Hydraulic Structures and River or Reservoir Ice: A Brief Review

This paper addresses the following question: are hydraulic structures in Earth’s cold regions designed and operated to handle ice occurring in rivers and reservoirs? The question entails three spatial scales: global, molecular, and the hydraulic structure. At the global scale, cold regions (regions where frigid weather occurs) occupy approximately half the land surface of Earth’s northern hemisphere, including much of the continental US, and it primarily affects air temperature. At the molecular scale, water is the liquid phase of the chemical compound, H2O, whose material behavior is dictated by its molecular response to temperature and pressure. At the scale of hydraulic structures (a highly variable scale including dams, bridges, and their components), hydraulic structures in cold regions potentially interact with all phases of H2O, and this scale influences prevailing pressure. Four sets of short case-study examples illustrate hydraulic structure failure, or risk of failure, owing to ice and dynamic frigid weather conditions typically associated with ice in continental US. The examples include a labyrinth weir, a stepped spillway, a stilling basin, a dam, two bridges, an inverted siphon, a water intake, an earthen embankment, and a gated spillway. The problems can be challenging for hydraulic structures that experience their highest discharges during spring when snowmelt (often combined with rainfall) and ice-cover breakup influence flow. In answer to the question mentioned, although progress certainly has been made in understanding ice interaction with hydraulic structures, concerns regarding ice and hydraulic structures remain to be addressed adequately, and the possibility remains that ice is forgotten.