MODELING THERMAL BREAKUP ON THE MACKENZIE RIVER AT THE OUTLET OF GREAT SLAVE LAKE, NWT

Thermal breakup on the Mackenzie River at the outlet of Great Slave La ke was documented over the 4-year period, from 1992 to 1995. Measureme nts of ice and snow thickness, flow characteristics, open water develo pment, air temperature, solar insolation, wind speed, and relative hum idity facilitated the formulation of numerical models to forecast the development of open water downstream from the outlet of Great Slave La ke. The rate at which the open water developed was modelled using the complete energy budget equations and a more empirical linear approxima tion of the heat transfer processes. The linear heat transfer model, w hen calibrated with heal transfer coefficients from other studies, pro vided a good fit to the observed data for all 4 years of record. The r esults from the complete energy budget model were less consistent and it was concluded that given the practical limitations on the type and amount of data typically available to an engineer, the simpler heat tr ansfer approach is more suitable for modelling thermal breakup at this site.