Study Of Findings On Estuary Barrage

Press, Volume CIX, Issue 32077, 27 August 1969, Page 14

Study Of Findings On Estuary Barrage

It was not yet possible to make any recommendation on a barrage across the Estuary, the chief engineer (Mr P. J. McWilliam) said in his report to the Christchurch Drainage Board last evening on the preliminary findings of the British Hydraulics Research Station, Wallingford, which has been studying a model of the Estuary.

Considerably more information was required, Mr McWilfem said. The board agreed that Mr McWilliam should be authorised to make inquiries necessary and that there be discussions with the University of Canterbury on toe possible use of Mb resources to investigate some of the problems that bed been indicated by toe research station. Hie board had approved in principle toe construction of the Wooistoc cut from Maronan Street to Lcog Street, and toe research station again emphasised toe value of the work, Mr McWilliam said. Investigation needed should include hydraulic profiles across toe Estuary and up the

Avon and Heathcote rivers for various conditions of flood with and without a barrage, with and without channel dredging and more extensive dredging and with and without the Woolston cut and other improvements to the rivers. More information was also wanted on toe salinity in various parts of the Estuary under flood conditions.

The ecology of toe Estuary could be affected, Mr McWilliam said. Tins was where the University of Canterbury could advise.

Only when a full report had been received would it be possible to consider and assess

the possible benefits to be derived from control of toe Estuary, he said. This must Shen be weighed against possible adverse effects on navigation, recreatioi., birds, fish, shellfish and other wildlife and aesthetics. All must be considered in relation to the economics of toe proposals before a recommendation could be made.