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

Flood risk
The proposal footprint has an existing flood risk as it is located on flood-prone land
(refer to section 6.7.2). Following heavy rainfall, localised ponding and pooling
sometimes occur in low points within the proposal footprint and may lead to drainage
problems. In extreme events, the flood risk greatly increases and would potentially
lead to washout across entire streets.
The proposed work detailed in section 3.3 would not increase the risk of flooding
occurring within the proposal footprint or wider study area. However, if flooding
occurs, there is a risk that work areas could be destabilised or exposed earthworks
could be subject to sediment laden runoff. The impact of any work site flooding would
be greatest where there would be exposed ground excavations as listed in Table 3-3
to Table 3-7).
Water quality and hydrology impacts during operation
The proposal would not alter the impervious area. Consequently, runoff rates and
stormwater discharge loading into the main trunk sewers would not be impacted.
The stormwater drainage network would be unchanged following the works. The
proposed upgrades are limited to modifying the existing drainage infrastructure to
support kerb extension alterations. The catchment of each drain would be unaffected.
Again, there would be no operational impact.
All road drainage would continue to be managed under the current management and
maintenance program. No new drainage devices or pollutant controls would be
installed under the proposal.
6.7.4 Safeguards and management measures
Table 6-50 lists the water quality safeguards and management measures that would
be implemented to address the impacts identified above in section 6.7.3.
Table 6-50
Water quality safeguards and management measures
Impact Environmental safeguard Responsibility Timing
Accidental
spillage and
associated water
quality impacts
Keep emergency spill kits on site
at all times and make all staff
aware of the location of the spill
kits and trained in their use.
Construction
contractor
Construction
Accidental
spillage and
associated water
quality impacts
Refuel and store all fuels,
chemicals and liquids within an
impervious bunded area within
the construction
compound/laydown areas sited a
minimum of 50 metres away
from:
Construction
contractor
Construction
Rivers, creeks or any areas of
concentrated water flow
Flooded areas
Slopes above 10%.
Sydney City Centre Capacity Improvement 370
Review of Environmental Factors