in may 1974, several communities along the grand river were flooded as a result of 50 mm of rain falling in the upper part of the watershed, quickly overflowing reservoirs which had been filled to capacity in anticipation of the dry summers months. the flooding caused almost $7 million (unadjusted) in damage, with more the $5 million of that coming from galt, ontario. significant improvements were made to the dike system along the river which could withstand a flow rate of 2,352 m/s in cambridge and 3,400 m/s in brantford, significantly above the 1,800 m/s peak during the flood.