Motorists should expect delays Saturday as the City of Ottawa closes downtown streets for the annual St Patrick's Day parade.

Although the parade does not begin until 11 a.m., westbound lanes on Laurier Avenue between Nicholas Street and Elgin Street and lanes along the parade route will be closed from 7:30 a.m. until noon.

The parade begins at Ottawa City Hall and will travel west on Laurier Avenue, turn left on Bank Street and end at Marché Way near Lansdowne Park, where businesses will remain open. Roads will reopen as the parade passes.

The city says the Laurier Avenue entrance to city hall will be closed between 7:30 a.m. and 1:30 p.m. The entrance to city hall on Elgin Street will be open as usual.

Some OC Transpo routes including 1, 2, 5, 7 and 14 will face detours because of the parade road closures.