The City of St. Catharines, Ont., has declared a state of emergency after two extreme rainstorms in less than a week triggered widespread flooding, overwhelmed municipal infrastructure and caused significant damage to homes, businesses and public property.Mayor Mat Siscoe announced the declaration Monday, saying the measure is intended to strengthen the city’s response and recovery efforts while supporting requests for assistance from provincial and federal partners.”Many residents are reliving the devastating experience of flooding for the second time in less than a week, and Sunday’s storm extended those impacts to even more neighbourhoods across St. Catharines,” Siscoe said in a…