Even without this extreme, a drop in the height of the river made the passage of riverboats fraught with danger or even impossible. Hence the reference to the ‘open river’ in this document.
1927 10 18 SRSA grg53 1 unit 1057 file 1160 John Gore Stewart to the Commissioner of Public Works:
The site of Number Seven Lock and Weir has now been finalised and approved on the ground by the River Murray commission. Lock number two which has progressed very favourably is now nearing completion and it is important that the plant and temporary buildings should be transported to the site of number seven during the present open river, which will only be available for a comparatively short period. As pointed out by the Constructing Engineer in his minute of 17 October 1927, herein, if the advantage is not taken of this river, there will be a period of forced idleness, which will necessitate the discharge of a number of men until the next navigable river, and the cost of number seven would be considerably increased…..