"The source of the River Wandle has started flowing again for the first time in at least 15 years. The Wandle's original source is at the grotto in Carshalton Park off Ruskin Road but the water has not actually flowed from there several years. However, recent heavy rains means the section of the river is flowing once again." Then and now: River Wandle source flows for the first time in 15 years.
So I decided to cycle down The Wandle Trail and go have a look for myself - was 9.9 mile trip along a fairly muddy path. It is clear from Google maps what it had been like before the recent rains:
Now it is full of water the whole length of the channel.
View from the road before:
View from the road now:
The grotto itself is a Grade II Listed building [English Heritage Building ID: 206793]. It was built in about 1724 as one of the first features of the ambitious designs for building and landscaping in the park [Wikipedia].
My trusty steed:
It was getting a bit chilly so I wimped out of the return cycle and caught the train back to Clapham Junction.