I enjoyed this less than other books in Donna Leon's Brunetti series.
It would benefit from editing as there are several sections that add nothing to the plot or to the development of the characters. The bad guys are cardboard cutouts. And there are several extremely violent passages. (I've got nothing against descriptions of violence in principle but some of this felt simply gratuitous.)
As usual the descriptions of Venice are evocative.
Read Death at La Fenice before you read Acqua Alta as the back story to two of the main characters is given there.