** TTT - Destruction of Isengard

Ents and Huorns were digging great pits and trenches, and making great pools and dams, gathering all the waters of the Isen and every other spring and stream they could find....It must have been about midnight when the Ents broke the dams and poured all the gathered waters through a gap in the northern wall, down into Isengard.

--TTT, "Flotsam and Jetsam"