Bathymetric lidar to support pre-engineering analysis for marine liquefied natural gas transport infrastructure

Transcription

1 Bathymetric lidar to support pre-engineering analysis for marine liquefied natural gas transport infrastructure Candace MacDonald, Dr. Tim Webster Kate Collins, Nathan Crowell, Kevin McGuigan NSCC Applied Geomatics Research Group and Mark MacLellan Pieridae Energy

2 During this talk Jetty Brief project overview Existing data So-called white ribbon gap Topo-bathymetric lidar survey Validation Intensity vs side scan sonar Proposed structure location Before and after profiles Earth displacement estimates How the method can be applied to other areas

3 Project Overview Bathymetric lidar to support pre-engineering analysis for marine liquefied natural gas transport infrastructure Pieridae Energy is proposing construction of a marine LNG terminal in Goldboro, Guysborough County Construction includes wharf + jetty extending from shoreline into the water Need depth and intensity (bottom type) information to support site selection For more information:

4 Study Area Goldboro, NS ~ 10 km long, ~ 2.3 km wide Extends into deeper water (+15 m) Aim in part to fill in white ribbon gap left after a summer multibeam survey

5 Summer Multibeam Survey

6 Shallow Bathymetry Often Missed

7 White Ribbon Gap Multibeam survey very detailed, yet data collection limited by water depth White ribbon gap gap in high resolution coverage along coastline Aim to fill this with lidar data!

8 Topo-bathymetric Lidar Survey October 26, 2015 ~ hrs ADT Weather overcast with misting towards end of survey Had planned to use NS High Precision Network (HPN) monument used as GPS reference station HPNs are updated for vertical accuracy while NS Control Monuments are not Change in logistics required we use Active Control station (also updated frequently)

9 Survey Results Achieved depth to 11 m CGVD28 Elevation (m CGVD28) 112 ~ Ragged water surface

10 Survey Results Achieved depth to 11 m CGVD28 Obtained detailed bathymetric data from desired inlet potential site of wharf and jetty Elevation (m CGVD28) 112 ~ Ragged water surface

11 Survey Results Achieved depth to 11 m CGVD28 Obtained detailed bathymetric data from desired inlet potential site of wharf and jetty Filled in the white ribbon no data gap nicely! Elevation (m CGVD28) 112 Elevation (m CGVD28) ~ Pieridae s MB bathymetry

12 Filled the Gap!

13 Validation Resulting DEM was validated for mean vertical offset against various datasets Two datasets collected for Pieridae multibeam/singlebeam survey + RTK GPS land transects AGRG collected RTK GPS of roads (flat, hard surfaces) No ground truthing on the water was collected by AGRG due to continued poor weather in October, 2016

14 Validation Dataset Validation Point - DEM Mean Vertical Offset Std. Deviation RTK GPS of roads Overall agreement and normal distributions RTK GPS transects of shoreline * Multibeam area only * Singlebeam area only * Multibeam + singlebeam points * * Data provided by Pieridae Investigation underway on disagreement between DEM and RTK GPS transects of shoreline maybe different reference coordinate elevation?

15 Hybrid DEM Multibeam + Lidar Elevation (m CGVD28) 112 Elevation (m CGVD28) 112 ~ ~

16 Hybrid DEM Multibeam + Lidar Focus Area Elevation (m CGVD28) 112 Elevation (m CGVD28) 112 ~ ~

17 Hybrid DEM Focus Area

18 Hybrid DEM Focus Area MB L

19 Potential Wharf & Jetty Information

20 Wharf & Jetty Construction N Constructed TINs of each section of the wharf and jetty N

21 Wharf & Jetty Construction Elevation (m CGVD28) Constructed a DEM from each TIN, and merged them together

22 Wharf & Jetty Superimposition Existing pipelines, identifiable in both the MB and lidar DEM

23 Cross-section Profiles

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28 Intensity vs Side Scan Sonar No AGRG bottom sampling executed due to poor weather

29 Intensity vs Side Scan Sonar No AGRG bottom sampling executed due to poor weather

30 Intensity vs Side Scan Sonar No AGRG bottom sampling executed due to poor weather Intensity, typically: lighter areas = smoother seafloor fine-grained surficial sediments darker areas = increased seafloor roughness coarser sediments, bedrock, or anthropogenic debris Good qualitative agreement

31 Intensity vs Side Scan Sonar No AGRG bottom sampling executed due to poor weather Intensity, typically: lighter areas = smoother seafloor fine-grained surficial sediments darker areas = increased seafloor roughness coarser sediments, bedrock, or anthropogenic debris Good qualitative agreement

32 Intensity vs Air Photos

33 Intensity vs Air Photos Likely that some vegetation will be displaced Now a high resolution baseline exists against which to measure future change

34 Volumetric Estimates for Construction of Wharf/Jetty Volume* to REMOVE (m 3 ) Volume* to FILL (m 3 ) Ramp , North Bank , South Bank , m Landing , m Wharf , Total (hollow wharf) , Total (solid wharf) ,210, *approximate volume

35 Limitations Intensity not depth normalized (yet) Lack of bottom type validation to determine vegetation existence/type Inability to more accurately interpret intensity results Indian Brook, CB Other Applications of this Technology Barrachois Small craft harbours - where/how much to dredge - assessing existing infrastructure Archaeology Barrachois studies Limitless Possibilities!

36 Thank you! A very special thanks to our industry partners and funding organizations: We would also like to thank Golder and Associates and Canadian Seabed Research for their cooperation! Questions? Candace MacDonald candace.macdonald@nscc.ca For more information about Applied Geomatics Research Group, visit