Installation (chute formation) 1. Refer to approved plans for location and construction details. If there are questions or problems with the location or method of installation, contact the engineer or responsible on-site officer for assistance. 2. Ensure all necessary soil testing (e.g. soil pH, nutrient levels) and analysis has been completed, and required soil adjustments performed prior to planting. 3. Clear the location for the chute clearing only what is needed to provide access for personnel and equipment for installation. 4. Remove roots, stumps, and other debris and dispose of them properly. 5. Construct the subgrade to the elevations shown on the plans. Remove all unsuitable material and replace with stable material to achieve the desired foundations. 6. If the chute is temporary, then compact the subgrade to a firm consistency. If the chute is intended to be permanent, then compact and finish the subgrade as specified within the design plans. 7. Avoid compacting the subgrade to a condition that would prevent the turf from bonding with the subgrade. 8. Ensure the sides of the chute are no steeper than a 1.5:1 (H:V) slope. 9. Ensure the completed chute has sufficient deep along its full length. 10. Ensure the chute is straight from its crest to the toe of the chute. 11. On fill slopes, ensure that the soil is adequately compacted for a width of at least one metre each side of the chute to minimise the risk of soil erosion, otherwise protect the soil with suitable scour protection measures such as turf or erosion control mats. 12. Place and secure the turf as directed. 13. Install an appropriate outlet structure (energy dissipater) at the base of the chute (refer to separate specifications). 14. Ensure water leaving the chute and the outlet structure will flow freely without causing undesirable ponding or scour. 15. Appropriately stabilise all disturbed areas immediately after construction. Materials * Rock: hard, angular, durable, weather resistant and evenly graded with 50% by weight larger than the specified nominal rock size and sufficient small rock to fill the voids between the larger rock. The diameter of the largest rock size should be no larger than 1.5 times the nominal rock size. Specific gravity to be at least 2.5. * Geotextile fabric: heavy-duty, needle-punched, non-woven filter cloth, minimum 'bidim' A24 or equivalent. Installation (rock placement) 1. Over-cut the channel to a depth equal to the specified depth of rock placement such that the finished rock surface will be at the elevation of the surrounding land. 2. Rock must be placed within the channel as specified within the approved plans, including the placement of any specified filter layer. 3. If details are not provided on the rock placement, then the primary armour rock must be either placed on: * a filter bed formed from a layer of specified smaller rock (rock filter layer); * an earth bed lined with filter cloth; * an earth bed not lined in filter cloth, but only if all voids between the armour rock are to be filled with soil and pocket planted immediately after placement of the rock. 4. If a rock/aggregate filter layer is specified, then place the filter layer immediately after the foundations are prepared. Spread the filter rock in a uniform layer to the specified depth but a minimum of 150mm. Where more than one layer of filter material has been specified, spread each layer such that minimal mixing occurs between each layer of rock. 5. If a geotextile (filter cloth) underlay is specified, place the fabric directly on the prepared foundation. If more than one sheet of fabric is required to over the area, overlap the edge of each sheet at least 300mm and place anchor pins at minimum one metre spacing along the overlap. 6. Ensure the geotextile fabric is protected from punching or tearing during installation of the fabric and the rock. Repair any damage by removing the rock and placing with another piece of filter cloth over the damaged area overlapping the existing fabric a minimum of 300mm. 7. Where necessary, a minimum 100mm layer of fine gravel, aggregate or sand should be placed over the fabric to protect it from damage. 8. Placement of rock should follow immediately after placement of the filter layer. Place rock so that it forms a dense, well-graded mass of rock with a minimum of voids. 9. Place rock to its full thickness in one operation. Do not place rock by dumping through chutes or other methods that cause segregation of rock sizes. 10. The finished surface should be free of pockets of small rock or clusters of large rocks. Hand placing may be necessary to achieve the proper distribution of rock sizes to produce a relatively smooth, uniform surface. The finished grade of the rock should blend with the surrounding area. No overfall or protrusion of rock should be apparent. 11. Immediately upon completion of the channel, vegetate all disturbed areas or otherwise protect them against soil erosion. 12. Where specified, fill all voids with soil and vegetate the rock surface in accordance with the approved plan. Maintenance 1. During the construction period, inspect all chutes prior to forecast rainfall, daily during extended periods of rainfall, after significant runoff producing storm events, or otherwise on a weekly basis. Make repairs as necessary. 2. Check for scour or dislodged rock. Repair damaged areas immediately. 3. Closely inspect the outer edges of the rock protection. Ensure water entry into the channel or chute is not causing erosion along the edge of the rock protection. 4. Investigate the cause of any scour, and repair as necessary. 5. Carefully check the stability of the rock looking for indications of piping, scour holes, or bank failures. 6. Replace any displaced rock with rock of a significantly (minimum 110%) larger size than the displaced rock. 7. Ensure sediment is not partially blocking flow entry into the chute. Where necessary, remove any deposited material to allow free drainage. 8. Dispose of any sediment in a manner that will not create an erosion or pollution hazard. 9. 9. When making repairs, always restore the chute to its original configuration unless an amended layout is required. Removal 1. When the soil disturbance above the chute is finished and the area is stabilised, the chute and any associated flow diversion banks should be removed, unless it is to remain as a permanent drainage feature. 2. Dispose of any materials, sediment or earth in a manner that will not create an erosion or pollution hazard. 3. Grade the area in preparation for stabilisation, then stabilise the area as specified in the approved plan.