IntroductionTerrestrial surveying was performed using a Nikon total station. The bathymetry of the fjord and ikaite distribution were mapped using a Lowrance GPS guided sonar. Detailed underwater baseline mapping of a 50m x 50m area of the fjord bed was undertaken by hand. The quality of the maps produced were tested through a series of random dives covering 2% of the bed of the fjord.
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The survey of Ikka Fjord was undertaken with a Nikon electronic DEM-1 Total Station (1 second accuracy) linked to a DR-2 Datalogger. Observations from the DEM-1 were downloaded to the DR-2 which in turn were downloaded daily to a PC laptop (Dan Courier DX2-66 8/340) and translated using Atlas Economy software. Further processing and presentation of data was undertaken with Microsoft Excel 5.0, Golden Softwares' 'Surfer' and 'IDRISI'.
To assist in the hydrographic survey a Lowrance LMS-350A Sonar and GPS (kindly loaned to us by Simpson Lawrence), was deployed from the inflatable.
A 'floating' local grid network was established on grid north with its origin coinciding with a known latitude and longitude derived from the 1:75 000 Greenland Tourism Hiking Map (1994). After the establishment of a 2 km baseline alongside Ikka Fjord, grid north, latitude and longitude were derived from map measurements and averaged GPS readings taken over a period of a week. It is envisaged that any errors are within the plottable error of the final maps to be produced.
After completion of the baseline measurement, a network of ten survey stations were established around the full extent of the upper fjord. From this network it was possible to obtain over 200 observations from the DEM-1 detailing the high-tide mark of the shoreline of Ikka Bund. This outline and the station network produced from this survey was utilised for the hydrographic survey work and positioning of ikaite columns.
Data for a DEM of the surrounding environs was derived from the 1:75 000 Greenland Tourism Hiking Map (1994). Over 600 XYZ co-ordinates were obtained and compiled into a DEM comprising an area of approximately 10 km2. It is proposed to 'drape' further information, such as geology and vegetation, onto this model for the final presentation.
Our portable LoS / Echo sounder unit, set up for a days work
By traversing the fjord at regular intervals with the sonar and GPS devices attached to the inflatable, it was possible to record 541 XY positions and Z depth measurements, which were then processed to produce a depth contour plot of Ikka Bund. An additional 70 traverses across the upper fjord, at 50m intervals, observing the ikaite columns present on the screen of the Lowrance LMS-350A, resulted in the approximate positioning of 221 ikaite columns. Column heights were categorised as being either small (<1m), medium (1-10m) or large (>10m). The coverage of the resulting distribution map was verified by diving 30 random sites in Ikka Bund and checking the abundance of Ikaite columns using a 15m radius quantitative search pattern technique (see Diving section for details).
A selected area was also chosen for a more detailed underwater investigation utilising a team of divers. By measuring perpendicular offsets from a baseline to objects of interest on the fjord bottom, distributions and alignments were plotted to an accuracy of 10 cm over an area approximately 50m2. XYZ co-ordinates of either ends of the baselines were measured utilising the DEM-1 and taught buoys.
Three discrete permanent stations (XYZ) have been deployed on the shoreline of the upper fjord for future reference.
From the array of information collected in Ikka Fjord, several data sets have been compiled within the local grid network (the translation from this local grid to latitude, longitude is easily accomplished). These data set are graphically presented in the appendices.
The 50m x 50m survey was inconclusive, with no obvious trends.
The XYZ (Local) co-ordinates of the permanent stations are:
1. Navigation post marker inland 7825.124mE 2456.278mN 7.16m
2. Navigation post marker shore 7792.589mE 2415.604mN 5.29m
3. STNK 8154.304mE 2817.696mN 0.5m (painted red cross on rock exposure next to shore).
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