The pipeline is made of high density polyethylene (HDPE), 315mm or 355mm in diameter, with a wall thickness of 30mm. The wall thickness has been designed to accommodate abrasive wear from the sand slurry.
The pipeline is laid in trenches, with the top of the pipe approximately 0.7 metre below the ground surface. In a few locations the pipe is much deeper, where directional drilling was used to install it under infrastructure including stormwater outfalls and trees. Where the pipeline is in the beach, it is laid at -1.25 metres AHD (Australian Height Datum). The pipeline is protected by existing seawalls or its depth being below the depth of erosion during storms.
The pipe used to transport the seawater to the sand collection unit is also made of HDPE, approximately 400mm in diameter. Where possible it is in the same trench as the slurry pipeline.
Slurry pump stations
The main slurry pump stations are located at Glenelg and West Beach and measure 12.3m x 6.4m. The top of the station at Glenelg is level with the nearby stone wall. The station at West Beach is underground and the roof is level with the surrounding natural surface.
A vent 2m x 1.5m and 4m high extends from the roof of the stations to allow for air intake and outflow to cool the pump and associated equipment. The pumps are electrically operated, quiet and have no exhaust emissions.
The councils at both locations have enhanced landscaping in the area to reduce the visual impact of the pump stations and ensure that the path and landscaping details around the stations blend with the surrounding areas.
Booster pump stations
The booster pump stations are underground and measure 12.3m x 6.4m.
The station surface is level with the surrounding dune surface or footpath level. At Whyte Street, Somerton Park and Wattle Avenue, Hove the stations are adjacent to the footpath, allowing easy access for people to use the station as a viewing platform.
A vent 2m x 1.5m and 4m high extends from the roof of each station to allow for air intake and outflow purposes to cool the pump and associated equipment. The pumps are electrically operated and are quiet with no exhaust emissions.
A discharge station is incorporated into the booster pump structures to allow sand to be discharged onto the beach at these locations.
The road, footpath and seawall that were removed to allow for construction of the booster pump stations were reinstated after construction was completed.
The discharge stations were installed underground and are concrete boxes that measure 1.9m x 1.7m x 1.5m in depth.
Where placed within the dunes the top of the stations are level with the surrounding dune surface. Where placed adjacent to roads or rock seawalls the top of the stations are level with the adjoining footpath.
A pipeline was installed underground in the dune or within the rock seawall to link the discharge station to the discharge site at the top of the beach. Pipe extensions allow for wider distribution of the sand slurry over a larger area at each discharge site.
Each discharge station contains a removable pipe section to allow a 90 degree pipe bend to direct the discharge to the beach.
The removable sections of pipe are also used to assess abrasive wear in the pipeline against design allowances.
Sand collection unit
The sand collection unit is 8m x 3.4m. It is stored off-site and is brought to the beach only when sand pumping is required. It is placed within a temporary fenced area measuring 28m x 12.5m.
Sand is collected from the beach using a land plane which scrapes sand from the beach surface and then brings it to the collection hopper. Sand is then screened using a trommel to remove stones, larger shell fragments and other debris and mixed with seawater to form the slurry.
Water intake unit
Submersible pumps are located at the Adelaide Shores Boat Harbour and at the end of the Glenelg jetty to supply seawater to the sand collection unit to create the sand slurry. At the end of each pumping session, seawater is pumped to flush the pipelines of any sand sediment.
The seawater pumps have been designed to operate in low and high tide, and stormy conditions. They include screening to prevent unsafe local water conditions and limit the quantity of seagrass ingested.