Scour at culvert outlets under ice cover and ice jam conditions

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One of the major considerations in the design and construction of a highway system is the conveyance of tributary drainage through a culvert system. The investigation of scour by swift-flowing water at culvert outlets has been on-going for several decades. Various studies have examined many scour parameters that affect the degree of erosion; however, there is limited research on culvert outlet design and scour control in cold regions. Culverts may become fully inlet-covered in rigid winter climates and may also face ice jamming in early spring, which can result in embankment flooding and excessive scour. Additionally, due to the extra boundary imposed by ice cover and ice jam, the flow field inside the culvert is different from that under open channel conditions. Excessive scour at culvert outlets due to ice cover and ice jamming can*cause embankment flooding, which can result in highway failure. The*impact of covered and jammed culvert inlets has never been addressed*experimentally. Furthermore, there are no available experimental or*numerical simulations to investigate the flow profiles inside the*culvert under covered conditions. ***The research focuses on the experimental and numerical investigation of culvert scour under ice cover and ice jam conditions. The following objectives will be evaluated: a) to assess temporal scour development at culvert outlets under ice cover conditions; b) to establish associated equations describing the dependence of scour processes on flow intensity, culvert shape, particle grain size, and boundary conditions; c) to determine how ice cover and ice jams alter the geometry of scour holes at culvert outlets in non-uniform sands ; d) to investigate the impacts of ice jamming on the scouring at culvert outlets; e) to develop a numerical model for simulating the scour process for rectangular culvert outlets. ***In the proposed research, small scale, medium scale and large scale experiments will be conducted at three different hydraulic flumes. The experiments, together with numerical simulation, will generate a set of empirical equations that will predict the maximum scour depth at culvert outlets under ice conditions. A compilation of review on culvert design and maintenance in hydraulic engineering will occur. The ice cover and ice jam impacts will be discussed in depth. The present research will provide a practical approach to address the scouring at culvert outlets. The ability to predict the magnitude and geometry of scour at culvert outlets is an extremely useful evaluation tool in the control and management of erosion along highways in Canada. The research will be beneficial to practicing engineers and the scientific community.