Most parks in Australian cities are dominated by lawns. Is that what people really want in a park? Are there good alternatives that don’t require as much expenditure on irrigation?

I’ve done PDs on the results of Claire Doll’s PhD research a few times before (see PD375, PD395 and PD404).  The paper I’ll talk about today is, in a way, the culmination of her project.

We saw in PD395 that many Perth residents would like to see a change of emphasis in the design of small local parks. Currently, a typical park design has about 80% watered grass and around 20% mulch, plus trees, of course. They support switching some of the ground cover from watered grass to either native vegetation or non-watered grass.

Claire’s latest paper in this series takes the earlier results and feeds them into a Benefit-Cost Analysis. She looks at six different percentages of watered grass, from zero to 100%, optimising the remainder of the area according to people’s preferences, and weighing up the benefits and costs of each. The key results are shown in Figure 1.

You need to mentally subtract one of the cost lines from the benefits line to get the net benefits of each design option. The results reinforce the earlier result that 80% watered grass is not the best option for local parks. Almost anything lower than that would have a higher net benefit, as long as it doesn’t go all the way to zero. The best of the six options analysed had 40% watered grass and 60% native vegetation, while 60% watered grass was not far behind that. The results were broadly similar for a newly created park and for modifying an existing park.

Happily, this paper won the award for best paper by an early-mid career researcher in the Australian Journal of Agricultural and Resource Economics for 2024.

Further reading

Doll, C.A., Pannell, D.J. and Burton, M.P. (2024). Economic evaluation of alternative urban park designs that conserve irrigation water, Australian Journal of Agricultural and Resource Economics https://doi.org/10.1111/1467-8489.12582

Claire’s research web page is here: https://www.econclaire.com/