Italy's Lake Bracciano was used as a seaplane airport, beginning in 1906, known as Aeroporto di Bracciano-Vigna di Valle, on the Southern shore, during the 1930s as part of Rome's airport infrastructure. It is only 15 miles from Rome

It was recognized as one of the most famous water airports in Italy and holds the Italian Air Force Historical Museum.

Rome's first international airport, Leonardo da Vinci Airport (Fiumicino), opened in 1960, gradually taking over, and now the lake is the water source for Rome, carefully protected from all pollution

The lake owes its origin to intense volcanic and tectonic activity from 600,000 to 40,000 years ago, which created many small volcanoes in the Sabatino territory. The main magma chamber was situated under the present lake of Bracciano. Its collapse created the depressed area now occupied by the lake

it serves as a drinking water reservoir for the city of Rome, it has been under control since 1986 in order to avoid pollution of its waters. The use of motorboats is strictly forbidden (exceptions being made for a few professional fishermen and the authorities), and a centralized sewer system has been built for all the bordering towns in order to avoid any spoiling of the water quality, making Bracciano one of the cleanest lakes in Italy. The absence of motorized navigation favors sailing, canoeing and swimming.

https://www.forgottenairfields.com/airfield-vigna-di-valle-1334.html

https://en.m.wikipedia.org/wiki/Lake_Bracciano