Sustainability practices during Ellerslie Racecourse redevelopment

When redeveloping Ellerslie Racecourse, sustainable engineering practices were a key consideration for our infrastructure team. We caught up with our National Land Development Manager, Campbell McGregor to find out more about the sustainable practices implemented during the project and how the racecourse is reaping the rewards.

‘’It seems cliché, but we really are committed to creating infrastructure that is there to serve people for years to come. While decisions always have a cost driver, with the Ellerslie Racecourse we were able to find a number of solutions that were both sustainable and cost beneficial, achieving the proverbial win-win,’’ says Campbell who says clients Auckland Thoroughbred Racing were like-minded in their approach to sustainability.

Ellerslie Racecourse is on approximately 40ha of land in the central suburb of Ellerslie in Tāmaki Makaurau and has been holding race meets for over 100 years. Our brief from the client was to ensure that legacy continued.

Campbell and the team knew early on there were some multi-faceted benefits like environmental, operational and costs to applying sustainable design principles.

‘’Given the scale of the project we knew we had to focus on earthworks cut full depths to manage the earthworks volumes required to achieve the desired built form but also maximise reuse of material onsite.

We meticulously planned the site including integrating the pond seamlessly with the surrounding infield area.’’

Payoffs for the racecourse include the ability to reuse collected water from a site catchment of approximately 30ha to irrigate the track.

‘’Balancing assessments determined an optimal pond size, minimising the need for mains water supply during dry periods while also providing flood storage during major rainfall events. This was determined at a permanent water volume of approximately 9,000m³. Through the development of the track the client made the decision to further increase the capacity of the pond doubling the available storage volume to 18,000m³ and further reducing reliance on the public water supply network,’’ says Campbell.

Water tanks were installed as a buffer for when reticulated water is required to be used for irrigation. This ensures the irrigation pond is not filled with reticulated water as was the case with the old pond. This also saves water loss due to evaporation from the pond.

The site also takes advantage of its location on the edge of the Onehunga volcanic field continuing to discharge some stormwater flow and overflow from the pond to ground through soakage, ensuring recharge of the underlying ground aquifer is maintained.

‘’We also explored and actioned all opportunities to reuse as much of the 15,000m³ of rock which was excavated as part of the construction phase,’’ says Campbell.

The design team came up with a few solutions for the rock to ensure we minimised the impact to the environment including crushing off-site and reuse as aggregate in construction, utilising stone masons to build rock walls on an adjacent residential development and for the new gated entry to the racecourse, and several contractors took rock offsite to be used on various other projects around the region including in flood restoration works after the Auckland Anniversary Weekend flooding

If you’d like to talk to us more about sustainable engineering practices, get in touch with Campbell McGregor c.mcgregor@harrisongrierson.com