Terms of Reference

Technical review of final 3D modelling - potential effects of marine structures on site hydrodynamics and sedimentation from the construction of the Pacific Northwest liquefied natural gas terminal

Science Response Process – Pacific Region

December 2015
Nanaimo, British Columbia

Chairperson: Lesley MacDougall

Context

Pacific NorthWest Liquid Natural Gas Ltd. (PNW LNG) is proposing to construct a large scale liquefied natural gas (LNG) export terminal within the Skeena River estuary (hereafter referred to as the ‘Project’).  The Project will require dredging, blasting and pile driving to construct a suspended trestle and terminal berths.

On April 8, 2013 the Canadian Environmental Assessment Agency (the Agency) issued a Notice of Commencement that they had commenced an environmental assessment pursuant to the Canadian Environmental Assessment Act (CEAA 2012) for the PNW LNG project located on Lelu Island, BC.

The Environmental Impact Statement (EIS) and Addendum submitted by PNW LNG to the Canadian Environmental Assessment Agency (CEAA) on 28 Feb 2014 and 12 Dec 2014, respectively, provided information with regard to potential effects of marine operations and marine structures upon the sea bed and habitat at Agnew and Flora Banks. The Addendum also provided detailed responses to Information Requests posed by the Government of Canada in regard to sediment deposition; including a report that provides a sediment transport and deposition analysis that utilized 2D models conducted by PNW LNG’s marine engineering consultant, Hatch Ltd.

On Feb 23 2015, PNW LNG received a new Information Request from CEAA, requesting additional 3D hydrodynamic and sedimentation modelling. A Terms of Reference was developed to guide the additional assessment.

Fisheries and Oceans Canada (DFO) Science Branch provided informal advice to DFO Fisheries Protection Program (FPP) on previous drafts of baseline and post-construction modelling undertaken by PNW LNG to assess the potential effects of marine operations and marine structures upon the sea bed and habitat at Agnew and Flora Banks.  Subsequently, a Canadian Science Advisory Secretariat (CSAS) Science Response (DFO, 2015) was developed in response to a request from FPP to Science Branch to provide a formal technical review of PNW LNG’s draft 3D baseline and post-construction hydrodynamics modelling.  FPP has not requested, nor has PNW LNG provided, hydrodynamics modelling to simulate potential impacts during construction, or potential impacts associated with any post-construction maintenance that may be required. The CSAS Science Response (DFO, 2015) outlined primary areas of concern with respect to the draft model submissions, and was incorporated in a DFO response to CEAA highlighting key deficiencies in PNW LNG’s submission.

On June 2, 2015, PNW LNG received notification from CEAA that the technical reviews provided by Natural Resources Canada (NRCan), and DFO, “indicates that their expert advice and direction to PNW in conducting its modelling work was not sufficiently taken in to consideration, which has resulted in a lack of information”. CEAA indicated to PNW LNG that their conclusions needed to be substantiated by further rigorous and thorough modelling results. CEAA informed the PNW LNG that additional information was required before they could complete their environmental assessment report. Key concerns regarding 3D modelling that were identified in the June 2, 2015 CEAA correspondence can be described as follows:

• Concerns regarding modelling of wind and wave fields
• Concerns with wave, wind and current model inputs
• Concerns with the calculation of extreme storm values and modelling procedures (application of Delft3D)
• Concerns with the modelling of flows at the Anchor Block and Tower Base
• Concerns regarding model outputs for total suspended solids (TSS) and sediment transport

DFO FPP is requesting that DFO Science review PNW LNG’s final submission of modelling of potential effects of proposed structures to Flora Bank and Agnew Bank areas in response to the June 2, 2015 CEAA correspondence, to assess whether the five key concerns as outlined above have been addressed with sufficient accuracy and adequacy to facilitate an evaluation of PNW LNG’s conclusions.

Objectives

Science information and advice will be prepared to address the above five key concerns, based on a review of information provided in the Proponent’s November 10, 2015 Response Summary (Pacific NorthWest LNG Ltd., 2015a), November 10, 2015 Supplementary Modelling Report H345670-0000-12-124-0013 (Hatch Ltd., 2015), the December 2 detailed response tracking table (Pacific NorthWest LNG Ltd., 2015b), the December 7 Figures (Pacific NorthWest LNG Ltd., 2015c), and in the following document:

DFO. 2015. Technical review of 3D modelling of potential effects of marine structures on site hydrodynamics and sedimentation from the construction of the pacific northwest liquefied natural gas terminal. DFO Can. Sci. Advis. Sec. Sci. Resp. 2015/027.

This Science Response will address the following objectives:

• Assess the technical acceptability of the methods and models as proposed, and identify gaps.
• Determine if the conclusions are adequately supported by the methods used to assess potential hydrodynamic impacts associated with the project.
• Identify key uncertainties, and describe consequences associated with the uncertainties.

Expected Publication

• Science Response

Participation

• Fisheries and Oceans Canada (DFO), Science Branch Pacific Region

References

DFO. 2015. Technical review of 3D modelling of potential effects of marine structures on site hydrodynamics and sedimentation from the construction of the pacific northwest liquefied natural gas terminal. DFO Can. Sci. Advis. Sec. Sci. Resp. 2015/027.

Pacific NorthWest LNG Ltd., 2015a. Information Request #3 Response Summary. November 10, 2015

Pacific NorthWest LNG Ltd., 2015b. Detailed response tracking table. December 2, 2015

Pacific NorthWest LNG Ltd., 2015c. Updated Figures. December 7, 2015

Hatch Ltd., 2015. Pacific Northwest LNG Supplemental Modelling Report for 3D Modelling Update, H345670-0000-12-124-0013, Rev. O, September 16, 2015.