Big blocks beat the big wet on lake wall

The speed of construction of the MassBloc® earth retention system was critical in the construction of a retaining wall on the banks of Lake Eacham in the Crater Lakes National Park near Cairns.

Queensland Parks & Wildlife had only a small window of opportunity to build the wall, when the lake was at its lowest level, near the end of the dry season and before the wet season, when the lake is topped up by anything from one to four metres.

Before construction could begin, the lakeside had to be bunded with sheet piles, drained and a concrete slab footing laid.During the building of the MassBloc® wall, the rainy season began in earnest and cyclonic rain raised the lake by a metre.

Thanks to the speedy construction provided by the large, dry-stacked MassBloc® units, the partially-built wall remained above water level, allowing the works to be completed easily.

QPWS project officer, Lee Hess, said using a large block system was an advantage, as work was able to be undertaken despite the high water levels in the lake at the time.

Lake Eacham is the most popular swimming and picnicking destination in the Atherton Tablelands. During summer the lake is crowded with swimmers escaping the stingers on the beaches.The new wall not only protects the lake embankment against erosion, it also provides a safer entry point for young children and older swimmers.

Lee Hess said the permeability of the construction materials was also an advantage in helping drain stormwater from the picnic area behind the wall.

The wall was built by Parks & Wildlife’s own labour force, with structural design by Ganza Consulting Services in Cairns and Cardno in Sydney.