How Much Water Does Xeriscaping Conserve?

Lisa, Unfor(if necessary)tunately your question is too open ended. We developed a xeriscape park back in 2001/02 using various varieties of mainly eucalyptus trees, indigenous bushes and grasses with mulch cover in much of the space instead of lawn type grasses. Following a year of establishment there has been no supplimental irrigation despite a further 7 years of drought. How do you measure the saving? What planting are you replacing/comparing with the xeriscape? What plants, trees, grasses are you putting in? Savings equals what water you would have used (litres per hectare per annum) to irrigate the non-xeriscape, minus the required volume (litres per hectare per annum) to supplement (if necessary) to survival for your chosen plants of xeriscpe planting. Your Local Government Parks Deparment should have some idea of water figures needed for current type plantings and nurseries may suppliment with watering requirement information on the types of plants available in your region to xeriscape. There are no standard plantings.

You have a lovely location in which I enjoyed the lake, and roadside stalls of fruits, (and cherry juice) when I visited back in 1976. Carefully chosen plants for xeriscape will compliment what you have using minimal or no water but it will depend on what you chose from what is available.

Regards,


Peeter Kallista
Glen Eira City Council
Australia

Lisa,
As you are probably aware, in the end it is behavior change by the user that determnes the savings. However, with that said, we are initiating a "cash for grass" rebate program in the next month. I will be measuing the best i can, but there will be a lot of data noise to filter out. To maximize savings, we are requiring the exsting site to have living managed lawn with in-ground sprinklers to be elegible for the rebate. the new landscape must be 100% water-efficient landscaping (xeriscape) and must be irrigated with low volume/ drip irrigaion or hand watered. I beleive the combinatino of switching from lawn to xeriscape and from overhead spray irrigation to drip will result in a 50% or more reduction in annual water. We will see....

Thanks

Chris Dundon
Contra Costa Water District
United States
www.ccwater.com/conserve

The City of Santa Monica, CA has done an excellent job looking at the benefits of sustainable landscape design, including "xeriscaping." One of their demonstration gardens called Garden/Garden tracks a sustainable garden of approx. 1900 sq. ft. against the "legacy" turf-centric garden of the same size. Water use, maintenance hours and costs, runoff reduction, and other inputs are monitored and published on their website. I recommend you take a look at the incredible difference the sustainable garden makes at their website: http://www.smgov.net/Departments/OSE/Categories/Landscape/Demonstration_Gardens.aspx
or on the sustainable sites initiative: http://www.sustainablesites.org/cases/show.php?id=1

Our own personal experience designing and maintaining sustainable landscapes for the past 10 years is that the water reduction alone can be as much as 70% from the turf-centric or climate-inappropriate garden, and that we can eliminate dry-weather urban runoff, while reducing storm weather runoff by as much as 60%.

Best of luck.

pamela berstler
Managing Member
G3, Green Gardens Group
United States

Hi,

The largest study of xeriscape water savings for residential property was done in Las Vegas NV. More than 700 properties were monitored for five years (1995-2000). The study also cites a number of other similar studies. This study was important because it was a "study in the wild," measuring the results of homeowners with very little intervention. The property owners were given just a few minimum standards, allowing them broad discretion to choose thier own materials, designs and planting densities. These variables were accounted for in the monitoring phase.

In our case, the average water savings for homeowners who converted lawns to water efficient landscapes was 75% (which was 55.8 gal/sf/yr).

Since completion of the study, more than 40,000 projects, comprising 145 million square feet, have been completed through our incentive program. A pre/post analysis of the first 20,000 of those participants yielded near-identical results as the initial study. We estimate our 40,000 projects conserve more than 8 billion gallons, 52 million kWh and 25,000 metric tons of CO2 discharge annually.

We are always eager to share and encourage others to visit us to see the program first-hand.

http://www.snwa.com/html/cons_wsl_xeriscape.html


Doug Bennett
Conservation Manager
Southern Nevada Water Authority
United States
www.snwa.com