 The tunnels lead from the water cribs to Pumping Stations located onshore, then to water purification plants Jardine Water Purification Plant (the world's largest) and the Eugene Sawyer Water Purification Plant, where the water is then treated before being pumped to all parts of the city as well as 118 suburbs.The city has had nine permanent cribs of which six are still standing and two are in active use.The Two-Mile Crib was constructed as part of a scheme by Ellis S. Chesbrough in 1865, to help with the purification of the water because of damage caused by the city dumping sewage into the lake.