Enhanced Soil & Water Management
Sydney Construction Materials engaged GSS Environmental to develop a comprehensive Soil & Water Management Plan (1,741 kB pdf) for the Project. The plan addresses in detail all aspects of soil disturbance, erosion prevention, soil storage and movement, retention of any mobilised sediments, and soil-related aspects of water management on and off the site.
All proposed erosion and sediment control measures were formulated by GSSE in accordance with the NSW Department of Housing's manual Managing Urban Stormwater: Soils and Construction Volume 1 (4th Edition, 2004), otherwise known as the "Blue Book" in government circles.
Given the significant environmental sensitivity of the potential receiving waters of the Blue Mountains National Park, the principal objective of surface water management for the Project is to ensure that there is no uncontrolled discharge of water from the site whatsoever, and that the quality of controlled water discharges (if any) leaving the site meets the appropriate (ANZECC) quality standards. The principle design aspect of the development to achieve this goal is the use of accurate surface miner machinery to create infall benches to drain all surface water into the pit only and to eliminate out-of-pit runoff. Such water is held in retention ponds for use in irrigation of bench rehabilitation vegetation or dust suppression. Any remaining unnecessary surface water will pass through a water treatment plant to remove fine suspensions of sediment to a quality suitable for controlled release either to the to-be-re-established Newnes Junction Town Water Supply, or into the drainage lines leaving the site. The retention system and the onsite pit-storage capacity have been designed to contain more than the rainfall expected of the 100 year ARI, 72 hour duration (3 day) storm event and ensure no uncontrolled offsite discharges in such an event. Exposed slopes are not planned between the development and the National Park to further reduce potential for runoff and erosion issues.
This extensive level of sediment treatment and control is complimented by a number of minor erosion and sediment controls and management processes to minimise the amount of sediment entering the development water system and hence requiring treatment. This will be achieved by implementing the following controls:
• Conducting best-practice land clearing procedures for all proposed disturbance areas;
• Separating undisturbed runoff from disturbed runoff where possible to minimise and isolate the amount of disturbed runoff;
• Directing sediment-laden runoff into designated sediment control retention ponds and the water treatment plant;
• Diverting "clean water" runoff unaffected by the operations upstream into natural depressions;
• Constructing the haul road and working pit face with effective surface drainage;
• Maintaining sediment control structures to ensure that the designed capacities are maintained for optimum settling of sediments;
• Implementing an effective revegetation and maintenance program for the site; and
• Maintaining a buffer between the quarry and the National Park boundary.
This is a summary of some of the activities that will be employed throughout the life of the development. For more details, see the Soil and Water Management Plan (GSS Environmental, 2004) (1,741 kB pdf) in the Supplementary Information section under Project Credentials.
© Sydney Construction Materials 2010