Image courtesy JLH3Photography via Creative Commons. license |
HEC-RAS allows the user to model ice-covered channels with known ice properties, or to simulate wide-river jams. In the first case, the user specifies the ice cover thickness and roughness at each cross section. Different ice cover thicknesses and roughnesses can be specified for the main channel and for each overbank, and both can vary along the channel. In the second case, the ice jam thickness is determined at each section by solving the ice jam force balance equation. The ice jam can be confined to the main channel or can include both the main channel and the overbanks. The material properties of the wide-river jam can be selected by the user and can vary from cross section to cross section. The user can specify the hydraulic roughness of the ice jam or HEC-RAS will estimate the hydraulic roughness on the basis of empirical data.
Image courtesy of Steven F.Daly, Ph.D., USACE ERDC/CRREL |
The river ice capabilities of HEC-RAS were developed over 20 years ago through a joint effort by the HEC-RAS team at HEC and the Corps of Engineers’ Cold Regions Research and Engineering Laboratory (CRREL). Since that time, HEC-RAS with ice has been applied in rivers all around the world. It has been applied in river systems larger and more extensive than were imagined at the start. Recently, the HECRASController has been used to systematically vary the ice parameters over the course of hundreds (if not thousands) of separate simulations.
Image courtesy of Steven F.Daly, Ph.D., USACE ERDC/CRREL |