City crews began clearing trees on the bottom of Walterdale Hill Thursday to prepare for the construction of access roads needed to replace the 100-year-old bridge.
The city will also close river valley trails near the Walterdale Bridge on Monday.
Trails will remain closed with detours in place for pedestrians and cyclists until construction is completed in late 2015.
Construction will also include roadway work such as re-aligning Walterdale Hill Road and Queen Elizabeth Park Road and adding multi-use trail connections.
The city is building a $130-million signature one-span arch bridge to replace the aging Walterdale.