SER 04 Erosion & Sedimentation

Critical Controls

• Water diversion drains are in place to prevent clean water from entering the site from upstream/offsite areas
• Sediment basins are the required size and have stabilised emergency spillways (note: design criteria for spillways is 20-year average recurrence interval event)
• Sediment basins have provision for identifying the level of accumulated sediment within the basin and water level
• Sediment basins are treated using approved flocculants and discharged within 5 days of the cessation of rain
• Temporary drains are in place to divert construction run-off to sediment basins and have been designed to convey the design rainfall event. This is typically the 1 in 10 year, critical time of concentration rainfall event.
• There are no areas where run-off from disturbed areas can leave the site without sediment controls
• Temporary erosion controls are provided for areas disturbed by the project within waterways
• Sediment controls are maintained and have a minimum of 70% sediment storage capacity
• Wheel wash/shaker grid and hardstand are installed at site exits to prevent tracking sediment onto roadways. Roadways are clear of tracked sediment.
• Stormwater pits that receive site runoff and all stockpile areas have functioning sediment controls in place. Erosion control provided for long term stockpiles.
• Stockpiles are located away from any concentrated overland flows, and located outside of flood prone areas (i.e. above the 20-year average return interval flood event limit)
• Sediment basins are sized in accordance with the requirements of the Blue Book, Best Practice ESC (IECA 2008) guidelines, the environmental licence and the relevant conditions of approval