Comparison of bottom and surface cooling water withdrawals on the thermal regime of Hamilton Harbour

An analysis of the sensitivity of the annual thermal regime of Hamilton Harbour to the depth of intake of industrial cooling water was conducted using a one-dimensional thermodynamic model. The intake of approximately 20 m3/s of cooling water from the bottom of the harbour, as opposed to the current practice of surface withdrawal, was calculated; the result indicates marginally reduced thermal stratification and hypolimnetic volumes in summer. It was shown by a further sensitivity analysis that the reason for this relatively weak response to the withdrawal level was due to the overwhelming input of colder Lake Ontario water to the Harbour. Key words: harbour water quality, thermodynamic modelling.