Eventually the lake was drained by the channels and a tunnel to the Pánuco River, but even that could not stop floods, since by then most of the city was under the water table. The flooding could not be completely controlled until the twentieth century. In 1967, construction of the "Drenaje Profundo" ("Deep Drainage System"), a network of several hundred kilometers of tunnels, was done, at a depth between . The central tunnel has a diameter of and carries rain water out of the basin. The eastern discharge tunnel was inaugurated in 2019.