OMG Nuliajuk Mapping 2012

photo credit: Travis Hamilton

Nuliajuk 2012 Mapping Operations - Preliminary Results

James Muggah, Travis Hamilton, Steve Brucker, Weston Renoud, Anand Hiroji,
Ian Church and John Hughes Clarke
Ocean Mapping Group
Dept. Geodesy and Geomatics Engineering
University of New Brunswick

The web page presents an initial overview of the 2012 multibeam mapping program of the MV Nuliajuk. The Nuliajuk is a vessel owned and operated by the Government of Nunavut (GN), Dept. of the Environment, Fisheries and Sealing Division. This is the second year of Nuliajuk operations. For the 2012 field season, through a partnership between GN, ArcticNet (including the University of New Brunswick (UNB) and Memorial University (MUN)) and the Canadian Hydrographic Service (CHS), the vessel was outfitted with a geoscience/hydrographic survey suite including multibeam and subbottom.

The instrumentation, owned and operated by the Ocean Mapping Group at UNB, includes:

Kongsberg EM3002 300 kHz multibeam sonar.
Coda Octopus F185 GPS-aided inertial system.
Knudsen 3200 Chirped 2 element 3.5 kHz subbottom profiler.
C-Nav 3050 - RTG GPS receiver.
Kongsberg Seatex MRU-6.

The survey system complements the existing sonars suite on board including :

RDI 300 kHz WorkHorse Mariner ADCP
Furuno CH-300 searchlight sonar (60/153 or 85/215 kHz)
Furuno FCV-30 (38 kHz) fisheries multiple-beam sonar.

The new equipment was installed together with the FCV-30 on a dedicated new steel blister on the starboard underside of the vessel. This steel blister has proved to be ideal. No significant flow or engine-associated noise has been noted. Compared to the same sonar, when previously installed on the CSL Heron in the same conditions (Baffin Island fjords in 2006/8), the maximum depth now achieved is over 300m whereas the Heron only ever achieved 220m, suggesting improved noise characteristics.

The installations provides high quality data at speeds up to 10 knots (warp speed) and in +/-5 degrees of roll and or pitch. The installation is permanent, and the transducers will be left on board over winter for possible 2013 operations. All topside electronics are being returned to UNB for storage, maintenance and upgrading.

Nuliajuk Track Overview

Lake Melville Coverage

For 15 days in July and 5 days in November, the Nuliajuk operated in the western end of Lake Melville

Overview map from Clyde to Iqaluit.

Apart from a 2 day window in mid August, all the Nuliajuk mapping in Nunavut took place during a 30 day period covering the full month of October. The UNB mapping team boarded in Clyde River and disembarked in Iqaluit. The main target areas were:

Patricia Bay, Clyde River
Qikiqtarjuaq vicinity
Merchants Bay
Exeter Sound
Kekerten Island Region
Iqaluit harbour.

Clyde River Operations:

In support of ArcticNet science objectives, the Patricia Bay delta front and basin, in the vicinity of Clyde River was mapped up to the 10m contour along the face of the delta.

The whole survey was inside preexisting CHS single beam coverage.

Qikiqtarjuaq Vicinity:
Both GN and ArcticNet objectives were met here:

Clam Habitat Mapping: in August (2 days) and October (3 days).
ArcticNet Sealevel History: one day in Broughton Harbour.

August 2 days - expanding to the west of the CHS-covered region, specifically designed to overlap the Siferd coastal transects.
October 3 days - The transit in from Clyde and 2 days of mapping were utilized to build a new corridor to the NW through completely uncharted waters. The aim was to both expand the areas in which potential clam habitat might be found (20-100m depths) and build a safe coastal shipping corridor towards Kivitoo.
On the third day, the weather was bad from the NE, making the clam corridor too exposed. As a result coastline sections to the south of Broughton Island and into Kingnelling Fjord were undertaken to overlap the Siferd surveys.
ArcticNet single day was utilized searching for evidence of drowned terraces/boulder barricades within the harbour area itself. All the coverage was inside the preexisting CHS coverage.

The GN mapping is almost entirely outside the pre-existing CHS 50m line spacing single beam surveys (1995 and 2005) and thus could be used for a new edition of an ENC in the area.

Merchants Bay Mapping Objectives

The western flank of Merchants Bay had previously been identified from diving to be a possible hot-spot for Mya Truncata (soft-shelled clams). The two localities, identifed by Siferd were mapped in a single day. Additionally Boas Fjord was suspected to contain submerged terraces for sealevel history studies for MUN.

The only pre-existing charting surveys in Merchants Bay date from 1955, undertaken by the USS Tanner (AGS-15) in support of the Padloping Island weather station (VFU8) and the Durban Island DEW line station (FOX-E). The majority of the Bay, including four major fjords is completely uncharted. Interestingly, SE of Padloping Island, depths in excess of 525 fathoms (~960m) were reported by the USS Tanner in 1955 which, if this can be verified, makes it potentially the deepest fjord in Baffin Island. Sam Ford fjord, at ~ 900m is currently the deepest known.

Western Merchants Bay - GN Clam Sites

The two indicated clam sites proved to be on the flanks of very steep topography with the bathymetry extending beyond the EM3002 300m depth limit within a few hundred metres of the coast.
The eastern of the two specific clam sites appears to be a location with finer grained sediments as indicated by the EM3002 backscatter.

Merchants Bay East - ArcticNet sites

The focus site was Boas Fjord where a suspected terrace halfway in and one at the head of the fjord were both investigated. In addition, in order to get to the head of the fjord, a previously unknown sill was identified and partially surveyed (enough to safely get around it).

Note that the centre of the fjord is beyond EM3002 tracking depth. The FCV-30 sounder maintains tracking (up to > 1500m) and thus it is hoped that at least a crude representation of the bathymetry > 300m can be preserved.

As an anchorage site on the way out, the "Unnamed" cove was investigated and found to also contain a useful submerged terrace.

Cumberland Peninsula Mapping Objectives

There were two main objectives on the Cumberland Peninsula:

ArcticNet submerged Terrace investigations: Originally with two targets, weather and time dictated that all the effort be allocated to the Exeter Sound region.
GN parks surveys and anchorages: focused on Kekerten Territorial Park, but including potential anchorages for the Nuliajuk Cumberland Sound fisheries program.

Exeter Sound, Totnes Roads, Mermaid Fjord

The original objective for Exeter Sound was a drowned beach in the outermost approaches. But due to weather limitations, shelter had to be sought in the inner basins. In this area, secondary geoscience targets were investigated for ArcticNet. The maps adjacent illustrate the regions investigated. These include:

Bear Cove - excellent anchorage
Totnes Cove - serendipitous discovery of a submerged terrace.
Recce #3 Cove - usable anchorage - minor terrace
Mermaid Fjord - active sediment prodelta.

This work involved 2 days of mapping in the Sound (plus an extra day trying to rebuild the anchor winch). As part of this ArcticNet mapping, 4 safe anchorage havens were established (two of which indicated submerged terraces).

Transits between the havens provides new safe navigation corridors. Some of the sections are approaching the extinction limit of the EM3002 (~300m). With just a few more days on site, these corridors could be enlarged to justify a new (first ever) ENC of the Sound.

Kekerten, Kingnait Pangnirtung Region

The primary priority for mapping for the GN was the vicinity of the Kekerten Territorial Park which is a Nunavut Park. The area is accessed for tourism by local boats from Pangnirtung but also by visiting sailing yachts and cruise vessels (e.g. MV Orlova - at Kekerten and in Kingnait). The aim was to establish a safe access for visiting vessels and potentially identify any wreck sites within the anchorage. Three dedicated survey days were allocated for this project. The vessel approached from the SE from Cape Mercy, running a single track transit corrdor along the eastern side of Cumberland Sound outside any pre-existing coverage.
Kikistan Island Survey
On arrival at Kekerten, a circumnavigation reconnaisance of the Kikistan Island Group was performed to assess possible approach corridors. On the NW flank of the island group, a 2005 reconnaisance CHS single beam survey had been perfomed coming in from the deep part of Cumberland Sound. The main Park harbour was entered and it was noted that the channel betweek Kekerten and Akulagok Island, although shown as open on the small scale chart, is actually blocked at low tide for large craft transit. Interestingly the NRCan topographic sheets show this restriction. Over the next few days the survey was enlarged including a corridor through the island group between Akulagok and Tuapait Islands.
Corridors and Anchorages.
As crew and science staff had to be dropped off and picked up at Pangnirtung, a 6 swath wide transit corridor was generated. From that corridor, a new corridor was opened up into Browns harbour, an anchorage commonly used by the Nuliajuk. And during a stormy period Kingnait harbour and two other potential refuges on the south east side of Kingnait fjord were briefly investigated as possible anchorages. Within Pangnirtung fjord, while waiting to drop off and pick up staff, a survey was made of the immediate subtidal region off the community where the flood happened. Also the dump site for the dredge spoil from the Pangnirtung harbour expansion was surveyed.

Kikistan to Pangnirtung Corridor with section into Brown Harbour

Kikistan Island Reconnaisance

Kekerten Harbour Detail.

Iqaluit Region

page created by JEHC, November 2012 ... updated by JM, November 2012