sydney-city-centre-review-of-environmental-factors

Soil landscape
The soil landscape broadly replicates the underlying geology whereby four soil
landscapes underlie the study area:
Lucas Heights: a residual soilscape, comprising moderately deep yellow
podzolic (broad-leafed forest derived), yellow soloth (formed of saline
materials), and yellow earth soils. It is characterised by its moderately reactive
highly plastic subsoil and poor drainage
Blacktown: a residual soilscape, comprising deep yellow podzolic soils, yellow
brown, earth, red podzolic soils and structured loams. It is characterised by its
moderately reactive highly plastic subsoil and poor drainage
Deep Creek: a fluvial soilscape, comprising deep podzolic soils on well-drained
terraces. Siliceous (silica derived) sands overlay the former floodplain with
humus (decayed organic matter) podzols in low lying areas. It is characterised
by an extreme erosional and sedimentation hazard. The soils also contain
permanently high water tables
Gymea: an erosional soilscape, comprising moderately deep yellow earth and
earthy sands on gleyed (iron-rich) podzolic soil and yellow podzolic soils. It is
characterised by its steep slopes, high erodability and high permeability.
The one exception to the above is around Ultimo where the manmade fill has
resulted in the presence of disturbed terrain. Generally, this ‘soil’ is characterised by
turfed fill areas commonly capped with a sandy loam or compacted clay over fill and
waste materials. These soils are characterised by a risk of mass movement and are
generally impermeable, toxic and poorly drained. The majority of the proposal
footprint is underlain by Gymea soils, which commonly occurs on Hawkesbury
sandstone, with few exceptions as summarised in Table 6-52.
Table 6-52
Soil landscape other than Gymea soils
Work site Affected intersections/roads Soil landscape
R2: Market Street
S3: Pitt Street
S5: Broadway Entire work site
C1: Wentworth Avenue Entire work site
C2: College Street
G: George Street intersection
H: George Street to Pitt Street
I: Pitt Street intersection
J: Pitt Street to Castlereagh Street
K Castlereagh Street intersection
F: Campbell Street to Hay Street
G: Hay Street intersection
H: Hay Street to Rawson Place
I: Rawson Place intersection
Entire work site except Park Street
to Oxford Street (between Park
Street and Stanley Street)
Lucas Heights soils
(residual): poor
drainage and low
erosion
Deep Creek soils
(fluvial): waterlogged
and highly erodible
Disturbed terrain:
impermeable, Toxic and
poorly drained
Lucas Height soils
(residual): poor
drainage and low
erosion
Blacktown soils
(residual): poor
drainage and low
erosion
Sydney City Centre Capacity Improvement 375
Review of Environmental Factors