The 1996 Lake Ha! Ha! breakout flood, Québec: Test data for geomorphic flood routing methods

This paper describes a set of field data suitable for the testing and comparative assessment of geomorphic flood routing methods. The data pertain to a particularly severe and unusually well–documented flood event: the Lake Ha! Ha! breakout flood of July 1996 in the Saguenay Region of Québec. In this event, heavy rains combined with the incision of a new lake outlet caused a major flood, which significantly reworked the downstream valley. Published and unpublished data from multiple sources are assembled and co–registered in a common frame of reference. These data include vertical and oblique air photos, hydrological records, surface geology information, and digital terrain models of the pre– and post–flood valley topography. The spatial coverage encompasses the drained lake as well as the full length of the downstream valley. To meet the respective needs of two– and one–dimensional approaches, the topography is sampled on a Cartesian mesh as well as interpolated along evenly–spaced cross–sections. The data set described in the paper is provided in digital form in the electronic supplement to this special issue.