The main purpose of the investigation was to:

• Determine depth of topsoil and cap (if any) across landfill areas;
• Assess landfill settlement;
• Check for soil contamination;
• Undertake landfill gas monitoring;
• Comment on the implications for further development of the landfill site;

Most of Lindvart park was originally low lying swamp and unusable terrain. The landfill was in operation from pre-1950 to around mid-1998. The final stage of the landfill (1996-98) was lined with a clay liner, and the entire 4.0ha landfill area was capped with 600mm clay, overlain by topsoil. There is no landfill gas collection system.

Overall, our investigation found that the health/environmental risks associated with the closed landfill were considered to be low, especially for the rugby league field area, but this risk needs managing over the long term, particularly in relation to landfill gas. In particular, the landfill cap needs regrading to shed runoff, while some minor soil contamination from leachate pump station overflows was found, and further investigation of possible stormwater contamination by leachate was recommended.

Any further development on the landfill needs to maintain the integrity of the landfill cap and provide for mitigating landfill gas migration, using measures such as:

• Fencing, lighting, services trenches, trees, etc. should not penetrate the landfill cap.
• Any service trenches for power, water, stormwater, wastewater need to incorporate landfill gas migration mitigation measures.