smiths lake planning study volume 1: text - Great Lakes Council

SOILS AND GEOTECHNICAL 24
2.6.3 Erosion
The soils of the SLVA have a moderate to high erodibility and are prone to sheet and scour
erosion once disturbed. Development should be undertaken in accordance with Department of
Land and Water Conservation guidelines. The following guidelines can be adopted in planning
and development to minimise the impact of erosion and sedimentation:
• Investigate site features to ensure that land capability and the proposed development are
compatible.
• Undertake development in accordance with an erosion and sediment control plan.
• Undertake erosion control involving managing runoff at a non- erosive velocity, controlling
runoff onto, through and from the site, minimising the duration and area of soil exposed
during earthworks and providing protection for the soil surface.
• Undertake sediment control involving trapping and containing soil particles that have been
eroded.
• Undertake rehabilitation and re-vegetation of disturbed areas within 14 days of completion
of earthworks. Re-use topsoil.
• Maintain erosion and sediment control measures.
2.6.4 Acid Sulphate Soils
Acid sulphate soil investigation should be undertaken for all developments proposed in the
medium and high risk areas as shown on Figure 2-2. This includes all activities where soils are
to be excavated or disturbed (roadworks, foundations, drains etc) and where groundwater levels
may be lowered (drains, groundwater extraction etc). Investigation should comprise a detailed
soil survey with analytical data on the sulfide content down the profile. The acid producing
potential of the soil needs to be quantified and evaluated in the context of the local
environment.
Where areas of acid sulphate soil are quantified (analytical results exceed the action criteria
outlined in Table 2-7), options are to avoid the area / site identified or undertake development
in accordance with an Acid Sulphate Management Plan. The plan should provide a framework
for the on going management and monitoring of the impacts throughout construction and
operation of any project. The plan should comprise the following:
• A summary of the soil and groundwater conditions.
• Discussion of construction activities likely to impact on ASS.
• The expected degree of impact of construction activities.
• Control and management of construction activities to minimise impact.
• Monitoring requirements to assess impacts.
• Contingencies should monitoring demonstrate the occurrence of significant impact.
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