Angel Places returns to the 1866 brick open drains enclosed in 1876. This form continues between Angel Place and Hunter Street for 95 metres before being interrupted by a 36-metre section of modern cement lined pipe laid in 1962 and a steel section laid in 1958 and 1978 (both are 1350mm). From Hunter to Bond Street the Stream is a semi-circular stone arch with a shallow V shaped floor for 35 metres (1500 by 3000mm). The 1790 cut tanks were originally located in this area, but are not thought to have survived. For the following 86 metres, below Australia Square, the original sewer has been replaced with concrete box-profile pipe (1220 by 1830mm), inserted during the construction of the Square in 1962. The Australia Square Tower basement houses the access to Tank Stream for public tours and as an inspection point for Sydney Water. The boxed concrete section (1220 by 1830mm) continues from Bond Street to Abercrombie Lane, a distance of 60 metres. Tank Stream between Abercrombie Lane and Bridge Street, a length of 40 metres, is of c.1860 semi-circular stone arch (1500 by 3000mm). From Bridge Street Tank Stream diverts to run under Pitt Street to Circular Quay, a length of 185 metres. Beginning with a stone oviform sewer of 810mm by 1220mm, constructed in c.1878, the shape changes to a semi-elliptic stone arch of 3000mm and varying between 1100 and 1400mm. Modifications and dates Major modification include the following: 1788-1826: Clearing of vegetation within the vicinity of stream, construction of dwellings, grazing and watering of animals. 1790: Cutting of tanks for water storage 1790: Chiselling of stone and inset of additional slabs into base of stream to improve flow in a shallow V profile. 1791: Enclosure within a fence against livestock and trespass. 1792: First bridge crossing. 1810: Cut-off drains alongside of Tank Stream channel to reduce inflow of polluted stormwater 1826: Tank Stream disallowed for drinking by Governor Brisbane. Governor Darling arranged for seven wells to be dug in the city. Governor Darling employed people to repair existing sewers. 1832: Construction of sewers seriously discussed. 1833: Water from partly built Busby's Bore used to pipe water to ships. 1842: City Council incorporated. c.1850: Semi Circular Quay was formed which necessitated the extension of the Tank Stream for the area north of Bridge St. 1855: Brickworks at Newtown was purchased, along with vitreous clay pipes and Roman Cement.