I happened upon this article which says that shortly after the flood, a request for aid was being requested. Does that mean that there was, in fact, significant damage?
https://www.wantedinrome.com/news/matera-european-capital-of-culture-seeks-state-help-after-devastating-floods.html
"The Matera city council has now approved a resolution requesting the recognition of a state of emergency and natural disaster "due to the exceptional atmospheric events of 11 and 12 November", with the Sassi districts flooded with mud and debris."
"The mayor, Raffaello De Ruggieri, estimated the financial cost of the damage at €8 million and stressed that "the situation in the city has returned to normal: the wave of bad weather has however created difficulties that are hard to overcome with the ordinary budget of Matera city council".