 A notable achievement of the Board was the creation of the core London sewerage system, including 75 miles (120 km) of main and 1000 miles (1650 km) of street sewers, which solved the problem.A large part of the work of the MBW was under the charge of the Chief Engineer, Joseph Bazalgette, previously engineer with the Metropolitan Commission of Sewers.Its other activities included slum clearance, and the driving through of new streets to relieve traffic congestion.