Kilandan Burn Bridge (on the Drymen side of Conic Hill) is unstable and has been closed to ensure public safety. The diversion route will be to follow the low-level route down Creityhall Road to Milton of Buchanan and along the B837.
When water levels permit, there is a ford downstream of the bridge which could be used as an alternative at your own discretion.
Update: 23 Oct 2023