This paper reviews recent technological advances applicable to the measurement of ice gouges, describes a field program undertaken to test the performance of the most promising new technologies, and provides specific recommendations for future gouge measurement programs. Based upon the results of the field test, it is concluded that multi-beam sonar, when used in conjunction with side scan sonar and DGPS equipment, represents a substantial improvement over previous methods of quantifying ice gouge characteristics. Specific benefits of multi-beam technology include:
the ability to map gouges without regard to the relative orientation of the track line;
sufficient resolution to detect gouges with incision depths as small as 0.1 m;
the ability to quantify variations in gouge characteristics along the gouge track;
the ability to map complex bathymctry, as might result from a combination of ice gouges and shoals; and
a high degree of repeatability. The measurement strategy proposed in this paper offers the potential for improving both the quantity and quality of the ice gouge data that is essential for the design of subsea pipelines in ice-covered waters.
In many cold regions, gouging of the sea floor by ice keels constitutes a major design consideration for subsea pipelines (Leidersdorf, et al., 1996). The most common mitigative strategy, burial beneath the zone of sea floor disturbance, requires a site-specific knowledge of ice gouge characteristics. The specific parameters of interest are dependent on the computational methods employed. If one adopts a statistics-based approach, as proposed by Weeks (1983) and Wang (1990), then the key parameters consist of the gouge incision depth, incision width, orientation, and frequency of occurrence. The approach given in Wadhams (1983) relies on ridge keel depth and gouge width statistics to estimate rare ice gouge depths.
