Sextus Julius Frontinus,
The Stratagems, and, The Aqueducts of Rome
(1925)
“ The two Anios are less limpid, for they are drawn from a river, and are often muddy even in good weather, because the Anio, although flowing from a lake whose waters are very pure, is nevertheless made turbid by carrying away portions of its loose crumbling banks, before it enters the conduits—a pollution to which it is subject not only in the rainstorms of winter and spring, but also in the showers of summer, at which time of the year a more refreshing purity of the water is demanded. ”
