Where Has The River Gone?

This is the River Lathkill, in Lathkildale in the Derbyshire Dales.  When we walked through here 3 years ago the river was in full flow.  It seems that over the summer we had in UK this river has all but disappeared. The muddy damp patch was the only moist bit on the whole of the route through Lathkildale, about 4 miles.  

Worrying!