Determining the Effectiveness of a Navigable Ice Boom.

• Main Author: Perham,Roscoe E
• Other Authors: COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
• Format: Text
• Language: English
• Published: 1985
• Subjects: Snow; Ice and Permafrost; Civil Engineering; *ICE; *BOOMS(EQUIPMENT); CONTROL; THICKNESS; SHIPS; CONTROL SYSTEMS; OPENING(PROCESS); WINTER; NAVIGATION; MODEL TESTS; RELEASE; LEADING EDGES; COVERINGS; RIVERS; CHANNELS(WATERWAYS); HYDRAULIC EQUIPMENT; DOWNSTREAM FLOW; MICHIGAN; Saint Marys River(Michigan); St. Marys River; Ice; permafrost
• Online Access: http://www.dtic.mil/docs/citations/ADA162926; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA162926

The performance of a navigable ice boom was studied by monitoring the progression of the leading edge of the unconsolidated ice cover over a reach of the St. Marys River directly downstream of the boom. Ice and hydraulic data were obtained for four winters from 1975-76 through 1978-79 for the St. Marys River at Sault Ste. Marie, Michigan. The ice cover progression rate was highest in early winter. The unconsolidated ice cover in the channel was estimated to have a thickness of at least 0.91 m and a porosity of 30%. During early winter the ice discharge per vessel passage averaged approximately 5500 cu m. for the four years. Model tests for this site had indicated that without an ice control structure of any type, an ice release of 63,000 cu m per ship passage could be expected; with an ice boom the release would be 12,300 cu m per ship passage. If a 100% effective boom releases no ice at all, then the measured rate indicates that the boom is 92% effective. On-site observations and time-lapse movies provided partial verification. Ice flowed down the ship track and through the navigation opening fairly often. Occasionally ice came over the boom in response to ship movements and natural causes. Keywords: Ice booms; Ice control; Winter navigation.