (p. 39). The proposed seismic lines overlap with the areas of concern for narwhals - both the June-September area and the October-November area. But as the survey is 2D, generally with widely separated lines and performed by one ship, this does not give reason to special regulation. The assessment The assessment section is nearly the same as in the 2013 and 2014-EIA reports. This means that most of DCE and GINR s comments to both are still valid. For example the Tables 7-2 and 7-3 are not obvious. Here it is not really clear what kind of interests the Factor-column refers to in Table 7-2; or why low likelihood of occurrence can only cause moderate impacts in Tables 7-3 to 7-5? Also, the impact tables should point out that the assessed impacts are based on the appropriate mitigation measures (Section 9) being followed. A new feature is however evaluation of impacts from helicopter and UAV flying (7.10 and 7.13).

4 Side4/7 DCE and GINR do not agree with the impacts of oil spills on bird populations, as these effects may potentially be more severe. The importance of most of the bird populations is set as national (Table 7-10). This may apply to common eider, king eider and long-tailed duck, while northern fulmar, Arctic tern, thick-billed murre and little auk certainly are of international importance, as most/many of the individuals of these species occurring in the survey area are from populations outside Greenland (Svalbard, Russia). In Table 7-13 on assessment of impacts from seismic survey on marine mammals, DCE and GINR dispute some of the evaluations. In the section Disturbance/displacement by underwater noise, narwhal is given medium as Degree of disturbance. Narwhals are considered as very sensitive to noise, why this certainly should be high. This results in an assessment as minor in the Magnitude of impact-column, which obviously is too low. The same reasoning applies to walrus, which is assessed as minor in the Magnitude of impact-column. In Chapter 8, the EIA assess the cumulative impacts over five years in a row of seismic surveys in the same general area. DCE and GINR agree that the use of 2D surveys will cause smaller impacts rather than 3D surveys therefore also smaller cumulative impacts over several years of repeated surveys. But this is not really relevant in this context. DCE and GINR also agree that the proposed mitigation efforts for activities will help to minimize environmental effects, and thereby also the cumulative impacts. However, DCE and GINR miss an acknowledgement of the fact that repeated surveys in the same areas potentially will cause cumulative effects. DCE and GINR agree with and acknowledge that monitoring efforts over several years in the same areas should be linked to conduct long term impact assessments. Despite these objections, the resulting assessment of impacts of the planned activities is generally sound. However, DCE and GINR miss an evaluation of the use of the multibeam echo sounder and sub-bottom profiling equipment, and this should be presented before the report is evaluated by Naalakkersuisut. DCE and GINR also miss an evaluation of the use of tracking bouys. The likelihood of retrieving them must be very small. Especially the use of Li-batteries and their potential environmental impacts shall be described in case they are not retrieved. The sound modelling The sound propagation model presented for the NEG15 survey is identical to the model presented for the NEG14 (and the NEG13) survey. There is also ref-

5 Side5/7 erence to the 2014-report on models of summed energy for all pulses for 24 hours indicating distances to defined SEL (sound exposure level) thresholds for pinnipeds and cetaceans. Both reports (2014 and 2015) state that...even for higher frequencies it is expected that seismic noise will remain above 150 db re 1µPa peak-peak for some tens of kilometers. However, this is not used further in the sound modelling, and on the contrary to this, both reports state that Noise modelling stopped at 1 khz since a test case demonstrated rapid attenuation of higher frequencies. It is unclear which test case they are referring to, and whether this test case was actually conducted in the relevant area (for 2014 and 2015 surveys) or based on a test case conducted elsewhere. In recent years, the suitability of M-weighted SELs for impact assessments, in particular for mid- to high frequency species (e.g. narwhals and porpoises), has been questioned, and there is increasing evidence that higher frequencies should be weighted higher. In general, the sound modelling is adequate, considering that much of the environmental input is based on assumptions. However, to improve the model results, DCE and GINR will underline that actual noise measurements should be conducted during the surveys, including determination of sound speed profiles (cf. section 6.3. in the EIA-guidelines). These measurements should be used for validation of the model, in particular to verify the assumption that sounds above 1 khz does not propagate out to considerable ranges. Furthermore, actual measurements can optimize the sound model, so that mitigation measures can be better fitted to actual exposure levels. Thereby TGS could minimize unnecessary mitigation measures, in comparison to when impact assessments are based on worst case assumptions. Apparently were such measurements undertaken during NEG2014, and DCE and GINR wonder why the results were not included in the 2015-modelling. MMSO s In total, four MMSO s are planned to participate in the survey and two of these will be PAM-operators. This is in accordance with new stipulations. As TGS-NOPEC in the 2012 and 2013 surveys failed to carry out the standardized seabird and marine mammal survey as specified, DCE and GINR will underline the importance of these observations. MMSO s shall follow the Manual for seabird and marine mammal survey on seismic vessels in Greenland (Link) and it is necessary to stress that it is the responsibility of the operator that an observation box for the MMSO s are in place on top of the

6 Side6/7 bridge ( monkey island ). The manual has been up-dated on the MMSO issue, and this section can be downloaded from the MLSA-website (Link). An updated version (4 th edition) of the manual will be available before the survey is initiated. Mitigation and monitoring The chapter on mitigation and monitoring (9) follows the DCE-guidelines closely. DCE and GINR acknowledge that TGS-NOPEC has introduced (as in 2013 and 2014) additional mitigation measures regarding bowhead whales and the walrus closed area (Sections 7.3/9.2). In total, four MMSO s are planned to participate in the survey and two of these will be PAM-operators. This is in accordance with new stipulations. According to the EIA-guidelines the actual sound exposure within the area where sound propagation has been modelled shall be documented. Such noise measurements are described in Section 9.2. It is stated that these measurements will take place in both the NEG15 and the SEG15 survey areas if possible. DCE and GINR find it very important that measurements are taken in both areas. Noise measurements As a part of the monitoring TGS-Nopec is requested to undertake measurements of the noise propagation during the seismic survey. Section 9.2 describes the proposed noise monitoring efforts. DCE and GINR agree with the suggested monitoring at ranges between 500 m and 5 km from the survey vessel, and at different depths to estimate both the horizontal and vertical propagation of sound. DCE and GINR emphasize the importance (as also suggested in section 9.2) to record broadband seismic pulses and the suggested limits of the recording system within the range 7 Hz (or 10 Hz depending on water depths) and 80 khz can be supported. This allows for evaluation also of the propagation of sound at frequencies above 1 khz, which is highly relevant in assessments of impacts on mid- to high-frequency whale species (e.g. narwhals and porpoises). TGS-Nopec may consider conducting noise measurements with stationary sound recorders instead of hydrophones. A sound recording chain on recorders at different depths can be deployed on a bouy to get actual exposure levels in relevant areas, such as near the borders to Narwhal/Walrus closed areas. Such a set-up can record continuously until equipment is retrieved. In this

7 Side7/7 case it also is important to determine sound speed profiles for the area, which could be done during deployment and retrieval of recording gear. As there is a risk of loss of equipment, it would be wise to deploy 2 or 3 recording chains. A description of such a set-up can be found in this report: Miscellaneous It is mentioned that a larger airgun volume (5,025 in 3 ) may be applied. If this is the case, this has to reported (start and stop of the use) after the survey. The results of the measurement of sound propagation shall be submitted to EAMRA and its scientific advisors within two months after the completion of the seismic survey.