LATE RFI - SCG 33114 (SWM) Rev A

Potential Causes
         •      Stormwater scour and erosion of excavated or stripped surfaces and stockpiled soils.
         •      Wind borne transportation of sediments.
         •      Disturbance/breakup of soil profile via vehicular traffic followed by stormwater scour
                and erosion.
         •      Transportation of sediments from site via excavation vehicles.
Mitigating Measures
         •      Construction of silt fences around the development site located to cut off all runoff.
         •      Construction of a sediment basin throughout construction at a low point of the
                development site.
         •      Provide 80-100mm crushed rock (no fines) hardstand under all vehicle paths expected
                during construction. Generally, this would be provided from the existing crossover and
                extended to a distance within the site that would accommodate the maximum delivery
                vehicle length expected.
         •      Provide rumble grates at exit points from the site for passing earthmoving vehicles.
         •      Where possible maintain existing landscaping/grasses downslope from construction areas
                to act as buffer/silt trap.
         •      Install temporary downpipes from completed roof structures and ensure runoff passes
                through silt fences.
         •      Minimise concentrating surface flows.
         •      Place silt barriers around council stormwater pits that the site drains to.
         •      Cover soil stockpiles with hessian or similar.




SCG Consulting Engineers                  Page 8                                SCG Ref: 33114(SWMP)