Application of HEC-2 for Ice-Covered Waterways

Abstract

HEC-2, the widely known open channel flow water surface profile computer program developed by the U. S. Army Corps of Engineers' Hydrologic Engineering Center, has been recently updated for the U. S. Army Cold Regions Research and Engineering Laboratory to account for the presence of a floating ice cover. It has been shown by many writers that at uniform flow the normal flow depth can be increased by as much as 30% by a floating ice cover. HEC-2 with the ice cover option will allow the Corps of Engineers and other users of the program to evaluate effectively the effect of an ice cover on the flow depth, flow velocity, unit discharge, etc. in a river reach or in an entire river system. This paper presents an overview of the modifications to the uniform flow equation, the required input data, and an analysis. Specific examples are presented for a straight rectangular channel with a downstream control, which exhibits gradually varying flow to uniform flow conditions of an ice cover, grown from the shores and progressively covering more and more of the channel width. Finally, the paper describes the effects on the water surface profile, the flow discharge in the open water section, and the departure from open channel uniform depth.