Materials * Rock: well graded, hard, angular, erosion resistant rock, nominal diameter of 50mm to 75mm (small disturbances) or 100 to 150mm (large disturbances). All reasonable measures must be taken to obtain rock of near uniform size. * Footpath stabilising aggregate: 25 to 50mm gravel or aggregate. * Geotextile fabric: heavy-duty, needle-punched, non-woven filter cloth ('bidim' A24 or equivalent). Installation 1. Refer to approved plans for location and dimensional details. If there are questions or problems with the location, dimensions, or method of installation, contact the engineer or responsible on-site officer for assistance. 2. Clear the location of the vibration grid, removing stumps, roots and other vegetation to provide a firm foundation so that the rock is not pressed into soft ground. Clear sufficient width to allow passage of large vehicles, but clear only that necessary for the exit. Do not clear adjacent areas until the required erosion and sediment control devices are in place. 3. Grade the location of the vibration grid so that runoff from the unit will not flow into the street, but will flow towards an appropriate sediment-trapping device. 4. Ensure that the installation of the vibration grid includes adequate sediment storage volume under the grid. Where necessary, install suitable precast sediment collection chambers. 5. Place a rock pad/ramp forming a minimum 200mm thick layer of clean, open-void rock over the roadway between the vibration grid and the sealed street to prevent tyres from picking up more soil after they have been cleaned. 6. The total length of the vibration grip and rock ramps should be at least 15m where practicable, and as wide as the full width of the entry or exit and at least 3m. The rock ramp should commence at the edge of the off-site sealed road or pavement. 7. Flare the end of the rock pad where it meets the pavement so that the wheels of turning vehicles do not travel over unprotected soil. 8. If the footpath is open to pedestrian movement, then cover the coarse rock with fine aggregate or gravel, or otherwise take whatever measures are needed to make the area safe Maintenance 1. Inspect vibration grid prior to forecast rain, daily during extended periods of rainfall, after significant runoff-producing rainfall, or otherwise at fortnightly intervals. 2. If sand, soil, sediment or mud is tracked or washed onto the adjacent sealed roadway, then such material must be physically removed, first using a square-edged shovel, and then a stiff-bristled broom, and then by a mechanical vacuum unit, if available. 3. If necessary for safety reasons, the roadway shall only be washed clean after all reasonable efforts have been taken to shovel and sweep the material from the roadway. 4. When the voids between the rock becomes filled with material and the effectiveness of the rock ramps are reduced to a point where sediment is being tracked off the site, a new 100mm layer of rock must be added and/or the rock pad must be extended. 5. Ensure any associated drainage control measures are maintained in accordance with their desired operational condition. 6. Dispose of sediment and debris in a manner that will not create an erosion or pollution hazard. Removal 1. The vibration grid should be removed only after it is no longer needed as a sediment control device. 2. Remove materials and collected sediment and dispose of in a suitable manner that will not cause an erosion or pollution hazard. 3. Re-grade and stabilise the disturbed ground as necessary to minimise the erosion hazard.