Dynamic Ice Formation within Culverts in Cold Regions

Dynamic ice accumulation within hydraulic structures in rivers and streams can have a significant impact on the connected natural habitat and adjoining transportation infrastructure. Excessive ice formation within culvert barrels reduces the available cross section area and increases the wetted surface subject to flow. These conditions reduce the overall capacity of culverts and can increase the potential for overtopping and subsequent road surface failure, especially during rapid thawing. Excessive ice formation was observed in several culverts of various design methods throughout the Superior National Forest in northeastern Minnesota. Air and water temperature sensors combined with time-lapse cameras indicate that culvert design characteristics such as available freeboard combined with repetitive temperature cycles above and below freezing contributed to excessive ice accumulation within the barrel of the study culverts. The objective of the study was to identify culvert characteristics conducive to dynamic ice formation and determine designs critical for mitigating culvert failure.