Constructing the pipeline

Hours of work

Construction works will generally be carried out between the hours of 7am to 6pm Monday to Friday and Saturday 8am-1pm. There may be infrequent occasions where work outside these hours will occur in order to shorten the construction period, or to reduce the potential for traffic impacts. Local residents will be notified well in advance of scheduled construction works and any traffic delays or temporary road closures. Construction works will generally be carried out between the hours of 7am to 6pm Monday to Friday and Saturday 8am-1pm. There may be infrequent occasions where work outside these hours will occur in order to shorten the construction period, or to reduce the potential for traffic impacts. Local residents will be notified well in advance of scheduled construction works and any traffic delays or temporary road closures.

Site establishment (early 2011)

Site facilities have been established at the corner of the Monaro Highway and Angle Crossing Road. Smaller site facilities have also been established at compounds at Angle Crossing, at the junction of Williamsdale and Burra Roads and along the pipeline route.

Felling of trees and clearing of wood (early-mid 2011)

The first step in establishing the pipeline corridor will be to remove trees within the construction corridor. Every effort will be made to retain trees of significance outside of the 15 metre permanent easement area. Excavators fitted with shears will be used to fell trees. Hand sawing will be undertaken on smaller trees, or to cut down larger pieces of felled wood. All wood will be mulched on site or left outside the corridor for the landowners personal use.

Installing fencing to establish construction corridor (early-mid 2011)

Next, a fence will be erected along the 40 metre construction corridor. In areas of sensitive ecological communities this corridor may be reduced to minimise impact. Fencing will be typical rural fencing or as agreed with landowners. Environmental protection of specific trees and sensitive ecological fencing will also be undertaken at this time. Fencing will be removed at the end of the project, which may be up to two years from completion date to allow for establishment of plantings.

Removing topsoil (mid-late 2011)

A grader and/or bulldozer will be used to scrape off topsoil and placed in windrows on the edge of corridor. This topsoil will be reused later. Where natural watercourses occur, temporary crossings and water paths will be constructed.

Preditching of trench in hard rock areas (as required)

In hard rock areas, an excavator fitted with a jackhammer/ rockbreaker may be used to break up soil and rock. The pipeline trench will generally not be left open as the broken-up rock will be left or placed back in the trench. Preditching need not occur in areas of soft soil. If needed to get through hard rock, localised blasting will be used, but only if necessary.

Delivery and stringing of pipe (mid-late 2011)

Pipes will be delivered to various locations along the pipeline route and unloaded onto laydown areas. Pipes will be taken from the laydown areas and placed along the construction corridor. This process is called ‘stringing of pipes’. Most of the pipes are 6 metres long and 1 metre in diameter.

Laying the pipe (mid-late 2011)

A trenching machine and an excavator will be used to dig the pipe and conduit trench. The excavated material will be placed beside the trench and bedding material will be placed at the bottom of the trench, and compacted before laying the pipe. The pipe will be laid using another excavator fitted with a vacuum lift. Back-filling, using the excavated material, will then take place around the pipe. This is followed by compaction of the back-fill to ensure pipe stability. Power and communications conduits between the Mini-hydro Plant and the High Lift Pump Station will also be installed in the trench during the back-fill process. It is at this stage hydrant points (for use by CFA fire fighting) and air and scour valves will be installed.

Reinstatement (mid-late 2011)

Topsoil which has been windrowed along the edge of the corridor will now be re-spread over the pipeline route using a combination of an excavator, grader or bobcat. A small roller will be used to compact soil. Grasses and seed will be planted in corridor as per the Landscape Reinstatement Management Plans, which have been developed in consultation with private landowners and environmental agencies. Trees will be planted between the 15 metre permanent easement and the 40 metre corridor used for construction. Native grasses will be planted within the 15 metre easement. Ongoing maintenance of plantings will continue until successful establishment of plantings (approximately two years after construction is complete), at which point the construction and protective fencing will be removed. ACTEW is committed to high quality, long-term rehabilitation of affected land and will work closely with landholders to ensure land is restored to as close to original condition as is possible.