It's due to a crack which appeared in part of it yesterday.
If you were planning to walk along the towpath of Chesterfield canal this morning, you may want to reconsider your route.
It's as a section of it, just south of Staveley Basin for around 500 metres, has been closed.
A crack appeared in part of it yesterday, so Derbyshire County Council are currently investigating.
We've closed a section of towpath along Chesterfield Canal just south of Staveley Basin for a stretch of around 500 metres.— Derbyshire CC (@Derbyshirecc) September 30, 2019
A crack has appeared in the path and the route has been closed so that we can investigate. We'll update you when we have further details. pic.twitter.com/qYV1v1yYAp