MONITORING FOR FRAZIL-ICE ACCUMULATION ON WATER INTAKES IN THE NEARSHORE ZONE

摘要

In cold regions, water-supply and thermal-power plants drawing water from the coastal nearshore zone face the prospect of their water intakes becoming blocked by frazil ice. Little is known about the processes whereby frazil-bearing supercooled water is drawn down to the depths at which the intakes are located. Moreover, there exists little guidance on how to prevent frazil from fully blocking intakes. This paper adds new insights regarding the processes, and it recommends a monitoring approach as being a potentially effective means for mitigating intake blockage by frazil. The insights and recommendation are based on experiences with intakes located in the US Great Lakes. The recommended monitoring requires checking of the rates of (1) water level drop in the onshore pump forebay, and (2) of headloss increase between the intake and the forebay.