Engineering sustainable sports fields

With 10,000 tonnes of fill material to contend with and a shallow water table, Warringah Council had to be innovative when it embarked on its mission to build Cromer Park — its first new sports field in more than 20 years.

Cromer Park was first established in the 1950s and over the next 20 years construction material from the development of the Cromer industrial area was used to build large spectator mounds.

In 2011 Warringah Council, responding to community needs, developed a master plan that identified the need to remove the central spectator mound to facilitate construction of a fifth field and the redevelopment of Cromer Park Field 1 using synthetic grass.

Warringah Mayor Michael Regan said the council was committed to providing leading edge recreational facilities.

“Our investment in extensive upgrades at Cromer Park, with its new sports field and facilities for more sports, is clear evidence of this,” he said.

The first major hurdle in providing the new facilities was how to maximise the reuse of the 10,000 tonnes of fill materials from the site. Council resolved this by reusing the high quality topsoils excavated as the growing medium for the new field, reusing the majority of the fill as sub-grade material for the car park and utilising the balance to provide the spectator mound with a gentler gradient.

Council also set out to provide best practice water– sustainable urban design principles for the drainage and irrigation of the site, while contending with a flood zone, reclaimed land fill, deep swampy subsoils and a shallow water table.

These issues were overcome by constructing 1.2 kilometres of pipes that drain water from the synthetic field, the local stormwater network and natural turf fields, with further harvesting mechanisms installed on the stadium roof and in the car park.

Secondly, a new 300kl water tank was constructed underneath the car park, enabling the bulk of the new tanks to be situated above the water table.

These systems increase the performance of the sports fields by draining water during the winter season and filling the water tank, ensuring the supply for the irrigation of the four natural turf fields and surrounding parkland, saving millions of litres of town water per year.

The reduction in the use of potable water also ensures that fertilisers and pesticides are kept on site and not released into the Dee Why Lagoon catchment.

“Cromer Park now has an enviable array of first class public sports facilities and is able to provide an additional 100 hours of play per week for the community,” said Cr Regan.

“With the new facilities – bike tracks, numerous fields for junior and professional sports plus a brand new cricket pitch — Warringah Council is confident that the community, including sporting and non-sporting users will enjoy these upgrades to Cromer Park.”