During an unrelenting stretch of dry, hot weather last August, Rachel Mahannah and her husband spent two hours a day hauling water from their other farm a kilometre and a half away, to make sure their dairy cows didn't get dehydrated. The well on the dairy farm, 70 metres deep, had almost run dry. "That was the first kind of red flag that came up for us," said Mahannah, who co-owns Mahvhays dairy farm in Brigham, Que., about 75 kilometres southeast of Montreal.