Until this time, central London's drains were built primarily to cope with rainwater, and the growing use of flush toilets frequently meant these became overloaded, flushing mud, shingle, sewage and industrial effluent into the River Thames. Bazalgette's London sewerage system project included the construction of intercepting sewers north and south of the Thames; the Northern Outfall Sewer diverts flows away from the Thames north of the river.
South of the river, three major interceptor sewers were constructed:
The high-level sewer starts at Herne Hill, and heads eastward under Peckham and New Cross to a pumping station at Deptford.
At Deptford pumping station the sewage is lifted by 18.9 ft (5.76 m) to the next section of the sewer[4] which then runs east under Greenwich and Woolwich. From Plumstead to Crossness Pumping Station, the covered sewer forms the southern boundary of Thamesmead and has been landscaped as an elevated footpath called the Ridgeway (similar to The Greenway built over the Northern Outfall Sewer).